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Sample records for endeavour hydrothermal system

  1. Isotopic evidence of magmatism and a sedimentary carbon source at the Endeavour hydrothermal system

    SciTech Connect

    Brown, T A; Proskurowski, G; Lilley, M D

    2004-01-07

    Stable and radiocarbon isotope measurements made on CO{sub 2} from high temperature hydrothermal vents on the Endeavour Segment of the Juan de Fuca Ridge indicate both magmatic and sedimentary sources of carbon to the hydrothermal system. The Endeavour segment is devoid of overlying sediments and has shown no observable signs of surficial magmatic activity during the {approx}20 years of ongoing studies. The appearance of isotopically heavy, radiocarbon dead CO{sub 2} after a 1999 earthquake swarm requires that this earthquake event was magmatic in origin. Evidence for a sedimentary organic carbon source suggests the presence of buried sediments at the ridge axis. These findings, which represent the first temporally coherent set of radiocarbon measurements from hydrothermal vent fluids, demonstrate the utility of radiocarbon analysis in hydrothermal studies. The existence of a sediment source at Endeavour and the occurrence of magmatic episodes illustrate the extremely complex and evolving nature of the Endeavour hydrothermal system.

  2. Geology of a vigorous hydrothermal system on the Endeavour segment, Juan de Fuca Ridge

    SciTech Connect

    Delaney, J.R.; Robigou, V.; McDuff, R.E. ); Tivey, M.K. )

    1992-12-10

    A high-precision, high-resolution geologic map explicitly documents relationships between tectonic features and large steep-sided, sulfide-sulfate-silica deposits in the vigorously venting Endeavour hydrothermal field near the northern end of the Juan de Fuca Ridge. Location of the most massive sulfide structures appears to be controlled by intersections of ridge-parallel normal faults and other fracture-fissure sets that trend oblique to, and perpendicular to the overall structural fabric of the axial valley. As presently mapped, the field is about 200 by 400 m on a side and contains at least 15 large (> 1,000 m[sup 3]) sulfide edifices and many tens of smaller, commonly inactive, sulfide structures. The larger sulfide structures are also the most vigorously venting features in the field; they are commonly more than 30 m in diameter and up to 20 m in height. Maximum venting temperatures of 375[degrees]C are associated with the smaller structures in the northern portion of the field are consistently 20[degrees]-30[degrees]C lower. Hydrothermal output from individual active sulfide features varies from no flow in the lower third of the edifice to vigorous output from fracture-controlled black smoker activity near the top of the structures. Two types of diffuse venting in the Endeavour field include a lower temperature 8[degrees]-15[degrees]C output through colonies of large tubeworms and 25[degrees]-50[degrees]C vent fluid that seems to percolate through the tops of overhanging flanges. The large size and steep-walled nature of these structures evidently results from sustained venting in a mature hydrothermal system, coupled with dual mineral depositional mechanisms involving vertical growth by accumulation of chimney sulfide debris and lateral growth by means of flange development.

  3. A Geographical Information System to Manage the Endeavour Hydrothermal Vents Marine Protected Area

    NASA Astrophysics Data System (ADS)

    Douglas, K. L.; Hillier, M. C. J.; Thornborough, K. J.; Jenkyns, R.; Juniper, K.

    2016-02-01

    The Endeavour Hydrothermal Vents Marine Protected Area (EHVMPA) is located approximately 250 km offshore of Vancouver Island, British Columbia. Since its discovery in 1982, there have been hundreds of dives, samples collected, measurements made, and debris left behind at the EHVMPA. In 2003, the Canadian government declared the region as a Marine Protected Area (MPA) under Canada's Oceans Act, to be managed by the Department of Fisheries and Oceans (DFO). Ocean Networks Canada (ONC) operates a cabled observatory in the EHVMPA, and streams data in near real-time via the Internet to science communities worldwide. ONC's observatory data, combined with observations made during maintenance expeditions provides insight assisting the management and preservation of the MPA. In 2014, DFO partnered with ONC to build a geodatabase to enhance and inform the knowledge base of the EHVMPA Management Plan. The geodatabase, built in ArcGIS, contains data integrated from ONC's Oceans 2.0 database, third parties, and relevant publications. Layers include annual observatory infrastructure deployments, remotely operated vehicle (ROV) dive tracks, sampling activity, anthropogenic debris, high-resolution bathymetry, observations of species of interest, and locations of hydrothermal vents. The combined data show both efforts to better understand the environment and the resulting stressors that impact the MPA. The tool also links observed features such as debris and biological observations to the time-correlated ROV dive video using ONC's SeaTube video viewing tool allowing for further analysis. Through 2017, the geodatabase will be maintained by ONC and enriched with expedition data from organizations such as Monterey Bay Aquarium Research Institute, Woods Hole Oceanographic Institute, and the University of Washington. The end result is a tool that can integrate many types of data obtained from the MPA, and encourages systematic management of a remote, dynamic and fragile environment.

  4. Geology and hydrothermal evolution of the Mothra Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Glickson, Deborah A.; Kelley, Deborah S.; Delaney, John R.

    2007-06-01

    Detailed characterization of the Mothra Hydrothermal Field, the most southern and spatially extensive field on the Endeavour Segment of the Juan de Fuca Ridge, provides new insights into its geologic and hydrothermal development. Meter-scale bathymetry, side-scan sonar imagery, and direct dive observations show that Mothra is composed of six actively venting sulfide clusters spaced 40-200 m apart. Chimneys within each cluster have similar morphology and venting characteristics, and all clusters host a combination of active and extinct sulfide structures. Black smoker chimneys venting fluids above 300°C are rare, while more common lower-temperature, diffusely venting chimneys support dense colonies of macrofauna and bacterial mat. Hydrothermal sediment and extinct sulfide debris cover 10-15 m of the seafloor surrounding each vent cluster, obscuring the underlying basaltic substrate of light to moderately sedimented pillow, lobate, sheet, and chaotic flows, basalt talus, and collapse terrain. Extinct sulfide chimneys and debris between the clusters indicate that hydrothermal flow was once more widespread and that it has shifted spatially over time. The most prominent structural features in the axial valley at Mothra are regional (020°) trending faults and fissures and north-south trending collapse basins. The location of actively venting clusters within the field is controlled by (1) localization of fluid upflow along the western boundary fault zone, and diversion of these fluids by antithetic faults to feed vent clusters near the western valley wall, and (2) tapping of residual magmatic heat in the central part of the axial valley, which drives flow beneath vent clusters directly adjacent to the collapse basins 70-90 m east of the western valley wall. These processes form the basis for a model of axial valley and hydrothermal system development at Mothra, in which the field is initiated by an eruptive-diking episode and sustained through intense microseismicity

  5. Microearthquakes Beneath the Endeavour Hydrothermal Vent Fields: Insights Into Reaction Zone Processes

    NASA Astrophysics Data System (ADS)

    Wilcock, W. S.; Hooft, E. E.; McGill, P. R.; Toomey, D. R.; Barclay, A. H.; Stakes, D. S.; Ramirez, T. M.

    2007-12-01

    From 2003-2006, a novel seismic network comprising seven short-period corehole seismometers and a broadband Guralp CMG-1T OBS was deployed using remotely operated vehicles in a subseafloor configuration on the Endeavour segment of the Juan de Fuca mid-ocean ridge. The seismic monitoring array was one part of a multi-disciplinary prototype NEPTUNE experiment designed to investigate the linkages between seismic deformation, hydrothermal fluxes, and microbial productivity along oceanic plate boundaries. The seismic network recorded high-quality data that illustrate the advantages of using an ROV to deploy seismometers in well- coupled configurations that are also away from the effects of ocean currents. A preliminary analysis of the first year of Keck seismic data was undertaken during a research apprenticeship class taught in the fall of 2004 at the University of Washington's Friday Harbor Laboratories. Eight post- baccalaureate students obtained a preliminary catalog of nearly 13,000 earthquakes on the Endeavour segment. Two of the apprentices conducted a second-pass analysis to refine the locations of ~3000 earthquakes that are within or near the network. Further analysis of these proximal earthquakes has focused on the application of cross-correlation and relative relocation techniques, the determination of focal mechanisms using P-wave first motions and P- to S-wave amplitudes ratios, and improved estimates of earthquake magnitudes. The results show that the entire Endeavour segment was seismically active during 2003-2004. Within the network, the earthquakes are located in tight clusters centered at ~2 km depth in the inferred location of the hydrothermal reaction zone immediately above a crustal magma chamber imaged by seismic reflection studies. The number of earthquakes below each hydrothermal vent field correlates with the heat flux measured by other researchers and the vertical thickness of this reaction zone, inferred from the distribution of seismicity, is

  6. Imaging hydrothermal roots along the Endeavour segment of the Juan de Fuca ridge using elastic full waveform inversion.

    NASA Astrophysics Data System (ADS)

    Arnulf, A. F.; Harding, A. J.; Kent, G. M.

    2016-12-01

    The Endeavour segment is a 90 km-long, medium-spreading-rate, oceanic spreading center located on the northern Juan de Fuca ridge (JDFR). The central part of this segment forms a 25-km-long volcanic high that hosts five of the most hydrothermally active vent fields on the MOR system, namely (from north to south): Sasquatch, Salty Dawg, High Rise, Main Endeavour and Mothra. Mass, heat and chemical fluxes associated to vigorous hydrothermal venting are large, however the geometry of the fluid circulation system through the oceanic crust remains almost completely undefined. To produce high-resolution velocity/reflectivity structures along the axis of the Endeavour segment, here, we combined a synthetic ocean bottom experiment (SOBE), 2-D traveltime tomography, 2D elastic full waveform and reverse time migration (RTM). We present velocity and reflectivity sections along Endeavour segment at unprecedented spatial resolutions. We clearly image a set of independent, geometrically complex, elongated low-velocity regions linking the top of the magma chamber at depth to the hydrothermal vent fields on the seafloor. We interpret these narrow pipe-like units as focused regions of hydrothermal fluid up-flow, where acidic and corrosive fluids form pipe-like alteration zones as previously observed in Cyprus ophiolites. Furthermore, the amplitude of these low-velocity channels is shown to be highly variable, with the strongest velocity drops observed at Main Endeavour, Mothra and Salty Dawg hydrothermal vent fields, possibly suggesting more mature hydrothermal cells. Interestingly, the near-seafloor structure beneath those three sites is very similar and highlights a sharp lateral transition in velocity (north to south). On the other hand, the High-Rise hydrothermal vent field is characterized by several lower amplitudes up-flow zones and relatively slow near-surface velocities. Last, Sasquatch vent field is located in an area of high near-surface velocities and is not

  7. Time-series measurement of hydrothermal heat flux at the Grotto mound, Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Xu, Guangyu; Jackson, Darrell R.; Bemis, Karen G.; Rona, Peter A.

    2014-10-01

    Continuous time-series observations are key to understanding the temporal evolution of a seafloor hydrothermal system and its interplay with thermal and chemical processes in the ocean and Earth interior. In this paper, we present a 26-month time series of the heat flux driving a hydrothermal plume on the Endeavour Segment of the Juan de Fuca Ridge obtained using the Cabled Observatory Vent Imaging Sonar (COVIS). Since 2010, COVIS has been connected to the North East Pacific Time-series Underwater Networked Experiment (NEPTUNE) observatory that provides power and real-time data transmission. The heat flux time series has a mean value of 18.10 MW and a standard deviation of 6.44 MW. The time series has no significant global trend, suggesting the hydrothermal heat source remained steady during the observation period. The steadiness of the hydrothermal heat source coincides with reduced seismic activity at Endeavour observed in the seismic data recorded by an ocean bottom seismometer from 2011 to 2013. Furthermore, first-order estimation of heat flux based on the temperature measurements made by the Benthic and Resistivity Sensors (BARS) at a neighboring vent also supports the steadiness of the hydrothermal heat source.

  8. High-resolution near-bottom vector magnetic anomalies over Raven Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Tivey, Maurice A.; Johnson, H. Paul; Salmi, Marie S.; Hutnak, Michael

    2014-10-01

    High-resolution, near-bottom vector magnetic data were collected by remotely operated vehicle Jason over the Raven hydrothermal vent field (47°57.3'N 129°5.75'W) located north of Main Endeavour vent field on the Endeavour segment of the Juan de Fuca Ridge. The survey was part of a comprehensive heat flow study of the Raven site using innovative thermal blanket technology to map the heat flux and crustal fluid pathways around a solitary hydrothermal vent field. Raven hydrothermal activity is presently located along the western axial valley wall, while additional inactive hydrothermal deposits are found to the NW on the upper rift valley wall. Magnetic inversion results show discrete areas of reduced magnetization associated with both active and inactive hydrothermal vent deposits that also show high conductive heat flow. Higher spatial variability in the heat flow patterns compared to the magnetization is consistent with the heat flow reflecting the currently active but ephemeral thermal environment of fluid flow, while crustal magnetization is representative of the static time-averaged effect of hydrothermal alteration. A general NW to SE trend in reduced magnetization across the Raven area correlates closely with the distribution of hydrothermal deposits and heat flux patterns and suggests that the fluid circulation system at depth is likely controlled by local crustal structure and magma chamber geometry. Magnetic gradient tensor components computed from vector magnetic data improve the resolution of the magnetic anomaly source and indicate that the hydrothermally altered zone directly beneath the Raven site is approximately 15 × 106 m3 in volume.

  9. Heat flux measured acoustically at Grotto Vent, a hydrothermal vent cluster on the Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Xu, G.; Jackson, D. R.; Bemis, K. G.; Rona, P. A.

    2013-12-01

    Over the past several decades, quantifying the heat output has been a unanimous focus of studies at hydrothermal vent fields discovered around the global ocean. Despite their importance, direct measurements of hydrothermal heat flux are very limited due to the remoteness of most vent sites and the complexity of hydrothermal venting. Moreover, almost all the heat flux measurements made to date are snapshots and provide little information on the temporal variation that is expected from the dynamic nature of a hydrothermal system. The Cabled Observatory Vent Imaging Sonar (COVIS, https://sites.google.com/a/uw.edu/covis/) is currently connected to the Endeavour node of the NEPTUNE Canada observatory network (http://www.neptunecanada.ca) to monitor the hydrothermal plumes issuing from a vent cluster (Grotto) on the Endeavour Segment of the Juan de Fuca Ridge. COVIS is acquiring a long-term (20-months to date) time series of the vertical flow rate and volume flux of the hydrothermal plume above Grotto through the Doppler analysis of the acoustic backscatter data (Xu et al., 2013). We then estimate the plume heat flux from vertical flow rate and volume flux using our newly developed inverse method. In this presentation, we will briefly summarize the derivation of the inverse method and present the heat-flux time series obtained consequently with uncertainty quantification. In addition, we compare our heat-flux estimates with the one estimated from the plume in-situ temperatures measured using a Remotely Operative Vehicle (ROV) in 2012. Such comparison sheds light on the uncertainty of our heat flux estimation. Xu, G., Jackson, D., Bemis, K., and Rona, P., 2013, Observations of the volume flux of a seafloor hydrothermal plume using an acoustic imaging sonar, Geochemistry, Geophysics Geosystems, 2013 (in press).

  10. Distribution of Particulates in Hydrothermal Plumes of the Endeavour Axial Valley: Preliminary Results from the Sea Breeze Project

    NASA Astrophysics Data System (ADS)

    Nassif, T. H.; McDuff, R. E.; Robigou, V.; Stahr, F.

    2004-12-01

    Hydrothermal vent plumes provide zones for chemical reactions between vent fluids and seawater, potential habitats for anaerobic bacteria and zooplankton, and a probable mechanism for the dispersal of vent larvae. Within the Endeavour Integrated Study Site are five known vent fields situated along the axial valley of the Endeavour Segment of the Juan de Fuca Ridge (N.E. Pacific Ocean). Each of these fields has a particle rich neutrally buoyant plume above it almost constantly, a common characteristic of vent systems worldwide. The purpose of this study was to determine 1) how plume particle distribution varies along the Endeavour segment axial valley; 2) whether a correlation exists between vent activity and particle density in the surrounding water, and 3) if the peak signals in backscatter and light transmission fall within a consistent range of potential density values along the axial valley. Light transmission and backscatter data were collected from vertically oscillating CTD casts at 21 stations along the axial valley covering the fields of Mothra, Main Endeavour, High Rise, Salty Dawg, and Sasquatch during the Sea Breeze - REVEL 2004 seagoing program. Plume particle density within ocean water was measured using a Wetlabs transmissometer and a Seapoint turbidity sensor. Preliminary results indicate a positive correlation between "black smoker" activity and signal strength in backscatter and light transmission. Main Endeavour and High Rise, known to exhibit the most rigorous hydrothermal activity, show correspondingly high amplitude signals in both backscatter and light transmission. Predicted diurnal currents seem to effect lateral plume particle movement away from vent sources, greatly impacting the particle density in surrounding areas. Peak signals in backscatter and light transmission occur in less dense water moving northward from Mothra to Salty Dawg.

  11. Recent Investigation of In-Situ pH in Hydrothermal Vent Fluids at Main Endeavour Field (MEF) and ASHES Vent Field (ASHES): Implications for Dynamic Changes in Subseafloor Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Ding, K.; Seyfried, W. E., Jr.; Tan, C.; Schaen, A. T.; Luhmann, A. J.

    2014-12-01

    In-situ pH is among the key factors affecting chemical reactions involved with fluid-rock interaction and metal transport in hydrothermal systems. A small variation in pH will often result in a large difference in dissolved metal concentrations. For instance, at 400oC, a decrease of ~0.15 pH unit will cause dissolved Fe concentration to double in fluid coexisting with a Fe-bearing mineral assemblage. This parameter also offers us an opportunity to better understand processes controlling the temporal evolution of hydrothermal vent fluid chemistry at mid-ocean ridges. During our recent cruise AT 26-17 with newly upgraded DSV2 Alvin, in-situ measurements of pH were carried out along with gas-tight sampling of vent fluids. Our efforts were focused at MEF and ASHES on the Juan de Fuca Ridge. These hydrothermal systems have been shown to be particularly responsive to subseafloor seismic and magmatic events. The measured fluid temperature was approximately 333˚C and 300˚C at Dante vent orifice of MEF and Inferno vent orifice of ASHES, respectively. The corresponding measured in-situ pH values for both vents are: 4.94 and 4.88, respectively. Dissolved gases and other species were also measured from gas-tight fluid samples providing a means of comparison with the in-situ data. As we have known the earthquake and magmatic activity often places the system at higher temperature and more reducing conditions in connection with a new evolutionary cycle. Comparing these relatively low in-situ pH values with those measured in the past, especially with the ones obtained at MEF in 1999 after an intense swarm of earthquakes, we see the system trending towards more acidic conditions along with decreasing temperature and dissolved H2 and H2S. Taking an example from Dante vent site, in-situ pH value of 5.15 was recorded with a measured temperature of 363oC two month after the event in 1999, which gives 0.2 pH unit greater than the more recent data. Measured dissolved H2 and H2S

  12. Hydrothermal sulfide accumulation along the Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Jamieson, J. W.; Clague, D. A.; Hannington, M. D.

    2014-06-01

    Hydrothermal sulfide deposits that form on the seafloor are often located by the detection of hydrothermal plumes in the water column, followed by exploration with deep-towed cameras, side-scan sonar imaging, and finally by visual surveys using remotely-operated vehicle or occupied submersible. Hydrothermal plume detection, however, is ineffective for finding hydrothermally-inactive sulfide deposits, which may represent a significant amount of the total sulfide accumulation on the seafloor, even in hydrothermally active settings. Here, we present results from recent high-resolution, autonomous underwater vehicle-based mapping of the hydrothermally-active Endeavour Segment of the Juan de Fuca Ridge, in the Northeast Pacific Ocean. Analysis of the ridge bathymetry resulted in the location of 581 individual sulfide deposits along 24 km of ridge length. Hydrothermal deposits were distinguished from volcanic and tectonic features based on the characteristics of their surface morphology, such as shape and slope angles. Volume calculations for each deposit results in a total volume of 372,500 m3 of hydrothermal sulfide-sulfate-silica material, for an equivalent mass of ∼1.2 Mt of hydrothermal material on the seafloor within the ridge's axial valley, assuming a density of 3.1 g/cm3. Much of this total volume is from previously undocumented inactive deposits outside the main active vent fields. Based on minimum ages of sulfide deposition, the deposits accumulated at a maximum rate of ∼400 t/yr, with a depositional efficiency (proportion of hydrothermal material that accumulates on the seafloor to the total amount hydrothermally mobilized and transported to the seafloor) of ∼5%. The calculated sulfide tonnage represents a four-fold increase over previous sulfide estimates for the Endeavour Segment that were based largely on accumulations from within the active fields. These results suggest that recent global seafloor sulfide resource estimates, which were based mostly

  13. Ascending and descending particle flux from hydrothermal plumes at Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Cowen, James P.; Bertram, Miriam A.; Wakeham, Stuart G.; Thomson, Richard E.; William Lavelle, J.; Baker, Edward T.; Feely, Richard A.

    2001-04-01

    Bio-acoustic surveys and associated zooplankton net tows have documented anomalously high concentrations of zooplankton within a 100 m layer above the hydrothermal plumes at Endeavour Segment, Juan de Fuca Ridge. These and other data suggest that congregating epi-plume zooplankton are exploiting a food substrate associated with the hydrothermal plume. Ascending, organic-rich particles could provide a connection. Consequently, two paired sequentially sampling ascending and descending particle flux traps and a current meter were deployed on each of three moorings from July 1994 to May 1995. Mooring sites included an on-axis site (OAS; 47°57.0'N, 129°05.7'W) near the main Endeavour vent field, a "down-current" site 3 km west of the main vent field (WS), and a third background station 43 km northeast of the vent field (ES). Significant ascending and descending particle fluxes were measured at all sites and depths. Lipid analyses indicated that ascending POC was derived from mid-depth and deep zooplankton whereas descending POC also contained a component of photosynthetically derived products from the sea surface. Highest ascending POC fluxes were found at the hydrothermal plume-swept sites (OAS and WS). The limited data available, however, precludes an unequivocal conclusion that hydrothermal processes contribute to the ascending flux of organic carbon at each site. Highest ascending to descending POC flux ratios were also found at WS. Observed trends in POC, PMn/PTi, and PFe/PTi clearly support a hydrothermal component to the descending flux at the plume-swept WS site (no descending data was recovered at OAS) but not at the background ES site. Alternative explanations for ascending particle data are discussed. First-order calculations for the organic carbon input (5-22 mg C m -2 d -1) required to sustain observed epi-plume zooplankton anomalies at Endeavour are comparable both to measured total POC flux to epi-plume depths (2-5 mg C m -2 d -1: combined hydrothermal

  14. Precipitation and growth of barite within hydrothermal vent deposits from the Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Jamieson, John William; Hannington, Mark D.; Tivey, Margaret K.; Hansteen, Thor; Williamson, Nicole M.-B.; Stewart, Margaret; Fietzke, Jan; Butterfield, David; Frische, Matthias; Allen, Leigh; Cousens, Brian; Langer, Julia

    2016-01-01

    Hydrothermal vent deposits form on the seafloor as a result of cooling and mixing of hot hydrothermal fluids with cold seawater. Amongst the major sulfide and sulfate minerals that are preserved at vent sites, barite (BaSO4) is unique because it requires the direct mixing of Ba-rich hydrothermal fluid with sulfate-rich seawater in order for precipitation to occur. Because of its extremely low solubility, barite crystals preserve geochemical fingerprints associated with conditions of formation. Here, we present data from petrographic and geochemical analyses of hydrothermal barite from the Endeavour Segment of the Juan de Fuca Ridge, northeast Pacific Ocean, in order to determine the physical and chemical conditions under which barite precipitates within seafloor hydrothermal vent systems. Petrographic analyses of 22 barite-rich samples show a range of barite crystal morphologies: dendritic and acicular barite forms near the exterior vent walls, whereas larger bladed and tabular crystals occur within the interior of chimneys. A two component mixing model based on Sr concentrations and 87Sr/86Sr of both seawater and hydrothermal fluid, combined with 87Sr/86Sr data from whole rock and laser-ablation ICP-MS analyses of barite crystals indicate that barite precipitates from mixtures containing as low as 17% and as high as 88% hydrothermal fluid component, relative to seawater. Geochemical modelling of the relationship between aqueous species concentrations and degree of fluid mixing indicates that Ba2+ availability is the dominant control on mineral saturation. Observations combined with model results support that dendritic barite forms from fluids of less than 40% hydrothermal component and with a saturation index greater than ∼0.6, whereas more euhedral crystals form at lower levels of supersaturation associated with greater contributions of hydrothermal fluid. Fluid inclusions within barite indicate formation temperatures of between ∼120 °C and 240 °C during

  15. Numerical simulation of mean currents and water property anomalies at Endeavour Ridge: Hydrothermal versus topographic forcing

    NASA Astrophysics Data System (ADS)

    Thomson, Richard E.; Subbotina, Marina M.; Anisimov, Mikhail V.

    2009-09-01

    Numerical simulations based on realistic seafloor topography are used to examine near-bottom currents in the region of the Endeavour segment of Juan de Fuca Ridge (Endeavour Ridge) in the northeast Pacific. Results support earlier findings that hydrothermal venting within the ˜2200-m deep axial valley, rather than topographically modified, basin-scale cross-ridge geostrophic flow, is responsible for the near-steady northward currents observed within the confines of the valley. Although it does not generate deep flow within the valley, the basin-scale circulation determines the horizontal redistribution of the hydrothermal plumes once they rise above the ridge crest. Simulations of the near-bottom temperature and salinity fields reveal that model runs that incorporate a deep westward background flow most closely reproduce the observed plume anomaly distributions above the ridge, indicating that bottom currents in the region are predominantly westward, counter to the prevailing southeasterly flow of the wind-driven California Current in the upper half of the water column.

  16. Impact-Facilitated Hydrothermal Alteration in the Rim of Endeavour Crater, Mars

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Schroeder, C.; Farrand, W. H.; Crumpler, L. S.; Yen, A. S.

    2017-01-01

    Endeavour crater, a Noachian-aged, 22 km diameter impact structure on Meridiani Planum, Mars, has been investigated by the Mars Exploration Rover Opportunuity for over 2000 sols (Mars days). The rocks of the western rim region (oldest to youngest) are: (i) the pre-impact Matijevic fm.; (ii) rim-forming Shoemaker fm. polymict impact breccias; (iii) Grasberg fm., fine-grained sediments draping the lower slopes; and (iv) Burns fm., sulfate-rich sandstones that onlap the Grasberg fm. The rim is segmented and transected by radial fracture zones. Evidence for fluid-mediated alteration includes m-scale detections of phyllosilicates from orbit, and cm-scale variations in rock/soil composition/mineralogy documented by the Opportunity instrument suite. The m-scale phyllosilicate detections include Fe(3+)-Mg and aluminous smectites that occur in patches in the Matijevic and Shoemaker fms. Rock compositions do not reveal substantial differences for smectite-bearing compared to smectite-free rocks. Interpretation: large-scale hydrothermal alteration powered by impact-deposited heat acting on limited water supplies engendered mineralogic transfomations under low water/rock, near-isochemical conditions. The cm-scale alterations, localized in fracture zones, occurred at higher water/rock as evidenced by enhanced Si and Al contents through leaching of more soluble elements, and deposition of Mg, Ni and Mn sulphates and halogen salts in soils. Visible/near infrared reflectance of narrow curvilinear red zones indicate higher nanophase ferric oxide contents and possibly hydration compared to surrounding outcrops. Broad fracture zones on the rim have reflectance features consistent with development of ferric oxide minerals. Interpretation: water fluxing through the fractures in a hydrothermal system resulting from the impact engendered alteration and leaching under high water/rock conditions. Late, localized alteration is documented by Ca-sulfate-rich veins that are not confined to

  17. Magnetite formation from ferrihydrite by hyperthermophilic archaea from Endeavour Segment, Juan de Fuca Ridge hydrothermal vent chimneys.

    PubMed

    Lin, T Jennifer; Breves, E A; Dyar, M D; Ver Eecke, H C; Jamieson, J W; Holden, J F

    2014-05-01

    Hyperthermophilic iron reducers are common in hydrothermal chimneys found along the Endeavour Segment in the northeastern Pacific Ocean based on culture-dependent estimates. However, information on the availability of Fe(III) (oxyhydr) oxides within these chimneys, the types of Fe(III) (oxyhydr) oxides utilized by the organisms, rates and environmental constraints of hyperthermophilic iron reduction, and mineral end products is needed to determine their biogeochemical significance and are addressed in this study. Thin-section petrography on the interior of a hydrothermal chimney from the Dante edifice at Endeavour showed a thin coat of Fe(III) (oxyhydr) oxide associated with amorphous silica on the exposed outer surfaces of pyrrhotite, sphalerite, and chalcopyrite in pore spaces, along with anhydrite precipitation in the pores that is indicative of seawater ingress. The iron sulfide minerals were likely oxidized to Fe(III) (oxyhydr) oxide with increasing pH and Eh due to cooling and seawater exposure, providing reactants for bioreduction. Culture-dependent estimates of hyperthermophilic iron reducer abundances in this sample were 1740 and 10 cells per gram (dry weight) of material from the outer surface and the marcasite-sphalerite-rich interior, respectively. Two hyperthermophilic iron reducers, Hyperthermus sp. Ro04 and Pyrodictium sp. Su06, were isolated from other active hydrothermal chimneys on the Endeavour Segment. Strain Ro04 is a neutrophilic (pH opt 7-8) heterotroph, while strain Su06 is a mildly acidophilic (pH opt 5), hydrogenotrophic autotroph, both with optimal growth temperatures of 90-92 °C. Mössbauer spectroscopy of the iron oxides before and after growth demonstrated that both organisms form nanophase (<12 nm) magnetite [Fe3 O4 ] from laboratory-synthesized ferrihydrite [Fe10 O14 (OH)2 ] with no detectable mineral intermediates. They produced up to 40 mm Fe(2+) in a growth-dependent manner, while all abiotic and biotic controls produced <3 mm Fe

  18. Evolution of the Mothra Hydrothermal Field, Endeavour Segment of the Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Glickson, D.; Kelley, D. S.; Delaney, J.

    2005-12-01

    The Mothra Hydrothermal Field (MHF) is a 600 m long, high-temperature hydrothermal field. It is located 2.7 km south of the Main Endeavour Field at the southern end of the central Endeavour Segment. Mothra is the most areally extensive field along the Endeavour Segment, composed of six active sulfide clusters that are 40-200 m apart. Each cluster contains rare black smokers (venting up to 319°C), numerous diffusely venting chimneys, and abundant extinct chimneys and sulfide talus. From north to south, these clusters include Cauldron, Twin Peaks, Faulty Towers, Crab Basin, Cuchalainn, and Stonehenge. As part of the Endeavour Integrated Study Site (ISS), the MHF is a site of intensive interdisciplinary studies focused on linkages among geology, geochemistry, fluid chemistry, seismology, and microbiology. Axial valley geology at MHF is structurally complex, consisting of lightly fissured flows that abut the walls and surround a core of extensively fissured, collapsed terrain. Fissure abundance and distribution indicates that tectonism has been the dominant process controlling growth of the axial graben. Past magmatic activity is shown by the 200 m long chain of collapse basins between Crab Basin and Stonehenge, which may have held at least ~7500 m3 of lava. Assuming a flow thickness of 0.5 m, this amount of lava could cover over half the valley floor during a single volcanic event. At a local scale, MHF clusters vary in size, activity, and underlying geology. They range in size from 400-1600 m2 and consist of isolated chimneys and/or coalesced cockscomb arrays atop ramps of sulfide talus. In the northern part of the field, Cauldron, Twin Peaks, Faulty Towers, and Crab Basin are located near the western valley wall, bounded by basalt talus and a combination of collapsed sheet flows, intermixed lobate and sulfide, disrupted terrain, and isolated pillow ridges. The southern clusters, Cuchalainn and Stonehenge, are associated with collapse basins in the central valley

  19. Hydrothermal flow at Main Endeavour Field imaged and measured with Cable Operated Vent Imaging Sonar

    NASA Astrophysics Data System (ADS)

    Rona, P. A.; Bemis, K. G.; Xu, G.; Jackson, D. R.; Jones, C. D.

    2011-12-01

    Initial acoustic monitoring of hydrothermal flow in the Main Endeavour Field (MEF) captures the spatial distribution of diffuse and focused discharge and shows potential for flux determinations. Our Cabled Observatory Vent Imaging Sonar (COVIS) was connected to the NEPTUNE Canada Endeavour Observatory in September 2010. Using a customized Reson 7125 multi-beam sonar, COVIS acquired a 29 day time series of black smoker plume and associated diffuse hydrothermal flow from Grotto, a 30 m diameter vent cluster in the MEF, Juan de Fuca Ridge. Detection of the spatial patterns of diffuse flow utilizes phase decorrelation of the acoustic signal (200kHz) by buoyancy-driven turbulence (acoustic scintillation) to produce a time series of maps. Substantial fluctuation in the detected diffuse flow area (0.1 - 18 m^2) was observed over the 29 days of observation, although position remained stable. Acoustic imaging of focused flow (400 kHz) utilizes high volume backscatter (attributed to particles and turbulent sound speed fluctuations) to image in 3D the initial tens of meters of rise of buoyant plumes. Spectral analysis of bending inclination of a strong plume from multiple fast smokers on the NW end of Grotto (north tower) indicates that the dominant modes correspond with the ambient mixed semi-diurnal tide (based on current meter data at a mooring 2.9 km to the north and on a tidal model), with at least one secondary mode attributable to sub-inertial flow related to inflow to the axial valley. A weaker plume from several slower smokers is present on the NE end of Grotto. On first analysis, the bending inclination of the weaker plume appears to be affected by the stronger plume. Quantification of flow velocity and volume flux of plumes begins with measuring the Doppler phase shift through plume cross-sections beginning at 5 m above source vents where discharge merges. The volume flux measurements enable calculation of entrainment coefficients, which prior work on the same

  20. Advanced Seismic Studies of the Endeavour Ridge: Understanding the Interplay among Magmatic, Hydrothermal, and Tectonic Processes at Mid-Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Arnoux, G. M.; VanderBeek, B. P.; Morgan, J. V.; Hooft, E. E. E.; Toomey, D. R.; Wilcock, W. S. D.; Warner, M.

    2014-12-01

    At mid-ocean ridges magmatic, hydrothermal, and tectonic processes are linked. Understanding their interactions requires mapping magmatic systems and tectonic structures, as well as their relationship to hydrothermal circulation. Three-dimensional seismic images of the crust can be used to infer the size, shape, and location of magma reservoirs, in addition to the structure of the thermal boundary layer that connects magmatic and hydrothermal processes. Travel time tomography has often been used to study these processes, however, the spatial resolution of travel time tomography is limited. Three-dimensional full waveform inversion (FWI) is a state-of-the art seismic method developed for use in the oil industry to obtain high-resolution models of the velocity structure. The primary advantage of FWI is that it has the potential to resolve subsurface structures on the order of half the seismic wavelength—a significant improvement on conventional travel time tomography. Here, we apply anisotropic FWI to data collected on the Endeavour segment of the Juan de Fuca Ridge. Starting models for anisotropic P-wave velocity were obtained by travel time tomography [Weekly et al., 2014]. During FWI, the isotropic velocity model is updated and anisotropy is held constant. We have recovered low-velocity zones approximately 2-3 km beneath the ridge axis that likely correspond to a segmented magma-rich body and are in concert with those previously resolved using multi-channel seismic reflection methods. The segmented crustal magma body underlies all five known high-temperature hydrothermal vent fields along the Endeavour segment. A high-velocity zone, shallower than the observed low-velocity zones, underlies the southernmost hydrothermal vent field. This may be indicative of waning hydrothermal activity in which minerals are crystallizing beneath the vent field. Our FWI study of the Endeavour Ridge will provide the most detailed three-dimensional images of the crustal structure to

  1. Aqueous Volatiles in Hydrothermal fluids from the Main Endeavour Vent Field: Temporal Variability Following Earthquake Activity

    NASA Astrophysics Data System (ADS)

    Seewald, J. S.; Cruse, A. M.; Saccocia, P. J.

    2001-12-01

    Volatile species play a critical role in a broad spectrum of physical, chemical, and biological processes associated with hydrothermal circulation at oceanic spreading centers. Earthquake activity at the Main Endeavour vent field, northern Juan de Fuca Ridge in June 1999 [1] provided and opportunity to assess factors that regulate the flux of volatile species from the oceanic crust to the water column following a rapid change in subsurface reaction zone conditions. High temperature vent fluids were collected in gas-tight samplers at the Main Endeavour field in September 1999, approximately four months after the earthquakes, and again in July 2000, and were analyzed for the abundance of aqueous volatile and non-volatile species. Measured concentrations of aqueous H2, H2S, and CO2 increased substantially in September 1999 relative to pre-earthquake values [2,3], and subsequently decreased in July 2000, while aqueous Cl concentrations initially decreased in 1999 and subsequently increased in 2000. Concentrations of Cl in all fluids were depleted relative to seawater values. Aqueous CH4 and NH3 concentrations decreased in both the 1999 and 2000 samples relative to pre- earthquake values. Variations in Cl concentration of Endeavour fluids reflect varying degrees of phase separation under near critical temperature and pressure conditions. Because volatile species efficiently partition into the vapor phase, variations in their abundance as a function of Cl concentration can be used to constrain conditions of phase separation and fluid-rock interaction. For example, concentrations of volatile species that are not readily incorporated into minerals (CH4 and NH3) correlated weakly with Cl suggesting phase separation was occurring under supercritical conditions after the earthquake activity. In contrast, compositional data for fluids prior to the earthquakes indicate a strong negative correlation between these species and Cl suggesting phase separation under subcritical

  2. Modeling mid-ocean ridge hydrothermal response to earthquakes, tides, and ocean currents: a case study at the Grotto mound, Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Xu, G.; Bemis, K. G.

    2014-12-01

    Seafloor hydrothermal systems feature intricate interconnections among oceanic, geological, hydrothermal, and biological processes. The advent of the NEPTUNE observatory operated by Ocean Networks Canada at the Endeavour Segment, Juan de Fuca Ridge enables scientists to study these interconnections through multidisciplinary, continuous, real-time observations. The multidisciplinary observatory instruments deployed at the Grotto Mound, a major study site of the NEPTUNE observatory, makes it a perfect place to study the response of a seafloor hydrothermal system to geological and oceanic processes. In this study, we use the multidisciplinary datasets recorded by the NEPTUNE Observatory instruments as observational tools to demonstrate two different aspects of the response of hydrothermal activity at the Grotto Mound to geological and oceanic processes. First, we investigate a recent increase in venting temperature and heat flux at Grotto observed by the Benthic and Resistivity Sensors (BARS) and the Cabled Observatory Vent Imaging Sonar (COVIS) respectively. This event started in Mar 2014 and is still evolving by the time of writing this abstract. An initial interpretation in light of the seismic data recorded by a neighboring ocean bottom seismometer on the NEPTUNE observatory suggests the temperature and heat flux increase is probably triggered by local seismic activities. Comparison of the observations with the results of a 1-D mathematical model simulation of hydrothermal sub-seafloor circulation elucidates the potential mechanisms underlying hydrothermal response to local earthquakes. Second, we observe significant tidal oscillations in the venting temperature time series recorded by BARS and the acoustic imaging of hydrothermal plumes by COVIS, which is evidence for hydrothermal response to ocean tides and currents. We interpret the tidal oscillations of venting temperature as a result of tidal loading on a poroelastic medium. We then invoke poroelastic

  3. METEORIC-HYDROTHERMAL SYSTEMS.

    USGS Publications Warehouse

    Criss, Robert E.; Taylor, Hugh P.

    1986-01-01

    This paper summarizes the salient characteristics of meteoric-hydrothermal systems, emphasing the isotopic systematics. Discussions of permeable-medium fluid dynamics and the geology and geochemistry of modern geothermal systems are also provided, because they are essential to any understanding of hydrothermal circulation. The main focus of the paper is on regions of ancient meteoric-hydrothermal activity, which give us information about the presently inaccessible, deep-level parts of modern geothermal systems. It is shown oxygen and hydrogen isotopes provide a powerful method to discover and map fossil hydrothermal systems and to investigate diverse associated aspects of rock alteration and ore deposition.

  4. Microearthquakes beneath the Hydrothermal Vent Fields on the Endeavour Segment of the Juan de Fuca Ridge: Results from the Keck Seismic/Hydrothermal Observatory

    NASA Astrophysics Data System (ADS)

    Bowman, D.; Parker, J.; Wilcock, W.; Hooft, E.; Barclay, A.; Toomey, D.; McGill, P.; Stakes, D.; Schmidt, C.; Patel, H.

    2005-12-01

    The W.M. Keck Foundation is supporting the operation of a small seismic network in the vicinity of the hydrothermal vent fields on the central portion of the Endeavour Segment of the Juan de Fuca Ridge. This is part of a program to conduct prototype seafloor observatory experiments to monitor the relationships between episodic deformation, fluid venting and microbial productivity at oceanic plate boundaries. The Endeavour seismic network was installed in the summer of 2003 and comprises seven GEOSense three-component short-period corehole seismometers and one buried Guralp CMG-1T broadband seismometer. A preliminary analysis of the first year of data was undertaken as part of an undergraduate research apprenticeship class taught at the University of Washington's Friday Harbor Laboratories and additional analysis has since been completed by two of the apprentices and by two IRIS undergraduate interns. Over 12,000 earthquakes were located along the ridge-axis of the Endeavour, of which ~3,000 occur within or near the network and appear to be associated with the hydrothermal systems. The levels of seismicity are strongly correlated with the intensity of venting with particularly high rates of seismicity beneath the Main and High Rise Fields and substantially lower rates to the north beneath the relatively inactive Salty Dawg and Sasquatch fields. We have used both HYPOINVERSE and a grid search algorithm to investigate the distribution of focal depths assuming a variety of one-dimensional velocity models. The preliminary results show that the majority of earthquakes occur within a narrow depth range and may represent an intense zone of seismicity within a reaction overlying the axial magma chamber at ~2.5 km depth. However, the mean focal depth is strongly dependent on the relative weights assigned to the S arrivals. We infer from the inspection of residuals that no combination of the P- and S-wave velocity models we have so far investigated are fully consistent with

  5. Age, Episodicity and Migration of Hydrothermal Activity within the Axial Valley, Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Jamieson, J. W.; Hannington, M. D.; Kelley, D. S.; Clague, D. A.; Holden, J. F.; Tivey, M. K.; Delaney, J. R.

    2011-12-01

    Hydrothermal sulfide deposits record the history of high-temperature venting along the Endeavour Segment. Active venting is currently located within five discreet vent fields, with minor diffuse venting occurring between the fields. However, inactive and/or extinct sulfide structures are found throughout the entire axial valley of the ridge segment, suggesting that hydrothermal activity has been more vigorous in the past or focused venting has migrated with time. Here, we present age constraints from U-series dating of 44 sulfide samples collected by manned submersible from between the Mothra Field in the south to Sasquatch in the north. Samples are dated using 226Ra/Ba ratios from hydrothermal barite that precipitates along with the sulfide minerals. Most samples have been collected from within or near the active vent fields. Fifteen samples from the Main Endeavour Field (MEF) show a spectrum of ages from present to 2,430 years old, indicating that this field has been continuously active for at least ~2,400 years. MEF appears to be oldest currently active field. This minimum value for the age of hydrothermal activity also provides a minimum age of the axial valley itself. Ages from thirteen samples from the High-Rise Field indicate continuous venting for at least the past ~1,250 years. These age data are used in conjunction with age constraints of the volcanic flows to develop an integrated volcanic, hydrothermal and tectonic history of the Endeavour Segment. The total volume of hydrothermal sulfide within the axial valley, determined from high-resolution bathymetry, is used in conjunction with the age constraints of the sulfide material to determine the mass accumulation rates of sulfide along the Endeavour Segment. These data can be used to calibrate the efficiency of sulfide deposition from the hydrothermal vents, and provide a time-integrated history of heat, fluid and chemical fluxes at the ridge-segment scale. The comparison of time-integrated rates with

  6. Temporal and spatial variation in temperature experienced by macrofauna at Main Endeavour hydrothermal vent field

    NASA Astrophysics Data System (ADS)

    Lee, Raymond W.; Robert, Katleen; Matabos, Marjolaine; Bates, Amanda E.; Juniper, S. Kim

    2015-12-01

    A significant focus of hydrothermal vent ecological studies has been to understand how species cope with various stressors through physiological tolerance and biochemical resistance. Yet, the environmental conditions experienced by vent species have not been well characterized. This objective requires continuous observations over time intervals that can capture environmental variability at scales that are relevant to animals. We used autonomous temperature logger arrays (four roughly parallel linear arrays of 12 loggers spaced every 10-12 cm) to study spatial and temporal variations in the thermal regime experienced by hydrothermal vent macrofauna at a diffuse flow vent. Hourly temperatures were recorded over eight months from 2010 to 2011 at Grotto vent in the Main Endeavour vent field on the Juan de Fuca Ridge, a focus area of the Ocean Networks Canada cabled observatory. The conspicuous animal assemblages in video footage contained Ridgeia piscesae tubeworms, gastropods (primarily Lepetodrilus fucensis), and polychaetes (polynoid scaleworms and the palm worm Paralvinella palmiformis). Two dimensional spatial gradients in temperature were generally stable over the deployment period. The average temperature recorded by all arrays, and in some individual loggers, revealed distinctive fluctuations in temperature that often corresponded with the tidal cycle. We postulate that this may be related to changes in bottom currents or fluctuations in vent discharge. A marked transient temperature increase lasting over a period of days was observed in April 2011. While the distributions and behavior of Juan de Fuca Ridge vent invertebrates may be partially constrained by environmental temperature and temperature tolerance, except for the one transient high-temperature event, observed fluid temperatures were generally similar to the thermal preferences for some species, and typically well below lethal temperatures for all species. Average temperatures of the four arrays

  7. Microbial diversity of a sulfide black smoker in main endeavour hydrothermal vent field, Juan de Fuca Ridge.

    PubMed

    Zhou, Huaiyang; Li, Jiangtao; Peng, Xiaotong; Meng, Jun; Wang, Fengping; Ai, Yuncan

    2009-06-01

    Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field (MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that the chimney was composed mainly of Fe-, Zn-and Cu-rich sulfides. According to phylogenetic analysis, within the Crenarchaeota, clones of the order Desulfurococcales predominated, comprising nearly 50% of archaeal clones. Euryarchaeota were composed mainly of clones belonging to Thermococcales and deep-sea hydrothermal vent Euryarchaeota (DHVE), each of which accounted for about 20% of all clones. Thermophilic or hyperthermophilic physiologies were common to the predominant archaeal groups. More than half of bacterial clones belonged to epsilon-Proteobacteria, which confirmed their prevalence in hydrothermal vent environments. Clones of Proteobacteria (gamma-, delta-, beta-), Cytophaga-Flavobacterium-Bacteroides (CFB) and Deinococcus-Thermus occurred as well. It was remarkable that methanogens and methanotrophs were not detected in our 16S rRNA gene library. Our results indicated that sulfur-related metabolism, which included sulfur-reducing activity carried out by thermophilic archaea and sulfur-oxidizing by mesophilic bacteria, was common and crucial to the vent ecosystem in Dudley hydrothermal site.

  8. Dissolved Carbon Species in Diffuse and Focused Flow Hydrothermal Vents at the Main Endeavour Field, Northern Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Foustoukos, D. I.; Seyfried, W. E.; Ding, K.; Pester, N. J.

    2006-12-01

    The magmatic and tectonic event of 1999 had a significant impact on the chemical composition of vent fluids issuing from the Main Endeavour Field (MEF), Juan de Fuca Ridge. Here, we report dissolved concentrations of H2, CO2, CO and C1-C3 alkanes measured in low and high-temperature hydrothermal fluids collected in August 2005 during an RV Atlantis/DSV Alvin expedition at MEF. In comparison with time series data, temperatures of the 2005 vent fluids were slightly lower than those recorded in the aftermaths of the tectonic event of 1999. The possible cooling of the hydrothermal subseafloor reaction zone is consistent with the observed increase in dissolved Cl to pre-1999 values. Converging compositional trends to pre-1999 conditions are also suggested for dissolved CO2 concentrations (~20 mmol/kg) in Puffer, Sully, Bastille and S&M vent fluids. In these focused flow and high-temperature vent fluids, dissolved CO2 is in thermodynamic equilibrium with CO(aq). The systematics of organic species in diffuse flow fluids, however, appears to be closely related to processes occurring within the near-seafloor environment. For example, excess CO(aq) observed in the diffuse flow fluids at Easter Island is attributed to sluggish CO- CO2(aq) equilibria at low temperatures, suggesting hydrothermal circulation of short-residence times. Short-lived hydrothermal circulation is further supported by the nearly identical C1/(C2+C3) ratios between focused and diffuse flow fluids. Furthermore, alkane distribution in the MEF diffuse flow fluids suggests direct mixing between seawater and hydrothermal fluid with minimal biological inputs, in contrast with the greater effect of microbial methanogenesis proposed in other ridge-crest hydrothermal environments. Thus, the coupling of CO2(aq)-CO(aq) redox equilibrium with dissolved carbon species in low- temperature vent fluids could provide a better understanding of the effect of subsurface microbial communities upon the composition of mid

  9. The Lassen hydrothermal system

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Bergfeld, Deborah; Clor, Laura; Evans, William C.

    2016-01-01

    The active Lassen hydrothermal system includes a central vapor-dominated zone or zones beneath the Lassen highlands underlain by ~240 °C high-chloride waters that discharge at lower elevations. It is the best-exposed and largest hydrothermal system in the Cascade Range, discharging 41 ± 10 kg/s of steam (~115 MW) and 23 ± 2 kg/s of high-chloride waters (~27 MW). The Lassen system accounts for a full 1/3 of the total high-temperature hydrothermal heat discharge in the U.S. Cascades (140/400 MW). Hydrothermal heat discharge of ~140 MW can be supported by crystallization and cooling of silicic magma at a rate of ~2400 km3/Ma, and the ongoing rates of heat and magmatic CO2 discharge are broadly consistent with a petrologic model for basalt-driven magmatic evolution. The clustering of observed seismicity at ~4–5 km depth may define zones of thermal cracking where the hydrothermal system mines heat from near-plastic rock. If so, the combined areal extent of the primary heat-transfer zones is ~5 km2, the average conductive heat flux over that area is >25 W/m2, and the conductive-boundary length <50 m. Observational records of hydrothermal discharge are likely too short to document long-term transients, whether they are intrinsic to the system or owe to various geologic events such as the eruption of Lassen Peak at 27 ka, deglaciation beginning ~18 ka, the eruptions of Chaos Crags at 1.1 ka, or the minor 1914–1917 eruption at the summit of Lassen Peak. However, there is a rich record of intermittent hydrothermal measurement over the past several decades and more-frequent measurement 2009–present. These data reveal sensitivity to climate and weather conditions, seasonal variability that owes to interaction with the shallow hydrologic system, and a transient 1.5- to twofold increase in high-chloride discharge in response to an earthquake swarm in mid-November 2014.

  10. Rhythms and community dynamics of a hydrothermal tubeworm assemblage at main endeavour field - a multidisciplinary deep-sea observatory approach.

    PubMed

    Cuvelier, Daphne; Legendre, Pierre; Laes, Agathe; Sarradin, Pierre-Marie; Sarrazin, Jozée

    2014-01-01

    The NEPTUNE cabled observatory network hosts an ecological module called TEMPO-mini that focuses on hydrothermal vent ecology and time series, granting us real-time access to data originating from the deep sea. In 2011-2012, during TEMPO-mini's first deployment on the NEPTUNE network, the module recorded high-resolution imagery, temperature, iron (Fe) and oxygen on a hydrothermal assemblage at 2186 m depth at Main Endeavour Field (North East Pacific). 23 days of continuous imagery were analysed with an hourly frequency. Community dynamics were analysed in detail for Ridgeia piscesae tubeworms, Polynoidae, Pycnogonida and Buccinidae, documenting faunal variations, natural change and biotic interactions in the filmed tubeworm assemblage as well as links with the local environment. Semi-diurnal and diurnal periods were identified both in fauna and environment, revealing the influence of tidal cycles. Species interactions were described and distribution patterns were indicative of possible microhabitat preference. The importance of high-resolution frequencies (<1 h) to fully comprehend rhythms in fauna and environment was emphasised, as well as the need for the development of automated or semi-automated imagery analysis tools.

  11. Cody hydrothermal system

    SciTech Connect

    Heasler, H.P.

    1982-01-01

    The hot springs of Colter's Hell are the surface manifestations of a much larger hydothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. The study area covers 2700 km/sup 2/ (1040 mi/sup 2/) in northwest Wyoming. Research and field work included locating and sampling the hot springs, geologic mapping, thermal logging of available wells, measuring thermal conductivities, analyzing over 200 oil and gas well bottom-hole temperatures, and compiling and analyzing hydrologic data. These data were used to generate a model for the hydrothermal system.

  12. Abundance and Distribution of Hydrothermal Chimneys and Mounds on the Endeavour Ridge Determined by 1-m Resolution AUV Multibeam Mapping Surveys

    NASA Astrophysics Data System (ADS)

    Clague, D. A.; Caress, D. W.; Thomas, H.; Thompson, D.; Calarco, M.; Holden, J.; Butterfield, D.

    2008-12-01

    High-resolution seafloor mapping surveys were conducted on the Endeavour Ridge using the MBARI AUV D. Allan B. during R/V Atlantis cruise AT15-36. The four surveys had a combined bottom time of about 46 hours, collected data along 238 km of track, and mapped roughly 35 km2 with 200 kHz multibeam bathymetry and 100 kHz chirp sidescan. The bathymetry data have a 1-m lateral resolution and 0.1-m vertical precision. The surveys focused on the axial valley from 48°0.0' to 47°53.1'N or from 4.3 km south of the Mothra vent field to 0.5 km north of the Sasquatch vent field. We also mapped the western flank of the ridge between the Mothra and High Rise vent fields. The AUV is navigated using an inertial navigation system (INS) aided by Doppler Velocity Log (DVL) estimates of velocity over bottom. For these deep-water surveys, the initial AUV location derives from USBL fixes communicated to the vehicle by acoustic modem. Cross-correlation of bathymetric features in overlapping or crossing swaths allowed solution for an optimal navigation model that is internally self-consistent and accurate to the bathymetric resolution of 1 m. The surveys imaged over 800 individual chimney or hydrothermal mound structures, roughly 20% from the five main vent fields. Chimney structures occur along the entire axial valley but are less common near the southern end of the survey. In addition, chimneys occur along faults and on fault slivers bounding the deepest part of the axial valley to the east and west and to the crest on the west side of the axis. The tallest structure, at 28 m, was located at the High Rise field just south of Godzilla vent. Many of the chimneys previously mapped at Mothra were below our detection levels or combined in single pixels, so the number of chimneys identified is clearly a minimum number with many smaller deposits and chimneys excluded from our count. A hydrothermal mound 135 m in diameter and 60 m tall occurs off-axis about 2 km SSW of the Mothra vent field

  13. Comparison of Magma Residence, Magma Ascent and Magma-Hydrothermal Interaction at EPR 9°N and Endeavour Segment

    NASA Astrophysics Data System (ADS)

    Michael, P. J.; Gill, J. B.; Ramos, F. C.

    2010-12-01

    the axis, as seen in the 2005-6 flow where CO2 decreases and bubble size increases away from the eruptive vent [3]. CO2 contents of Endeavour glasses are lower in general than EPR 9°N glasses despite their deeper AMC [4], suggesting that they had more time to exsolve. Highest values are lower than the CO2 content corresponding to the AMC roof, while lowest values are in equilibrium with their seafloor depths. Either the lavas took longer to ascend from depth or they flowed longer at the surface, or both. Young off-axis lavas on Endeavour have low CO2 that cannot be ascribed to post-eruptive flow away from the axis, because they occur outside an enclosed axial valley. The comparison of the CO2 and Cl data from the two ridges does not support a simple interpretation in which fast-rising magmas are less likely to interact with hydrothermally altered crust. [1] leRoux et al. (2003) EPSL 251, 209-231. [2] Michael & Schilling (1989) GCA 53, 3131-3143. [3] Michael et al. (2008) Fall AGU #V21B-2106. [4] vanArk et al., (2007) JGR 112, doi:10.1029/2005JB004210;

  14. Rapid variations in fluid chemistry constrain hydrothermal phase separation at the Main Endeavour Field

    NASA Astrophysics Data System (ADS)

    Love, Brooke; Lilley, Marvin; Butterfield, David; Olson, Eric; Larson, Benjamin

    2017-02-01

    Previous work at the Main Endeavour Field (MEF) has shown that chloride concentration in high-temperature vent fluids has not exceeded 510 mmol/kg (94% of seawater), which is consistent with brine condensation and loss at depth, followed by upward flow of a vapor phase toward the seafloor. Magmatic and seismic events have been shown to affect fluid temperature and composition and these effects help narrow the possibilities for sub-surface processes. However, chloride-temperature data alone are insufficient to determine details of phase separation in the upflow zone. Here we use variation in chloride and gas content in a set of fluid samples collected over several days from one sulfide chimney structure in the MEF to constrain processes of mixing and phase separation. The combination of gas (primarily magmatic CO2 and seawater-derived Ar) and chloride data, indicate that neither variation in the amount of brine lost, nor mixing of the vapor phase produced at depth with variable quantities of (i) brine or (ii) altered gas rich seawater that has not undergone phase separation, can explain the co-variation of gas and chloride content. The gas-chloride data require additional phase separation of the ascending vapor-like fluid. Mixing and gas partitioning calculations show that near-critical temperature and pressure conditions can produce the fluid compositions observed at Sully vent as a vapor-liquid conjugate pair or as vapor-liquid pair with some remixing, and that the gas partition coefficients implied agree with theoretically predicted values.Plain Language SummaryWhen the chemistry of fluids from deep sea hot springs changes over a short time span, it allows us to narrow down the conditions and processes that created those fluids. This gives us a better idea what is happening under the seafloor where the water is interacting with hot rocks and minerals, boiling, and taking on the character it will have when it emerges at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.V31D0661R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.V31D0661R"><span>En Echelon <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ryan, M. P.; Carr, P. M.; Daniels, D. L.; Sutphin, D. M.</p> <p>2005-12-01</p> <p>En echelon <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> develop within the porous rocks that surround, in three-dimensions, their distinctive plan-form and cross-sectional basaltic intrusion geometry. Examples that span several (self-similar) spatial scales include the en echelon off-set area of the East Rift Zone of Kilauea Volcano, Hawaii; the Northeast Rift Zone of Mauna Loa Volcano; the intrusive-eruptive fissures of the Krafla Central Volcano, Northeast Iceland; the ensemble of the three Icelandic central volcanoes Theistarekir-Krafla-Fremrinamur; major segments of the East Pacific Rise and the Mid-Atlantic Ridge; and several paleo-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of the Mesozoic basins of eastern North America, including the Culpeper Basin. An en echelon <span class="hlt">hydrothermal</span> <span class="hlt">system</span> comprises two or more en echelon--arranged magma-filled fractures enclosed in a fluid-saturated porous matrix. Blocks of country rock between individual offset fracture segments are similarly porous and fluid-saturated. In 3-D, the <span class="hlt">system</span> resembles the fan blades of a turbine rotor, with blades (dikes) emanating from a deep "master" fracture and turning smoothly in response to the local variations in the least compressive regional stress component. The primary geometric, hydrologic and thermal attributes of the <span class="hlt">system</span> (on a horizontal plane) include dike thickness, dike-to-dike offset and overlap, the (initial) intrusion temperature, duration of magma flow, dike widths and lengths, the mean seepage velocity of regional subsurface aqueous fluid flow, and the mean flow azimuth in relationship to the plan-form geometry of the en echelon array. Finite element single phase models in horizontal cross-section have been developed for dike widths of 100 m, dike lengths of 1,500 m, overlaps of 500 m, dike-to-dike offsets of 500 m, intrusion temperatures of 1,200 C, horizontal seepage fluxes imposed at the sides of ~ 1,000 g cm-2 yr-1, and a matrix permeability of 10-14 m2. The regional flow field has been parameterized in dike</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13C0479H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13C0479H"><span>Microbial and Mineral Descriptions of the Interior Habitable Zones of Active <span class="hlt">Hydrothermal</span> Chimneys from the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holden, J. F.; Lin, T.; Ver Eecke, H. C.; Breves, E.; Dyar, M. D.; Jamieson, J. W.; Hannington, M. D.; Butterfield, D. A.; Bishop, J. L.; Lane, M. D.</p> <p>2013-12-01</p> <p> hyperthermophilic iron reducers in this sample were 1,740 and 10 cells/gram (dry weight) of material from scrapings of the outer surface and the soft, marcasite-sphalerite-rich interior region, respectively. Two hyperthermophilic iron reducers, Hyperthermus sp. Ro04 and Pyrodictium sp. Su06, were isolated from other active <span class="hlt">hydrothermal</span> chimneys on the <span class="hlt">Endeavour</span> Segment. Strain Ro04 is a neutrophilic (pHopt 7-8) heterotroph while strain Su06 is a mildly acidophilic (pHopt 5), hydrogenotrophic autotroph. Mössbauer spectroscopy of the iron oxides before and after growth demonstrated that both organisms form nanophase (<12 nm) magnetite [Fe3O4] from ferrihydrite [Fe(OH)3] with no detectable mineral intermediates. Both organisms grew optimally at 90-92°C with growth yields of 0.5-5×1012 cells/mol Fe2+ and Fe2+ production rates between 0.03-0.54 pmol Fe2+/cell/h. They produced up to 40 mM Fe2+ in a growth-dependent manner while all abiotic controls produced < 3 mM Fe2+. Electron micrographs show that the cells form aggregates with iron oxide particles during growth. Hyperthermophilic iron reducers may be common in mildly reducing, iron-rich <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> where iron oxides are formed at hyperthermophile growth temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17..300L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17..300L"><span>Linkages between mineralogy, fluid chemistry, and microbial communities within <span class="hlt">hydrothermal</span> chimneys from the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, T. J.; Ver Eecke, H. C.; Breves, E. A.; Dyar, M. D.; Jamieson, J. W.; Hannington, M. D.; Dahle, H.; Bishop, J. L.; Lane, M. D.; Butterfield, D. A.; Kelley, D. S.; Lilley, M. D.; Baross, J. A.; Holden, J. F.</p> <p>2016-02-01</p> <p>Rock and fluid samples were collected from three <span class="hlt">hydrothermal</span> chimneys at the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge to evaluate linkages among mineralogy, fluid chemistry, and microbial community composition within the chimneys. Mössbauer, midinfrared thermal emission, and visible-near infrared spectroscopies were utilized for the first time to characterize vent mineralogy, in addition to thin-section petrography, X-ray diffraction, and elemental analyses. A 282°C venting chimney from the Bastille edifice was composed primarily of sulfide minerals such as chalcopyrite, marcasite, and sphalerite. In contrast, samples from a 300°C venting chimney from the Dante edifice and a 321°C venting chimney from the Hot Harold edifice contained a high abundance of the sulfate mineral anhydrite. Geochemical modeling of mixed vent fluids suggested the oxic-anoxic transition zone was above 100°C at all three vents, and that the thermodynamic energy available for autotrophic microbial redox reactions favored aerobic sulfide and methane oxidation. As predicted, microbes within the Dante and Hot Harold chimneys were most closely related to mesophilic and thermophilic aerobes of the Betaproteobacteria and Gammaproteobacteria and sulfide-oxidizing autotrophic Epsilonproteobacteria. However, most of the microbes within the Bastille chimney were most closely related to mesophilic and thermophilic anaerobes of the Deltaproteobacteria, especially sulfate reducers, and anaerobic hyperthermophilic archaea. The predominance of anaerobes in the Bastille chimney indicated that other environmental factors promote anoxic conditions. Possibilities include the maturity or fluid flow characteristics of the chimney, abiotic Fe2+ and S2- oxidation in the vent fluids, or O2 depletion by aerobic respiration on the chimney outer wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70170389','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70170389"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> and volcano geochemistry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fournier, R.O.</p> <p>2007-01-01</p> <p>The upward intrusion of magma from deeper to shallower levels beneath volcanoes obviously plays an important role in their surface deformation. This chapter will examine less obvious roles that <span class="hlt">hydrothermal</span> processes might play in volcanic deformation. Emphasis will be placed on the effect that the transition from brittle to plastic behavior of rocks is likely to have on magma degassing and <span class="hlt">hydrothermal</span> processes, and on the likely chemical variations in brine and gas compositions that occur as a result of movement of aqueous-rich fluids from plastic into brittle rock at different depths. To a great extent, the model of <span class="hlt">hydrothermal</span> processes in sub-volcanic <span class="hlt">systems</span> that is presented here is inferential, based in part on information obtained from deep drilling for geothermal resources, and in part on the study of ore deposits that are thought to have formed in volcanic and shallow plutonic environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS43A1996H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS43A1996H"><span>Monitoring Change on <span class="hlt">Hydrothermal</span> Edifices by Photogrammetric Time Series: Case Studies from the <span class="hlt">Endeavour</span> Segment (Juan de Fuca Ridge)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heesemann, M.; Kwasnitschka, T.; Kelley, D. S.; Mihaly, S. F.</p> <p>2015-12-01</p> <p>High-resolution photogrammetric surveys derived from ROV or AUV imagery yield seafloor geometry at centimeter resolution with full color texture while modeling overhangs and crevasses, generating vastly more detailed terrain models compared to most acoustic methods. The models furthermore serve as geographic reference frames for localized studies. Repetitive surveys consequently facilitate the precise, quantitative study of edifice buildup and erosion as well as the development of the biological habitat. We compare data gathered by the Ocean Networks Canada maintenance cruises with earlier surveys at two sites (Mothra, Main <span class="hlt">Endeavour</span> Field) along the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.T31A0488D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.T31A0488D"><span>In-situ Chemistry of <span class="hlt">Hydrothermal</span> Fluids from Black Smokers in Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, K.; Seyfried, W. E.; Zhang, Z.; Foustoukos, D.; Pester, N. J.</p> <p>2005-12-01</p> <p>After an off-axis earthquake swarm in 1999, dramatic changes were observed in vent fluids of Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge. Three month latter, we also recorded this sudden variation using a high temperature in-situ chemical sensor. The results at that time indicated some of the vent temperatures as high as 374°C. This change was also characterized by relatively high in-situ pH, high dissolved H2, and H2S concentrations in the fluids that were in excess of 5, 0.7 mmol/kg and 20 mmol/kg respectively. In order to further track time dependent changes over the past 6 years, we revisited Main <span class="hlt">Endeavour</span> Field during the recent AT 11-31 cruise in Aug.~Sept. 2005. The high temperature chemical sensor was again used on selected dives with DSV Alvin to conduct in-situ measurements of pH, dissolved H2 and H2S concentrations along with temperatures. The data were obtained in a real time mode of 3 seconds per-reading from a series of measurements at high temperature conditions in the depth of 2200 m. Conventional gas-tight samples were also collected for verification and further study. In this study, Puffer, Sully and Bastille black smoker vent sites were specifically investigated owing to the high fluid temperatures that characterize these vents in comparison with other vents in the area. The measured temperatures for these vents were 362°C, 358°C, and 361°C respectively, which were generally about 20~30°C higher than the others currently in the area, but approximately 10°C lower than the highest temperatures measured in the aftermath of the 1999 seismic-magmatic event. Although the drops in vent temperatures were not substantial, the measured in-situ chemistry showed large departures from previous reported data. The in-situ pH values in these vents ranged from 4.43 to 4.89, in comparison with values above 5 in 1999. This difference may be linked directly to the decrease in temperature. The measured in-situ dissolved H2 and H2S concentrations were 0</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034150','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034150"><span><span class="hlt">Hydrothermal</span> processes above the Yellowstone magma chamber: Large <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and large <span class="hlt">hydrothermal</span> explosions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.</p> <p>2009-01-01</p> <p> and vein-fi lling; and (5) areal dimensions of many large <span class="hlt">hydrothermal</span> explosion craters in Yellowstone are similar to those of its active geyser basins and thermal areas. For Yellowstone, our knowledge of <span class="hlt">hydrothermal</span> craters and ejecta is generally limited to after the Yellowstone Plateau emerged from beneath a late Pleistocene icecap that was roughly a kilometer thick. Large <span class="hlt">hydrothermal</span> explosions may have occurred earlier as indicated by multiple episodes of cementation and brecciation commonly observed in <span class="hlt">hydrothermal</span> ejecta clasts. Critical components for large, explosive <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> include a watersaturated <span class="hlt">system</span> at or near boiling temperatures and an interconnected <span class="hlt">system</span> of well-developed joints and fractures along which <span class="hlt">hydrothermal</span> fluids flow. Active deformation of the Yellowstone caldera, active faulting and moderate local seismicity, high heat flow, rapid changes in climate, and regional stresses are factors that have strong infl uences on the type of <span class="hlt">hydrothermal</span> <span class="hlt">system</span> developed. Ascending <span class="hlt">hydrothermal</span> fluids flow along fractures that have developed in response to active caldera deformation and along edges of low-permeability rhyolitic lava flows. Alteration of the area affected, self-sealing leading to development of a caprock for the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, and dissolution of silica-rich rocks are additional factors that may constrain the distribution and development of <span class="hlt">hydrothermal</span> fields. A partial lowpermeability layer that acts as a cap to the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> may produce some over-pressurization, thought to be small in most <span class="hlt">systems</span>. Any abrupt drop in pressure initiates steam fl ashing and is rapidly transmitted through interconnected fractures that result in a series of multiple large-scale explosions contributing to the excavation of a larger explosion crater. Similarities between the size and dimensions of large <span class="hlt">hydrothermal</span> explosion craters and thermal fields in Yellowstone may indicate that catastrophic events which result in l</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4014580','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4014580"><span>Rhythms and Community Dynamics of a <span class="hlt">Hydrothermal</span> Tubeworm Assemblage at Main <span class="hlt">Endeavour</span> Field – A Multidisciplinary Deep-Sea Observatory Approach</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cuvelier, Daphne; Legendre, Pierre; Laes, Agathe; Sarradin, Pierre-Marie; Sarrazin, Jozée</p> <p>2014-01-01</p> <p>The NEPTUNE cabled observatory network hosts an ecological module called TEMPO-mini that focuses on <span class="hlt">hydrothermal</span> vent ecology and time series, granting us real-time access to data originating from the deep sea. In 2011–2012, during TEMPO-mini’s first deployment on the NEPTUNE network, the module recorded high-resolution imagery, temperature, iron (Fe) and oxygen on a <span class="hlt">hydrothermal</span> assemblage at 2186 m depth at Main <span class="hlt">Endeavour</span> Field (North East Pacific). 23 days of continuous imagery were analysed with an hourly frequency. Community dynamics were analysed in detail for Ridgeia piscesae tubeworms, Polynoidae, Pycnogonida and Buccinidae, documenting faunal variations, natural change and biotic interactions in the filmed tubeworm assemblage as well as links with the local environment. Semi-diurnal and diurnal periods were identified both in fauna and environment, revealing the influence of tidal cycles. Species interactions were described and distribution patterns were indicative of possible microhabitat preference. The importance of high-resolution frequencies (<1 h) to fully comprehend rhythms in fauna and environment was emphasised, as well as the need for the development of automated or semi-automated imagery analysis tools. PMID:24810603</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993PhDT........40G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993PhDT........40G"><span>Magmatic intrusions and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gulick, Virginia Claire</p> <p>1993-01-01</p> <p>This dissertation investigates the possible role of <span class="hlt">hydrothermally</span> driven ground-water outflow in the formation of fluvial valleys on Mars. Although these landforms have often been cited as evidence for a past warmer climate and denser atmosphere, recent theoretical modeling precludes such climatic conditions on early Mars when most fluvial valleys formed. Because fluvial valleys continued to form throughout Mars' geological history and the most Earth-like stream valleys on Mars formed well after the decline of the early putative Earth-like climate, it may be unnecessary to invoke drastically different climatic conditions for the formation of the earliest stream valleys. The morphology of most Martian fluvial valleys indicates formation by ground-water sapping which is consistent with a subsurface origin. Additionally, many Martian fluvial valleys formed on volcanoes, impact craters, near fractures, or adjacent to terrains interpreted as igneous intrusions; all are possible locales of vigorous, geologically long-lived <span class="hlt">hydrothermal</span> circulation. Comparison of Martian valley morphology to similar features on Earth constrains valley genesis scenarios. Volumes of measured Martian fluvial valleys range from 1010 to 1013 m3. Based on terrestrial analogs, total water volumes required to erode these valleys range from approximately 1010 to 1015 m3. The clustered distribution of Martian valleys within a given terrain type, the sapping dominated morphology, and the general lack of associated runoff valleys all indicate the importance of localized ground-water outflow in the formation of these fluvial <span class="hlt">systems</span>. An analytic model of a conductively cooling cylindrical intrusion is coupled with the U.S. Geological Survey's numerical ground-water computer code SUTRA to evaluate the magnitude of ground-water outflow expected from magmatically-driven <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars. Results indicate that magmatic intrusions of several 102 km3 or larger can provide sufficient ground</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0752V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0752V"><span>Seismic Structure of the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge: Correlations of Crustal Magma Chamber Properties With Seismicity, Faulting, and <span class="hlt">Hydrothermal</span> Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Ark, E. M.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J. B.; Harding, A.; Kent, G.; Nedimovic, M. R.; Wilcock, W. S.</p> <p>2003-12-01</p> <p>Multichannel seismic reflection data collected in July 2002 at the RIDGE2000 Integrated Studies Site at the <span class="hlt">Endeavour</span> segment, Juan de Fuca Ridge show a high-amplitude, mid-crustal reflector underlying all of the known <span class="hlt">hydrothermal</span> vent fields at this segment. This reflector, which has been identified with a crustal magma body [Detrick et al., 2002], is found at a two-way travel time of 0.85-1.5 s (1.9-4.0 km) below the seafloor and extends approximately 25 km along axis although it is only 1-2 km wide on the cross-axis lines. The reflector is shallowest (2.5 km depth on the along-axis line) beneath the central, elevated part of the <span class="hlt">Endeavour</span> segment and deepens toward the segment ends, with a maximum depth of 4 km. The cross axis lines show the mid-crustal reflector dipping from 9 to 50? to the east with the shallowest depths under the ridge axis and greater depths under the eastern flank of the ridge. The amplitude-offset behavior of this mid-crustal axial reflector is consistent with a negative impedance contrast, indicating the presence of melt or a crystallizing mush. We have constructed partial offset stacks at 2-3 km offset to examine the variation of melt-mush content of the axial magma chamber along axis. We see a decrease in P-wave amplitudes with increasing offset for the mid-crustal reflector beneath the Mothra and Main <span class="hlt">Endeavour</span> vent fields and between the Salty Dawg and Sasquatch vent fields, indicating the presence of a melt-rich body. Beneath the High Rise, Salty Dawg, and Sasquatch vent fields P-wave amplitudes vary little with offset suggesting the presence of a more mush-rich magma chamber. Hypocenters of well-located microseismicity in this region [Wilcock et al., 2002] have been projected onto the along-axis and cross-axis seismic lines, revealing that most axial earthquakes are concentrated in a depth range of 1.5 - 2.7 km, just above the axial magma chamber. In general, seismicity is distributed diffusely within this zone indicating thermal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23401293','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23401293"><span>Free-living bacterial communities associated with tubeworm (Ridgeia piscesae) aggregations in contrasting diffuse flow <span class="hlt">hydrothermal</span> vent habitats at the Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Forget, Nathalie L; Kim Juniper, S</p> <p>2013-04-01</p> <p>We systematically studied free-living bacterial diversity within aggregations of the vestimentiferan tubeworm Ridgeia piscesae sampled from two contrasting flow regimes (High Flow and Low Flow) in the <span class="hlt">Endeavour</span> <span class="hlt">Hydrothermal</span> Vents Marine Protected Area (MPA) on the Juan de Fuca Ridge (Northeast Pacific). Eight samples of particulate detritus were recovered from paired tubeworm grabs from four vent sites. Most sequences (454 tag and Sanger methods) were affiliated to the Epsilonproteobacteria, and the sulfur-oxidizing genus Sulfurovum was dominant in all samples. Gammaproteobacteria were also detected, mainly in Low Flow sequence libraries, and were affiliated with known methanotrophs and decomposers. The cooccurrence of sulfur reducers from the Deltaproteobacteria and the Epsilonproteobacteria suggests internal sulfur cycling within these habitats. Other phyla detected included Bacteroidetes, Actinobacteria, Chloroflexi, Firmicutes, Planctomycetes, Verrucomicrobia, and Deinococcus-Thermus. Statistically significant relationships between sequence library composition and habitat type suggest a predictable pattern for High Flow and Low Flow environments. Most sequences significantly more represented in High Flow libraries were related to sulfur and hydrogen oxidizers, while mainly heterotrophic groups were more represented in Low Flow libraries. Differences in temperature, available energy for metabolism, and stability between High Flow and Low Flow habitats potentially explain their distinct bacterial communities. © 2013 The Authors. Published by Blackwell Publishing Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633350','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633350"><span>Free-living bacterial communities associated with tubeworm (Ridgeia piscesae) aggregations in contrasting diffuse flow <span class="hlt">hydrothermal</span> vent habitats at the Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Forget, Nathalie L; Kim Juniper, S</p> <p>2013-01-01</p> <p>We systematically studied free-living bacterial diversity within aggregations of the vestimentiferan tubeworm Ridgeia piscesae sampled from two contrasting flow regimes (High Flow and Low Flow) in the <span class="hlt">Endeavour</span> <span class="hlt">Hydrothermal</span> Vents Marine Protected Area (MPA) on the Juan de Fuca Ridge (Northeast Pacific). Eight samples of particulate detritus were recovered from paired tubeworm grabs from four vent sites. Most sequences (454 tag and Sanger methods) were affiliated to the Epsilonproteobacteria, and the sulfur-oxidizing genus Sulfurovum was dominant in all samples. Gammaproteobacteria were also detected, mainly in Low Flow sequence libraries, and were affiliated with known methanotrophs and decomposers. The cooccurrence of sulfur reducers from the Deltaproteobacteria and the Epsilonproteobacteria suggests internal sulfur cycling within these habitats. Other phyla detected included Bacteroidetes, Actinobacteria, Chloroflexi, Firmicutes, Planctomycetes, Verrucomicrobia, and Deinococcus–Thermus. Statistically significant relationships between sequence library composition and habitat type suggest a predictable pattern for High Flow and Low Flow environments. Most sequences significantly more represented in High Flow libraries were related to sulfur and hydrogen oxidizers, while mainly heterotrophic groups were more represented in Low Flow libraries. Differences in temperature, available energy for metabolism, and stability between High Flow and Low Flow habitats potentially explain their distinct bacterial communities. PMID:23401293</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS41C1835Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS41C1835Y"><span>Boron isotope systematics of <span class="hlt">hydrothermal</span> fluids from submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamaoka, K.; Hong, E.; Ishikawa, T.; Gamo, T.; Kawahata, H.</p> <p>2013-12-01</p> <p>Boron is highly mobile in submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and useful to trace the process of water-rock reaction. In this study, we measured the boron content and isotopic composition of vent fluids collected from arc-backarc <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western Pacific. In sediment-starved <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> (Manus Basin, Suiyo Seamount, and Mariana Trough), the boron content and isotopic composition of vent fluids are dependent on type of host rock. The end member fluids from MORB-like basalt-hosted Vienna Woods in the Manus Basin showed low boron content and high δ11B value (0.53 mM, 29.8‰), while dacite-hosted PACMANUS and the Suiyo Seamount showed high boron contents and low δ11B values (1.45 and 1.52 mM, 13.6 and 18.5‰, respectively). The Alice Springs and Forecast Vent field in the Mariana Trough showed values intermediate between them (0.72 and 0.63 mM, 19.9 and 24.0‰, respectively), reflecting reaction of seawater and basalt influenced by slab material. In phase separated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> (North Fiji Basin), boron content and isotopic composition of vent fluids (0.44-0.56 mM, 34.5-35.9‰) were similar to those in the Vienna Woods. Considering little fractionation of boron and boron isotope during phase separation demonstrated by the previous experimental studies, it is suggested that the host rock in the North Fiji Basin is MORB-like basalt. In sediment-hosted <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (Okinawa Trough), the reaction with boron-enriched sediment following seawater-rock reaction resulted in significantly high boron contents and low δ11B values of vent fluids (4.4-5.9 mM, 1.5-2.6‰). The water-sediment ratio was estimated to be ~2. In spite of the different geological settings, the end member fuids from all vent fields are enriched in B relative to seawater (0.41 mM, 39.6‰) and the δ11B values are inversely propotional to the boron concentrations. It suggests that boron isotopic composition of vent fluid predominantly depends on the amount of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/895893','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/895893"><span>What Defines a Separate <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lawless, J.V.; Bogie, I.; Bignall, G.</p> <p>1995-01-01</p> <p>Separate <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> can be defined in a variety of ways. Criteria which have been applied include separation of heat source, upflow, economic resource and geophysical anomaly. Alternatively, connections have been defined by the effects of withdrawal of economically useful fluid and subsidence, effects of reinjection, changes in thermal features, or by a hydrological connection of groundwaters. It is proposed here that: ''A separate <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is one that is fed by a separate convective upflow of fluid, at a depth above the brittle-ductile transition for the host rocks, while acknowledging that separate <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> can be hydrologically interconnected at shallower levels''.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70111059','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70111059"><span>Dynamics of the Yellowstone <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hurwitz, Shaul; Lowenstern, Jacob B.</p> <p>2014-01-01</p> <p>The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and <span class="hlt">hydrothermal</span> explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Specific advances include more refined geophysical images of the magmatic <span class="hlt">system</span>, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of <span class="hlt">hydrothermal</span> explosions and their relation to glacial cycles, defining possible links between <span class="hlt">hydrothermal</span> activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive <span class="hlt">hydrothermal</span> activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RvGeo..52..375H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RvGeo..52..375H"><span>Dynamics of the Yellowstone <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurwitz, Shaul; Lowenstern, Jacob B.</p> <p>2014-09-01</p> <p>The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and <span class="hlt">hydrothermal</span> explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Specific advances include more refined geophysical images of the magmatic <span class="hlt">system</span>, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of <span class="hlt">hydrothermal</span> explosions and their relation to glacial cycles, defining possible links between <span class="hlt">hydrothermal</span> activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive <span class="hlt">hydrothermal</span> activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930004270','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930004270"><span>Chemical environments of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.</p> <p>1992-01-01</p> <p>Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> were involved in the origin of life has caused many investigators to focus on the eye-catching <span class="hlt">hydrothermal</span> vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature <span class="hlt">hydrothermal</span> vents to the near exclusion of the enormous underlying <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. However, in the submarine <span class="hlt">systems</span> the scale can be considerably more vast. Like Old Faithful, submarine <span class="hlt">hydrothermal</span> vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic <span class="hlt">systems</span> operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of <span class="hlt">hydrothermal</span> processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, assemble a description of the fundamental physical and chemical attributes of these <span class="hlt">systems</span>, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMOS51D..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMOS51D..02L"><span>Volatiles in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span>: Then and Now</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lilley, M. D.</p> <p>2004-12-01</p> <p>Jack Diamond was one of the principal investigators on the original proposal to dive on the Galapagos <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Jack participated on the cruise and, along with his graduate student (Richard Cobbler), made the first measurements of radon in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Louis I. Gordon and the author were also participants on this cruise and we made measurements of methane and hydrogen. In the ensuing 27 years much has been learned about volatiles in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. For example, we have learned that phase separation and water/rock reactions play major roles in the volatile composition of <span class="hlt">hydrothermal</span> fluids and that temporal variability is the rule rather than the exception. A summary of progress in this field will be given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9325H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9325H"><span><span class="hlt">Hydrothermal</span> mineralising <span class="hlt">systems</span> as critical <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hobbs, Bruce</p> <p>2015-04-01</p> <p><span class="hlt">Hydrothermal</span> mineralising <span class="hlt">systems</span> as critical <span class="hlt">systems</span>. Bruce E Hobbs1,2, Alison Ord1 and Mark A. Munro1. 1. Centre for Exploration Targeting, The University of Western Australia, M006, 35 Stirling Highway, Crawley, WA 6009, Australia. 2. CSIRO Earth and Resource Engineering, Bentley, WA, Australia <span class="hlt">Hydrothermal</span> mineralising <span class="hlt">systems</span> are presented as large, open chemical reactors held far from equilibrium during their life-time by the influx of heat, fluid and dissolved chemical species. As such they are nonlinear dynamical <span class="hlt">systems</span> and need to be analysed using the tools that have been developed for such <span class="hlt">systems</span>. <span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> undergo a number of transitions during their evolution and this paper focuses on methods for characterising these transitions in a quantitative manner and establishing whether they resemble first or second (critical) phase transitions or whether they have some other kind of nature. Critical phase transitions are characterised by long range correlations for some parameter characteristic of the <span class="hlt">system</span>, power-law probability distributions so that there is no characteristic length scale and a high sensitivity to perturbations; as one approaches criticality, characteristic parameters for the <span class="hlt">system</span> scale in a power law manner with distance from the critical point. The transitions undergone in mineralised <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are: (i) widespread, non-localised mineral alteration involving exothermic mineral reactions that produce hydrous silicate phases, carbonates and iron-oxides, (ii) strongly localised veining, brecciation and/or stock-work formation, (iii) a series of endothermic mineral reactions involving the formation of non-hydrous silicates, sulphides and metals such as gold, (iv) multiple repetitions of transitions (ii) and (iii). We have quantified aspects of these transitions in gold deposits from the Yilgarn craton of Western Australia using wavelet transforms. This technique is convenient and fast. It enables one to establish if</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7369562','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7369562"><span>Geothermal reservoirs in <span class="hlt">hydrothermal</span> convection <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sorey, M.L.</p> <p>1982-01-01</p> <p>Geothermal reservoirs commonly exist in <span class="hlt">hydrothermal</span> convection <span class="hlt">systems</span> involving fluid circulation downward in areas of recharge and upwards in areas of discharge. Because such reservoirs are not isolated from their surroundings, the nature of thermal and hydrologic connections with the rest of the <span class="hlt">system</span> may have significant effects on the natural state of the reservoir and on its response to development. Conditions observed at numerous developed and undeveloped geothermal fields are discussed with respect to a basic model of the discharge portion of an active <span class="hlt">hydrothermal</span> convection <span class="hlt">system</span>. Effects of reservoir development on surficial discharge of thermal fluid are also delineated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMOS12A..04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMOS12A..04H"><span>Parameterization of and Brine Storage in MOR <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoover, J.; Lowell, R. P.; Cummings, K. B.</p> <p>2009-12-01</p> <p>Single-pass parameterized models of high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at oceanic spreading centers use observational constraints such as vent temperature, heat output, vent field area, and the area of heat extraction from the sub-axial magma chamber to deduce fundamental <span class="hlt">hydrothermal</span> parameters such as total mass flux Q, bulk permeability k, and the thickness of the conductive boundary layer at the base of the <span class="hlt">system</span>, δ. Of the more than 300 known <span class="hlt">systems</span>, constraining data are available for less than 10%. Here we use the single pass model to estimate Q, k, and δ for all the seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> for which the constraining data are available. Mean values of Q, k, and δ are 170 kg/s, 5.0x10-13 m2, and 20 m, respectively; which is similar to results obtained from the generic model. There is no apparent correlation with spreading rate. Using observed vent field lifetimes, the rate of magma replenishment can also be calculated. Essentially all high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at oceanic spreading centers undergo phase separation, yielding a low chlorinity vapor and a high salinity brine. Some <span class="hlt">systems</span> such as the Main <span class="hlt">Endeavour</span> Field on the Juan de Fuca Ridge and the 9°50’N sites on the East Pacific Rise vent low chlorinity vapor for many years, while the high density brine remains sequestered beneath the seafloor. In an attempt to further understand the brine storage at the EPR, we used the mass flux Q determined above, time series of vent salinity and temperature, and the depth of the magma chamber to determine the rate of brine production at depth. We found thicknesses ranging from 0.32 meters to ~57 meters over a 1 km2 area from 1994-2002. These calculations suggest that brine maybe being stored within the conductive boundary layer without a need for lateral transport or removal by other means. We plan to use the numerical code FISHES to further test this idea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950057138&hterms=ketone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dketone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950057138&hterms=ketone&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dketone"><span>Thermodynamics of Strecker synthesis in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schulte, Mitchell; Shock, Everett</p> <p>1995-01-01</p> <p>Submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the early Earth may have been the sites from which life emerged. The potential for Strecker synthesis to produce biomolecules (amino and hydroxy acids) from starting compounds (ketones, aldehydes, HCN and ammonia) in such environments is evaluated quantitatively using thermodynamic data and parameters for the revised Helgeson-Kirkham-Flowers (HKF) equation of state. Although there is an overwhelming thermodynamic drive to form biomolecules by the Strecker synthesis at <span class="hlt">hydrothermal</span> conditions, the availability and concentration of starting compounds limit the efficiency and productivity of Strecker reactions. Mechanisms for concentrating reactant compounds could help overcome this problem, but other mechanisms for production of biomolecules may have been required to produce the required compounds on the early Earth. Geochemical constraints imposed by <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide important clues for determining the potential of these and other <span class="hlt">systems</span> as sites for the emergence of life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950057138&hterms=synthesis+ammonia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsynthesis%2Bammonia','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950057138&hterms=synthesis+ammonia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsynthesis%2Bammonia"><span>Thermodynamics of Strecker synthesis in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schulte, Mitchell; Shock, Everett</p> <p>1995-01-01</p> <p>Submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the early Earth may have been the sites from which life emerged. The potential for Strecker synthesis to produce biomolecules (amino and hydroxy acids) from starting compounds (ketones, aldehydes, HCN and ammonia) in such environments is evaluated quantitatively using thermodynamic data and parameters for the revised Helgeson-Kirkham-Flowers (HKF) equation of state. Although there is an overwhelming thermodynamic drive to form biomolecules by the Strecker synthesis at <span class="hlt">hydrothermal</span> conditions, the availability and concentration of starting compounds limit the efficiency and productivity of Strecker reactions. Mechanisms for concentrating reactant compounds could help overcome this problem, but other mechanisms for production of biomolecules may have been required to produce the required compounds on the early Earth. Geochemical constraints imposed by <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide important clues for determining the potential of these and other <span class="hlt">systems</span> as sites for the emergence of life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035042','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035042"><span>Peptide synthesis in early earth <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.</p> <p>2009-01-01</p> <p>We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made <span class="hlt">hydrothermal</span> reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol-1) exergonic shift. In contrast to previous <span class="hlt">hydrothermal</span> studies, we demonstrate that peptide synthesis is favored in <span class="hlt">hydrothermal</span> fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> will enhance peptide chain elongation. It is anticipated that the abundant <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7630S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7630S"><span>Numerical Modeling for Large Scale <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sohrabi, Reza; Jansen, Gunnar; Malvoisin, Benjamin; Mazzini, Adriano; Miller, Stephen A.</p> <p>2017-04-01</p> <p>Moderate-to-high enthalpy <span class="hlt">systems</span> are driven by multiphase and multicomponent processes, fluid and rock mechanics, and heat transport processes, all of which present challenges in developing realistic numerical models of the underlying physics. The objective of this work is to present an approach, and some initial results, for modeling and understanding dynamics of the birth of large scale <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Numerical modeling of such complex <span class="hlt">systems</span> must take into account a variety of coupled thermal, hydraulic, mechanical and chemical processes, which is numerically challenging. To provide first estimates of the behavior of this deep complex <span class="hlt">systems</span>, geological structures must be constrained, and the fluid dynamics, mechanics and the heat transport need to be investigated in three dimensions. Modeling these processes numerically at adequate resolution and reasonable computation times requires a suite of tools that we are developing and/or utilizing to investigate such <span class="hlt">systems</span>. Our long-term goal is to develop 3D numerical models, based on a geological models, which couples mechanics with the hydraulics and thermal processes driving <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Our first results from the Lusi <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in East Java, Indonesia provide a basis for more sophisticated studies, eventually in 3D, and we introduce a workflow necessary to achieve these objectives. Future work focuses with the aim and parallelization suitable for High Performance Computing (HPC). Such developments are necessary to achieve high-resolution simulations to more fully understand the complex dynamics of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS51B1867F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS51B1867F"><span>Characterization of Magma-Driven <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> at Oceanic Spreading Centers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farough, A.; Lowell, R. P.; Corrigan, R.</p> <p>2012-12-01</p> <p>Fluid circulation in high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> involves complex water-rock chemical reactions and phase separation. Numerical modeling of reactive transport in multi-component, multiphase <span class="hlt">systems</span> is required to obtain a full understanding of the characteristics and evolution of <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span>. We use a single-pass parameterized model of high-temperature <span class="hlt">hydrothermal</span> circulation at oceanic spreading centers constrained by observational parameters such as vent temperature, heat output, and vent field area, together with surface area and depth of the sub-axial magma chamber, to deduce fundamental <span class="hlt">hydrothermal</span> parameters such as mass flow rate, bulk permeability, conductive boundary layer thickness at the base of the <span class="hlt">system</span>, magma replenishment rate, and residence time in the discharge zone. All of these key subsurface characteristics are known for fewer than 10 sites out of 300 known <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. The principal limitations of this approach stem from the uncertainty in heat output and vent field area. For <span class="hlt">systems</span> where data are available on partitioning of heat and chemical output between focused and diffuse flow, we determined the fraction of high-temperature vent fluid incorporated into diffuse flow using a two-limb single pass model. For EPR 9°50` N and ASHES, the diffuse flow temperatures calculated assuming conservative mixing are nearly equal to the observed temperatures indicating that approximately 80%-90% of the <span class="hlt">hydrothermal</span> heat output occurs as high-temperature flow derived from magmatic heat even though most of the heat output appears as low-temperature diffuse discharge. For the Main <span class="hlt">Endeavour</span> Field and Lucky Strike, diffuse flow fluids show significant conductive cooling and heating respectively. Finally, we calculate the transport of various geochemical constituents in focused and diffuse flow at the vent field scale and compare the results with estimates of geochemical transports from the Rainbow <span class="hlt">hydrothermal</span> field where</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040089658&hterms=Nucleotide+Sequence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DNucleotide%2BSequence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040089658&hterms=Nucleotide+Sequence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DNucleotide%2BSequence"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> and the emergence of life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, E. L.</p> <p>1994-01-01</p> <p>The author reviews current thought about life originating in hyperthermophilic microorganisms. Hyperthermophiles obtain food from chemosynthesis of sulfur and have an RNA nucleotide sequence different from bacteria and eucarya. It is postulated that a hyperthermophile may be the common ancestor of all life. Current research efforts focus on the synthesis of organic compounds in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040089658&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040089658&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydrothermal"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> and the emergence of life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, E. L.</p> <p>1994-01-01</p> <p>The author reviews current thought about life originating in hyperthermophilic microorganisms. Hyperthermophiles obtain food from chemosynthesis of sulfur and have an RNA nucleotide sequence different from bacteria and eucarya. It is postulated that a hyperthermophile may be the common ancestor of all life. Current research efforts focus on the synthesis of organic compounds in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13B0463C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13B0463C"><span>Microbial Activity and Volatile Fluxes in Seafloor <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corrigan, R. S.; Lowell, R. P.</p> <p>2013-12-01</p> <p>Understanding geographically and biologically the production or utilization of volatile chemical species such as CO2, CH4, and H2 is crucial not only for understanding <span class="hlt">hydrothermal</span> processes but also for understanding life processes in the oceanic crust. To estimate the microbial effect on the transport of these volatiles, we consider a double-loop single pass model as shown in Figure 1 to estimate the mass fluxes shown. We then use a simple mixing formulation: C4Q4 = C3 (Q1 -Q3)+ C2Q2, where C2 is the concentration of the chemical in seawater, C3 is the average concentration of the chemical in high temperature focused flow, C4 is the expected concentration of the chemical as a result of mixing, and the relevant mass flows are as shown in Figure 1. Finally, we compare the calculated values of CO2, CH4, and H2 in diffuse flow fluids to those observed. The required data are available for both the Main <span class="hlt">Endeavour</span> Field on the Juan de Fuca Ridge and the East Pacific Rise 9°50' N <span class="hlt">systems</span>. In both cases we find that, although individual diffuse flow sites have observed concentrations of some elements that are greater than average, the average concentration of these volatiles is smaller in all cases than the concentration that would be expected from simple mixing. This indicates that subsurface microbes are net utilizers of these chemical constituents at the Main <span class="hlt">Endeavour</span> Field and at EPR 9°50' N on the vent field scale. Figure 1. Schematic of a 'double-loop' single-pass model above a convecting, crystallizing, replenished AMC (not to scale). Heat transfer from the vigorously convecting, cooling, and replenished AMC across the conductive boundary layer δ drives the overlying <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The deep circulation represented by mass flux Q1 and black smoker temperature T3 induces shallow circulation noted by Q2. Some black smoker fluid mixes with seawater resulting in diffuse discharge Q4, T4, while the direct black smoker mass flux with temperature T3 is reduced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JGR....9519235K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JGR....9519235K"><span>Spatial and temporal evolution of magmatic <span class="hlt">systems</span> beneath the <span class="hlt">endeavour</span> segment, Juan de Fuca Ridge: Tectonic and petrologic constraints</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karsten, Jill L.; Delaney, John R.; Rhodes, J. Michael; Liias, Raimo A.</p> <p>1990-11-01</p> <p>Major and trace element data for a suite of lavas from fifty-six dredges and ALVEN dives on the ridge axis and adjacent abyssal hills have been used to investigate the geometry and evolution of magmatic <span class="hlt">systems</span> beneath the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge. The morphology of the <span class="hlt">Endeavour</span> Segment between the northward propagating Cobb Offset and the recently formed (<0.2 m.y.) <span class="hlt">Endeavour</span> Offset is dominated by a shallow, rifted, elongate crestal volcano (<span class="hlt">Endeavour</span> Ridge) that deepens along-strike into a broad, deep basin at each offset. A set of ridges, interpreted to be previous crestal volcanoes rifted apart by spreading, flank the <span class="hlt">Endeavour</span> Ridge and chronicle the "dueling" propagator history of the Cobb Offset The tectonic evidence strongly suggests that a large portion of the <span class="hlt">Endeavour</span> Segment may be a failing rift segment at this time. Lavas from the current axis of the <span class="hlt">Endeavour</span> Segment are moderately fractionated (MgO: 6-8.5 wt %) and have generally higher SiO2, Al2O3, Na2O, and K2O, and lower FeO* man lavas from south of the Cobb Offset (SOCO lavas). Incompatible trace element abundances and ratios indicate the <span class="hlt">Endeavour</span> lavas are primarily enriched E-MORBs and T-MORBs (e.g., Zr/Nb: 7-24; Zr/Y: 2.5-5.9; and Ba/TiO2: 6-64), in contrast with the SOCO lavas, which are more depleted in character. Thus, the 30-km wide Cobb Offset appears to mark a major geochemical boundary beneath the Juan de Fuca Ridge. In contrast with the <span class="hlt">Endeavour</span> Segment axial lavas, samples from adjacent abyssal hills are more similar to the SOCO lavas in their major and trace element characteristics. These observations suggest that the parental magmas of the <span class="hlt">Endeavour</span> Segment exhibit temporal variability, with more enriched material arriving only recently beneath the ridge axis. Pronounced compositional variability is observed at small spatial scales within the <span class="hlt">Endeavour</span> Segment axial lavas, which does not correlate with axial morphology. This variability is interpreted to reflect</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010091026&hterms=sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dsulfur','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010091026&hterms=sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dsulfur"><span>The Biogeochemistry of Sulfur in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schulte, Mitchell; Rogers, K. L.; DeVincenzi, Donald L. (Technical Monitor)</p> <p>2001-01-01</p> <p>The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Understanding how sulfur became prevalent in biochemical processes and many biomolecules requires knowledge of the reaction properties of sulfur-bearing compounds. We have previously estimated thermodynamic data for thiols, the simplest organic sulfur compounds, at elevated temperatures and pressures. If life began in <span class="hlt">hydrothermal</span> environments, it is especially important to understand reactions at elevated temperatures among sulfur-bearing compounds and other organic molecules essential for the origin and persistence of life. Here we examine reactions that may have formed amino acids with thiols as reaction intermediates in hypothetical early Earth <span class="hlt">hydrothermal</span> environments. (There are two amino acids, cysteine and methionine, that contain sulfur.) Our calculations suggest that significant amounts of some amino acids were produced in early Earth <span class="hlt">hydrothermal</span> fluids, given reasonable concentrations H2, NH3, H2S and CO. For example, preliminary results indicate that glycine activities as high as 1 mmol can be reached in these <span class="hlt">systems</span> at 100 C. Alanine formation from propanethiol is also a favorable reaction. On the other hand, the calculated equilibrium log activities of cysteine and serine from propanethiol are -21 and -19, respectively, at 100 C. These results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010091026&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DSulfur','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010091026&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DSulfur"><span>The Biogeochemistry of Sulfur in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schulte, Mitchell; Rogers, K. L.; DeVincenzi, Donald L. (Technical Monitor)</p> <p>2001-01-01</p> <p>The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Understanding how sulfur became prevalent in biochemical processes and many biomolecules requires knowledge of the reaction properties of sulfur-bearing compounds. We have previously estimated thermodynamic data for thiols, the simplest organic sulfur compounds, at elevated temperatures and pressures. If life began in <span class="hlt">hydrothermal</span> environments, it is especially important to understand reactions at elevated temperatures among sulfur-bearing compounds and other organic molecules essential for the origin and persistence of life. Here we examine reactions that may have formed amino acids with thiols as reaction intermediates in hypothetical early Earth <span class="hlt">hydrothermal</span> environments. (There are two amino acids, cysteine and methionine, that contain sulfur.) Our calculations suggest that significant amounts of some amino acids were produced in early Earth <span class="hlt">hydrothermal</span> fluids, given reasonable concentrations H2, NH3, H2S and CO. For example, preliminary results indicate that glycine activities as high as 1 mmol can be reached in these <span class="hlt">systems</span> at 100 C. Alanine formation from propanethiol is also a favorable reaction. On the other hand, the calculated equilibrium log activities of cysteine and serine from propanethiol are -21 and -19, respectively, at 100 C. These results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMOS43A1993B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMOS43A1993B"><span>COVIS Detects Interconnections Between Atmospheric, Oceanic and Geologic <span class="hlt">systems</span> at a Deep Sea <span class="hlt">Hydrothermal</span> Vent</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bemis, K. G.; Xu, G.; Lee, R.</p> <p>2015-12-01</p> <p>COVIS (Cabled Observatory Vent Imaging Sonar) is an innovative sonar <span class="hlt">system</span> designed to quantitatively monitor focused and diffuse flows from deep-sea <span class="hlt">hydrothermal</span> vent clusters. From 9/2010 to 9/2015, COVIS was connected to the NEPTUNE observatory at Grotto vent in the Main <span class="hlt">Endeavour</span> Field, JdFR. COVIS monitored plumes and diffuse discharge by transmitting high-frequency (200-400 kHz), pulsed acoustic waves and recording the backscattered signals to yield time series of plume heat and volume transports, plume bending, and diffuse flow area. Temporal variations indicate the rate of <span class="hlt">hydrothermal</span> plume mixing with the ambient seawater increases with the magnitude of ocean currents. Such current-driven entrainment links the dynamics of a deep-sea <span class="hlt">hydrothermal</span> plume with oceanic and atmospheric processes. We estimate the direction and relative amplitude of the local bottom currents from the bending angles of the plumes. A comparison with currents from an ADCP (~80 m south of Grotto) reveals significant complexity in the mean bottom flow structure within a <span class="hlt">hydrothermal</span> vent field. Diffuse flow area, temperature, and faunal densities vary periodically reflecting some combination of tidal pressure and current interactions. The heat transport time series suggests the heat source driving the plume remained relatively steady for 41 months. Local seismic data reveals that increased heat transport in 2000 followed seismic events in 1999 and 2000 and the steady heat flux from 10/2011 to 2/2015 coincided with quiescent seismicity. Such a correlation points to the close linkage of a seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span> with geological processes. These findings demonstrate the intimate interconnections of seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with processes spanning the Earth's interior to the sea surface. Further, they (and the time-series acquired by COVIS) testify to the effectiveness and robustness of employing an acoustic-imaging sonar for long-term monitoring of a seafloor <span class="hlt">hydrothermal</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18163874','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18163874"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> in small ocean planets.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vance, Steve; Harnmeijer, Jelte; Kimura, Jun; Hussmann, Hauke; Demartin, Brian; Brown, J Michael</p> <p>2007-12-01</p> <p>We examine means for driving <span class="hlt">hydrothermal</span> activity in extraterrestrial oceans on planets and satellites of less than one Earth mass, with implications for sustaining a low level of biological activity over geological timescales. Assuming ocean planets have olivine-dominated lithospheres, a model for cooling-induced thermal cracking shows how variation in planet size and internal thermal energy may drive variation in the dominant type of <span class="hlt">hydrothermal</span> <span class="hlt">system</span>-for example, high or low temperature <span class="hlt">system</span> or chemically driven <span class="hlt">system</span>. As radiogenic heating diminishes over time, progressive exposure of new rock continues to the current epoch. Where fluid-rock interactions propagate slowly into a deep brittle layer, thermal energy from serpentinization may be the primary cause of <span class="hlt">hydrothermal</span> activity in small ocean planets. We show that the time-varying hydrostatic head of a tidally forced ice shell may drive <span class="hlt">hydrothermal</span> fluid flow through the seafloor, which can generate moderate but potentially important heat through viscous interaction with the matrix of porous seafloor rock. Considering all presently known potential ocean planets-Mars, a number of icy satellites, Pluto, and other trans-neptunian objects-and applying Earth-like material properties and cooling rates, we find depths of circulation are more than an order of magnitude greater than in Earth. In Europa and Enceladus, tidal flexing may drive <span class="hlt">hydrothermal</span> circulation and, in Europa, may generate heat on the same order as present-day radiogenic heat flux at Earth's surface. In all objects, progressive serpentinization generates heat on a globally averaged basis at a fraction of a percent of present-day radiogenic heating and hydrogen is produced at rates between 10(9) and 10(10) molecules cm(2) s(1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812226T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812226T"><span>Anhydrite precipitation in seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Theissen-Krah, Sonja; Rüpke, Lars H.</p> <p>2016-04-01</p> <p>The composition and metal concentration of <span class="hlt">hydrothermal</span> fluids venting at the seafloor is strongly temperature-dependent and fluids above 300°C are required to transport metals to the seafloor (Hannington et al. 2010). Ore-forming <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and high temperature vents in general are often associated with faults and fracture zones, i.e. zones of enhanced permeabilities that act as channels for the uprising <span class="hlt">hydrothermal</span> fluid (Heinrich & Candela, 2014). Previous numerical models (Jupp and Schultz, 2000; Andersen et al. 2015) however have shown that high permeabilities tend to decrease fluid flow temperatures due to mixing with cold seawater and the resulting high fluid fluxes that lead to short residence times of the fluid near the heat source. A possible mechanism to reduce the permeability and thereby to focus high temperature fluid flow are mineral precipitation reactions that clog the pore space. Anhydrite for example precipitates from seawater if it is heated to temperatures above ~150°C or due to mixing of seawater with <span class="hlt">hydrothermal</span> fluids that usually have high Calcium concentrations. We have implemented anhydrite reactions (precipitation and dissolution) in our finite element numerical models of <span class="hlt">hydrothermal</span> circulation. The initial results show that the precipitation of anhydrite efficiently alters the permeability field, which affects the <span class="hlt">hydrothermal</span> flow field as well as the resulting vent temperatures. C. Andersen et al. (2015), Fault geometry and permeability contrast control vent temperatures at the Logatchev 1 <span class="hlt">hydrothermal</span> field, Mid-Atlantic Ridge, Geology, 43(1), 51-54. M. D. Hannington et al. (2010), Modern Sea-Floor Massive Sulfides and Base Metal Resources: Toward an Estimate of Global Sea-Floor Massive Sulfide Potential, in The Challenge of Finding New Mineral Resources: Global Metallogeny, Innovative Exploration, and New Discoveries, edited by R. J. Goldfarb, E. E. Marsh and T. Monecke, pp. 317-338, Society of Economic Geologists</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s130e012456.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s130e012456.html"><span><span class="hlt">Endeavour</span> Payload Bay</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-20</p> <p>S130-E-012456 (20 Feb. 2010) --- Backdropped by a blue and white part of Earth, a partial view of space shuttle <span class="hlt">Endeavour</span>'s payload bay, vertical stabilizer, orbital maneuvering <span class="hlt">system</span> (OMS) pods and docking mechanism are featured in this image photographed by an STS-130 crew member from an aft flight deck window.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3864048','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3864048"><span>Fungal colonization of an Ordovician impact-induced <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan</p> <p>2013-01-01</p> <p>Impacts are common geologic features on the terrestrial planets throughout the solar <span class="hlt">system</span>, and on at least Earth and Mars impacts have induced <span class="hlt">hydrothermal</span> convection. Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> have been suggested to possess the same life supporting capability as <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown <span class="hlt">hydrothermal</span> minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the <span class="hlt">hydrothermal</span> activity and migration of hydrocarbons in the <span class="hlt">system</span>. Our results from the Lockne impact structure show that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with impact structures can support colonization by microbial life. PMID:24336641</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24336641','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24336641"><span>Fungal colonization of an Ordovician impact-induced <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan</p> <p>2013-12-16</p> <p>Impacts are common geologic features on the terrestrial planets throughout the solar <span class="hlt">system</span>, and on at least Earth and Mars impacts have induced <span class="hlt">hydrothermal</span> convection. Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> have been suggested to possess the same life supporting capability as <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown <span class="hlt">hydrothermal</span> minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the <span class="hlt">hydrothermal</span> activity and migration of hydrocarbons in the <span class="hlt">system</span>. Our results from the Lockne impact structure show that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with impact structures can support colonization by microbial life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NatSR...3E3487I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NatSR...3E3487I"><span>Fungal colonization of an Ordovician impact-induced <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan</p> <p>2013-12-01</p> <p>Impacts are common geologic features on the terrestrial planets throughout the solar <span class="hlt">system</span>, and on at least Earth and Mars impacts have induced <span class="hlt">hydrothermal</span> convection. Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> have been suggested to possess the same life supporting capability as <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown <span class="hlt">hydrothermal</span> minerals from the 458 Ma Lockne impact structure, Sweden. Based on morphological characteristics the fossilized microorganisms are interpreted as fungi. We further infer the kerogenization of the microfossils, and thus the life span of the fungi, to be contemporaneous with the <span class="hlt">hydrothermal</span> activity and migration of hydrocarbons in the <span class="hlt">system</span>. Our results from the Lockne impact structure show that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with impact structures can support colonization by microbial life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034244','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034244"><span>Numerical simulation of magmatic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ingebritsen, S.E.; Geiger, S.; Hurwitz, S.; Driesner, T.</p> <p>2010-01-01</p> <p>The dynamic behavior of magmatic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> entails coupled and nonlinear multiphase flow, heat and solute transport, and deformation in highly heterogeneous media. Thus, quantitative analysis of these <span class="hlt">systems</span> depends mainly on numerical solution of coupled partial differential equations and complementary equations of state (EOS). The past 2 decades have seen steady growth of computational power and the development of numerical models that have eliminated or minimized the need for various simplifying assumptions. Considerable heuristic insight has been gained from process-oriented numerical modeling. Recent modeling efforts employing relatively complete EOS and accurate transport calculations have revealed dynamic behavior that was damped by linearized, less accurate models, including fluid property control of <span class="hlt">hydrothermal</span> plume temperatures and three-dimensional geometries. Other recent modeling results have further elucidated the controlling role of permeability structure and revealed the potential for significant <span class="hlt">hydrothermally</span> driven deformation. Key areas for future reSearch include incorporation of accurate EOS for the complete H2O-NaCl-CO2 <span class="hlt">system</span>, more realistic treatment of material heterogeneity in space and time, realistic description of large-scale relative permeability behavior, and intercode benchmarking comparisons. Copyright 2010 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA11837&hterms=annotations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dannotations','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA11837&hterms=annotations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dannotations"><span><span class="hlt">Endeavour</span> Crater in Context</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2009-01-01</p> <p><p/> [figure removed for brevity, see original site] <p/> The largest crater in this mosaic of images taken by the Context Camera on NASA's Mars Reconnaissance Orbiter is <span class="hlt">Endeavour</span> Crater, which is 22 kilometers (14 miles) in diameter. <p/> The team operating NASA's Mars Exploration Rover Opportunity in the Meridiani Planum region of Mars chose to drive the rover toward <span class="hlt">Endeavour</span> after Opportunity ascended out of smaller Victoria Crater in August 2008. <p/> Opportunity caught its first glimpse of <span class="hlt">Endeavour</span>'s rim on March 7, 2008, during the 1,820th Martian day, or sol, of the rover's mission on Mars. The rover was about 12 kilometers (7 miles) from the closest point of the crater. <p/> Annotations on Figure 1 show vectors from Opportunity's position on that date toward the portions of the rim seen in images that Opportunity's panoramic camera (Pancam) took from the Sol 1820 location. In addition to three portions of <span class="hlt">Endeavour</span>'s rim, the rim of a smaller, more distant crater, Iazu, appears faintly on the horizon in the Pancam images. <p/> NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space <span class="hlt">Systems</span>, Denver, is the prime contractor for the project and built the spacecraft. Malin Space Science <span class="hlt">Systems</span>, San Diego, provided and operates the Context Camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040173290&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040173290&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal"><span>Stable light isotope biogeochemistry of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Des Marais, D. J.</p> <p>1996-01-01</p> <p>The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. <span class="hlt">Hydrothermal</span> alteration of the 18O/16O and D/H values of minerals can be used to detect fossil <span class="hlt">systems</span> and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of <span class="hlt">hydrothermal</span> fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at <span class="hlt">hydrothermal</span> temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9243011','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9243011"><span>Stable light isotope biogeochemistry of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Des Marais, D J</p> <p>1996-01-01</p> <p>The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. <span class="hlt">Hydrothermal</span> alteration of the 18O/16O and D/H values of minerals can be used to detect fossil <span class="hlt">systems</span> and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of <span class="hlt">hydrothermal</span> fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at <span class="hlt">hydrothermal</span> temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6314D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6314D"><span>Modelling magmatic gas scrubbing in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Di Napoli, Rossella; Aiuppa, Alessandro; Valenza, Mariano; Bergsson, Baldur; Ilyinskaya, Evgenia; Pfeffer, Melissa Anne; Rakel Guðjónsdóttir, Sylvía</p> <p>2015-04-01</p> <p>In volcano-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, the chemistry of deeply rising magmatic gases is extensively modified by gas-water-rock interactions taking place within the <span class="hlt">hydrothermal</span> reservoir, and/or at shallow groundwaters conditions. These reactions can scrub reactive, water-soluble species (S, halogens) from the magmatic gas phase, so that their quantitative assessment is central to understanding the chemistry of surface gas manifestations, and brings profound implications to the interpretation of volcanic-<span class="hlt">hydrothermal</span> unrests. Here, we present the results of numerical simulations of magmatic gas scrubbing, in which the reaction path modelling approach (Helgeson, 1968) is used to reproduce <span class="hlt">hydrothermal</span> gas-water-rock interactions at both shallow (temperature up to 109°C; low-T model runs) and deep reservoir (temperature range: 150-250 °C; high-T model runs) conditions. The model was built based upon the EQ3/6 software package (Wolery and Daveler, 1992), and consisted into a step by step addition of a high-temperature magmatic gas to an initial meteoric water, in the presence of a dissolving aquifer rock. The model outputted, at each step of gas addition, the chemical composition of a new aqueous solution formed after gas-water-rock interactions; which, upon reaching gas over-pressuring (PgasTOT > Psat(H2O) at run T), is degassed (by single-step degassing) to separate a scrubbed gas phase. As an application of the model results, the model compositions of the separated gases are finally compared with compositions of natural gas emissions from Hekla volcano (T< 100°C) and from Krisuvik geothermal <span class="hlt">system</span> (T> 100°C), resulting into an excellent agreement. The compositions of the model solutions are also in fair agreement with compositions of natural thermal water samples. We conclude that our EQ3/6-based reaction path simulations offer a realistic representation of gas-water-rock interaction processes occurring underneath active magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H33B0803T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H33B0803T"><span>Porosity evolution in Icelandic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thien, B.; Kosakowski, G.; Kulik, D. A.</p> <p>2014-12-01</p> <p>Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal <span class="hlt">systems</span>, grant number CRSII2_141843/1) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal <span class="hlt">systems</span>. These are typically high enthalphy <span class="hlt">systems</span> where a magmatic pluton is located at a few kilometers depth. These shallow plutons increase the geothermal gradient and trigger the circulation of <span class="hlt">hydrothermal</span> waters with a steam cap forming at shallow depth. Field observations suggest that active and fossil Icelandic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are built from a superposition of completely altered and completely unaltered layers. With help of 1D and 2D reactive transport models (OpenGeoSys-GEM code), we investigate the reasons for this finding, by studying the mineralogical evolution of protoliths with different initial porosities at different temperatures and pressures, different leaching water composition and gas content, and different porosity geometries (i.e. porous medium versus fractured medium). From this study, we believe that the initial porosity of protoliths and volume changes due to their transformation into secondary minerals are key factors to explain the different alteration extents observed in field studies. We also discuss how precipitation and dissolution kinetics can influence the alteration time scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014633','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014633"><span>CONCEPTUAL MODELS FOR THE LASSEN <span class="hlt">HYDROTHERMAL</span> <span class="hlt">SYSTEM</span>.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ingebritsen, S.E.; Sorey, M.L.</p> <p>1987-01-01</p> <p>The Lassen <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, like a number of other <span class="hlt">systems</span> in regions of moderate to great topographic relief, includes steam-heated features at higher elevations and high-chloride springs at lower elevations, connected to and fed by a single circulation <span class="hlt">system</span> at depth. Two conceptual models for such <span class="hlt">systems</span> are presented. They are similar in several ways: however, there are basic differences in terms of the nature and extent of vapor-dominated conditions beneath the steam-heated features. For some Lassen-like <span class="hlt">systems</span>, these differences could have environmental and economic implications. Available data do not make it possible to establish a single preferred model for the Lassen <span class="hlt">system</span>, and the actual <span class="hlt">system</span> is complex enough that both models may apply to different parts of the <span class="hlt">system</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B13A0213S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B13A0213S"><span>Abiotic Organic Chemistry in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simoneit, B. R.; Rushdi, A. I.</p> <p>2004-12-01</p> <p>Abiotic organic chemistry in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is of interest to biologists, geochemists and oceanographers. This chemistry consists of thermal alteration of organic matter and minor prebiotic synthesis of organic compounds. Thermal alteration has been extensively documented to yield petroleum and heavy bitumen products from contemporary organic detritus. Carbon dioxide, carbon monoxide, ammonia and sulfur species have been used as precursors in prebiotic synthesis experiments to organic compounds. These inorganic species are common components of hot spring gases and marine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. It is of interest to further test their reactivities in reductive aqueous thermolysis. We have synthesized organic compounds (lipids) in aqueous solutions of oxalic acid, and with carbon disulfide or ammonium bicarbonate at temperatures from 175-400° C. The synthetic lipids from oxalic acid solutions consisted of n-alkanols, n-alkanoic acids, n-alkyl formates, n-alkanones, n-alkenes and n-alkanes, typically to C30 with no carbon number preferences. The products from CS2 in acidic aqueous solutions yielded cyclic thioalkanes, alkyl polysulfides, and thioesters with other numerous minor compounds. The synthesis products from oxalic acid and ammonium bicarbonate solutions were homologous series of n-alkyl amides, n-alkyl amines, n-alkanes and n-alkanoic acids, also to C30 with no carbon number predominance. Condensation (dehydration) reactions also occur under elevated temperatures in aqueous medium as tested by model reactions to form amide, ester and nitrile bonds. It is concluded that the abiotic formation of aliphatic lipids, condensation products (amides, esters, nitriles, and CS2 derivatives (alkyl polysulfides, cyclic polysulfides) is possible under <span class="hlt">hydrothermal</span> conditions and warrants further studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..4312027P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..4312027P"><span>Geophysical imaging of shallow degassing in a Yellowstone <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pasquet, S.; Holbrook, W. S.; Carr, B. J.; Sims, K. W. W.</p> <p>2016-12-01</p> <p>The Yellowstone Plateau Volcanic Field, which hosts over 10,000 thermal features, is the world's largest active continental <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, yet very little is known about the shallow "plumbing" <span class="hlt">system</span> connecting <span class="hlt">hydrothermal</span> reservoirs to surface features. Here we present the results of geophysical investigations of shallow <span class="hlt">hydrothermal</span> degassing in Yellowstone. We measured electrical resistivity, compressional-wave velocity from refraction data, and shear wave velocity from surface-wave analysis to image shallow <span class="hlt">hydrothermal</span> degassing to depths of 15-30 m. We find that resistivity helps identify fluid pathways and that Poisson's ratio shows good sensitivity to saturation variations, highlighting gas-saturated areas and the local water table. Porosity and saturation predicted from rock physics modeling provide critical insight to estimate the fluid phase separation depth and understand the structure of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Finally, our results show that Poisson's ratio can effectively discriminate gas- from water-saturated zones in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1817495B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1817495B"><span>Entropy Production in Convective <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boersing, Nele; Wellmann, Florian; Niederau, Jan</p> <p>2016-04-01</p> <p>Exploring <span class="hlt">hydrothermal</span> reservoirs requires reliable estimates of subsurface temperatures to delineate favorable locations of boreholes. It is therefore of fundamental and practical importance to understand the thermodynamic behavior of the <span class="hlt">system</span> in order to predict its performance with numerical studies. To this end, the thermodynamic measure of entropy production is considered as a useful abstraction tool to characterize the convective state of a <span class="hlt">system</span> since it accounts for dissipative heat processes and gives insight into the <span class="hlt">system</span>'s average behavior in a statistical sense. Solving the underlying conservation principles of a convective <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is sensitive to initial conditions and boundary conditions which in turn are prone to uncertain knowledge in subsurface parameters. There exist multiple numerical solutions to the mathematical description of a convective <span class="hlt">system</span> and the prediction becomes even more challenging as the vigor of convection increases. Thus, the variety of possible modes contained in such highly non-linear problems needs to be quantified. A synthetic study is carried out to simulate fluid flow and heat transfer in a finite porous layer heated from below. Various two-dimensional models are created such that their corresponding Rayleigh numbers lie in a range from the sub-critical linear to the supercritical non-linear regime, that is purely conductive to convection-dominated <span class="hlt">systems</span>. Entropy production is found to describe the transient evolution of convective processes fairly well and can be used to identify thermodynamic equilibrium. Additionally, varying the aspect ratio for each Rayleigh number shows that the variety of realized convection modes increases with both larger aspect ratio and higher Rayleigh number. This phenomenon is also reflected by an enlarged spread of entropy production for the realized modes. Consequently, the Rayleigh number can be correlated to the magnitude of entropy production. In cases of moderate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70023395','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70023395"><span>Stable isotopes in seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: Vent fluids, <span class="hlt">hydrothermal</span> deposits, <span class="hlt">hydrothermal</span> alteration, and microbial processes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shanks, Wayne C.</p> <p>2001-01-01</p> <p>The recognition of abundant and widespread <span class="hlt">hydrothermal</span> activity and associated unique life-forms on the ocean floor is one of the great scientific discoveries of the latter half of the twentieth century. Studies of seafloor <span class="hlt">hydrothermal</span> processes have led to revolutions in understanding fluid convection and the cooling of the ocean crust, the chemical and isotopic mass balance of the oceans, the origin of stratiform and statabound massive-sulfide ore-deposits, the origin of greenstones and serpentinites, and the potential importance of the subseafloor biosphere. Stable isotope geochemistry has been a critical and definitive tool from the very beginning of the modern era of seafloor exploration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1390221','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1390221"><span>Combined <span class="hlt">hydrothermal</span> liquefaction and catalytic <span class="hlt">hydrothermal</span> gasification <span class="hlt">system</span> and process for conversion of biomass feedstocks</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.</p> <p>2017-09-12</p> <p>A combined <span class="hlt">hydrothermal</span> liquefaction (HTL) and catalytic <span class="hlt">hydrothermal</span> gasification (CHG) <span class="hlt">system</span> and process are described that convert various biomass-containing sources into separable bio-oils and aqueous effluents that contain residual organics. Bio-oils may be converted to useful bio-based fuels and other chemical feedstocks. Residual organics in HTL aqueous effluents may be gasified and converted into medium-BTU product gases and directly used for process heating or to provide energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9243009','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9243009"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> as environments for the emergence of life.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shock, E L</p> <p>1996-01-01</p> <p>Analysis of the chemical disequilibrium provided by the mixing of <span class="hlt">hydrothermal</span> fluids and seawater in present-day <span class="hlt">systems</span> indicates that organic synthesis from CO2 or carbonic acid is thermodynamically favoured in the conditions in which hyperthermophilic microorganisms are known to live. These organisms lower the Gibbs free energy of the chemical mixture by synthesizing many of the components of their cells. Primary productivity is enormous in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> because it depends only on catalysis of thermodynamically favourable, exergonic reactions. It follows that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may be the most favourable environments for life on Earth. This fact makes <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> logical candidates for the location of the emergence of life, a speculation that is supported by genetic evidence that modern hyperthermophilic organisms are closer to a common ancestor than any other forms of life. The presence of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the early Earth would correspond to the presence of liquid water. Evidence that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> existed early in the history of Mars raises the possibility that life may have emerged on Mars as well. Redox reactions between water and rock establish the potential for organic synthesis in and around <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Therefore, the single most important parameter for modelling the geochemical emergence of life on the early Earth or Mars is the composition of the rock which hosts the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040173291&hterms=Emergence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEmergence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040173291&hterms=Emergence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEmergence"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> as environments for the emergence of life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, E. L.</p> <p>1996-01-01</p> <p>Analysis of the chemical disequilibrium provided by the mixing of <span class="hlt">hydrothermal</span> fluids and seawater in present-day <span class="hlt">systems</span> indicates that organic synthesis from CO2 or carbonic acid is thermodynamically favoured in the conditions in which hyperthermophilic microorganisms are known to live. These organisms lower the Gibbs free energy of the chemical mixture by synthesizing many of the components of their cells. Primary productivity is enormous in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> because it depends only on catalysis of thermodynamically favourable, exergonic reactions. It follows that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may be the most favourable environments for life on Earth. This fact makes <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> logical candidates for the location of the emergence of life, a speculation that is supported by genetic evidence that modern hyperthermophilic organisms are closer to a common ancestor than any other forms of life. The presence of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the early Earth would correspond to the presence of liquid water. Evidence that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> existed early in the history of Mars raises the possibility that life may have emerged on Mars as well. Redox reactions between water and rock establish the potential for organic synthesis in and around <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Therefore, the single most important parameter for modelling the geochemical emergence of life on the early Earth or Mars is the composition of the rock which hosts the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040173291&hterms=Disequilibrium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DDisequilibrium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040173291&hterms=Disequilibrium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DDisequilibrium"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> as environments for the emergence of life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, E. L.</p> <p>1996-01-01</p> <p>Analysis of the chemical disequilibrium provided by the mixing of <span class="hlt">hydrothermal</span> fluids and seawater in present-day <span class="hlt">systems</span> indicates that organic synthesis from CO2 or carbonic acid is thermodynamically favoured in the conditions in which hyperthermophilic microorganisms are known to live. These organisms lower the Gibbs free energy of the chemical mixture by synthesizing many of the components of their cells. Primary productivity is enormous in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> because it depends only on catalysis of thermodynamically favourable, exergonic reactions. It follows that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may be the most favourable environments for life on Earth. This fact makes <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> logical candidates for the location of the emergence of life, a speculation that is supported by genetic evidence that modern hyperthermophilic organisms are closer to a common ancestor than any other forms of life. The presence of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the early Earth would correspond to the presence of liquid water. Evidence that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> existed early in the history of Mars raises the possibility that life may have emerged on Mars as well. Redox reactions between water and rock establish the potential for organic synthesis in and around <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Therefore, the single most important parameter for modelling the geochemical emergence of life on the early Earth or Mars is the composition of the rock which hosts the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5752591','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5752591"><span>Methane and radioactive isotopes in submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, K.R.</p> <p>1983-01-01</p> <p>This thesis consists of two parts: 1) methane and 2) radioactive isotopes, especially radon, in submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Both parts deal with the use of these gases as tracers for mapping <span class="hlt">hydrothermal</span> vents at sea, and with their relationships to other sensitive tracers such as helium, manganese, and temperature. <span class="hlt">Hydrothermal</span> methane was used as a real-time tracer for locating new submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> along spreading axes, discovering new <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at two locations in Pacific Ocean: 1) 20/sup 0/S on East Pacific Rise, and 2) Mariana Trough Back-arc Basin. Methane shows good correlations with helium-3 and temperature with similar ratios in various <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, 3 to 42 x 10/sup 6/ for the methane to helium-3 ratio, and 3 to 19 ..mu.. cc/kg/sup 0/C for the methane to temperature anomaly. These similar ratios from different areas provide evidence for chemical homogeneity of submarine <span class="hlt">hydrothermal</span> waters. A good correlation between methane and manganese appears to be associated only with high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Radioisotopes in the vent waters of 21/sup 0/N high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">system</span> have end-member concentrations of 7.5 to 40 dpm/kg for Ra-226, 360 dpm/kg for Rn 222, 62 dpm/kg for Pb-210, and 19 dpm/kg for Po-210. The radon activity for this <span class="hlt">system</span> is one order of magnitude lower, and the Pb-210 activity is one order or magnitude higher, than those a the low temperature Galapagos <span class="hlt">system</span>. All these observations suggest that the high radon, and low Pb-210 activity observed in Galapagos <span class="hlt">system</span> may originate from the extensive subsurface mixing and water-rock interaction in this <span class="hlt">system</span> (direct injection of radon and scavenging of Pb-210).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V14C..03T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V14C..03T"><span>Overview of Results from the <span class="hlt">Endeavour</span> Seismic Tomography Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toomey, D. R.; Hooft, E. E.; Wilcock, W. S.; Weekly, R. T.; Wells, A. E.; Soule, D. C.</p> <p>2011-12-01</p> <p>We report on our continuing analyses of a multi-scale seismic tomography experiment of the <span class="hlt">Endeavour</span> segment of the Juan de Fuca Ridge. In August 2009 we deployed 68 four-component ocean bottom seismometers (OBSs) at 64 sites throughout a 90x50 km2 area to record seismic energy from 5567 shots of the 36-element, 6600 in.3 airgun array of the R/V Marcus G. Langseth. The experimental geometry utilized 3 nested scales and was designed to image (1) crustal thickness variations within 25 km of the axial high (0 to 900 kyr); (2) the map view heterogeneity and anisotropy of the topmost mantle beneath the spreading axis; (3) the three-dimensional structure of the crustal magmatic <span class="hlt">system</span> and (4) the detailed three-dimensional, shallow crustal thermal structure beneath the <span class="hlt">Endeavour</span> vent fields. The 90-km-long <span class="hlt">Endeavour</span> segment lies between the Cobb and <span class="hlt">Endeavour</span> overlapping spreading centers (OSCs), which are converging and thus shortening the <span class="hlt">Endeavour</span> segment. Previous seismic reflection studies indicate that the central <span class="hlt">Endeavour</span> segment is on a 40-km-wide plateau of greater crustal thickness that is interpreted to have developed when the ridge overrode the mantle melt anomaly associated with the Heckle seamount chain. The central <span class="hlt">Endeavour</span> is also underlain by an axial magma chamber (AMC) reflector that is shallowest and most prominent beneath the <span class="hlt">hydrothermal</span> fields. Geophysical studies of <span class="hlt">Endeavour</span> thus permit investigation of the competing effects of tectonic, magmatic and <span class="hlt">hydrothermal</span> processes on crustal structure and architecture. Ongoing analyses include tomographic inversion of first-arriving P waves that sample the upper- and mid-crustal regions, characterization of off-axis magma bodies via travel time and amplitude anomalies of crustal phases, estimation of regional-scale crustal thickness variations from analysis of PmP arrivals and imaging of mantle structure using Pn to constrain mantle flow and melt distribution [Weekly et al.; Wells et al.; Soule et al</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930034008&hterms=Submarines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DSubmarines','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930034008&hterms=Submarines&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DSubmarines"><span>Chemical environments of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. [supporting abiogenetic theory</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.</p> <p>1992-01-01</p> <p>The paper synthesizes diverse information about the inorganic geochemistry of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, provides a description of the fundamental physical and chemical properties of these <span class="hlt">systems</span>, and examines the implications of high-temperature, fluid-driven processes for organic synthesis. Emphasis is on a few general features, i.e., pressure, temperature, oxidation states, fluid composition, and mineral alteration, because these features will control whether organic synthesis can occur in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930034008&hterms=alteration+hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dalteration%2Bhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930034008&hterms=alteration+hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dalteration%2Bhydrothermal"><span>Chemical environments of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. [supporting abiogenetic theory</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.</p> <p>1992-01-01</p> <p>The paper synthesizes diverse information about the inorganic geochemistry of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, provides a description of the fundamental physical and chemical properties of these <span class="hlt">systems</span>, and examines the implications of high-temperature, fluid-driven processes for organic synthesis. Emphasis is on a few general features, i.e., pressure, temperature, oxidation states, fluid composition, and mineral alteration, because these features will control whether organic synthesis can occur in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.T31A0483G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.T31A0483G"><span><span class="hlt">Endeavour</span> basalt geology and petrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gill, J. B.; Stakes, J.; Ramos, F.; Michael, P.; Stakes, D.</p> <p>2005-12-01</p> <p>We report major and trace element and isotope data from 250 basalt samples recently collected by submersible from the axial valley and flanks of the <span class="hlt">Endeavour</span> segment of the Juan de Fuca Ridge. Off-axis volcanism is abundant on both flanks which are mirror images of one another geologically. Axial valley walls up to 1 km off axis appear to be steps of in tact but variably fractured sheet, lobate, and hackly lava flows similar to the youngest lavas seen in collapse features in the axis. Coverage by pillow terrane increases with distance off axis and coverage becomes complete after 1 km. The similarity of the two flanks suggests that the currently asymmetric axial magma chamber (van Ark et al., 2004) may be shorter-lived than the off-axis volcanism. MgO contents range from 6.0-8.5% and generally are lower on the flanks consistent with consistently cooler chamber edges there. La/Yb ratios vary 3-fold within 100 m in the axial valley, with normalized La/Sm = 0.8-2.5 in contrast to constant Sr and Nd isotopes. However, Th/U and 230Th/232Th ratios vary only slightly in the axial valley, which may enable dating of off-axis samples. H2O/Ce is less than 170, typical of values throughout much of the Pacific. Variations in depth and degree of melting, and in source composition, are implied. At times, these heterogeneities escaped homogenization in axial magma chambers. Cl concentrations and Cl/K ratios are surprisingly low considering the active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in close proximity and the potential for brine incorporation into the magma chamber.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010LPICo1538.5134A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010LPICo1538.5134A"><span>Geochemical Energy for Life in Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amend, J. P.; McCollom, T. M.; Hentscher, M.; Bach, W.</p> <p>2010-04-01</p> <p>Thermodynamic calculations show that the energetics of both catabolic and anabolic reactions are vastly different in peridotite- and troctolite-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> compared with their basalt- and felsic rock-hosted counterparts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020046438&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020046438&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dhydrothermal"><span>Impact-induced <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> and Mineral Deposition on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thorsos, I. E.; Newsom, H. E.; Davies, A. G.</p> <p>2002-01-01</p> <p>Modeling of <span class="hlt">hydrothermal</span> circulation at impact craters on Mars to determine <span class="hlt">system</span> duration and potential mineral deposition in the context of Mars exploration. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300006HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300006HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>Chief Executive Officer of the Planetary Society, Bill Nye "The Science Guy", acts as emcee from a podium underneath the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300009HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300009HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>The space shuttle <span class="hlt">Endeavour</span> is seen as workers prepare for the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300015HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300015HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>A space shuttle main engine (SSME) is on display near the space shuttle <span class="hlt">Endeavour</span> at the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300007HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300007HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>Vocalist James Ingram sings "I Believe I Can Fly" from underneath the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300003HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300003HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>David D. McBride, director of NASA's Dryden Flight Research Center, speaks from a podium underneath the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300002HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300002HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>California Governor Jerry Brown speaks from a podium underneath the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300014HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300014HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>President and CEO of the California Science Center Jeffrey N. Rudolph speaks from a podium underneath the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300010HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300010HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>A police officer is seen underneath the wing of the space shuttle <span class="hlt">Endeavour</span> during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DSRI...52.1515O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DSRI...52.1515O"><span>High abundances of viruses in a deep-sea <span class="hlt">hydrothermal</span> vent <span class="hlt">system</span> indicates viral mediated microbial mortality</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ortmann, Alice C.; Suttle, Curtis A.</p> <p>2005-08-01</p> <p>Little is known about the distribution and abundance of viruses at deep-sea <span class="hlt">hydrothermal</span> vents. Based on estimates made using epifluorescence microscopy and the dye YoPro-1, much higher viral abundances were observed at active <span class="hlt">hydrothermal</span> vents than in the surrounding deep sea. This indicates that viral production was occurring and that viruses were a source of microbial mortality. Samples collected from three actively venting sites (Clam Bed, S&M and Salut) within the <span class="hlt">Endeavour</span> Ridge <span class="hlt">system</span> off the west coast of North America had viral abundances ranging from 1.45×10 5 to 9.90×10 7 ml -1, while the abundances of prokaryotes ranged from 1.30×10 5 to 4.46×10 6 ml -1. The abundances of viruses and prokaryotes in samples collected along the neutrally buoyant plume associated with the Main <span class="hlt">Endeavour</span> Field were lower than at actively venting sites, with a mean of 5.3×10 5 prokaryotes ml -1 (s.d. 2.9×10 5, n=64) and 3.50×10 6 viruses ml -1 (s.d. 1.89×10 6, n=64), but were higher than non-plume samples (2.7×10 5 prokaryotes ml -1, s.d. 5.0×10 4, n=15 and 2.94×10 6 viruses ml -1, s.d. 1.08×10 6, n=15). Prokaryotic and viral abundances in non-<span class="hlt">hydrothermal</span> regions were as much as 10-fold higher than found in previous studies, in which sample fixation likely resulted in underestimates. This suggests that viral infection may be a greater source of prokaryotic mortality throughout the deep sea than previously recognized. Overall, our results indicate that virus-mediated mortality of prokaryotes at these <span class="hlt">hydrothermal</span>-vent environments is significant and may reduce energy flow to higher trophic levels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Icar..224..347O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Icar..224..347O"><span>Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Earth and Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Osinski, Gordon R.; Tornabene, Livio L.; Banerjee, Neil R.; Cockell, Charles S.; Flemming, Roberta; Izawa, Matthew R. M.; McCutcheon, Jenine; Parnell, John; Preston, Louisa J.; Pickersgill, Annemarie E.; Pontefract, Alexandra; Sapers, Haley M.; Southam, Gordon</p> <p>2013-06-01</p> <p>It has long been suggested that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> might have provided habitats for the origin and evolution of early life on Earth, and possibly other planets such as Mars. In this contribution we show that most impact events that result in the formation of complex impact craters (i.e., >2-4 and >5-10 km diameter on Earth and Mars, respectively) are potentially capable of generating a <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Consideration of the impact cratering record on Earth suggests that the presence of an impact crater lake is critical for determining the longevity and size of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We show that there are six main locations within and around impact craters on Earth where impact-generated <span class="hlt">hydrothermal</span> deposits can form: (1) crater-fill impact melt rocks and melt-bearing breccias; (2) interior of central uplifts; (3) outer margin of central uplifts; (4) impact ejecta deposits; (5) crater rim region; and (6) post-impact crater lake sediments. We suggest that these six locations are applicable to Mars as well. Evidence for impact-generated <span class="hlt">hydrothermal</span> alteration ranges from discrete vugs and veins to pervasive alteration depending on the setting and nature of the <span class="hlt">system</span>. A variety of <span class="hlt">hydrothermal</span> minerals have been documented in terrestrial impact structures and these can be grouped into three broad categories: (1) <span class="hlt">hydrothermally</span>-altered target-rock assemblages; (2) primary <span class="hlt">hydrothermal</span> minerals precipitated from solutions; and (3) secondary assemblages formed by the alteration of primary <span class="hlt">hydrothermal</span> minerals. Target lithology and the origin of the <span class="hlt">hydrothermal</span> fluids strongly influences the <span class="hlt">hydrothermal</span> mineral assemblages formed in these post-impact <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. There is a growing body of evidence for impact-generated <span class="hlt">hydrothermal</span> activity on Mars; although further detailed studies using high-resolution imagery and multispectral information are required. Such studies have only been done in detail for a handful of martian craters. The best example so</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121...41S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121...41S"><span>Thermal response of mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to perturbations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Shreya; Lowell, Robert P.</p> <p>2015-11-01</p> <p>Mid-ocean ridges are subject to episodic disturbances in the form of magmatic intrusions and earthquakes. Following these events, the temperature of associated <span class="hlt">hydrothermal</span> vent fluids is observed to increase within a few days. In this paper, we aim to understand the rapid thermal response of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to such disturbances. We construct a classic single-pass numerical model and use the examples of the 1995 and 1999 non-eruptive events at East Pacific Rise (EPR) 9°50‧N and Main <span class="hlt">Endeavour</span> Field (MEF), respectively. We model both the thermal effects of dikes and permeability changes that might be attributed to diking and/or earthquake swarms. We find that the rapid response of vent temperatures results from steep thermal gradients close to the surface. When the perturbations are accompanied by an increase in permeability, the response on the surface is further enhanced. For EPR9°50‧N, the observed ~7 °C rise can be obtained for a ~50% increase in permeability in the diking zone. The mass flow rate increases as a result of change in permeability deeper in the <span class="hlt">system</span>, and, therefore, the amount of hot fluid in the diffused flow also increases. Using a thermal energy balance, we show that the ~10 °C increase in diffuse flow temperatures recorded for MEF after the 1999 event may result from a 3-4 times increase in permeability. The rapid thermal response of the <span class="hlt">system</span> resulting from a change in permeability also occurs for cases in which there is no additional heat input, indicating that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may respond similarly to purely seismic and non-eruptive magmatic events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H33B0793S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H33B0793S"><span>The Thermal Response of Mid-Ocean Ridge <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> to Perturbations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, S.; Lowell, R. P.</p> <p>2014-12-01</p> <p>Mid-ocean ridges are subject to episodic disturbances in the form of magmatic intrusions and earthquakes. Following these events, the temperature of associated <span class="hlt">hydrothermal</span> vent fluids is observed to increase within a few days. In this paper, we aim to understand the rapid thermal response of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to such disturbances. We construct a classic single-pass numerical model and use the examples of the 1995 and 1999 non-eruptive events at East Pacific Rise 9⁰50' N and Main <span class="hlt">Endeavour</span> Field, respectively. We model both the thermal effects of dikes and permeability changes that might be attributed to diking and/or earthquake swarms. We find that the rapid response of vent temperatures results from steep thermal gradients close to the surface. When the perturbations are accompanied by an increase in permeability, the response on the surface is enhanced further. For East Pacific Rise 9⁰50' N, the observed ~7°C rise can be obtained for a ~ 50% increase in permeability in the diking zone. The mass flow rate increases as a result of change in permeability deeper in the <span class="hlt">system</span>, and, therefore, the amount of hot fluid in the diffused flow also increases. Using a thermal energy balance, we show that the ~ 10 ⁰C increase in diffuse flow temperatures recorded for MEF after the 1999 event may result from a 3-4 times increase in permeability. The rapid thermal response of the <span class="hlt">system</span> resulting from a change in permeability also occurs for cases in which there is no additional heat input, indicating that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may respond similarly to purely seismic and non-eruptive magmatic events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6254717','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6254717"><span>Enhanced heat transfer in partially-saturated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bixler, N.E.; Carrigan, C.R.</p> <p>1986-01-01</p> <p>The role of capillarity is potentially important for determining heat transfer in <span class="hlt">hydrothermal</span> regions. Capillarity allows mixing of phases in liquid/vapor <span class="hlt">systems</span> and results in enhanced two-phase convection. Comparisons involving a numerical model with capillarity and analytical models without indicate that heat transfer can be enhanced by about an order of magnitude. Whether capillarity can be important for a particular <span class="hlt">hydrothermal</span> region will depend on the nature of mineral precipitation as well as pore and fracture size distributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PEPS....1....5N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PEPS....1....5N"><span>Theoretical constraints of physical and chemical properties of <span class="hlt">hydrothermal</span> fluids on variations in chemolithotrophic microbial communities in seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Kentaro; Takai, Ken</p> <p>2014-12-01</p> <p>In the past few decades, chemosynthetic ecosystems at deep-sea <span class="hlt">hydrothermal</span> vents have received attention as plausible analogues to the early ecosystems of Earth, as well as to extraterrestrial ecosystems. These ecosystems are sustained by chemical energy obtained from inorganic redox substances (e.g., H2S, CO2, H2, CH4, and O2) in <span class="hlt">hydrothermal</span> fluids and ambient seawater. The chemical and isotope compositions of the <span class="hlt">hydrothermal</span> fluid are, in turn, controlled by subseafloor physical and chemical processes, including fluid-rock interactions, phase separation and partitioning of fluids, and precipitation of minerals. We hypothesized that specific physicochemical principles describe the linkages among the living ecosystems, <span class="hlt">hydrothermal</span> fluids, and geological background in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. We estimated the metabolic energy potentially available for productivity by chemolithotrophic microorganisms at various <span class="hlt">hydrothermal</span> vent fields. We used a geochemical model based on <span class="hlt">hydrothermal</span> fluid chemistry data compiled from 89 globally distributed <span class="hlt">hydrothermal</span> vent sites. The model estimates were compared to the observed variability in extant microbial communities in seafloor <span class="hlt">hydrothermal</span> environments. Our calculations clearly show that representative chemolithotrophic metabolisms (e.g., thiotrophic, hydrogenotrophic, and methanotrophic) respond differently to geological and geochemical variations in the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Nearly all of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide abundant energy for organisms with aerobic thiotrophic metabolisms; observed variations in the H2S concentrations among the <span class="hlt">hydrothermal</span> fluids had little effect on the energetics of thiotrophic metabolism. Thus, these organisms form the base of the chemosynthetic microbial community in global deep-sea <span class="hlt">hydrothermal</span> environments. In contrast, variations in H2 concentrations in <span class="hlt">hydrothermal</span> fluids significantly impact organisms with aerobic and anaerobic hydrogenotrophic metabolisms</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/895920','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/895920"><span>Fractionation of Boron Isotopes in Icelandic <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aggarwal, J.K.; Palmer, M.R.</p> <p>1995-01-01</p> <p>Boron isotope ratios have been determined in a variety of different geothermal waters from <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> across Iceland. Isotope ratios from the high temperature meteoric water recharged <span class="hlt">systems</span> reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal <span class="hlt">systems</span> exhibit more positive {delta}{sup 11}B values than the meteoric water recharged geothermal <span class="hlt">systems</span>. Water/rock ratios can be assessed from boron isotope ratios in the saline <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Low temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> also exhibit more positive {delta}{sup 11}B than the high temperature <span class="hlt">systems</span>, indicating fractionation of boron due to adsorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H51A1418W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H51A1418W"><span>Optimization of <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> Operations with multiple Objectives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, J.; Cheng, C.; Shen, J.; Cao, R.; Zhao, Z.; Yeh, W. W. G.</p> <p>2016-12-01</p> <p>This paper proposes a procedure for optimizing large-scale <span class="hlt">hydrothermal</span> <span class="hlt">system</span> operations. The overall procedure is to optimize, in turn, a monthly model over a period of one year and a daily model over a period of up to one month. The outputs from the monthly model are used as inputs and boundary conditions to the daily model, iterating and updating when new information becomes available. The monthly <span class="hlt">hydrothermal</span> model uses nonlinear programming to minimize fuel cost, while maximizing hydropower production. The outputs from this model specify the boundary conditions for the daily model. The daily model consists of a hydro model, a thermal model and a combined <span class="hlt">hydrothermal</span> model. The hydro and thermal models generate the initial feasible solutions for the <span class="hlt">hydrothermal</span> model. The two conflicting objectives considered in the <span class="hlt">hydrothermal</span> model are minimizing fuel cost and minimizing thermal emission. We use the constraint method to develop the trade-off curve (Pareto front) between these two objectives. Application of the proposed methodology is made to the Yunnan <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in China. The <span class="hlt">system</span> consists of 140 hydropower plants with an installed capacity of 45,786 MW and 11 individual thermal plants with an installed capacity of 12,400 MW. We use the historical load demand and reservoir inflows to test the methodology. The results demonstrate the practicability and validity of the proposed procedure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS22A..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS22A..07S"><span>Microbiological production and ecological flux of northwestern subduction <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sunamura, M.; Okamura, K.; Noguchi, T.; Yamamoto, H.; Fukuba, T.; Yanagawa, K.</p> <p>2012-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is one of the most important sources for heat and chemical flux from the oceanic crust to the global ocean. The rich biological community around the <span class="hlt">hydrothermal</span> vent shows chemolithoautotrophic microbial production are important in deep sea ecosystems. More than 99% of microbiological available chemical components in <span class="hlt">hydrothermal</span> vent fluid, e.g. sulfide, methane, hydrogen, Fe2+, and Mn2+, is released into surrounding seawater to construct <span class="hlt">hydrothermal</span> plume, suggesting that the chemolithoautotrophic-microbial primary production in the <span class="hlt">hydrothermal</span> plume is huge and important in the whole <span class="hlt">hydrothermal</span> ecosystems. To understand the impact of <span class="hlt">hydrothermal</span> plume to a microbial ecosystem and a connectivity with zooplankton, we targeted and investigated a total of 16 <span class="hlt">hydrothermal</span> fileds (7 sites in Okinawa trough, 3 sites in Ogasawara arc, and 6 sites in Mariana arc and back arc) and investigated in several cruises under the TAIGA project in Japan. <span class="hlt">Hydrothermal</span> fluids in the subduction <span class="hlt">system</span> are rich in sulfide. The <span class="hlt">hydrothermal</span> fluids in the Okinawa trough, Ogasawara arc. and Mariana trough are characterized by rich in methane, poor in other reduced chemicals, and rich in iron, respectively. The major microbial composition was a potential sulfur oxidizing microbes SUP05 in the plume ecosystems, while an aerobic methanotrophic bacteria was secondary major member in methane-rich <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in Okinawa trough. Microbial quantitative and spatial distribution analyses of each plume site showed that the microbial population size and community structures are influenced by original chemical components of <span class="hlt">hydrothermal</span> fluid, e.g. sulfide, methane and iron concentration. Microbial quantitative data indicated the removal/sedimentation of microbial cells from the plume and effect of phase separation in a same vent field through construction of gas-rich or gas-poor plumes. After the correlation of plume mixing effect, we estimates that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3133S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3133S"><span>Heat and mass transfer in volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scott, S. W.</p> <p>2015-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> re-distribute heat and mass derived from subsurface magma bodies over large temporal and spatial scales. Numerical models of fluid flow and heat transfer provide a quantitative basis for understanding the thermo-hydrological structure and transient behavior of volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. At the brittle-ductile transition around a magma body, the rate of conductive heat transfer from the impermeable intrusion is balanced by the rate of advective heat transfer by the fluid. Using the Complex <span class="hlt">Systems</span> Modeling Platform (CSMP++) to model fluid flow up to near-magmatic conditions, we examine the effect of geologic factors such as host rock permeability, magma emplacement depth, the temperature conditions of the brittle-ductile transition, and rock/magma thermal conductivity on the rates of heat and mass transfer around magma bodies. Additionally, we investigate the role of these factors on the thermo-hydrological structure of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, including patterns of phase separation, gravity-driven phase segregation, and fluid mixing. Passive tracers are included in the fluid flow models to simulate the input of magmatic volatiles into <span class="hlt">hydrothermal</span> fluids and their fractionation between the liquid and vapor phases. Ultimately, we compare our model results against measured heat and gas fluxes from volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to help inform the interpreation of these measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950057137&hterms=Calorie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCalorie','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950057137&hterms=Calorie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCalorie"><span>Geochemical constraints on chemolithoautotrophic reactions in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.; Mccollom, Thomas; Schulte, Mithell D.</p> <p>1995-01-01</p> <p>Thermodynamic calculations provide the means to quantify the chemical disequilibrium inherent in the mixing of reduced <span class="hlt">hydrothermal</span> fluids with seawater. The chemical energy available for metabolic processes in these environments can be evaluated by taking into account the pressure and temperature dependence of the apparent standard Gibbs free energies of reactions in the S-H2-H2O <span class="hlt">system</span> together with geochemical constraints on pH, activities of aqueous sulfur species and fugacities of H2 and/or O2. Using present-day mixing of <span class="hlt">hydrothermal</span> fluids and seawater as a starting point, it is shown that each mole of H2S entering seawater from <span class="hlt">hydrothermal</span> fluids represents about 200,000 calories of chemical energy for metabolic <span class="hlt">systems</span> able to catalyze H2S oxidation. Extrapolating to the early Earth, which was likely to have had an atmosphere more reduced than at present, shows that this chemical energy may have been a factor of two or so less. Nevertheless, mixing of <span class="hlt">hydrothermal</span> fluids with seawater would have been an abundant source of chemical energy, and an inevitable consequence of the presence of an ocean on an initially hot Earth. The amount of energy available was more than enough for organic synthesis from CO2 or CO, and/or polymer formation, indicating that the vicinity of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at the sea floor was an ideal location for the emergence of the first chemolithoautotrophic metabolic <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950057137&hterms=Disequilibrium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DDisequilibrium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950057137&hterms=Disequilibrium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DDisequilibrium"><span>Geochemical constraints on chemolithoautotrophic reactions in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.; Mccollom, Thomas; Schulte, Mithell D.</p> <p>1995-01-01</p> <p>Thermodynamic calculations provide the means to quantify the chemical disequilibrium inherent in the mixing of reduced <span class="hlt">hydrothermal</span> fluids with seawater. The chemical energy available for metabolic processes in these environments can be evaluated by taking into account the pressure and temperature dependence of the apparent standard Gibbs free energies of reactions in the S-H2-H2O <span class="hlt">system</span> together with geochemical constraints on pH, activities of aqueous sulfur species and fugacities of H2 and/or O2. Using present-day mixing of <span class="hlt">hydrothermal</span> fluids and seawater as a starting point, it is shown that each mole of H2S entering seawater from <span class="hlt">hydrothermal</span> fluids represents about 200,000 calories of chemical energy for metabolic <span class="hlt">systems</span> able to catalyze H2S oxidation. Extrapolating to the early Earth, which was likely to have had an atmosphere more reduced than at present, shows that this chemical energy may have been a factor of two or so less. Nevertheless, mixing of <span class="hlt">hydrothermal</span> fluids with seawater would have been an abundant source of chemical energy, and an inevitable consequence of the presence of an ocean on an initially hot Earth. The amount of energy available was more than enough for organic synthesis from CO2 or CO, and/or polymer formation, indicating that the vicinity of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at the sea floor was an ideal location for the emergence of the first chemolithoautotrophic metabolic <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995OLEB...25..141S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995OLEB...25..141S"><span>Geochemical constraints on chemolithoautotrophic reactions in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shock, Everett L.; McCollom, Thomas; Schulte, Mitchell D.</p> <p>1995-06-01</p> <p>Thermodynamic calculations provide the means to quantify the chemical disequilibrium inherent in the mixing of redeuced <span class="hlt">hydrothermal</span> fluids with seawater. The chemical energy available for metabolic processes in these environments can be evaluated by taking into account the pressure and temperature dependence of the apparent standard Gibbs free energies of reactions in the S-H2-H2O <span class="hlt">system</span> together with geochemical constraints on pH, activities of aqueous sulfur species and fugacities of H2 and/or O2. Using present-day mixing of <span class="hlt">hydrothermal</span> fluids and seawater as a starting point, it is shown that each mole of H2S entering seawater from <span class="hlt">hydrothermal</span> fluids represents about 200,000 calories of chemical energy for metabolic <span class="hlt">systems</span> able to catalyze H2S oxidation. Extrapolating to the early Earth, which was likely to have had an atmosphere more reduced than at present, shows that this chemical energy may have been a factor of two or so less. Nevertheless, mixing of <span class="hlt">hydrothermal</span> fluids with seawater would have been an abundant source of chemical energy, and an inevitable consequence of the presence of an ocean on an initially hot Earth. The amount of energy available was more than enough for organic synthesis from CO2 or CO, and/or polymer formation, indicating that the vicinity of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at the sea floor was an ideal location for the emergence of the first chemolithoautotrophic metabolic <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210130019HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210130019HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-13</p> <p>The space shuttle <span class="hlt">Endeavour</span> is seen as it is maneuvered through the streets of Inglewood on its way to its new home at the California Science Center, Saturday, Oct. 13, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210120017HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210120017HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-12</p> <p>The space shuttle <span class="hlt">Endeavour</span> moves out of the Los Angeles International Airport and onto the streets of Los Angeles to make its way to its new home at the California Science Center, Friday, Oct. 12, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210130016HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210130016HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-13</p> <p>A 3D camera films the space shuttle <span class="hlt">Endeavour</span> as it makes its way through the streets of Inglewood on its way to its new home at the California Science Center, Saturday, Oct. 13, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300016HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300016HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>Tires from space shuttle <span class="hlt">Endeavour</span>'s final flight are on display at the California Science Center's, California Experience gallery, Tuesday, Oct. 30, 2012, in Los Angeles. The grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion took place on Tuesday, Oct. 30, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210120029HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210120029HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-12</p> <p>The space shuttle <span class="hlt">Endeavour</span> is seen as it traverses through Inglewood, Calif. on Friday, Oct. 12, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210120009HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210120009HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-12</p> <p>The space shuttle <span class="hlt">Endeavour</span> is seen as it traverses through Inglewood, California on Friday, Oct. 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201106010003HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201106010003HQ.html"><span><span class="hlt">Endeavour</span> STS-134 Lands</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-06-01</p> <p>NASA Administrator Charles Bolden looks at the Space Shuttle <span class="hlt">Endeavour</span> (STS-134) from the air traffic control tower at the Shuttle Landing Facility (SLF) shortly after <span class="hlt">Endeavour</span> made its final landing at the Kennedy Space Center, Wednesday, June 1, 2011, in Cape Canaveral, Fla. <span class="hlt">Endeavour</span>, after completing a 16-day mission to outfit the International Space Station, spent 299 days in space and traveled more than 122.8 million miles during its 25 flights. It launched on its first mission on May 7, 1992. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MarGR..38...61S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MarGR..38...61S"><span>The potential <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> unexplored in the Southwest Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suo, Yanhui; Li, Sanzhong; Li, Xiyao; Zhang, Zhen; Ding, Dong</p> <p>2017-06-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> vents possess complex ecosystems and abundant metallic mineral deposits valuable to human being. On-axial vents along tectonic plate boundaries have achieved prominent results and obtained huge resources, while nearly 90% of the global mid-ocean ridge and the majority of the off-axial vents buried by thick oceanic sediments within plates remain as relatively undiscovered domains. Based on previous detailed investigations, <span class="hlt">hydrothermal</span> vents have been mapped along five sections along the Southwest Indian Ridge (SWIR) with different bathymetry, spreading rates, and gravity features, two at the western end (10°-16°E Section B and 16°-25°E Section C) and three at the eastern end (49°-52°E Section D, 52°-61°E Section E and 61°-70°E Section F). <span class="hlt">Hydrothermal</span> vents along the Sections B, C, E and F with thin oceanic crust are hosted by ultramafic rocks under tectonic-controlled magmatic-starved settings, and <span class="hlt">hydrothermal</span> vents along the Section D are associated with exceed magmatism. Limited coverage of investigations is provided along the 35°-47°E SWIR (between Marion and Indomed fracture zones) and a lot of research has been done around the Bouvet Island, while no <span class="hlt">hydrothermal</span> vents has been reported. Analyzing bathymetry, gravity and geochemical data, magmatism settings are favourable for the occurrence of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> along these two sections. An off-axial <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the southern flank of the SWIR that exhibits ultra-thin oceanic crust associated with an oceanic continental transition is postulated to exist along the 100-Ma slow-spreading isochron in the Enderby Basin. A discrete, denser enriched or less depleted mantle beneath the Antarctic Plate is an alternative explanation for the large scale thin oceanic crust concentrated on the southern flank of the SWIR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MarGR.tmp....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MarGR.tmp....1S"><span>The potential <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> unexplored in the Southwest Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suo, Yanhui; Li, Sanzhong; Li, Xiyao; Zhang, Zhen; Ding, Dong</p> <p>2017-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> vents possess complex ecosystems and abundant metallic mineral deposits valuable to human being. On-axial vents along tectonic plate boundaries have achieved prominent results and obtained huge resources, while nearly 90% of the global mid-ocean ridge and the majority of the off-axial vents buried by thick oceanic sediments within plates remain as relatively undiscovered domains. Based on previous detailed investigations, <span class="hlt">hydrothermal</span> vents have been mapped along five sections along the Southwest Indian Ridge (SWIR) with different bathymetry, spreading rates, and gravity features, two at the western end (10°-16°E Section B and 16°-25°E Section C) and three at the eastern end (49°-52°E Section D, 52°-61°E Section E and 61°-70°E Section F). <span class="hlt">Hydrothermal</span> vents along the Sections B, C, E and F with thin oceanic crust are hosted by ultramafic rocks under tectonic-controlled magmatic-starved settings, and <span class="hlt">hydrothermal</span> vents along the Section D are associated with exceed magmatism. Limited coverage of investigations is provided along the 35°-47°E SWIR (between Marion and Indomed fracture zones) and a lot of research has been done around the Bouvet Island, while no <span class="hlt">hydrothermal</span> vents has been reported. Analyzing bathymetry, gravity and geochemical data, magmatism settings are favourable for the occurrence of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> along these two sections. An off-axial <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the southern flank of the SWIR that exhibits ultra-thin oceanic crust associated with an oceanic continental transition is postulated to exist along the 100-Ma slow-spreading isochron in the Enderby Basin. A discrete, denser enriched or less depleted mantle beneath the Antarctic Plate is an alternative explanation for the large scale thin oceanic crust concentrated on the southern flank of the SWIR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=FyPMLAK-MdQ','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=FyPMLAK-MdQ"><span><span class="hlt">Endeavour</span>'s Final Voyage</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>After nearly two decades of achievements in space, <span class="hlt">Endeavour</span> makes one last reach for the stars on its 25th and final mission, STS-134. This webcast examines the mission to come and explores the st...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-9262853&hterms=japanese+women&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Djapanese%2Bwomen','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-9262853&hterms=japanese+women&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Djapanese%2Bwomen"><span>Space Shuttle <span class="hlt">Endeavour</span> launch</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>A smooth countdown culminated in a picture-perfect launch as the Space Shuttle <span class="hlt">Endeavour</span> (STS-47) climbed skyward atop a ladder of billowing smoke. Primary payload for the plarned seven-day flight was Spacelab-J science laboratory. The second flight of <span class="hlt">Endeavour</span> marks a number of historic firsts: the first space flight of an African-American woman, the first Japanese citizen to fly on a Space Shuttle, and the first married couple to fly in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300008HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300008HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>Members of the Debbie Allen Dance Academy perform “Men in Black” choreographed by the legendary Debbie Allen during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300012HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300012HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>Mayor of Los Angeles Antonio Villaraigosa addresses a class of fourth graders during the grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS41C1963T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS41C1963T"><span>The <span class="hlt">hydrothermal</span> exploration <span class="hlt">system</span> on the 'Qianlong2' AUV</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, W.; Tao, C.; Jinhui, Z.; Cai, L.; Guoyin, Z.</p> <p>2016-12-01</p> <p>ABSTRACT: Qianlong2, is a fully Autonomous Underwater Vehicle (AUV) designed for submarine resources research, especially for polymetallic sulphides, and the survey depths of is up to 4500 m. Qianlong2 had successfully explored <span class="hlt">hydrothermal</span> vent field on the Southwest Indian Ridge (SWIR), and collected conductance, temperature and depth (CTD), turbidity, and Oxidation-Reduction Potential (ORP) data. It also had mapped precise topography by high resolution side scan sonar (HRBSSS) during every dive; and obtained photographs of sulfide deposits during some dives. Here, we detailedly described the implementation of investigation, data administration, and fast mapping of <span class="hlt">hydrothermal</span> exploration <span class="hlt">system</span> by Qianlong2. Giving a description of how to remove the platform magnetic interference by using magnetic data during Qianlong2 spin. Based on comprehensive hydrochemical anomalies, we get a rapid method for finding the localization of <span class="hlt">hydrothermal</span> vents. Taking one dive as an example, we <span class="hlt">systemically</span> showed the process about how to analyse <span class="hlt">hydrothermal</span> survey data and acquire the location results of <span class="hlt">hydrothermal</span> vents. Considering that this method is effective and can be used in other deep-submergence assets such as human occupied vehicles (HOVs) and remotely operated vehicles (ROVs) during further studies. Finally, we discussed how to promote and optimize the installation and application of those sensors and how to improve Qianlong2's autonomy of investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950032316&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950032316&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dhydrothermal"><span>The potential for prebiotic synthesis in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. [Abstract only</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ferris, James P.</p> <p>1994-01-01</p> <p>Contemporary <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide a reducing environment where organic compounds are formed and may react to generate the molecules used in the first living <span class="hlt">systems</span>. The organic compounds percolate through mineral assemblages at a variety of temperatures so the proposed synthetic reactions are driven by heat and catalyzed by minerals (Ferris, 1992). Some examples of potential prebiotic reactions are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993Geo....21..499T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993Geo....21..499T"><span><span class="hlt">Hydrothermal</span> vents in Lake Tanganyika, East African, Rift <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tiercelin, Jean-Jacques; Pflumio, Catherine; Castrec, Maryse; Boulégue, Jacques; Gente, Pascal; Rolet, Joël; Coussement, Christophe; Stetter, Karl O.; Huber, Robert; Buku, Sony; Mifundu, Wafula</p> <p>1993-06-01</p> <p>Sublacustrine <span class="hlt">hydrothermal</span> vents with associated massive sulfides were discovered during April 1987 at Pemba and Cape Banza on the Zaire side of the northern basin of Lake Tanganyika, East African Rift <span class="hlt">system</span>. New investigations by a team of ten scuba divers during the multinational (France, Zaire, Germany, and Burundi) TANGANYDRO expedition (August-October 1991) found <span class="hlt">hydrothermal</span> vents down to a depth of 46 m along north-trending active faults bounding the Tanganyika rift on the western side. Temperatures from 53 to 103 °C were measured in <span class="hlt">hydrothermal</span> fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with vents at the Pemba site. At Cape Banza,active vents are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of <span class="hlt">hydrothermal</span> pipes. <span class="hlt">Hydrothermal</span> fluid end members show distinctive compositions at the two sites. The Pemba end member is a NaHCO3-enriched fluid similar to the NaHCO3 thermal fluids from lakes Magadi and Bogoria in the eastern branch off the rift. The Cape Banza end member is a solution enriched in NaCl. Such brines may have a deep-seated basement origin, as do the Uvinza NaCl brines on the eastern flank of the Tanganyika basin. Geothermometric calculations have yielded temperatures of fluid-rock interaction off 219 and 179 °C in the Pemba and Cape Banza <span class="hlt">systems</span>, respectively. Abundant white or reddish-brown microbial colonies resembling Beggiatoa</em> mats were found surrounding the active vents. Thermal fluid circulation is permitted by opening of cracks related to 130 °N normal-dextral faults that intersect the north- south major rift trend. The source of heat for such <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may relate to the existence of magmatic bodies under the rift, which is suggested by the isotopic composition of carbon dioxide released at Pemba and Cape Banza.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9243021','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9243021"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> on Mars: an assessment of present evidence.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Farmer, J D</p> <p>1996-01-01</p> <p><span class="hlt">Hydrothermal</span> processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and <span class="hlt">hydrothermal</span> processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for <span class="hlt">hydrothermal</span> mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> being dominated by magma-cryosphere interactions. Given the smaller</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040173286&hterms=climatic+floors&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dclimatic%2Bfloors','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040173286&hterms=climatic+floors&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dclimatic%2Bfloors"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> on Mars: an assessment of present evidence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farmer, J. D.</p> <p>1996-01-01</p> <p><span class="hlt">Hydrothermal</span> processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and <span class="hlt">hydrothermal</span> processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for <span class="hlt">hydrothermal</span> mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> being dominated by magma-cryosphere interactions. Given the smaller</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040173286&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040173286&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> on Mars: an assessment of present evidence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farmer, J. D.</p> <p>1996-01-01</p> <p><span class="hlt">Hydrothermal</span> processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and <span class="hlt">hydrothermal</span> processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for <span class="hlt">hydrothermal</span> mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> being dominated by magma-cryosphere interactions. Given the smaller</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985RpESc....Q.101K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985RpESc....Q.101K"><span>Thermohydrodynamic model: <span class="hlt">Hydrothermal</span> <span class="hlt">system</span>, shallowly seated magma chamber</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kiryukhin, A. V.</p> <p>1985-02-01</p> <p>The results of numerical modeling of heat exchange in the Hawaiian geothermal reservoir demonstrate the possibility of appearance of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> over a magma chamber. This matter was investigated in <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The equations for the conservation of mass and energy are discussed. Two possible variants of interaction between the magma chamber and the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> were computated stationary dry magma chamber and dry magma chamber changing volume in dependence on the discharge of magma and taking into account heat exchange with the surrounding rocks. It is shown that the thermal supplying of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> can be ensured by the extraction of heat from a magma chamber which lies at a depth of 3 km and is melted out due to receipt of 40 cubic km of basalt melt with a temperature of 1,300 C. The initial data correspond with computations made with the model to the temperature values in the geothermal reservoir and a natural heat transfer comparable with the actually observed values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.1660B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.1660B"><span>Poroelastic response of mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to ocean tidal loading: Implications for shallow permeability structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barreyre, Thibaut; Sohn, Robert A.</p> <p>2016-02-01</p> <p>We use the time delay between tidal loading and exit-fluid temperature response for <span class="hlt">hydrothermal</span> vents to model the poroelastic behavior and shallow upflow zone (SUZ) effective permeability structure of three mid-ocean ridge (MOR) sites with different spreading rates. <span class="hlt">Hydrothermal</span> vents at Lucky Strike field exhibit relatively small phase lags corresponding to high SUZ effective permeabilities of ≥ ~10-10 m2, with variations that we interpret as resulting from differences in the extrusive layer thickness. By contrast, vents at East Pacific Rise site exhibit relatively large phase lags corresponding to low SUZ effective permeabilities of ≤ ~10-13 m2. Vents at Main <span class="hlt">Endeavour</span> field exhibit both high and low phase lags, suggestive of a transitional behavior. Our results demonstrate that tidal forcing perturbs <span class="hlt">hydrothermal</span> flow across the global MOR <span class="hlt">system</span>, even in places where the tidal amplitude is very low, and that the flow response can be used to constrain variations in SUZ permeability structure beneath individual vent fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040065880&hterms=Starting&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DStarting','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040065880&hterms=Starting&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3DStarting"><span>Starting Conditions for <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> Underneath Martian Craters: Hydrocode Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pierazzo, E.; Artemieva, N. A.; Ivanov, B. A.</p> <p>2004-01-01</p> <p>Mars is the most Earth-like of the Solar <span class="hlt">System</span> s planets, and the first place to look for any sign of present or past extraterrestrial life. Its surface shows many features indicative of the presence of surface and sub-surface water, while impact cratering and volcanism have provided temporary and local surface heat sources throughout Mars geologic history. Impact craters are widely used ubiquitous indicators for the presence of sub-surface water or ice on Mars. In particular, the presence of significant amounts of ground ice or water would cause impact-induced <span class="hlt">hydrothermal</span> alteration at Martian impact sites. The realization that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are possible sites for the origin and early evolution of life on Earth has given rise to the hypothesis that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may have had the same role on Mars. Rough estimates of the heat generated in impact events have been based on scaling relations, or thermal data based on terrestrial impacts on crystalline basements. Preliminary studies also suggest that melt sheets and target uplift are equally important heat sources for the development of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, while its lifetime depends on the volume and cooling rate of the heat source, as well as the permeability of the host rocks. We present initial results of two-dimensional (2D) and three-dimensional (3D) simulations of impacts on Mars aimed at constraining the initial conditions for modeling the onset and evolution of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> on the red planet. Simulations of the early stages of impact cratering provide an estimate of the amount of shock melting and the pressure-temperature distribution in the target caused by various impacts on the Martian surface. Modeling of the late stage of crater collapse is necessary to characterize the final thermal state of the target, including crater uplift, and distribution of the heated target material (including the melt pool) and hot ejecta around the crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040065880&hterms=Hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040065880&hterms=Hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DHydrothermal"><span>Starting Conditions for <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> Underneath Martian Craters: Hydrocode Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pierazzo, E.; Artemieva, N. A.; Ivanov, B. A.</p> <p>2004-01-01</p> <p>Mars is the most Earth-like of the Solar <span class="hlt">System</span> s planets, and the first place to look for any sign of present or past extraterrestrial life. Its surface shows many features indicative of the presence of surface and sub-surface water, while impact cratering and volcanism have provided temporary and local surface heat sources throughout Mars geologic history. Impact craters are widely used ubiquitous indicators for the presence of sub-surface water or ice on Mars. In particular, the presence of significant amounts of ground ice or water would cause impact-induced <span class="hlt">hydrothermal</span> alteration at Martian impact sites. The realization that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are possible sites for the origin and early evolution of life on Earth has given rise to the hypothesis that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may have had the same role on Mars. Rough estimates of the heat generated in impact events have been based on scaling relations, or thermal data based on terrestrial impacts on crystalline basements. Preliminary studies also suggest that melt sheets and target uplift are equally important heat sources for the development of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, while its lifetime depends on the volume and cooling rate of the heat source, as well as the permeability of the host rocks. We present initial results of two-dimensional (2D) and three-dimensional (3D) simulations of impacts on Mars aimed at constraining the initial conditions for modeling the onset and evolution of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> on the red planet. Simulations of the early stages of impact cratering provide an estimate of the amount of shock melting and the pressure-temperature distribution in the target caused by various impacts on the Martian surface. Modeling of the late stage of crater collapse is necessary to characterize the final thermal state of the target, including crater uplift, and distribution of the heated target material (including the melt pool) and hot ejecta around the crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210120004HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210120004HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-12</p> <p>The driver of the Over Land Transporter is seen as he maneuvers the space shuttle <span class="hlt">Endeavour</span> on the streets of Los Angeles as it heads to its new home at the California Science Center, Friday, Oct. 12, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Bill Ingalls)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210120027HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210120027HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-12</p> <p>The driver of the Over Land Transporter (OLT) is seen as he maneuvers the space shuttle <span class="hlt">Endeavour</span> on the streets of Los Angeles as it heads to its new home at the California Science Center, Friday, Oct. 12, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210130071HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210130071HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-13</p> <p>From left to right are seen Apollo 7 astronaut Walter Cunningham (second from right), NASA astronaut Kay Hire, Hildreth Walker, Founder of A-MAN Inc. STEM International Science Center; NASA astronauts Michael Fincke and Gregory Johnson at the <span class="hlt">Endeavour</span> Kick-Off Ceremony, Saturday, Oct. 13, 2012 in Inglewood. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210130069HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210130069HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-13</p> <p>Jeffrey Rudolph, President and CEO, California Science Center speaks at the <span class="hlt">Endeavour</span> Kick-Off Ceremony at The Forum in Inglewood, Saturday, Oct. 13, 2012. Behind him are seen Hildreth Walker, Founder of A-Man Inc. STEM International Science Center, far left; James T. Butts, Jr., Mayor of Inglewood; NASA astronauts Michael Fincke and Gregory Johnson, far right. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Beginning Oct. 30, the shuttle will be on display in the CSC’s Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, embarking on its new mission to commemorate past achievements in space and educate and inspire future generations of explorers. Photo Credit: (NASA/Carla Cioffi)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4832301C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4832301C"><span>Catalytic Diversity in Alkaline <span class="hlt">Hydrothermal</span> Vent <span class="hlt">Systems</span> on Ocean Worlds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik</p> <p>2016-10-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> formed by serpentinization can create moderate-temperature, alkaline <span class="hlt">systems</span> and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline <span class="hlt">hydrothermal</span> vents (Russell et al., 2014). <span class="hlt">Hydrothermal</span> chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock <span class="hlt">systems</span> on ocean worlds may lead to <span class="hlt">hydrothermal</span> precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent <span class="hlt">systems</span>.Therefore, further understanding on the electroactive roles of various organic species within <span class="hlt">hydrothermal</span> chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311-318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm. 51</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017870','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017870"><span>Dynamic behavior of Kilauea Volcano and its relation to <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and geothermal energy</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kauhikaua, Jim; Moore, R.B.; ,</p> <p>1993-01-01</p> <p>Exploitation of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on active basaltic volcanoes poses some unique questions about the role of volcanism and <span class="hlt">hydrothermal</span> <span class="hlt">system</span> evolution. Volcanic activity creates and maintains <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> while earthquakes create permeable fractures that, at least temporarily, enhance circulation. Magma and water, possibly <span class="hlt">hydrothermal</span> water, can interact violently to produce explosive eruptions. Finally, we speculate on whether volcanic behavior can be affected by high rates of heat extraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300013HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300013HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>A government Transfer Order for Excess Personal Property is seen framed outside the office of President and CEO, California Science Center, Jeffrey N. Rudolph, on Tuesday, Oct. 30, 2012, in Los Angeles. The grand opening ceremony for the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion took place on Tuesday, Oct. 30, 2012. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201210300011HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201210300011HQ.html"><span><span class="hlt">Endeavour</span> Grand Opening Ceremony</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-10-30</p> <p>NASA Astronauts, from left, Danny Olivas, Garrett Reisman, Barbara Morgan, and, NASA Associate Administrator for Education and Astronaut, Leland Melvin give high fives to school children as they enter the California Science center's Samuel Oschin Space Shuttle <span class="hlt">Endeavour</span> Display Pavilion, Tuesday, Oct. 30, 2012, in Los Angeles. <span class="hlt">Endeavour</span>, built as a replacement for space shuttle Challenger, completed 25 missions, spent 299 days in orbit, and orbited Earth 4,671 times while traveling 122,883,151 miles. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSME24D0741B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSME24D0741B"><span>Chasing plumes at the <span class="hlt">Endeavour</span> Segment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Book, J. W.; Jeffries, M. A.; Mihaly, S. F.; Jenkyns, R.; Timmerman, R.</p> <p>2016-02-01</p> <p>The five major <span class="hlt">hydrothermal</span> vents of the <span class="hlt">Endeavour</span> Segment along the Juan de Fuca Ridge are estimated to emit the heat energy of a small nuclear power plant. From high temperature vent structures, this energy, along with mineral-rich vent fluids, is emitted chimney-like into the ocean, subsequently mixing with seawater and rising to neutral buoyancy between 150 and 300m above the seafloor. At this elevation, the <span class="hlt">hydrothermal</span> vent plume is above the protection of the rift valley and is free to be carried away in the ambient ocean currents. In addition to anomalous chemical properties and particulates, the plume also carries planktonic residents of the deep-sea vent area. These larvae are key to the ongoing success of the existing ecosystems and their transport can facilitate the rapid colonization of newly formed venting sites. During Ocean Network Canada's 2015 maintenance expedition at the <span class="hlt">Endeavour</span> Segment, we surveyed the vent plume both along and across-axis using optical transmission to locate the plume. Analysis of our observations reveals that the plume is retained over the central axis of the valley, thus exhibiting favorable conditions for the promulgation of vent ecosystems. We compare this analysis with earlier surveys conducted by Ocean Networks Canada as well as historic data collected since 1986 by the Institute of Ocean Sciences to estimate the spatial variability of the plume. Using this we propose a "climatology" of plume spreading over the <span class="hlt">Endeavour</span> Segment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004EOSTr..85...37E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004EOSTr..85...37E"><span>Explorations of Mariana Arc Volcanoes Reveal New <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Embley, R. W.; Baker, E. T.; Chadwick, W. W., Jr.; Lupton, J. E.; Resing, J. A.; Massoth, G. J.; Nakamura, K.</p> <p>2004-01-01</p> <p>Some 20,000 km of volcanic arcs, roughly one-third the length of the global mid-ocean ridge (MOR) <span class="hlt">system</span>, rim the western Pacific Ocean. Compared to 25 years of <span class="hlt">hydrothermal</span> investigations along MORs, exploration of similar activity on the estimated ~600 submarine arc volcanoes is only beginning [Ishibashi and Urabe, 1995; De Ronde et al., 2003]. To help alleviate this under-sampling, the R/V T. G. Thompson was used in early 2003 (9 February to 5 March) to conduct the first complete survey of <span class="hlt">hydrothermal</span> activity along 1200 km of the Mariana intra-oceanic volcanic arc. This region includes both the Territory of Guam and the Commonwealth of the Northern Mariana Islands. The expedition mapped over 50 submarine volcanoes with stunning new clarity (Figures 1 and 2) and found active <span class="hlt">hydrothermal</span> discharge at 12 sites, including the southern back-arc site. This includes eight new sites along the arc (West Rota, Northwest Rota, E. Diamante, Zealandia Bank, Maug Caldera, Ahyi, Daikoku, and Northwest Eifuku) and four sites of previously known <span class="hlt">hydrothermal</span> activity (Seamount X, Esmeralda, Kasuga 2, and Nikko) (Figures 1 and 2). The mapping also fortuitously provided a ``before'' image of the submarine flanks of Anatahan Island, which had its first historical eruption on 10 May 2003 (Figures 1 and 3).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4606B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4606B"><span>Asymmetrical <span class="hlt">hydrothermal</span> <span class="hlt">system</span> below Merapi volcano imaged by geophysical data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrdina, Svetlana; Friedel, Sven; Budi-Santoso, Agus; Suryanto, Wiwit; Suhari, Aldjarishy; Vandemeulebrouck, Jean; Rizal, Mohhamed H.; Grandis, Hendra</p> <p>2017-04-01</p> <p>A high-resolution image of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Merapi volcano is obtained using electrical resistivity tomography (ERT), self-potential, and CO2 flux mappings. The ERT inversions identify two distinct low-resistivity bodies, at the base of the south flank and in the summit area, that represent likely two parts of an interconnected <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. In the summit area, the extension of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is clearly limited by the main geological structures which are actual and ancient craters. A sharp resistivity contrast at ancient crater rim Pasar-Bubar separates a conductive <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (20 - 50 Ωm) from the resistive andesite lava flows and pyroclastic deposits (2000 - 50 000 Ωm). High diffuse CO2 degassing (with a median value of 400g m -2 d -1) is observed in a narrow vicinity of the active crater rim and close to the Pasar-Bubar. The existence of preferential fluid circulation along this ancient crater rim is also evidenced by self-potential data. The total CO2 degassing across the accessible summit area with a surface of 1.4 · 10 5 m 2 is around 20 td -1. Before the 2010 eruption, Toutain et al. (2009) estimated a higher value of the total diffuse degassing from the summit area (about 200 - 230 td -1). This drop in the diffuse degassing can be related to the decrease in the magmatic activity, to the change of the summit morphology or to a combination of these factors. On the south flank of Merapi, the resistivity model shows spectacular stratification. While surficial recent andesite lava flows are characterized by resistivity exceeding 100 000 Ωm, resistivity as low as 10 Ωm has been encountered at a depth of 200 m at the base of the south flank and was interpreted as a presence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We suggest that a sandwich-like structure of stratified pyroclastic deposits on the flanks of Merapi screen and separate the flow of <span class="hlt">hydrothermal</span> fluids with the degassing occurring mostly through the fractured crater rims</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V22D..05R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V22D..05R"><span>Selenium Isotopes as Biosignatures in Seafloor <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rouxel, O.; Ludden, J.; Fouquet, Y.</p> <p>2001-12-01</p> <p>Chemically similar to sulphur, Se occurs as +6, +4, 0 and -2 valences in a variety of organic compounds and geological settings. This makes the study of Se stable isotope ratios a potential indicator of geological and biological processes. Se isotopes were first determined in the early 60's (Krouse and Thode, 1962; Rashid et al., 1978) using gas-source MS and recently by N-TIMS (Herbel et al., 2000; Johnson et al., 1999) using the double spike technique. The previous results showed that the 82Se/76Se ratio vary by as much as 15‰ and indicate that abiotic and bacterial reduction of soluble oxyanions is the dominant cause of Se isotope fractionation. Our isotopic analyses of Se were performed using a continuous flow hydride generation <span class="hlt">system</span> coupled to a Micromass MC-ICP-MS after chemical purification. The estimated external precision of the 82Se/76Se isotope ratio is 0.25‰ (2σ ) for a quantity of Se per analysis as low as 50 ng and the data are reported relative to our internal standards (MERCK elemental standard solution). In this study we have used Se isotopes in conjunction with S isotopes to provide additional constraints on the fractionation processes in seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Several fields were studied along the Mid Atlantic Ridge and include the Lucky Strike field where the setting is in a caldera <span class="hlt">system</span> with abundant low-permeability layers of cemented breccia which result in fluid cooling and mixing below the <span class="hlt">hydrothermal</span> vents. Based on vent structures, mineral abundance, and geochemistry, two types of <span class="hlt">hydrothermal</span> deposits were identified: (1) high-T vents with δ 34S between 1.5 and 4.5‰ and Se values up to 2000 ppm; (2) low-T vents where pyrite and marcasite generally have lower δ 34S values (down to -1.0‰ ) and low concentration of Se (<50ppm). Se-depletion in low temperature <span class="hlt">hydrothermal</span> deposits is interpreted as a result of subsurface precipitation of sulfides (scavenging Se from the fluid) during the conductive cooling of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5119283','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5119283"><span><span class="hlt">Hydrothermal</span> <span class="hlt">system</span> in Southern Grass Valley, Pershing County, Nevada</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Welch, A.H.; Sorey, M.L.; Olmsted, F.H.</p> <p>1981-01-01</p> <p>Southern Grass Valley is a fairly typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active <span class="hlt">hydrothermal</span> flow <span class="hlt">system</span> with an estimated deep aquifer temperature of 163 to 176/sup 0/C. Results of geologic, hydrologic, geophysical and geochemical investigations are discussed in an attempt to construct an internally consistent model of the <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017437','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017437"><span>The <span class="hlt">hydrothermal</span>-convection <span class="hlt">systems</span> of kilauea: an historical perspective</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Moore, R.B.; Kauahikaua, J.P.</p> <p>1993-01-01</p> <p>Kilauea is one of only two basaltic volcanoes in the world where geothermal power has been produced commercially. Little is known about the origin, size and longevity of its <span class="hlt">hydrothermal</span>-convection <span class="hlt">systems</span>. We review the history of scientific studies aimed at understanding these <span class="hlt">systems</span> and describe their commercial development. Geothermal energy is a controversial issue in Hawai'i, partly because of hydrogen sulfide emissions and concerns about protection of rain forests. ?? 1993.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1981/0915/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1981/0915/report.pdf"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in southern Grass Valley, Pershing County, Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Welch, Alan H.; Sorey, M.L.; Olmsted, F.H.</p> <p>1981-01-01</p> <p>Southern Grass Valley is typical extensional basin in the Basin and Range province. Leach Hot Springs, in the southern part of the valley, represents the discharge end of an active <span class="hlt">hydrothermal</span> flow <span class="hlt">system</span> with an estimated deep aquifer temperature of 163-173C. This report discusses results of geologic, hydrologic, geophysical and geochemical investigations used in an attempt to construct an internally consistent model of the <span class="hlt">system</span>. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5698254','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5698254"><span>The <span class="hlt">hydrothermal</span>-convection <span class="hlt">systems</span> of Kilauea: An historical perspective</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Moore, R.B. . Federal Center); Kauahikaua, J.P. . Hawaiian Volcano Observatory)</p> <p>1993-08-01</p> <p>Kilauea is one of only two basaltic volcanoes in the world where geothermal power has been produced commercially. Little is known about the origin, size and longevity of its <span class="hlt">hydrothermal</span>-convection <span class="hlt">systems</span>. The authors review the history of scientific studies aimed at understanding these <span class="hlt">systems</span> and describe their commercial development. Geothermal energy is a controversial issue in Hawaii, partly because of hydrogen sulfide emissions and concerns about protection of rain forests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B13A0200P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B13A0200P"><span>The Use of Stable Hydrogen Isotopes as a Geothermometer in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Proskurowski, G.; Lilley, M. D.; Früh-Green, G. L.; Olson, E. J.; Kelley, D. S.</p> <p>2004-12-01</p> <p>Terrestrial geothermal work by Arnason in the 1970's demonstrated the utility of stable hydrogen isotopes as a geothermometer[1]. However, with the exception of two data points from 9°N in a study by Horibe and Craig[2], the value of this geothermometer in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> has never been rigorously assessed. Equilibrium fractionation factors for H2-H2O and H2-CH4 have previously been determined experimentally and theoretically over a range of temperatures and provide an expression relating alpha (fractionation) and temperature. We have measured the dD of H2(g), CH4(g) and H2O from a diverse selection of <span class="hlt">hydrothermal</span> vent localities including Lost City, Middle Valley, <span class="hlt">Endeavour</span>, Guaymas, Logatchev, Broken Spur, and SWIR. These samples were chosen to represent a wide range of fluid temperatures and a variety of environmental settings. We see a strong correlation between measured vent temperature and predicted vent temperature using both the hydrogen-water and the methane-hydrogen geothermometers over a temperature range of 25-400°C. In the case of the H2-H2O geothermometer, the predicted temperatures are slightly elevated with respect to the measured temperatures at the low temperature Lost City site, and are in good agreement at high temperature vent sites. The H2-CH4 geothermometer predicts temperatures that are 40-80°C elevated with respect to the measured temperature in both the low and high temperature sites. These measurements demonstrate that the hydrogen isotope geothermometer in the hydrogen-methane-water <span class="hlt">system</span> is robust in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and may be a useful tool in determining the temperature of the root zone. 1. Arnason, B., The Hydrogen-Water Isotope Thermometer Applied to Geothermal Areas In Iceland. Geothermics, 1977. 5: p. 75-80. 2. Horibe, Y. and H. Craig, D/ H fractionation in the <span class="hlt">system</span> methane-hydrogen-water. Geochimica et Cosmochimica Acta, 1995. 59(24): p. 5209-5217.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/889386','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/889386"><span>Instabilities during liquid migration into superheated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fitzgerald, Shaun D.; Woods, Andrew W.</p> <p>1995-01-26</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> typically consist of hot permeable rock which contains either liquid or liquid and saturated steam within the voids. These <span class="hlt">systems</span> vent fluids at the surface through hot springs, fumaroles, mud pools, steaming ground and geysers. They are simultaneously recharged as meteoric water percolates through the surrounding rock or through the active injection of water at various geothermal reservoirs. In a number of geothermal reservoirs from which significant amounts of hot fluid have been extracted and passed through turbines, superheated regions of vapor have developed. As liquid migrates through a superheated region of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, some of the liquid vaporizes at a migrating liquid-vapor interface. Using simple physical arguments, and analogue laboratory experiments we show that, under the influence of gravity, the liquid-vapor interface may become unstable and break up into fingers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12891356','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12891356"><span>Constrained circulation at <span class="hlt">Endeavour</span> ridge facilitates colonization by vent larvae.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thomson, Richard E; Mihály, Steven F; Rabinovich, Alexander B; McDuff, Russell E; Veirs, Scott R; Stahr, Frederick R</p> <p>2003-07-31</p> <p>Understanding how larvae from extant <span class="hlt">hydrothermal</span> vent fields colonize neighbouring regions of the mid-ocean ridge <span class="hlt">system</span> remains a major challenge in oceanic research. Among the factors considered important in the recruitment of deep-sea larvae are metabolic lifespan, the connectivity of the seafloor topography, and the characteristics of the currents. Here we use current velocity measurements from <span class="hlt">Endeavour</span> ridge to examine the role of topographically constrained circulation on larval transport along-ridge. We show that the dominant tidal and wind-generated currents in the region are strongly attenuated within the rift valley that splits the ridge crest, and that <span class="hlt">hydrothermal</span> plumes rising from vent fields in the valley drive a steady near-bottom inflow within the valley. Extrapolation of these findings suggests that the suppression of oscillatory currents within rift valleys of mid-ocean ridges shields larvae from cross-axis dispersal into the inhospitable deep ocean. This effect, augmented by plume-driven circulation within rift valleys having active <span class="hlt">hydrothermal</span> venting, helps retain larvae near their source. Larvae are then exported preferentially down-ridge during regional flow events that intermittently over-ride the currents within the valley.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JVGR..329...30B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JVGR..329...30B"><span>Geophysical image of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Merapi volcano</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrdina, S.; Friedel, S.; Vandemeulebrouck, J.; Budi-Santoso, A.; Suhari; Suryanto, W.; Rizal, M. H.; Winata, E.; Kusdaryanto</p> <p>2017-01-01</p> <p>We present an image of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Merapi volcano based on results from electrical resistivity tomography (ERT), self-potential, and CO2 flux mappings. The ERT models identify two distinct low-resistivity bodies interpreted as two parts of a probably interconnected <span class="hlt">hydrothermal</span> <span class="hlt">system</span>: at the base of the south flank and in the summit area. In the summit area, a sharp resistivity contrast at ancient crater rim Pasar-Bubar separates a conductive <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (20-50 Ω m) from the resistive andesite lava flows and pyroclastic deposits (2000-50,000 Ω m). The existence of preferential fluid circulation along this ancient crater rim is also evidenced by self-potential data. The significative diffuse CO2 degassing (with a median value of 400 g m-2 d-1) is observed in a narrow vicinity of the active crater rim and close to the ancient rim of Pasar-Bubar. The total CO2 degassing across the accessible summital area with a surface of 1.4 ṡ 105 m2 is around 20 t d-1. Before the 2010 eruption, Toutain et al. (2009) estimated a higher value of the total diffuse degassing from the summit area (about 200-230 t d-1). This drop in the diffuse degassing from the summit area can be related to the decrease in the magmatic activity, to the change of the summit morphology, to the approximations used by Toutain et al. (2009), or, more likely, to a combination of these factors. On the south flank of Merapi, the resistivity model shows spectacular stratification. While surficial recent andesite lava flows are characterized by resistivity exceeding 100,000 Ω m, resistivity as low as 10 Ω m has been encountered at a depth of 200 m at the base of the south flank and was interpreted as a presence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. No evidence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is found on the basis of the north flank at the same depth. This asymmetry might be caused by the asymmetry of the heat supply source of Merapi whose activity is moving south or/and to the asymmetry in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B13E..05R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B13E..05R"><span>Geochemical Constraints on Archaeal Diversity in the Vulcano <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogers, K. L.; Amend, J. P.</p> <p>2006-12-01</p> <p>The shallow marine <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Vulcano, Italy hosts a wide diversity of cultured thermophilic Archaea, including Palaeococcus helgesonii, Archaeoglobus fulgidus, and Pyrococcus furiosus, to name a few. However, recent studies have revealed a plethora of uncultured archaeal lineages in the Vulcano <span class="hlt">system</span>. For example, a 16S rRNA gene survey of an onshore geothermal well identified a diverse archaeal community including deeply-branching uncultured Crenarchaeota, Korarchaeota, and Euryarchaeota. Additionally, culture-independent hybridization techniques suggested that Archaea account for nearly half of the microbial community in the Vulcano <span class="hlt">system</span>. Furthermore, geochemical characterization of fluids revealed numerous lithotrophic and heterotrophic exergonic reactions that could support as yet uncultured organisms. Archaeal diversity throughout the Vulcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was investigated using 16S rRNA gene surveys at five submarine vents and an onshore sediment seep. Overall, archaeal diversity was higher (10 groups) at submarine vents with moderate temperatures (59°C) compared with higher temperature (94°C) vents (4 groups). Archaeal communities at the moderately thermal vents were dominated by Thermococcales and also contained Archaeoglobales, Thermoproteales, and uncultured archaea among the Korarchaeota, Marine Group I, and the Deep-sea <span class="hlt">Hydrothermal</span> Vent Euryarchaeota (DHVE). Fluid composition also affects the microbial community structure. At two high-temperature sites variations in archaeal diversity can be attributed to differences in iron and hydrogen concentrations, and pH. Comparing sites with similar temperature and pH conditions suggests that the presence of Desulfurococcales is limited to sites at which metabolic energy yields exceed 10 kJ per mole of electrons transferred. The Vulcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span> hosts diverse archaeal communities, containing both cultured and uncultured species, whose distribution appears to be constrained by</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS41C1832S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS41C1832S"><span>Modeling of Perturbations in Mid-Ocean <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, S.; Lowell, R. P.</p> <p>2013-12-01</p> <p>Mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are complex fluid circulation <span class="hlt">systems</span> straddling the locations of formation of oceanic crust. Due to the dynamic nature of the crust building process, these <span class="hlt">systems</span> are episodically subject to magmatic and seismic perturbations. Magma may be emplaced deep or shallow in the oceanic crust thereby changing the thermal structure and permeability of the <span class="hlt">system</span>. Such events would enhance <span class="hlt">hydrothermal</span> venting resulting in an increase in vent temperature and heat output along with a decrease in vent salinity in a phase separating <span class="hlt">system</span>. Event plumes, which may be associated with dike intrusions into the shallow crust, are an important class of such perturbations. In this case, the formation of low salinity vapor may add to the thermal buoyancy flux and allow the plume to rise rapidly to a considerable height above the seafloor. Additionally, seismic or tectonic disturbances may occur both deep and shallow in the crust, changing the fluid-flow structure in the <span class="hlt">system</span>. Upon knowledge of a major magmatic or seismotectonic event, temporary surveillance at the respective mid ocean ridge site is often increased as a result of rapid response cruises. One of the most common observations made after such events is the temperature of vent fluids, which is then correlated to time of observed activity and used to estimate the residence time of fluids in the <span class="hlt">system</span>. However, our numerical results indicate that for deep-seated perturbations, surface salinity may show quicker response than temperature. This result serves as our motivation to seek better understanding of propagation mechanism of perturbations through <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. We construct analytical models for fluid flow, heat and salt transfer in both single cracks and through porous media to investigate how perturbations affect both heat and salt transfer to the surface. Our preliminary results for simplified fluid circulation <span class="hlt">systems</span> tend to support the results from numerical modeling</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012947','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012947"><span>YELLOWSTONE MAGMATIC-<span class="hlt">HYDROTHERMAL</span> <span class="hlt">SYSTEM</span>, U. S. A.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fournier, R.O.; Pitt, A.M.; ,</p> <p>1985-01-01</p> <p>At Yellowstone National Park, the deep permeability and fluid circulation are probably controlled and maintained by repeated brittle fracture of rocks in response to local and regional stress. Focal depths of earthquakes beneath the Yellowstone caldera suggest that the transition from brittle fracture to quasi-plastic flow takes place at about 3 to 4 km. The maximum temperature likely to be attained by the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is 350 to 450 degree C, the convective thermal output is about 5. 5 multiplied by 10**9 watts, and the minimum average thermal flux is about 1800 mW/m**2 throughout 2,500 km**2. The average thermal gradient between the heat source and the convecting <span class="hlt">hydrothermal</span> <span class="hlt">system</span> must be at least 700 to 1000 degree C/km. Crystallization and partial cooling of about 0. 082 km**3 of basalt or 0. 10 km**3 of rhyolite annually could furnish the heat discharged in the hot-spring <span class="hlt">system</span>. The Yellowstone magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> as a whole appears to be cooling down, in spite of a relatively large rate of inflation of the Yellowstone caldera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015215','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015215"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of the Calabozos caldera, central Chilean Andes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Grunder, A.L.; Thompson, J.M.; Hildreth, W.</p> <p>1987-01-01</p> <p>Active thermal springs associated with the late Pleistocene Calabozos caldera complex occur in two groups: the Colorado group which issues along structures related to caldera collapse and resurgence, and the Puesto Calabozos group, a nearby cluster that is chemically distinct and probably unrelated to the Colorado springs. Most of the Colorado group can be related to a hypothetical parent water containing ???400 ppm Cl at ???250??C by dilution with ???50% of cold meteoric water. The thermal springs in the most deeply eroded part of the caldera were derived from the same parent water by boiling. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> has probably been active for at least as long as 300,000 years, based on geologic evidence and calculations of paleo-heat flow. There is no evidence for economic mineralization at shallow depth. The Calabozos <span class="hlt">hydrothermal</span> <span class="hlt">system</span> would be an attractive geothermal prospect were its location not so remote. ?? 1987.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/495688','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/495688"><span>Flow and permeability structure of the Beowawe, Nevada <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faulder, D.D.; Johnson, S.D.; Benoit, W.R.</p> <p>1997-05-01</p> <p>A review of past geologic, geochemical, hydrological, pressure transient, and reservoir engineering studies of Beowawe suggests a different picture of the reservoir than previously presented. The Beowawe <span class="hlt">hydrothermal</span> contains buoyant thermal fluid dynamically balanced with overlying cold water, as shown by repeated temperature surveys and well test results. Thermal fluid upwells from the west of the currently developed reservoir at the intersection of the Malpais Fault and an older structural feature associated with mid-Miocene rifting. A tongue of thermal fluid rises to the east up the high permeability Malpais Fault, discharges at the Geysers area, and is in intimate contact with overlying cooler water. The permeability structure is closely related to the structural setting, with the permeability of the shallow <span class="hlt">hydrothermal</span> <span class="hlt">system</span> ranging from 500 to 1,000 D-ft, while the deeper <span class="hlt">system</span> ranges from 200 to 400 D-ft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987JVGR...32..287G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987JVGR...32..287G"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of the Calabozos caldera, central Chilean Andes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grunder, Anita L.; Thompson, J. Michael; Hildreth, W.</p> <p>1987-07-01</p> <p>Active thermal springs associated with the late Pleistocene Calabozos caldera complex occur in two groups: the Colorado group which issues along structures related to caldera collapse and resurgence, and the Puesto Calabozos group, a nearby cluster that is chemically distinct and probably unrelated to the Colorado springs. Most of the Colorado group can be related to a hypothetical parent water containing ˜400 ppm Cl at ˜250°C by dilution with ≥50% of cold meteoric water. The thermal springs in the most deeply eroded part of the caldera were derived from the same parent water by boiling. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> has probably been active for at least as long as 300,000 years, based on geologic evidence and calculations of paleo-heat flow. There is no evidence for economic mineralization at shallow depth. The Calabozos <span class="hlt">hydrothermal</span> <span class="hlt">system</span> would be an attractive geothermal prospect were its location not so remote.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/543373','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/543373"><span><span class="hlt">Hydrothermal</span> vents is Lake Tanganyika, East African Rift <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tiercelin, J.J.; Pflumio, C.; Castrec, M.</p> <p>1993-06-01</p> <p>Sublacustrine <span class="hlt">hydrothermal</span> vents with associated massive sulfides were discovered during April 1987 at Pemba and Cape Banza on the Zaire side of the northern basin of Lake Tanganyika, East African Rift <span class="hlt">system</span>. New investigations by a team of ten scuba divers during the multinational (France, Zaire, Germany, and Burundi) TANGANYDRO expedition (August-October 1991) found <span class="hlt">hydrothermal</span> vents down to a depth of 46 m along north-trending active faults bounding the Tanganyika rift on the western side. Temperatures from 53 to 103 {degrees}C were measured in <span class="hlt">hydrothermal</span> fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with vents at the Pemba site. At Cape Banza, active vents are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of <span class="hlt">hydrothermal</span> pipes. <span class="hlt">Hydrothermal</span> fluid end members show distinctive compositions at the two sites. The Pemba end member is a NaHCO{sub 3}-enriched fluid similar to the NaHCO{sub 3} thermal fluids form lakes Magadi and Bogoria in the eastern branch of the rift. The Cape Banza end member is a solution enriched in NaCl. Such brines may have a deep-seated basement origin, as do the Uvinza NaCl brines on the eastern flank of the Tanganyika basin. Geothermometric calculations have yielded temperatures of fluid-rock interaction of 219 and 179 {degrees}C in the Pemba and Cape Banza <span class="hlt">systems</span>, respectively. Abundant white or reddish-brown microbial colonies resembling Beggiatoa mats were found surrounding the active vents. Thermal fluid circulation is permitted by opening of cracks related to 130{degrees}N normal-dextral faults that intersect the north-south major rift trend. The sources of heat for such <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may relate to the existence of magmatic bodies under the rift, which is suggested by the isotopic composition of carbon dioxide released at Pemba and Cape Banza. 21 refs., 2 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=3F4u5iFIISg','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=3F4u5iFIISg"><span>Space Shuttle <span class="hlt">Endeavour</span> Heads West</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>NASA's Shuttle Carrier Aircraft, a modified 747, flew retired shuttle <span class="hlt">Endeavour</span> from Kennedy Space Center in Florida to Houston on Sept. 19, 2012, to complete the first leg of <span class="hlt">Endeavour</span>'s trip to L...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..825V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..825V"><span>Tracing fluid pathways in Archean <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with imaging spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>von Ruitenbeek, F. J. A.; Cudahy, T.; Hale, M.; van der Werff, H. M. A.; van der Meer, F. D.</p> <p>2008-09-01</p> <p>Abstract Fossil submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in Archean greenstone belts and other geologic terranes are important because of their relationship with volcanic massive sulfide (VMS) mineral deposits and their association with environments that are favorable for early forms of life. Interpretation and reconstruction of these <span class="hlt">systems</span> is difficult because of their geologic complexity. Airborne imaging spectroscopy provides information about the presence, abundance, and composition of near-infrared active minerals at continuous spatial coverage and high spatial resolution, and can therefore be used to obtain new geologic insights into of the Archean <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. It was applied to the Panorama VMS-district in the Soanesville greenstone belt, Western Australia. Results from the analyses of 189 hand specimen showed that the wavelength position of the main absorption feature of white micas, a proxy for their Al content, varied between 2195 nm and 2225 nm. These wavelength variations and the relative abundance of white micas were used to reconstruct fossil fluid pathways from low-temperature recharge to hightemperature discharge zones. Results also showed that the absorption-wavelength variations of white micas could be mapped from airborne imaging spectroscopy using a stochastic method where the presence of white mica minerals and their absorption wavelengths in field measurements were predicted from hyperspectral band ratios. Analysis of the spatial patterns in segmented images, covering 52 km2, of white mica probability and their absorption wavelengths and their comparison with field data resulted in the identification of regional scale <span class="hlt">hydrothermal</span> fluid pathways, a regional-scale K alteration event, and differences in <span class="hlt">hydrothermal</span> regime between the northern and southern parts of the test area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OLEB...45...93K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OLEB...45...93K"><span><span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> of Kamchatka are Models of the Prebiotic Environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kompanichenko, V. N.; Poturay, V. A.; Shlufman, K. V.</p> <p>2015-06-01</p> <p>The composition of organic matter and fluctuations of thermodynamic parameters were investigated in the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of the Kamchatka peninsula in the context of the origin of life. Organics were analyzed by gas-chromatography/mass spectrometry, and 111 organic compounds belonging to 14 homologous series (aromatic hydrocarbons, alkanes and isoalkanes, halogenated aromatic hydrocarbons, carboxylic acids, esters, etc.) were found in hot springs inhabited by Archaeal and Bacterial thermophiles. The organics detected in the sterile condensate of water-steam mixture taken from deep boreholes (temperature 108-175 °C) consisted of 69 compounds of 11 homologous series, with aromatic hydrocarbons and alkanes being prevalent. The organic material included important prebiotic components such as nitrogen-containing compounds and lipid precursors. A separate organic phase (oil) was discovered in the Uzon Caldera. A biogenic origin is supported by the presence of sterane and hopane biomarkers and the δ13C value of the bulk oil; its age determined by 14C measurements was 1030 ± 40 years. Multilevel fluctuations of thermodynamic parameters proposed to be required for the origin of life were determined in the Mutnovsky and Pauzhetsky <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. The low-frequency component of the <span class="hlt">hydrothermal</span> fluid pressure varied by up to 2 bars over periods of hours to days, while mid-frequency variations had regular micro-oscillations with periods of about 20 min; the high-frequency component displayed sharp changes of pressure and microfluctuations with periods less than 5 min. The correlation coefficient between pressure and temperature ranges from 0.89 to 0.99 (average 0.96). The natural regimes of pressure and temperature fluctuations in Kamchatka <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> can guide future experiments on prebiotic chemistry under oscillating conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5111&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5111&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss"><span><span class="hlt">Endeavour</span> after RSS rollback</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>After rollback of the Rotating Service Structure, Space Shuttle <span class="hlt">Endeavour</span> shines under spotlights. At the top of the external tank is the Gaseous Oxygen Vent Arm and its vent hood, known as the '''beanie cap.''' The hood is raised to clear the external tank 2.5 minutes before launch. <span class="hlt">Endeavour</span> is targeted for launch Nov. 30 at about 10:06 p.m. EST on mission STS-97. In the background, the sky prepares for dawn. The mission to the International Space Station carries the P6 Integrated Truss Segment containing solar arrays and batteries that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5698143','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5698143"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Nevado del Ruiz Volcano, Colombia</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lopez, D.A.L.</p> <p>1992-01-01</p> <p>Nevado del Ruiz is an andesitic stratovolcano located 150 km northwest of Bogota, Columbia characterized by a large <span class="hlt">hydrothermal</span> <span class="hlt">system</span> with two very distinctive types of water: acid sulfate waters, and bicarbonate and neutral chloride waters. The waters within each group fall in well-defined lines on compositional cross plots with an apparent lack of mixing between the two water types. The acid sulfate waters appear to be related to the north-west striking and seismically active Villamaria-Termales fault. The neutral chloride waters are clustered to the west and south-east of the volcano. The bicarbonate waters are more widespread. Several <span class="hlt">hydrothermally</span>-altered samples from Nevado del Ruiz volcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span> were analyzed using X-ray diffraction techniques. It was possible to distinguish two sets of mineral assemblages which correspond to the two water types. The acid sulfate waters produce cristobalite, sulfates, hematite or pyrite, sulfur and minor amounts of trydimite, kaolinite, smectite, and illite. The alteration products at the neutral chloride and bicarbonate waters include mainly carbonates and cristobalite. Simulation of the reaction between the <span class="hlt">hydrothermal</span> fluids and the basaltic andesites of the lower volcanic units at Ruiz using the computer program CHILLER yielded mineral assemblages which are consistent with the observed alteration mineralogy. High chloride and sulfate concentrations, and helium and sulfur isotopes suggest that the acid sulfate waters have an important magmatic contribution. The composition of the neutral chloride an bicarbonate waters suggests mineral equilibria with feldspars and carbonates. Both types of waters appear to be the product of mixing of high salinity end members with different proportions of meteoric water. Linear variations in composition of the gases discharged at Ruiz suggested that the gas phase also represents mixing. Faults and contacts play a key role in the circulation of fluids at Ruiz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7088340','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7088340"><span>Petroleum generation and migration in submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>; An overview</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Simoneit, B.R.T. )</p> <p>1990-03-01</p> <p>The conversion of organic matter to petroleum by <span class="hlt">hydrothermal</span> activity is an easy process,occurring in nature in many types of environments. Geologically immature organic matter of mariner sediments is being altered by this process in Guaymas Basin (Gulf of California), Escanaba Trough and Middle Valley (northeast Pacific), Bransfield Strait (Antarctica), and Atlantis II and Kebrit Deeps (Red Sea). Contemporary organic detritus and viable microorganisms are also converted in part to petroleum-like products by the same process when present to become entrained, as for example on the East Pacific Rise at 13{degrees}N and 21{degrees}N and on the mid-Atlantic Ridge at 26{degrees}N. The hydrocarbon products (methane to asphalt) generated in all these areas have been elucidated in terms of composition, organic matter sources, and analogy to reservoir petroleum. This petroleum represents a major input of carbon to the primary chemosynthetic productivity of <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span> and may be important to interactions with metals in <span class="hlt">hydrothermal</span> ore formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.V21B0601J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.V21B0601J"><span>Reconstruction of Ancestral <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> on Mount Rainier Using <span class="hlt">Hydrothermally</span> Altered Rocks in Holocene Debris Flows and Tephras</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>John, D. A.; Breit, G. N.; Sisson, T. W.; Vallance, J. W.; Rye, R. O.</p> <p>2005-12-01</p> <p> geophysical data, as well as analog fossil <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in volcanoes elsewhere, constrain <span class="hlt">hydrothermal</span> alteration geometry on the pre-Osceola-collapse edifice of Mount Rainier. Relatively narrow zones of acid magmatic-<span class="hlt">hydrothermal</span> alteration in the central core of the volcano grade to more widely distributed smectite-pyrite alteration farther out on the upper flanks, capped by steam-heated alteration with a large component of alteration resulting from condensation of fumarolic vapor above the water table. Alteration was polygenetic in zones formed episodically, and was strongly controlled by fluxes of heat and magmatic fluid and by local permeability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1171957','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1171957"><span>Aqueous geochemistry of the Thermopolis <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, southern Bighorn Basin, Wyoming, U.S.A.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaszuba, John P.; Sims, Kenneth W.W.; Pluda, Allison R.</p> <p>2014-06-01</p> <p>The Thermopolis <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is located in the southern portion of the Bighorn Basin, in and around the town of Thermopolis, Wyoming. It is the largest <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in Wyoming outside of Yellowstone National Park. The <span class="hlt">system</span> includes hot springs, travertine deposits, and thermal wells; published models for the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> propose the Owl Creek Mountains as the recharge zone, simple conductive heating at depth, and resurfacing of thermal waters up the Thermopolis Anticline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1171957-aqueous-geochemistry-thermopolis-hydrothermal-system-southern-bighorn-basin-wyoming','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1171957-aqueous-geochemistry-thermopolis-hydrothermal-system-southern-bighorn-basin-wyoming"><span>Aqueous geochemistry of the Thermopolis <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, southern Bighorn Basin, Wyoming, U.S.A.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Kaszuba, John P.; Sims, Kenneth W.W.; Pluda, Allison R.</p> <p>2014-06-01</p> <p>The Thermopolis <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is located in the southern portion of the Bighorn Basin, in and around the town of Thermopolis, Wyoming. It is the largest <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in Wyoming outside of Yellowstone National Park. The <span class="hlt">system</span> includes hot springs, travertine deposits, and thermal wells; published models for the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> propose the Owl Creek Mountains as the recharge zone, simple conductive heating at depth, and resurfacing of thermal waters up the Thermopolis Anticline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.H21B0807S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.H21B0807S"><span>Simple Poroelastic Models for the Tidal Modulation of <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, A.; Jupp, T.</p> <p>2002-12-01</p> <p>Time-series measurements of the temperature and velocity of hydothermal effluent suggest that seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are tidally modulated. Here, we apply the theory of poroelasticity to predict the magnitude and phase of tidally induced temperature and velocity signals at the seafloor relative to each harmonic component of the ocean tide. Firstly, we consider the idealised case of a one-dimensional permeable layer of depth H in which hot effluent ascends with bouyancy-driven volume flux w. Pore pressure variations of a given frequency ω penetrate the crust over a lengthscale D, known as the diffusive skindepth. The subsequent tidal variations in temperature and flow rate are controlled by two dimensionless parameters. The first parameter H/D measures the depth of the permeable layer relative to the skindepth. The second parameter ω D / w measures the timescale of the tidal loading relative to the timescale of the background bouyancy driven flow. We derive analytical solutions in this simplified one-dimensional case as a function of the dimensionless parameters, and discuss discuss their application to real <span class="hlt">systems</span>. Secondly, we consider how the temperature variations within an idealised (two-dimensional) <span class="hlt">hydrothermal</span> cell affect its poroelastic paramaters. In <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, the interstitial water is `liquid-like' below ~ 400o {C} and `gas-like' above ~ 400o {C}. This leads to a marked difference in the poroelastic response between the majority of the cell (in which the water is `liquid-like') and the very hot region at the base of the <span class="hlt">system</span> (in which it is `gas-like').</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-03pd2949.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-03pd2949.html"><span><span class="hlt">Endeavour</span> Impulse Tests</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2003-10-27</p> <p>In the Orbiter Processing Facility, Eric Madaras, NASA-Langley Research Center, conducts impulse tests on the right wing leading edge (WLE) of Space Shuttle <span class="hlt">Endeavour</span>. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s130e012451.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s130e012451.html"><span><span class="hlt">Endeavour</span> Payload Bay</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-20</p> <p>S130-E-012451 (20 Feb. 2010) --- The empty cargo bay and the aft portion of the Earth-orbiting space shuttle <span class="hlt">Endeavour</span> are featured in this image photographed by an STS-130 crew member from inside the spacecraft?s crew cabin. The view is toward the west across southern Africa to the Atlantic ocean. The view follows along the Orange River, which also serves as the border between Namibia (to the right of the river) and South Africa (to the left of the river) nearer to the coast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DPS....33.4801V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DPS....33.4801V"><span>Geochemical energy potentially available to organisms in martian <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varnes, E. S.; Jakosky, B. M.; McCollom, T. M.</p> <p>2001-11-01</p> <p>Although a global average of energy available to potentially support life from chemosynthesis on Mars has been estimated, issues of how the energy is distributed and which environments have the greatest potential to support life remain unresolved. We have begun to address these questions by developing numerical geochemical models of martian <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> using the software package EQ3/6. In order to model <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, the elemental composition of the initial fluid (the groundwater) and the initial host rock with which it interacts must be defined. The host rock was defined using the composition of LEW 88516, which is similar to the martian mantle. This host rock was reacted at high temperature (350 deg C) with a series of groundwaters. Groundwaters are either pure water in equilibrium with present martian atmosphere or in equilibrium with Pathfinder-composition soils and the atmosphere. The hot fluid resulting from the rock/groundwater reaction was then reacted with increments of fresh groundwater, simulating the mixing that occurs in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. During mixing, oxidation and reduction reactions are kinetically inhibited; organisms may exploit this inhibition to derive metabolic energy. The maximum amount of energy an organism can obtain from a given reaction is determined from the Gibbs free energy of that reaction. For each model run, we have calculated the Gibbs free energy of reactions that are important for terrestrial chemosynthetic organisms and likely representative for putative martians. Our results indicate that substantial amounts of energy may be derived from these reactions, but they depend sensitively on the oxidation state of the groundwater and whether saturated species precipitate to equilibrium. Thus, it is unknown whether sufficient energy is available to support martian life, although it is likely that suitable environments exist.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5112&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5112&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss"><span><span class="hlt">Endeavour</span> after RSS rollback</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>After rollback of the Rotating Service Structure, Space Shuttle <span class="hlt">Endeavour</span> is spotlighted against the still-black sky of pre-dawn. At the top of the external tank is the Gaseous Oxygen Vent Arm and its vent hood, known as the '''beanie cap.''' The hood is raised to clear the external tank 2.5 minutes before launch. <span class="hlt">Endeavour</span> is targeted for launch Nov. 30 at about 10:06 p.m. EST on mission STS-97. In the background, the sky prepares for dawn. The mission to the International Space Station carries the P6 Integrated Truss Segment containing solar arrays and batteries that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4561896','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4561896"><span>Lithium isotope traces magmatic fluid in a seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yang, Dan; Hou, Zengqian; Zhao, Yue; Hou, Kejun; Yang, Zhiming; Tian, Shihong; Fu, Qiang</p> <p>2015-01-01</p> <p>Lithium isotopic compositions of fluid inclusions and hosted gangue quartz from a giant volcanogenic massive sulfide deposit in China provide robust evidence for inputting of magmatic fluids into a Triassic submarine <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The δ7Li results vary from +4.5‰ to +13.8‰ for fluid inclusions and from +6.7‰ to +21.0‰ for the hosted gangue quartz(9 gangue quartz samples containing primary fluid inclusions). These data confirm the temperature-dependent Li isotopic fractionation between <span class="hlt">hydrothermal</span> quartz and fluid (i.e., Δδ7Liquartz-fluid = –8.9382 × (1000/T) + 22.22(R2 = 0.98; 175 °C–340 °C)), which suggests that the fluid inclusions are in equilibrium with their hosted quartz, thus allowing to determine the composition of the fluids by using δ7Liquartz data. Accordingly, we estimate that the ore-forming fluids have a δ7Li range from −0.7‰ to +18.4‰ at temperatures of 175–340 °C. This δ7Li range, together with Li–O modeling , suggest that magmatic fluid played a significant role in the ore formation. This study demonstrates that Li isotope can be effectively used to trace magmatic fluids in a seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span> and has the potential to monitor fluid mixing and ore-forming process. PMID:26347051</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5669K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5669K"><span><span class="hlt">Hydrothermal</span> fluxes of magmatic chlorine and sulfur from volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of the Kuril Islands (Russia).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalacheva, Elena; Taran, Yuri</p> <p>2017-04-01</p> <p>The <span class="hlt">hydrothermal</span> flux may be provided by the discharge of fluids formed at depth over the magma body and/or by acid waters, which are formed by the absorption of the ascending volcanic vapor by shallow groundwater. Thus, the anion composition (Cl and SO4) of the discharging thermal waters from a volcano-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> in many cases originates from the volcanic vapor and should be taken into account in estimations of the magmatic volatile output and volatile recycling in subduction zones. Here we report the chemical composition of thermal waters and the measured solute fluxes from volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of Kuril Islands including Paramushir (Ebeko volcanic centre), Shiashkotan (volcanoes Sinarka and Kuntomintar), Ketoy (Pallas volcano), Kunashir (volcanoes Mendeleev and Golovnin). The fluxes were estimated after measuring flow rates and water composition of streams that drain thermal fields of islands. The maximal <span class="hlt">hydrothermal</span> flux of Cl and S within the Kuril Chain was measured for Ebeko volcano, Paramushir (drained by Yurieva River) as 82 t/d and 222 t/d of chloride and sulfate, respectively. This is comparable with output by fumaroles of Ebeko. The total discharge of Cl and SO4 from Shiashkotan Island to the Sea of Okhotsk and Pacific Ocean associated with magmatic activity of two volcanoes is estimated as 20 t/d and 102 t/d, respectively, which is significantly lower than the fumarolic output. The <span class="hlt">hydrothermal</span> flux of Ketoy Island is also low, 8.5 t/d of Cl and 30 t/d of SO4, much lower than the fumarolic flux. There are two volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at the Kunashir, the southern island of Kurils. The Ozernaya River drains all thermal fields inside of the Golovnin caldera into the Sea of Okhotsk. The Lesnaya River drains two main thermal fields and thermal springs on the Mendeleev volcano slopes into Pacific Ocean. The volcano-<span class="hlt">hydrothermal</span> output of chloride and sulfate from Mendeleev volcano was measured as 7.8 t/d of Cl and 11.6 of SO4, and from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10123674','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10123674"><span>Testing geochemical modeling codes using New Zealand <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.</p> <p>1993-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of selected portions of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with predictions of fluid-solid equilibria made using geochemical modeling codes will: (1) ensure that we are providing adequately for all significant processes occurring in natural <span class="hlt">systems</span>; (2) determine the adequacy of the mathematical descriptions of the processes; (3) check the adequacy and completeness of thermodynamic data as a function of temperature for solids, aqueous species and gases; and (4) determine the sensitivity of model results to the manner in which the problem is conceptualized by the user and then translated into constraints in the code input. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions. The kinetics of silica precipitation in EQ6 will be tested using field data from silica-lined drain channels carrying hot water away from the Wairakei borefield.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V13B2850J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V13B2850J"><span>The <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> at the Grand Canyon of the Yellowstone River: Exposed and Hidden</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaworowski, C.; Heasler, H. P.; Susong, D. D.; Neale, C. M.; Sivarajan, S.; Masih, A.</p> <p>2012-12-01</p> <p>Combining calibrated and corrected night-time, airborne thermal infrared imaging with field information from the 2008 drilling of the Canyon borehole strainmeter (B206) in Yellowstone National Park emphasizes the extensive nature of Yellowstone's <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Both studies contributed to an understanding of the vertical and horizontal flow of heat and fluids through the bedrock in this area. Night-time, airborne thermal infrared imagery, corrected for emissivity and atmosphere clearly shows north-trending faults and fractures transmitting heat and fluids through the rhyolitic bedrock and into the overlying glacial sediments near the Canyon borehole. Along the Grand Canyon of the Yellowstone, the Clear Lake <span class="hlt">hydrothermal</span> area is an example of <span class="hlt">hydrothermal</span> alteration at the ground surface. The numerous <span class="hlt">hydrothermal</span> features exposed in the nearby Grand Canyon of the Yellowstone River and its <span class="hlt">hydrothermally</span> altered walls are clear evidence of the exposed <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The bedrock geology, geologic processes, and <span class="hlt">hydrothermal</span> activity combined to form the dramatic Grand Canyon of the Yellowstone. The night-time thermal infrared imagery provides a new view of this exposed <span class="hlt">hydrothermal</span> <span class="hlt">system</span> for scientists and visitors. Scientists and Yellowstone Park managers carefully sited the Canyon borehole strainmeter in a green, grassy meadow to insure successful completion of the borehole in a non-<span class="hlt">hydrothermal</span> area. The closest <span class="hlt">hydrothermal</span> feature to the drilling site was about 2.5 km to the east. Although excellent exposures of <span class="hlt">hydrothermal</span> altered bedrock are present about 1.5 km east at the Lower Falls and the Grand Canyon of the Yellowstone River, the connection between exposed <span class="hlt">hydrothermal</span> areas and the borehole site was not obvious. After drilling through 9 m of brown-gray muds and 113 m of rock, a bottom hole temperature of 81.2 degrees Celsius precluded drilling the hole any deeper than 122 m. The post-drilling data collected from B206 and the airborne</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhDT.......200A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhDT.......200A"><span>Long-term optimal operation of <span class="hlt">hydrothermal</span> power <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ardekaaniaan, Rezaa</p> <p></p> <p>When new construction projects are postponed or cancelled because of socio-economic concerns, greater emphasis is placed on enhanced operational planning---to get the most at the least cost, from the existing projects. Of the approaches that made significant improvement in the operation of energy production <span class="hlt">systems</span> is the co-ordination between hydro and thermal power plants. In this research, the problem of "Long-term Optimal Operation of <span class="hlt">Hydro-Thermal</span> Power <span class="hlt">Systems</span>" is addressed. Considering the uncertainty in reservoir inflows, the problem is defined as a "two-stage stochastic linear network programming with recourse". To avoid dimensionality problem generally associated with the employment of dynamic programming in large scale applications, Benders' decomposition approach is employed as the solution algorithm basis for the defined problem. Using the "General Algebraic Modelling <span class="hlt">System</span>", a modelling code, the "<span class="hlt">Hydro-Thermal</span> Co-ordinating Model (HTCOM)" is developed. In HTCOM, each sequence of hydrologic inflows generates a subproblem which is solved deterministically. The solutions of all subproblems are next co-ordinated by a master problem to determine a single feasible optimal policy for the original problem. This policy includes optimal reservoirs releases as well as allocation of energy generation at different power plants in the subsequent time period. The objective minimizes the expected total cost of meeting the energy demands while satisfying the <span class="hlt">system</span> constraints over the long-term horizon of one to three years. To demonstrate the applicability of HTCOM, a real world case study named the "Khozestan Water and Power Authority (KWPA)" in Iran is employed as a <span class="hlt">system</span> of two multipurpose reservoirs with five <span class="hlt">hydro-thermal</span> power plants and transactions of energy. The KWPA <span class="hlt">system</span> components and operating policies are simulated as the network flow model and an integrated solution procedure is planned to determine the optimal operation policies. This procedure</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1021991','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1021991"><span>Mechanisms of iron oxide transformations in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Otake, Tsubasa; Wesolowski, David J; Anovitz, Lawrence {Larry} M; Allard Jr, Lawrence Frederick; Ohmoto, Hiroshi</p> <p>2010-01-01</p> <p>Coexistence of magnetite and hematite in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> has often been used to constrain the redox potential of fluids, assuming that the redox equilibrium is attained among all minerals and aqueous species. However, as temperature decreases, disequilibrium mineral assemblages may occur due to the slow kinetics of reaction involving the minerals and fluids. In this study, we conducted a series of experiments in which hematite or magnetite was reacted with an acidic solution under H2-rich <span class="hlt">hydrothermal</span> conditions (T = 100 250 C,) to investigate the kinetics of redox and non-redox transformations between hematite and magnetite, and the mechanisms of iron oxide transformation under <span class="hlt">hydrothermal</span> conditions. The formation of euhedral crystals of hematite in 150 and 200 C experiments, in which magnetite was used as the starting material, indicates that non-redox transformation of magnetite to hematite occurred within 24 h. The chemical composition of the experimental solutions was controlled by the non-redox transformation between magnetite and hematite throughout the experiments. While solution compositions were controlled by the non-redox transformation in the first 3 days in a 250 C experiment, reductive dissolution of magnetite became important after 5 days and affected the solution chemistry. At 100 C, the presence of maghemite was indicated in the first 7 days. Based on these results, equilibrium constants of non-redox transformation between magnetite and hematite and those of non-redox transformation between magnetite and maghemite were calculated. Our results suggest that the redox transformation of hematite to magnetite occurs in the following steps: (1) reductive dissolution of hematite to and (2) non-redox transformation of hematite and to magnetite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1007864','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1007864"><span>Mechanisms of iron oxide transformation in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Otake, Tsubasa; Wesolowski, David J; Anovitz, Lawrence {Larry} M</p> <p>2010-11-01</p> <p>Coexistence of magnetite and hematite in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> has often been used to constrain the redox potential of fluids, assuming that the redox equilibrium is attained among all minerals and aqueous species. However, as temperature decreases, disequilibrium mineral assemblages may occur due to the slow kinetics of reaction involving the minerals and fluids. In this study, we conducted a series of experiments in which hematite or magnetite was reacted with an acidic solution under H{sub 2}-rich <span class="hlt">hydrothermal</span> conditions (T = 100-250 C, P{sub H{sub 2}} = 0.05-5 MPa) to investigate the kinetics of redox and non-redox transformations between hematite and magnetite, and the mechanisms of iron oxide transformation under <span class="hlt">hydrothermal</span> conditions. The formation of euhedral crystals of hematite in 150 and 200 C experiments, in which magnetite was used as the starting material, indicates that non-redox transformation of magnetite to hematite occurred within 24 h. The chemical composition of the experimental solutions was controlled by the non-redox transformation between magnetite and hematite throughout the experiments. While solution compositions were controlled by the non-redox transformation in the first 3 days in a 250 C experiment, reductive dissolution of magnetite became important after 5 days and affected the solution chemistry. At 100 C, the presence of maghemite was indicated in the first 7 days. Based on these results, equilibrium constants of non-redox transformation between magnetite and hematite and those of non-redox transformation between magnetite and maghemite were calculated. Our results suggest that the redox transformation of hematite to magnetite occurs in the following steps: (1) reductive dissolution of hematite to Fe{sub (aq)}{sup 2+} and (2) non-redox transformation of hematite and Fe{sub (aq)}{sup 2+} to magnetite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/840686','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/840686"><span>Products of an Artificially Induced <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> at Yucca Mountain</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>S. Levy</p> <p>2000-08-07</p> <p>Studies of mineral deposition in the recent geologic past at Yucca Mountain, Nevada, address competing hypotheses of <span class="hlt">hydrothermal</span> alteration and deposition from percolating groundwater. The secondary minerals being studied are calcite-opal deposits in fractures and lithophysal cavities of ash-flow tuffs exposed in the Exploratory Studies Facility (ESF), a 7.7-km tunnel excavated by the Yucca Mountain Site Characterization Project within Yucca Mountain. An underground field test in the ESF provided information about the minerals deposited by a short-lived artificial <span class="hlt">hydrothermal</span> <span class="hlt">system</span> and an opportunity for comparison of test products with the natural secondary minerals. The heating phase lasted nine months, followed by a nine-month cooling period. Natural pore fluids were the only source of water during the thermal test. Condensation and reflux of water driven away from the heater produced fluid flow in certain fractures and intersecting boreholes. The mineralogic products of the thermal test are calcite-gypsum aggregates of less than 4-micrometer crystals and amorphous silica as glassy scale less than 0.2 mm thick and as mounds of tubules with diameters less than 0.7 micrometers. The minute crystal sizes of calcite and gypsum from the field test are very different from the predominantly coarser calcite crystals (up to cm scale) in natural secondary-mineral deposits at the site. The complex micrometer-scale textures of the amorphous silica differ from the simple forms of opal spherules and coatings in the natural deposits, even though some natural spherules are as small as 1 micrometer. These differences suggest that the natural minerals, especially if they were of <span class="hlt">hydrothermal</span> origin, may have developed coarser or simpler forms during subsequent episodes of dissolution and redeposition. The presence of gypsum among the test products and its absence from the natural secondary-mineral assemblage may indicate a higher degree of evaporation during the test than</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=hWsg3FgE-Ds','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=hWsg3FgE-Ds"><span>STS-134 Tribute to <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>STS-134 Commander Mark Kelly pays tribute to space shuttle <span class="hlt">Endeavour</span> and the spacecraft's contribution to human spaceflight. Mission specialists Andrew Feustel, Mike Fincke, Roberto Vittori, Greg C...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6110416','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6110416"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in central Twin Falls County, Idaho</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lewis, R.E.; Young, H.W.</p> <p>1989-01-01</p> <p>This report describes the results of a study to define the areal extent and thickness of the <span class="hlt">hydrothermal</span> reservoir in Twin Falls County and to propose a generalized conceptual model of the <span class="hlt">system</span>. Specific objectives of the study, done in cooperation with the Idaho Department of Water Resources, were to evaluate the existing resource as to its volume, temperature, pressure, and water chemistry, and to determine the effects of present development on the resource. The study was limited to Twin Falls County. Some geologic, geochemical, and hydrologic data for the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> were available from earlier studies. However, information about the subsurface at depths greater than 1000 feet was sparse. One well for which data were available was drilled to 2525 feet; several others were drilled to depths between 1200 and 2200 feet. Direct-current electrical resistivity soundings conducted during the summer of 1985 as part of the study provided valuable information about the subsurface at depths less than about 6000 feet. Interpretation of computer-generated subsurface profiles constructed from the soundings provided the basis for determining the thickness of the Idavada Volcanics over much of the study area. 42 refs., 9 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5113&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-00PD-5113&hterms=rss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drss"><span><span class="hlt">Endeavour</span> after RSS rollback</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>A rising sun illuminates the coastal waters beyond Space Shuttle <span class="hlt">Endeavour</span>, poised for launch on Nov. 30 at about 10:06 p.m. EST on mission STS-97. On the left, extending toward the orbiter, is the orbiter access arm. The mission to the International Space Station carries the P6 Integrated Truss Segment containing solar arrays and batteries that will be temporarily installed to the Unity connecting module by the Z1 truss, recently delivered to and installed on the Station on mission STS-92. The two solar arrays are each more than 100 feet long. They will capture energy from the sun and convert it to power for the Station. Two spacewalks will be required to install the solar array connections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15066838','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15066838"><span>Spatial distribution of marine crenarchaeota group I in the vicinity of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takai, Ken; Oida, Hanako; Suzuki, Yohey; Hirayama, Hisako; Nakagawa, Satoshi; Nunoura, Takuro; Inagaki, Fumio; Nealson, Kenneth H; Horikoshi, Koki</p> <p>2004-04-01</p> <p>Distribution profiles of marine crenarchaeota group I in the vicinity of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> were mapped with culture-independent molecular techniques. Planktonic samples were obtained from the waters surrounding two geographically and geologically distinct <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, and the abundance of marine crenarchaeota group I was examined by 16S ribosomal DNA clone analysis, quantitative PCR, and whole-cell fluorescence in situ hybridization. A much higher proportion of marine crenarchaeota group I within the microbial community was detected in deep-sea <span class="hlt">hydrothermal</span> environments than in normal deep and surface seawaters. The highest proportion was always obtained from the ambient seawater adjacent to <span class="hlt">hydrothermal</span> emissions and chimneys but not from the <span class="hlt">hydrothermal</span> plumes. These profiles were markedly different from the profiles of epsilon-Proteobacteria, which are abundant in the low temperatures of deep-sea <span class="hlt">hydrothermal</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B11D..01A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B11D..01A"><span>Microbial Geochemistry in Shallow-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amend, J. P.; Pichler, T.</p> <p>2006-12-01</p> <p>Shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are far more ubiquitous than generally recognized. Approximately 50-60 <span class="hlt">systems</span> are currently known, occurring world-wide in areas of high heat flow, such as, volcanic island arcs, near-surface mid-ocean ridges, and intraplate oceanic volcanoes. In contrast to deep-sea <span class="hlt">systems</span>, shallow- sea vent fluids generally include a meteoric component, they experience phase separation near the sediment- water interface, and they discharge into the photic zone (<200 m). They also are characterized by wide ranges in chemical composition, hundreds of redox disequilibria that translate to potential metabolisms, and broad phylogenetic diversity among the thermophilic bacteria and archaea. Perhaps because deep-sea smokers and continental hot springs are visually more stunning, shallow-sea <span class="hlt">systems</span> are often overlooked study sites. We will discuss their particular features that afford unique opportunities in microbial geochemistry. Two of the better studied examples are at Vulcano Island (Italy) and Ambitle Island (Papua New Guinea). The vents and sediment seeps at Vulcano are the "type locality" for numerous cultured hyperthermophiles, including the bacteria Aquifex and Thermotoga, the crenarchaeon Pyrodictium, and the Euryarchaeota Archaeoglobus and Pyrococcus. Isotope-labeled incubation experiments of heated sediments and an array of culturing studies have shown that simple organic compounds are predominantly fermented or anaerobically respired with sulfate. 16S rRNA gene surveys, together with fluorescent in situ hybridization studies, demonstrated the dominance of key thermophilic bacteria and archaea (e.g., Aquificales, Thermotogales, Thermococcales, Archaeoglobales) in the sediments and the presence of a broad spectrum of mostly uncultured crenarchaeota in several vent waters, sediment samples, and geothermal wells. Thermodynamic modeling quantified potential energy yields from aerobic and anaerobic respiration reactions and fermentation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811039H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811039H"><span>Tracing Origin of sulfur in <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Eastern Taiwan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsu, Hsiao-Yuan; You, Chen-Feng; Chung, Chuan-Hsiung; Aggarwal, Suresh Kumar</p> <p>2016-04-01</p> <p>Multiple sulfur isotope results and sulfate concentrations are reported for different <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in many countries. However, Taiwan is a seismically active country with plenty of hot spring resources, but only a few studies discuss about sulfur isotopes of them. No exhaustive study has been done to explain the high concentration and origin of sulfur in <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Taiwan, and chemical reaction between sulfide and sulfate. The true sulfur speciation in geothermal waters is difficult to preserve in samples for laboratory analysis. However, isotopic analysis is possible for the two species SO42- and S2O32-, together. Analysis of other species was also carried out for a possible study to understand the inter-conversion mechanism of sulfur species, and transport of other elements in aquifers, along with sulfur cycling in <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Taiwan. Fifteen samples, hot spring (5) and river water (10) were collected from East Taiwan and 5 hot spring samples were also collected from Japan for comparison. The samples were pre-concentrated and subjected to separation with anion exchange resin AGI-X8 and isotopic analysis with MC-ICPMS. The anions and cations were determined by Ion chromatography and ICP-OES, respectively. Samples from western Japan have been defined as Na-Cl type ground water and originate from 'fossil seawater' entrapped in the formations. The K/Cl and SO4/Cl ratios in hot spring water samples lie into a range between rain water and sea water. The Br/Cl ratios in hot spring water samples were close to that of sea water line, and could be distinguished from river water samples. Trace elements Li and B were high in hot spring samples from eastern Taiwan. This can be due to strong weathering in groundwater <span class="hlt">system</span>. δ34S values in most of the hot spring samples were in the range between 15.74-24.87 ‰ which is close to δ34S in seawater(+21). However, δ34S in samples from Zhiben (Taiwan) and Kurama (Japan) were -1.50‰ and -3.17 </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GMS...188..369K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GMS...188..369K"><span><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span>: A decade of discovery in slow spreading environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelley, Deborah S.; Shank, Timothy M.</p> <p></p> <p>Although much of the Mid-Atlantic Ridge is unexplored, investigations this past decade show that it hosts a rich diversity of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with fluid chemistries and biogeographic heterogeneity that span much greater compositional ranges than those within intermediate and fast spreading mid-ocean ridge <span class="hlt">systems</span>. Extreme attenuation of the crust and formation of detachment faults are now known to be key to this diversity, resulting in three classes of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Type 1 <span class="hlt">systems</span> host high-temperature, black smokers driven by heat extracted from cooling magma and/or proximal gabbroic crust. Acidic vent fluids are enriched in magmatically derived carbon dioxide, with variable concentrations of methane, hydrogen, and hydrogen sulfide. Type II fields host black smokers driven by cooling of variable mixtures of gabbroic and ultramafic material. Fluids are enriched in carbon dioxide, reflecting the magmatic-gabbroic influence, but they also contain elevated concentrations of methane, hydrogen, and low-molecular weight hydrocarbons: hallmarks of serpentinization reactions. Type III <span class="hlt">systems</span> are low-temperature, peridotite-hosted environments where fluid circulation is driven predominantly by cooling of mantle material. Carbon dioxide is absent, but fluids are enriched in methane, hydrogen, and low-molecular weight hydrocarbons of abiogenic origin. There are now more than 225 endemic species inhabiting slow spreading ridges with full species diversity ranging from ˜30 to >100 species within a given site. The fundamental drivers of vent faunal community structure are considered to be a function of geologic setting, composition, and variability of the resulting vent fluid chemistry, differences in depth, life history strategies of individual species, and the great geographic distance typically separating vent sites on slow spreading ridges.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-04pd0347.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-04pd0347.html"><span>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (left) listens to Kathy Laufenberg, Orbiter Airframe Engineering ground area manager, with United Space Alliance, about corrosion work being done on the external tank door of orbiter <span class="hlt">Endeavour</span>. On either side of Laufenberg are Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, also with USA, and Joy Huff, with KSC Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2004-02-25</p> <p>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (left) listens to Kathy Laufenberg, Orbiter Airframe Engineering ground area manager, with United Space Alliance, about corrosion work being done on the external tank door of orbiter <span class="hlt">Endeavour</span>. On either side of Laufenberg are Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, also with USA, and Joy Huff, with KSC Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-04pd0345.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-04pd0345.html"><span>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (left) looks at an external tank door corrosion work being done on <span class="hlt">Endeavour</span>. At right, Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist with United Space Alliance, is describing the work. At right is Kathy Laufenberg, Orbiter Airframe Engineering ground area manager,also with USA. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2004-02-25</p> <p>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (left) looks at an external tank door corrosion work being done on <span class="hlt">Endeavour</span>. At right, Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist with United Space Alliance, is describing the work. At right is Kathy Laufenberg, Orbiter Airframe Engineering ground area manager,also with USA. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70186946','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70186946"><span>Heat flux from magmatic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> related to availability of fluid recharge</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Harvey, M. C.; Rowland, J.V.; Chiodini, G.; Rissmann, C.F.; Bloomberg, S.; Hernandez, P.A.; Mazot, A.; Viveiros, F.; Werner, Cynthia A.</p> <p>2015-01-01</p> <p>Magmatic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are of increasing interest as a renewable energy source. Surface heat flux indicates <span class="hlt">system</span> resource potential, and can be inferred from soil CO2 flux measurements and fumarole gas chemistry. Here we compile and reanalyze results from previous CO2 flux surveys worldwide to compare heat flux from a variety of magma-<span class="hlt">hydrothermal</span> areas. We infer that availability of water to recharge magmatic <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is correlated with heat flux. Recharge availability is in turn governed by permeability, structure, lithology, rainfall, topography, and perhaps unsurprisingly, proximity to a large supply of water such as the ocean. The relationship between recharge and heat flux interpreted by this study is consistent with recent numerical modeling that relates <span class="hlt">hydrothermal</span> <span class="hlt">system</span> heat output to rainfall catchment area. This result highlights the importance of recharge as a consideration when evaluating <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> for electricity generation, and the utility of CO2 flux as a resource evaluation tool.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS21C1517M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS21C1517M"><span>Monitoring <span class="hlt">Endeavour</span> vent field deep-sea ecosystem dynamics through NEPTUNE Canada seafloor observatory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matabos, M.; NC Endeavour Science Team</p> <p>2010-12-01</p> <p>Mid-ocean ridges are dynamic <span class="hlt">systems</span> where the complex linkages between geological, biological, chemical, and physical processes are not yet well understood. Indeed, the poor accessibility to the marine environment has greatly limited our understanding of deep-sea ecosystems. Undersea cabled observatories offer the power and bandwidth required to conduct long-term and high-resolution time-series observations of the seafloor. Investigations of mid-ocean ridge <span class="hlt">hydrothermal</span> ecosystem require interdisciplinary studies to better understand the dynamics of vent communities and the physico-chemical forces that influence them. NEPTUNE Canada (NC) regional observatory is located in the Northeast Pacific, off Vancouver Island (BC, Canada), and spans ecological environments from the beach to the abyss. In September-October 2010, NC will be instrumenting its 5th node, including deployment of a multi-disciplinary suite of instruments in two vent fields on the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge. These include a digital camera, an imaging sonar for vent plumes and flow characteristics (i.e. COVIS), temperature resistivity probes, a water sampler and seismometers. In 2011, the TEMPO-mini, a new custom-designed camera and sensor package created by IFREMER for real-time monitoring of <span class="hlt">hydrothermal</span> faunal assemblages and their ecosystems (Sarrazin et al. 2007), and a microbial incubator, will added to the network in the Main <span class="hlt">Endeavour</span> and Mothra vent fields. This multidisciplinary approach will involve a scientific community from different institutions and countries. Significant experience aids in this installation. For example, video <span class="hlt">systems</span> connected to VENUS and NC have led to the development of new experimental protocols for time-series observations using seafloor cameras, including sampling design, camera calibration and image analysis methodologies (see communication by Aron et al. and Robert et al.). Similarly, autonomous deployment of many of the planned instruments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5259842','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5259842"><span>Sulfur gas geochemical detection of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rouse, G.E.</p> <p>1984-01-01</p> <p>The purpose of this investigation was to determine whether a <span class="hlt">system</span> of exploration using sulfur gases was capable of detecting convecting <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Three surveying techniques were used at the Roosevelt Hot Springs KGRA in Utah. These were (a) a sniffing technique, capable of instantaneous determinations of sulfur gas concentration, (b) an accumulator technique, capable of integrating the sulfur gas emanations over a 30 day interval, and (c) a method of analyzing the soils for vaporous sulfur compounds. Because of limitations in the sniffer technique, only a limited amount of surveying was done with this method. The accumulator and soil sampling techniques were conducted on a 1000 foot grid at Roosevelt Hot Springs, and each sample site was visited three times during the spring of 1980. Thus, three soil samples and two accumulator samples were collected at each site. The results are shown as averages of three soil and two accumulator determinations of sulfur gas concentrations at each site. Soil surveys and accumulator surveys were conducted at two additional KGRA's which were chosen based on the state of knowledge of these <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and upon their differences from Roosevelt Hot Springs in an effort to show that the exploration methods would be effective in detecting geothermal reservoirs in general. The results at Roosevelt Hot Springs, Utah show that each of the three surveying methods was capable of detecting sulfur gas anomalies which can be interpreted to be related to the source at depth, based on resistivity mapping of that source, and also correlatable with major structural features of the area which are thought to be controlling the geometry of the geothermal reservoir. The results of the surveys at Roosevelt did not indicate that either the soil sampling technique or the accumulator technique was superior to the other.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts061-73-040.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts061-73-040.html"><span>Hubble Space Telescope nears Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1993-12-04</p> <p>STS061-73-040 (4 Dec 1993) --- Backdropped against the blackness of space, the Hubble Space Telescope (HST) nears the Space Shuttle <span class="hlt">Endeavour</span>. With the aid of the Remote Manipulator <span class="hlt">System</span> (RMS), the STS-61 crew members later grappled the spacecraft and berthed it in the cargo bay for five-days of servicing chores by four space walkers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10114744','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10114744"><span>Modeling of the fault-controlled <span class="hlt">hydrothermal</span> ore-forming <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pek, A.A.; Malkovsky, V.I.</p> <p>1993-07-01</p> <p>A necessary precondition for the formation of <span class="hlt">hydrothermal</span> ore deposits is a strong focusing of <span class="hlt">hydrothermal</span> flow as fluids move from the fluid source to the site of ore deposition. The spatial distribution of <span class="hlt">hydrothermal</span> deposits favors the concept that such fluid flow focusing is controlled, for the most part, by regional faults which provide a low resistance path for <span class="hlt">hydrothermal</span> solutions. Results of electric analog simulations, analytical solutions, and computer simulations of the fluid flow, in a fault-controlled single-pass advective <span class="hlt">system</span>, confirm this concept. The influence of the fluid flow focusing on the heat and mass transfer in a single-pass advective <span class="hlt">system</span> was investigated for a simplified version of the metamorphic model for the genesis of greenstone-hosted gold deposits. The spatial distribution of ore mineralization, predicted by computer simulation, is in reasonable agreement with geological observations. Computer simulations of the fault-controlled thermoconvective <span class="hlt">system</span> revealed a complex pattern of mixing <span class="hlt">hydrothermal</span> solutions in the model, which also simulates the development of the modern <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the ocean floor. The specific feature of the model considered, is the development under certain conditions of an intra-fault convective cell that operates essentially independently of the large scale circulation. These and other results obtained during the study indicate that modeling of natural fault-controlled <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is instructive for the analysis of transport processes in man-made <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> that could develop in geologic high-level nuclear waste repositories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MinDe..50..281S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MinDe..50..281S"><span>Mo isotope fractionation during <span class="hlt">hydrothermal</span> evolution of porphyry Cu <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shafiei, Behnam; Shamanian, GholamHossein; Mathur, Ryan; Mirnejad, Hassan</p> <p>2015-03-01</p> <p>We present Mo isotope compositions of molybdenite types from three successive stages of ore deposition in several porphyry copper deposits of the Kerman region, Iran. The data provide new insights into controlling processes on Mo isotope fractionation during the <span class="hlt">hydrothermal</span> evolution of porphyry <span class="hlt">systems</span>. The Mo isotope compositions of 27 molybdenite samples show wide variations in δ97Mo ranging from -0.37 to +0.92 ‰. The data reveal that molybdenites in the early and transitional stages of mineralization (preferentially 2H polytypes; δ97Mo mean = 0.35 ‰) have higher δ97Mo values than late stage (mainly 3R polytypes; δ97Mo mean = 0.02 ‰) molybdenites. This trend suggests that fractionation of Mo isotopes occurred in high-temperature stages of mineralization and that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> generally evolve towards precipitation of molybdenite with lower δ97Mo values. Taking into account the genetic models proposed for porphyry Cu deposits along with the temperature-dependent fractionation of Mo isotope ratios, it is proposed that large variations of Mo isotopes in the early and the transitional stages of ore deposition could be controlled by the separation of the immiscible ore-forming fluid phases with different density, pH, and ƒO2 properties (i.e., brine and vapor). The fractionation of Mo isotopes during fluid boiling and Rayleigh distillation processes likely dominates the Mo isotope budget of the remaining ore-forming fluids for the late stage of mineralization. The lower δ97Mo values in the late stage of mineralization can be explained by depletion of the late ore-forming <span class="hlt">hydrothermal</span> solutions in 97Mo, as these fluids have moved to considerable distance from the source. Finally, the relationship observed between MoS2 polytypes (2H and 3R) and their Mo isotopic compositions can be explained by the molecular vibration theory, in which heavier isotopes are preferentially partitioned into denser primary 2H MoS2 crystals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H21E1176Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H21E1176Z"><span>Compartmentalized Fluid Flow In The Nevado Del Ruiz Volcano <span class="hlt">Hydrothermal</span> <span class="hlt">System(S</span>)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zuluaga, C. A.; Mejia, E.</p> <p>2011-12-01</p> <p>Combination of several extensive and compressive fault/fracture <span class="hlt">systems</span> with different lithologic units compartmentalized the <span class="hlt">hydrothermal</span> <span class="hlt">system(s</span>) in the vicinity of the Nevado del Ruiz volcano. Three main fault/fracture <span class="hlt">systems</span> are observed in the Ruiz volcano area, a N10°-20°E <span class="hlt">system</span> (San Jerónimo and Palestina faults), a N40°-60°W <span class="hlt">system</span> (Villamaría-Termales, San Ramón, Nereidas, Río Claro, San Eugenio and Campoalegrito faults), and a N60°-80°E <span class="hlt">system</span> (Santa Rosa fault). The NW trend <span class="hlt">system</span> act as the main path for fluid circulation, location of faults and fractures belonging to this <span class="hlt">system</span> and their intersections with other fault <span class="hlt">systems</span> and/or with lithologic contacts control hot springs location. The observed fault location and hot spring location pattern allow to subdivide the <span class="hlt">hydrothermal</span> <span class="hlt">system(s</span>) in at least five blocks. In the southernmost block, hot springs are mostly located in one of the four quadrants originated by fault intersections suggesting that there is a compartmentalization into higher and lower permeability quadrants. It is still unknown if all blocks belong to the same <span class="hlt">hydrothermal</span> <span class="hlt">system</span> or if there is more than one <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS061-105-024.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS061-105-024.html"><span><span class="hlt">Endeavour</span> backdropped against space with Sun displaying rayed effect</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1993-12-09</p> <p>STS061-105-024 (2-13 Dec. 1993) --- One of <span class="hlt">Endeavour</span>'s space walkers captured this view of <span class="hlt">Endeavour</span> backdropped against the blackness of space, with the Sun displaying a rayed effect. The extended Remote Manipulator <span class="hlt">System</span> (RMS) arm that the astronaut was standing on is seen on the left side of the view.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/1044a/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/1044a/report.pdf"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Long Valley Caldera, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sorey, M.L.; Lewis, Robert Edward; Olmsted, F.H.</p> <p>1978-01-01</p> <p>Long Valley caldera, an elliptical depression covering 450 km 2 on the eastern front of the Sierra Nevada in east-central California, contains a hot-water convection <span class="hlt">system</span> with numerous hot springs and measured and estimated aquifer temperatures at depths of 180?C to 280?C. In this study we have synthesized the results of previous geologic, geophysical, geochemical, and hydrologic investigations of the Long Valley area to develop a generalized conceptual and mathematical model which describes the gross features of heat and fluid flow in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Cenozoic volcanism in the Long Valley region began about 3.2 m.y. (million years) ago and has continued intermittently until the present time. The major event that resulted in the formation of the Long Valley caldera took place about 0.7 m.y. ago with the eruption of 600 km 3 or more of Bishop Tuff of Pleistocene age, a rhyolitic ash flow, and subsequent collapse of the roof of the magma chamber along one or more steeply inclined ring fractures. Subsequent intracaldera volcanism and uplift of the west-central part of the caldera floor formed a subcircular resurgent dome about 10 km in diameter surrounded by a moat containing rhyolitic, rhyodacitic, and basaltic rocks ranging in age from 0.5 to 0.05 m.y. On the basis of gravity and seismic studies, we estimate an aver- age thickness of fill of 2.4 km above the precaldera granitic and metamorphic basement rocks. A continuous layer of densely welded Bishop Tuff overlies the basement rocks, with an average thickness of 1.4 km; the fill above the welded Bishop Tuff consists of intercalated volcanic flows and tuffs and fluvial and lacustrine deposits. Assuming the average grain density of the fill is between 2.45 and 2.65 g/cm 3 , we calculate the average bulk porosity of the total fill as from 0.11 to 0.21. Comparison of published values of porosity of the welded Bishop Tuff exposed southeast of the caldera with calculated values indicates average bulk porosity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1410718M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1410718M"><span>Secondary <span class="hlt">hydrothermal</span> mineral <span class="hlt">system</span> in the Campi Flegrei caldera, Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mormone, A.; Piochi, M.; Di Vito, M. A.; Troise, C.; De Natale, G.</p> <p>2012-04-01</p> <p>Mineral <span class="hlt">systems</span> generally develop around the deep root of the volcanoes down to the degassing magma chamber due the selective enrichment process of elements within the host-rock. The mineralization process depends on i) volcanic structure, ii) magma and fluid chemistry, iii) host-rock type and texture, iv) temperature and pressure conditions, and v) action timing that affect the transport and precipitation conditions of elements in the solution. Firstly, it generates a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> that in a later phase may generate considerable metallogenic mineralization, in terms of both spatial extension and specie abundance. The study of secondary assemblages through depth and, possibly, through time, together with the definition of the general geological, structural, mineralogical and petrological context is the background to understand the genesis of mineral-to-metallogenic <span class="hlt">systems</span>. We report our study on the Campi Flegrei volcano of potassic Southern Italy belt. It is a sub-circular caldera characterized by an active high-temperature and fluid-rich geothermal <span class="hlt">system</span> affected by seismicity and ground deformation in the recent decades. The circulating fluids originate at deeper level within a degassing magma body and give rise at the surface up to 1500 tonnes/day of CO2 emissions. Their composition is intermediate between meteoric water and brines. Saline-rich fluids have been detected at ~3000 in downhole. The <span class="hlt">hydrothermal</span> alteration varies from argillitic to phillitic, nearby the caldera boundary, to propilitic to thermo-metamorphic facies towards its centre. The Campi Flegrei caldera was defined as analogue of mineralized <span class="hlt">system</span> such as White Island (New Zealand) that is an example of an active magmatic and embryonic copper porphyry <span class="hlt">system</span>. In order to enhance the knowledge of such a type of embryonic-like metallogenic <span class="hlt">system</span>, we have carried out macroscopic and microscopic investigations, SEM-EDS and electron microprobe analyses on selected samples from deep wells</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6347786','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6347786"><span>Stochastic long-term <span class="hlt">hydrothermal</span> optimization for a multireservoir <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sherkat, V.R.; Campo, R.; Lo, E.O.; Moslehi, K.</p> <p>1985-08-01</p> <p>The problem of planning the long-term (multiyear) operation of a multireservoir <span class="hlt">hydrothermal</span> electric power generation <span class="hlt">system</span> is solved by a stochastic dynamic programming (SDP) algorithm using successive approximations. The hydro <span class="hlt">system</span> model consists of a set of disjoint hydro chains each modeled by an equivalent reservoir and hydroplant. The inflow to the equivalent reservoir in each hydro chain is modeled as an independent log-normal random variable with a time correlation of lag one. The remaining river inflows in the <span class="hlt">system</span> are modeled as a function of the equivalent reservoir inflows. Thermal unit and load curtailment cost curves are modeled as piecewise linear and convex. The successive approximations algorithm involves the solution of a 2-state stochastic dynamic programming problem for each hydro chain which has as its objective the minimization of the expected discounted production cost, plus the terminal hydro cost, subject to satisfying a number of constraints on the hydro and thermal <span class="hlt">system</span> and the monthly demand which is represented by a load duration curve. A production-grade computer program has been developed and tested with data for a real <span class="hlt">system</span>. Numerical results are reported for two study cases with up to eight reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-03pd2790.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-03pd2790.html"><span><span class="hlt">Endeavour</span> Return to Flight Maintenance</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2003-10-10</p> <p>In the Orbiter Processing Facility, David Sanborn and Rick Cady, with United Space Alliance, check tiles on the underside of <span class="hlt">Endeavour</span>. Tile check is part of routine maintenance and return to flight activities on the orbiter fleet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts089-375-018.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts089-375-018.html"><span>Cdr. Wilcutt shaves onboard <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1998-03-02</p> <p>STS089-375-018 (22-31 Jan. 1998) --- Astronaut Terrence W. (Terry) Wilcutt, STS-89 mission commander, uses a battery-powered razor to shave aboard the Earth-orbiting space shuttle <span class="hlt">Endeavour</span>. Photo credit: NASA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-03pd2786.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-03pd2786.html"><span><span class="hlt">Endeavour</span> Return to Flight Maintenance</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2003-10-10</p> <p>In the Orbiter Processing Facility, Tim Chastain (left) and John Peterson (right), with United Space Alliance, prepare to remove the body flap actuator from the orbiter <span class="hlt">Endeavour</span>. The work is part of return to flight activities on the orbiter fleet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-200907310004HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-200907310004HQ.html"><span>STS-127 Shuttle <span class="hlt">Endeavour</span> Landing</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-07-31</p> <p>Astronaut Mark Polansky, STS-127 mission commander, poses for a photograph by the front wheel of the space shuttle <span class="hlt">Endeavour</span> shortly after it and its crew landed, Friday, July 31, 2009 at NASA's Kennedy Space Center in Cape Canaveral, Fla., completing a 16-day journey of more than 6.5 million miles. <span class="hlt">Endeavour</span> delivered the final segment to the Japan Aerospace Exploration Agency's Kibo laboratory and a new crew member to the International Space Station. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012989','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012989"><span>QUANTITATIVE ANALYSIS OF THE LASSEN <span class="hlt">HYDROTHERMAL</span> <span class="hlt">SYSTEM</span>, NORTH CENTRAL CALIFORNIA.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ingebritsen, S.E.; Sorey, M.L.</p> <p>1985-01-01</p> <p>Our conceptual model of the Lassen <span class="hlt">system</span> is termed a liquid-dominated <span class="hlt">hydrothermal</span> <span class="hlt">system</span> with a parasitic vapor-dominated zone. The essential feature of this model is that steam and steam-heated discharge at relatively high altitudes in Lassen Volcanic National Park (LVNP) and liquid discharge with high chloride concentrations at relatively low altitudes outside LVNP are both fed by an upflow of high-enthalpy two-phase fluid within the Park. Liquid flows laterally away from the upflow area toward the areas of high-chloride discharge, and steam rises through a vapor-dominated zone to feed the steam and steam-heated features. Numerical simulations show that several conditions are necessary for the development of this type of <span class="hlt">system</span>, including (1) large-scale topographic relief; (2) an initial period of convective heating within an upflow zone followed by (3) a change in hydrologic or geologic conditions that initiates drainage of liquid from portions of the upflow zone; and (4) low-permeability barriers that inhibit the movement of cold water into the vapor zone. Refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhDT.......232L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhDT.......232L"><span>Numerical modeling of two-phase flow in the sodium chloride-water <span class="hlt">system</span> with applications to seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lewis, Kayla C.</p> <p></p> <p>In order to explain the observed time-dependent salinity variations in seafloor <span class="hlt">hydrothermal</span> vent fluids, quasi-numerical and fully numerical fluid flow models of the NaCl-H2O <span class="hlt">system</span> are constructed. For the quasi-numerical model, a simplified treatment of phase separation of seawater near an igneous dike is employed to obtain rough estimates of the thickness and duration of the two-phase zone, the amount of brine formed, and its distribution in the subsurface. Under the assumption that heat transfer occurs mainly by thermal conduction it is shown that, for a two-meter wide dike, the maximum width of the two phase zone is approximately 20 cm and that a zone of halite is deposited near the dike wall. The two-phase zone is mainly filled with vapor. After 13 days, the two-phase zone begins to disappear at the base of the <span class="hlt">system</span>, and disappears completely by 16 days. The results of this simplified model agree reasonably well with transient numerical solutions for the analogous two-phase flow in a pure water <span class="hlt">system</span>. The seafloor values of vapor salinity given by the model are compared with vapor salinity data from the "A" vent at 9-10°N on the East Pacific Rise and it is argued that either non-equilibrium thermodynamic behavior or near-surface mixing of brine with vapor in the two-phase region may explain the discrepancies between model predictions and data. For the fully numerical model, the equations governing fluid flow, the thermodynamic relations between various quantities employed, and the coupling of these elements together in a time marching scheme is discussed. The thermodynamic relations are expressed in terms of equations of state, and the latter are shown to vary both smoothly and physically in P-T-X space. In particular, vapor salinity values near the vapor-liquid-halite coexistence surface are shown to be in strong agreement with recently measured values. The fully numerical model is benchmarked against previously published heat pipe and Elder problem</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017404','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017404"><span>Geophysical characteristics of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of Kilauea volcano, Hawaii</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kauahikaua, J.</p> <p>1993-01-01</p> <p>Clues to the overall structure of Kilauea volcano can be obtained from spatial studies of gravity, magnetic, and seismic velocity variations. The rift zones and summit are underlain by dense, magnetic, high P-wave-velocity rocks at depths of about 2 km less. The gravity and seismic velocity studies indicate that the rift structures are broad, extending farther to the north than to the south of the surface features. The magnetic data give more definition to the rift structures by allowing separation into a narrow, highly-magnetized, shallow zone and broad, flanking, magnetic lows. The patterns of gravity, magnetic variations, and seismicity document the southward migration of the upper cast rift zone. Regional, hydrologic features of Kilauea can be determined from resistivity and self-potential studies. High-level groundwater exists beneath Kilauea summit to elevations of +800 m within a triangular area bounded by the west edge of the upper southwest rift zone, the east edge of the upper east rift zone, and the Koa'c fault <span class="hlt">system</span>. High-level groundwater is present within the east rift zone beyond the triangular summit area. Self-potential mapping shows that areas of local heat produce local fluid circulation in the unconfined aquifer (water table). The dynamics of Kilauea eruptions are responsible for both the source of heat and the fracture permeability of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Shallow seismicity and surface deformation indicate that magma is intruding and that fractures are forming beneath the rift zones and summit area. Magma supply estimates are used to calculate the rate of heat input to Kilauea's <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Heat flows of 370-820 mW/m2 are calculated from deep wells within the lower east rift zone. The estimated heat input rate for Kilauea of 9 gigawatts (GW) is at least 25 times higher than the conductive heat loss as estimated from the heat flow in wells extrapolated over the area of the summit caldera and rift zones. Heat must be dissipated by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28273951','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28273951"><span>Vein networks in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide constraints for the monitoring of active volcanoes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cucci, Luigi; Di Luccio, Francesca; Esposito, Alessandra; Ventura, Guido</p> <p>2017-03-10</p> <p>Vein networks affect the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of many volcanoes, and variations in their arrangement may precede <span class="hlt">hydrothermal</span> and volcanic eruptions. However, the long-term evolution of vein networks is often unknown because data are lacking. We analyze two gypsum-filled vein networks affecting the <span class="hlt">hydrothermal</span> field of the active Lipari volcanic Island (Italy) to reconstruct the dynamics of the <span class="hlt">hydrothermal</span> processes. The older network (E1) consists of sub-vertical, N-S striking veins; the younger network (E2) consists of veins without a preferred strike and dip. E2 veins have larger aperture/length, fracture density, dilatancy, and finite extension than E1. The fluid overpressure of E2 is larger than that of E1 veins, whereas the hydraulic conductance is lower. The larger number of fracture intersections in E2 slows down the fluid movement, and favors fluid interference effects and pressurization. Depths of the E1 and E2 <span class="hlt">hydrothermal</span> sources are 0.8 km and 4.6 km, respectively. The decrease in the fluid flux, depth of the <span class="hlt">hydrothermal</span> source, and the pressurization increase in E2 are likely associated to a magma reservoir. The decrease of fluid discharge in <span class="hlt">hydrothermal</span> fields may reflect pressurization at depth potentially preceding <span class="hlt">hydrothermal</span> explosions. This has significant implications for the long-term monitoring strategy of volcanoes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70023045','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70023045"><span>Carbon dioxide in magmas and implications for <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lowenstern, J. B.</p> <p>2001-01-01</p> <p>This review focuses on the solubility, origin, abundance, and degassing of carbon dioxide (CO2) in magma-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, with applications for those workers interested in intrusion-related deposits of gold and other metals. The solubility of CO2 increases with pressure and magma alkalinity. Its solubility is low relative to that of H2O, so that fluids exsolved deep in the crust tend to have high CO2/H2O compared with fluids evolved closer to the surface. Similarly, CO2/H2O will typically decrease during progressive decompression- or crystallization-induced degassing. The temperature dependence of solubility is a function of the speciation of CO2, which dissolves in molecular form in rhyolites (retrograde temperature solubility), but exists as dissolved carbonate groups in basalts (prograde). Magnesite and dolomite are stable under a relatively wide range of mantle conditions, but melt just above the solidus, thereby contributing CO2 to mantle magmas. Graphite, diamond, and a free CO2-bearing fluid may be the primary carbon-bearing phases in other mantle source regions. Growing evidence suggests that most CO2 is contributed to arc magmas via recycling of subducted oceanic crust and its overlying sediment blanket. Additional carbon can be added to magmas during magma-wallrock interactions in the crust. Studies of fluid and melt inclusions from intrusive and extrusive igneous rocks yield ample evidence that many magmas are vapor saturated as deep as the mid crust (10-15 km) and that CO2 is an appreciable part of the exsolved vapor. Such is the case in both basaltic and some silicic magmas. Under most conditions, the presence of a CO2-bearing vapor does not hinder, and in fact may promote, the ascent and eruption of the host magma. Carbonic fluids are poorly miscible with aqueous fluids, particularly at high temperature and low pressure, so that the presence of CO2 can induce immiscibility both within the magmatic volatile phase and in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/60580','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/60580"><span>Contact zones and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> as analogues to repository conditions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wollenberg, H.A.; Flexser, S.</p> <p>1984-10-01</p> <p>Radioactive waste isolation efforts in the US are currently focused on examining basalt, tuff, salt, and crystalline rock as candidate rock types to encompass waste repositories. As analogues to near-field conditions, the distributions of radio- and trace-elements have been examined across contacts between these rocks and dikes and stocks that have intruded them. The intensive study of the Stripa quartz monzonite has also offered the opportunity to observe the distribution of uranium and its daughters in groundwater and its relationship to U associated with fracture-filling and alteration minerals. Investigations of intrusive contact zones to date have included (1) a tertiary stock into Precambrian gneiss, (2) a stock into ash flow tuff, (3) a rhyodacite dike into Columbia River basalt, and (4) a kimberlite dike into salt. With respect to temperature and pressure, these contact zones may be considered "worst-case scenario" analogues. Results indicate that there has been no appreciable migration of radioelements from the more radioactive intrusives into the less radioactive country rocks, either in response to the intrusions or in the fracture-controlled hydrological <span class="hlt">systems</span> that developed following emplacement. In many cases, the radioelements are locked up in accessory minerals, suggesting that artificial analogues to these would make ideal waste forms. Emphasis should now shift to examination of active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, studying the distribution of key elements in water, fractures, and alteration minerals under pressure and temperature conditions most similar to those expected in the near-field environment of a repository. 14 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V41B1394K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41B1394K"><span>Microbial Community in the <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> at Southern Mariana Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kato, S.; Itahashi, S.; Kakegawa, T.; Utsumi, M.; Maruyama, A.; Ishibashi, J.; Marumo, K.; Urabe, T.; Yamagishi, A.</p> <p>2004-12-01</p> <p>There is unique ecosystem around deep-sea <span class="hlt">hydrothermal</span> area. Living organisms are supported by chemical free energy provided by the <span class="hlt">hydrothermal</span> water. The ecosystem is expected to be similar to those in early stage of life history on the earth, when photosynthetic organisms have not emerged. In this study, we have analyzed the microbial diversity in the <span class="hlt">hydrothermal</span> area at southern Mariana trough. In the "Archaean Park Project" supported by special Coordination Fund, four holes were bored and cased by titanium pipes near <span class="hlt">hydrothermal</span> vents in the southern Mariana trough in 2004. <span class="hlt">Hydrothermal</span> fluids were collected from these cased holes and natural vents in this area. Microbial cells were collected by filtering the <span class="hlt">hydrothermal</span> fluid in situ or in the mother sip. Filters were stored at -80C and used for DNA extraction. Chimneys at this area was also collected and stored at -80C. The filters and chimney samples were crushed and DNA was extracted. DNA samples were used for amplification of 16S rDNA fragments by PCR using archaea specific primers and universal primers. The PCR fragments were cloned and sequenced. These PCR clones of different samples will be compared. We will extend our knowledge about microbiological diversity at Southern Mariana trough to compare the results obtained at other area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS33F..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS33F..05M"><span><span class="hlt">Hydrothermal</span> Vents at 5000m on the Mid-Cayman Rise: The Deepest and Hottest <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> Yet Discovered!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murton, B. J.; Connelly, D. P.; Copley, J. T.; Stansfield, K. L.; Tyler, P. A.; Cruise Jc044 Sceintific Party</p> <p>2010-12-01</p> <p>This contribution describes the geological setting of <span class="hlt">hydrothermal</span> activity within the Mid- Cayman Rise (MCR) using data acquired during cruise JC044 (MAR-APR 2010) from the deep-towed sidescan sonar TOBI, AUV Autosub6000 and the ROTV HyBIS. The 110 km-long Mid- Cayman Rise (MCR), located within Caribbean Sea, is the deepest spreading centre known, reaching over 6000m. Hence it poses an end-member of extreme depth for <span class="hlt">hydrothermal</span> circulation. Accretion of new volcanic crust is focused within two ridge segments, to the north and south of a centrally located massif of peridotite and gabbro. Following earlier indications of <span class="hlt">hydrothermal</span> plumes (German et al., in 2009), we discovered two high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">system</span>: one at a depth of 5000m in the neovolcanic zone of the northern segment, and another at 2300m on the flanks of the MCR. These sites show contrasting styles of fluid venting, mineralisation, geological setting and host rock interaction. At 5000m-depth, the ultra-deep vent site forms the deepest <span class="hlt">hydrothermal</span> <span class="hlt">system</span> known. Venting is focused at the western side of a 100m diameter, 30m high mound, while inactive sulphides extend eastwards for at least 800m. Fluids discharge from clusters of chimneys whose location is related to basement faults. Changes in salinity in the venting fluids indicate discharge of a low salinity phase and a brine phase. At 500bar, this is definitive evidence for supercritical fluid emission. We also found the sulphide mineralization to be copper-rich, giving a characteristic green hue to many of the deposits, probably a result of the super-critical state of the vent fluids. A prominent axial volcanic ridge nearby indicates a robust magma supply to the northern MCR segment. Thus it is likely the ultra-deep vent site derives its thermal energy from magmatic sources, similar to those thought to underlie other slow-spreading ridge volcanic-hosted vent sites (e.g. Broken Spur: MAR). The shallower (2300m) MCR <span class="hlt">hydrothermal</span> vent</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JGRB..110.2212V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JGRB..110.2212V"><span>Analogue modeling of instabilities in crater lake <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vandemeulebrouck, Jean; Stemmelen, Didier; Hurst, Tony; Grangeon, Jacques</p> <p>2005-02-01</p> <p>We carried out analogue experiments on two-phase boiling <span class="hlt">systems</span>, using a porous vertical cylinder, saturated with water. The base of the cylinder was heated, and the top was cooled, as in a natural <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Previous work had shown that once the two-phase zone reached a certain level, thermal instabilities would develop. We made measurements of the acoustic energy related to boiling, and we found that high levels of acoustic noise were associated with the part of the cycle in which there was upward water movement. We repeated our experiments with a cooling water tank at the top of the <span class="hlt">system</span>, representing a crater lake. This showed that periodic thermal instabilities still developed in this situation. We then compared our analogue measurements to two natural <span class="hlt">systems</span> known to exhibit periodic behavior. There is good agreement between the thermal and acoustic cycling seen in our model and the observations made at Inferno Crater Lake in the Waimangu Geothermal area, New Zealand, whose level cycles by nearly 10 m, with a typical period of 38 days. Particularly notable is how in both <span class="hlt">systems</span> high levels of acoustic noise are associated with rising water level. The much larger Ruapehu Crater Lake, also in New Zealand, cycled with a period of several months to a year for over a decade prior to the 1995 eruption. Strong acoustic and seismic energy usually occurred just before the lake temperature started to rise. This suggests a slightly different model, in which the increasing two-phase flow zone triggers more general convection once it reaches the base of the lake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70189738','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70189738"><span>New insights into the Kawah Ijen <span class="hlt">hydrothermal</span> <span class="hlt">system</span> from geophysical data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Caudron, Corentin; Mauri, G.; Williams-Jones, Glyn; Lecocq, Thomas; Syahbana, Devy Kamil; de Plaen, Raphael; Peiffer, Loic; Bernard, Alain; Saracco, Ginette</p> <p>2017-01-01</p> <p>Volcanoes with crater lakes and/or extensive <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> pose significant challenges with respect to monitoring and forecasting eruptions, but they also provide new opportunities to enhance our understanding of magmatic–<span class="hlt">hydrothermal</span> processes. Their lakes and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> serve as reservoirs for magmatic heat and fluid emissions, filtering and delaying the surface expressions of magmatic unrest and eruption, yet they also enable sampling and monitoring of geochemical tracers. Here, we describe the outcomes of a highly focused international experimental campaign and workshop carried out at Kawah Ijen volcano, Indonesia, in September 2014, designed to answer fundamental questions about how to improve monitoring and eruption forecasting at wet volcanoes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1890497','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1890497"><span>Extreme accumulation of nucleotides in simulated <span class="hlt">hydrothermal</span> pore <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Baaske, Philipp; Weinert, Franz M.; Duhr, Stefan; Lemke, Kono H.; Russell, Michael J.; Braun, Dieter</p> <p>2007-01-01</p> <p>We simulate molecular transport in elongated <span class="hlt">hydrothermal</span> pore <span class="hlt">systems</span> influenced by a thermal gradient. We find extreme accumulation of molecules in a wide variety of plugged pores. The mechanism is able to provide highly concentrated single nucleotides, suitable for operations of an RNA world at the origin of life. It is driven solely by the thermal gradient across a pore. On the one hand, the fluid is shuttled by thermal convection along the pore, whereas on the other hand, the molecules drift across the pore, driven by thermodiffusion. As a result, millimeter-sized pores accumulate even single nucleotides more than 108-fold into micrometer-sized regions. The enhanced concentration of molecules is found in the bulk water near the closed bottom end of the pore. Because the accumulation depends exponentially on the pore length and temperature difference, it is considerably robust with respect to changes in the cleft geometry and the molecular dimensions. Whereas thin pores can concentrate only long polynucleotides, thicker pores accumulate short and long polynucleotides equally well and allow various molecular compositions. This setting also provides a temperature oscillation, shown previously to exponentially replicate DNA in the protein-assisted PCR. Our results indicate that, for life to evolve, complicated active membrane transport is not required for the initial steps. We find that interlinked mineral pores in a thermal gradient provide a compelling high-concentration starting point for the molecular evolution of life. PMID:17494767</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T51D2614Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T51D2614Y"><span>Role of tectonic and volcanic activity in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at the southern Mariana Trough: detailed bathymetric characteristics of the <span class="hlt">hydrothermal</span> sites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoshikawa, S.; Okino, K.; Asada, M.; Nogi, Y.; Mochizuki, N.; Nakamura, K.</p> <p>2012-12-01</p> <p>We present the detailed bathymetric characterization of field-scale geological features associated with <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the southern Mariana Trough near 12°57'N, 143°37'E, using near-bottom swath mapping data collected by the autonomous underwater vehicle (AUV) Urashima during cruise YK09-08 and dive observation data acquired by the submersible Shinkai6500 during cruise YK10-11. In the study area, two of the <span class="hlt">hydrothermal</span> sites are located on the active backarc spreading axis (the Snail and Yamanaka sites), one is located at the eastern foot of the axial high (the Archean site), and two are located on an off-axis knoll about 5 km from the spreading axis (the Pika and Urashima sites). We examined 1) the nature of' tectonic and volcanic controls on the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, and 2) the relationship between geomorphological characteristics and <span class="hlt">hydrothermal</span> activity based on the survey results (Yoshikawa et al., 2012). The two on-axis <span class="hlt">hydrothermal</span> sites are possibly locally developed on a 4th order spreading segment, in association with diking events (on the basis of comparisons with previously studied cases on the East Pacific Rise). The three off-axis sites (the Archean, Urashima, and Pika sites) appear to represent locations of sustained <span class="hlt">hydrothermal</span> activity that has created relatively large-scale <span class="hlt">hydrothermal</span> features compared with those in the on-axis area. The formation of off-axis <span class="hlt">hydrothermal</span> sites is likely to be closely related to an off-axis magma upwelling <span class="hlt">system</span>, as evidenced by the absence of fault <span class="hlt">systems</span> and the undeformed morphology of the mound and knoll. The three off-axis <span class="hlt">hydrothermal</span> sites are composed mainly of breccia assemblages that probably originated from <span class="hlt">hydrothermal</span> activity with black smoker venting. These areas are characterized by numerous ridge lines (height, mainly 1-6 m), conical mounds (height: < 100 m, diameter: < 300 m), and bumpy seabed. Most of the ridge lines have formed as a result of collapse of the seafloor. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010LPICo1538.5636P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010LPICo1538.5636P"><span>Terrestrial Iron Hot Springs as Analogs for Ancient Martian <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parenteau, M. N.; Farmer, J. D.; Jahnke, L. L.; Cady, S. L.</p> <p>2010-04-01</p> <p>We have been studying a subaerial terrestrial iron hot spring as an potential analog for <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars. In this multidisciplinary study, we have characterized the aqueous geochemistry, mineralogy, and microbial biosignatures at Chocolate Pots hot springs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS51E..02C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS51E..02C"><span>Near-Seafloor Magnetic Exploration of Submarine <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> in the Kermadec Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caratori Tontini, F.; de Ronde, C. E. J.; Tivey, M.; Kinsey, J. C.</p> <p>2014-12-01</p> <p>Magnetic data can provide important information about <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> because <span class="hlt">hydrothermal</span> alteration can drastically reduce the magnetization of the host volcanic rocks. Near-seafloor data (≤70 m altitude) are required to map <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in detail; Autonomous Underwater Vehicles (AUVs) are the ideal platform to provide this level of resolution. Here, we show the results of high-resolution magnetic surveys by the ABE and Sentry AUVs for selected submarine volcanoes of the Kermadec arc. 3-D magnetization models derived from the inversion of magnetic data, when combined with high resolution seafloor bathymetry derived from multibeam surveys, provide important constraints on the subseafloor geometry of <span class="hlt">hydrothermal</span> upflow zones and the structural control on the development of seafloor <span class="hlt">hydrothermal</span> vent sites as well as being a tool for the discovery of previously unknown <span class="hlt">hydrothermal</span> sites. Significant differences exist between the magnetic expressions of <span class="hlt">hydrothermal</span> sites at caldera volcanoes ("donut" pattern) and cones ("Swiss cheese" pattern), respectively. Subseafloor 3-D magnetization models also highlight structural differences between focused and diffuse vent sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27131783','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27131783"><span>Candidate gene prioritization with <span class="hlt">Endeavour</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tranchevent, Léon-Charles; Ardeshirdavani, Amin; ElShal, Sarah; Alcaide, Daniel; Aerts, Jan; Auboeuf, Didier; Moreau, Yves</p> <p>2016-07-08</p> <p>Genomic studies and high-throughput experiments often produce large lists of candidate genes among which only a small fraction are truly relevant to the disease, phenotype or biological process of interest. Gene prioritization tackles this problem by ranking candidate genes by profiling candidates across multiple genomic data sources and integrating this heterogeneous information into a global ranking. We describe an extended version of our gene prioritization method, <span class="hlt">Endeavour</span>, now available for six species and integrating 75 data sources. The performance (Area Under the Curve) of <span class="hlt">Endeavour</span> on cross-validation benchmarks using 'gold standard' gene sets varies from 88% (for human phenotypes) to 95% (for worm gene function). In addition, we have also validated our approach using a time-stamped benchmark derived from the Human Phenotype Ontology, which provides a setting close to prospective validation. With this benchmark, using 3854 novel gene-phenotype associations, we observe a performance of 82%. Altogether, our results indicate that this extended version of <span class="hlt">Endeavour</span> efficiently prioritizes candidate genes. The <span class="hlt">Endeavour</span> web server is freely available at https://<span class="hlt">endeavour</span>.esat.kuleuven.be/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002910','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002910"><span>Degradation of <span class="hlt">Endeavour</span> Crater, Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grant, J. A.; Crumpler, L. S.; Parker, T. J.; Golombek, M. P.; Wilson, S. A.; Mittlefehldt, D. W.</p> <p>2015-01-01</p> <p>The Opportunity rover has traversed portions of two western rim segments of <span class="hlt">Endeavour</span>, a 22 km-diameter crater in Meridiani Planum, for the past three years. The resultant data enables the evaluation of the geologic expression and degradation state of the crater. <span class="hlt">Endeavour</span> is Noa-chian-aged, complex in morphology, and originally may have appeared broadly similar to the more pristine 20.5 km-diameter Santa Fe complex crater in Lunae Palus (19.5degN, 312.0degE). By contrast, <span class="hlt">Endeavour</span> is considerably subdued and largely buried by younger sulfate-rich plains. Exposed rim segments dubbed Cape York (CY) and Solander Point/Murray Ridge/Pillinger Point (MR) located approximately1500 m to the south reveal breccias interpreted as remnants of the ejecta deposit, dubbed the Shoemaker Formation. At CY, the Shoemaker Formation overlies the pre-impact rocks, dubbed the Matijevic Formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6630994','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6630994"><span>Particulate DNA in smoker fluids: Evidence for existence of microbial populations in hot <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Straube, W.L.; Colwell, R.R. Univ. of Maryland, Baltimore ); Deming, J.W.; Baross, J.A. ); Somerville, C.C. )</p> <p>1990-05-01</p> <p>As part of an interdisciplinary study of <span class="hlt">hydrothermal</span> vents on the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge, we used the submersible ALVIN to collect 57 fluid samples from 17 different hot vents (smokers and flanges) and their environs for the purpose of extracting particulate DNA. Particulate material concentrated from these samples was lysed enzymatically (enz) and by a combination of enzyme and French press treatment (fp). Concentrations of partially purified DNA recovered from these lysates were determined spectrofluorometrically. Ambient seawater surrounding the vents was found to contain low DNA concentrations, 0.18 to 0.32 ng of DNA per ml, while low-temperature vent samples yielded significantly higher concentrations of 0.37 to 2.12 ng of DNA per ml. Although DNA recovery values from superheated (210 to 345{degree}C) flange samples were not significantly different from ambient seawater values, most of the superheated (174 to 357{degree}C) smoker fluid samples contained particulate DNA in concentrations too high to be attributable to entrained seawater. Detailed sampling at one smoker site demonstrated not only the existence of significant levels of particulate DNA in the superheated smoker fluids but also the presence of an elevated microbial population in the buoyant plume 20 to 100 m above the smoker. These results underscore the heterogeneity of smoker environments within a given <span class="hlt">hydrothermal</span> vent fluid and indicate that microorganisms exist in some superheated fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-02PD-1129&hterms=Progress+optics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProgress%2Boptics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-02PD-1129&hterms=Progress+optics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProgress%2Boptics"><span>STS-113 <span class="hlt">Endeavour</span> processing with fiber-optic camera</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>KENNEDY SPACE CENTER, FLA. -- With the engines removed from <span class="hlt">Endeavour</span>, the inside of <span class="hlt">Endeavour</span> is exposed. At left center, Scott Minnick, with United Space Alliance, operates a fiber-optic camera inside the flow line. Other USA team members, right, watching the progress on a screen in front, are Gerry Kathka (with controls), Mike Fore and Peggy Ritchie. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion <span class="hlt">System</span> (MPS) flow liners in other orbiters. <span class="hlt">Endeavour</span> is next scheduled to fly on mission STS-113.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=KSC-02PD-1129&hterms=Progress+Optics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProgress%2BOptics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=KSC-02PD-1129&hterms=Progress+Optics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProgress%2BOptics"><span>STS-113 <span class="hlt">Endeavour</span> processing with fiber-optic camera</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>KENNEDY SPACE CENTER, FLA. -- With the engines removed from <span class="hlt">Endeavour</span>, the inside of <span class="hlt">Endeavour</span> is exposed. At left center, Scott Minnick, with United Space Alliance, operates a fiber-optic camera inside the flow line. Other USA team members, right, watching the progress on a screen in front, are Gerry Kathka (with controls), Mike Fore and Peggy Ritchie. The inspection is the result of small cracks being discovered on the LH2 Main Propulsion <span class="hlt">System</span> (MPS) flow liners in other orbiters. <span class="hlt">Endeavour</span> is next scheduled to fly on mission STS-113.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-200907310005HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-200907310005HQ.html"><span>STS-127 Shuttle <span class="hlt">Endeavour</span> Landing</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2009-07-31</p> <p>NASA Administrator Charles Bolden, left, STS-127 mission commander Mark Polansky, and NASA Kennedy Space Center Director Bob Cabana, right, walk around the space shuttle <span class="hlt">Endeavour</span> shortly after it and its crew landed, Friday, July 31, 2009 at NASA's Kennedy Space Center in Cape Canaveral, Fla., completing a 16-day journey of more than 6.5 million miles. <span class="hlt">Endeavour</span> delivered the final segment to the Japan Aerospace Exploration Agency's Kibo laboratory and a new crew member to the International Space Station. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/889656','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/889656"><span><span class="hlt">Hydrothermal</span> model of the Momotombo geothermal <span class="hlt">system</span>, Nicaragua</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Verma, M.P.; Martinez, E.; Sanchez, M.; Miranda, K.; Gerardo, J.Y.; Araguas, L.</p> <p>1996-01-24</p> <p>The Momotombo geotherinal field is situated on the northern shore of Lake Managua at the foot of the active Momotombo volcano. The field has been producing electricity since 1983 and has an installed capacity of 70 MWe. The results of geological, geochemical and geophysical studies have been reported in various internal reports. The isotopic studies were funded by the International Atomic Energy Agency (IAEA), Vienna to develop a <span class="hlt">hydrothermal</span> model of the geothermal <span class="hlt">system</span>. The chemical and stable isotopic data (δ<sup>18</sup>O and δD) of the geothermal fluid suggest that the seasonal variation in the production characteristics of the wells is related to the rapid infiltration of local precipitation into the reservoir. The annual average composition of Na<sup>+</sup>, K<sup>+</sup> and Mg<sup>2+</sup> plotted on the Na- K-Mg triangular diagram presented by Giggenbach (1988) to identify the state of rock-water interaction in geothermal reservoirs, shows that the fluids of almost every well are shifting towards chemically immature water due to resenroir exploitation. This effect is prominent in wells Mt-2. Mt-12, Mt-22 and Mt-27. The local groundwaters including surface water from Lake Managua have much lower tritium concentrations than sonic of the geothermal well fluids, which have about 6 T.U. The high-tritium wells are located along a fault inferred froin a thermal anomaly. The tritium concentration is also higher in fluids from wells close to the lake. This could indicate that older local precipitation waters are stored in a deep layer within the lake and that they are infiltrating into the geothermal reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/472054','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/472054"><span><span class="hlt">Hydrothermal</span> model of the Momotombo geothermal <span class="hlt">system</span>, Nicaragua</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Verma, M.P.; Martinez, E.; Sanchez, M.; Miranda, K.</p> <p>1996-12-31</p> <p>The Momotombo geothermal field is situated on the northern shore of Lake Managua at the foot of the active Momotombo volcano. The field has been producing electricity since 1983 and has an installed capacity of 70 MWe. The results of geological, geochemical and geophysical studies have been reported in various internal reports. The isotopic studies were funded by the International Atomic Energy Agency (IAEA), Vienna to develop a <span class="hlt">hydrothermal</span> model of the geothermal <span class="hlt">system</span>. The chemical and stable isotopic data ({delta}{sup 18}O and {delta}D) of the geothermal fluid suggest that the seasonal variation in the production characteristics of the wells is related to the rapid infiltration of local precipitation into the reservoir. The annual average composition of Na{sup +}, K{sup +} and Mg{sup 2+} plotted on the Na-K-Mg triangular diagram presented by Giggenbach (1988) to identify the state of rock-water interaction in geothermal reservoirs, shows that the fluids of almost every well are shifting towards chemically immature water due to reservoir exploitation. This effect is prominent in wells Mt-2, Mt-12, Mt-22 and Mt-27. The local groundwaters including surface water from Lake Managua have much lower tritium concentrations than some of the geothermal well fluids, which have about 6 T.U. The high-tritium wells are located along a fault inferred from a thermal anomaly. The tritium concentration is also higher in fluids from wells close to the lake. This could indicate that older local precipitation waters are stored in a deep layer within the lake and that they are infiltrating into the geothermal reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993Geo....21..113J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993Geo....21..113J"><span>Zonation patterns of skarn garnets: Records of <span class="hlt">hydrothermal</span> <span class="hlt">system</span> evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jamtveit, Bjørn; Wogelius, Roy A.; Fraser, Donald G.</p> <p>1993-02-01</p> <p>Chemically zoned skarn garnets provide a continuous record of <span class="hlt">hydrothermal</span> processes in lower Paleozoic sedimentary rocks within the contact aureole around the Drammen granite in the Oslo rift, southern Norway. Major and trace element zonation profiles, the latter obtained using a scanning high-resolution proton microprobe, reveal early infiltration-controlled growth of relatively grossular rich garnets, the major and trace elements compositions being buffered by local mineral dissolution. Subsequent rapid, epitaxial growth of andradite-rich garnet on grossular-rich cores marks the onset of vigorous and focused fluid flow along high-permeability zones. During this later stage, the <span class="hlt">hydrothermal</span> fluid composition was to a large extent externally controlled, and the andradite precipitating from these fluids was characterized by high As and W contents. The zonation patterns of the andradite-rich garnets record at least five intermittent growth periods, with rapid andradite precipitation from fluid batches with high f</em>O2, and progressively decreasing As and W contents. Thin layers, poor in Fe, As, and W, but relatively high in Al and Mn, represent periods of slow growth rates between the major pulses of <span class="hlt">hydrothermal</span> fluids. The marked rimward decrease in the As and W contents of the garnets may reflect influx of meteoric waters or exhaustion of these elements in the <span class="hlt">hydrothermal</span> fluid reservoir caused by boiling-controlled distillation processes at depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22970260','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22970260"><span>Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yao; Zhao, Zihao; Chen, Chen-Tung Arthur; Tang, Kai; Su, Jianqiang; Jiao, Nianzhi</p> <p>2012-01-01</p> <p>To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span> off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white <span class="hlt">hydrothermal</span> vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different <span class="hlt">hydrothermal</span> plumes. The bacterial and archaeal communities from the white <span class="hlt">hydrothermal</span> plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow <span class="hlt">hydrothermal</span> plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4)) concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4) was less tied to microbial processes in this shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We speculated that mixing between <span class="hlt">hydrothermal</span> fluids and the sea or meteoric water leads to distinctly different CH(4) concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> off the coast of NE Taiwan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3436782','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3436782"><span>Sulfur Metabolizing Microbes Dominate Microbial Communities in Andesite-Hosted Shallow-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Yao; Zhao, Zihao; Chen, Chen-Tung Arthur; Tang, Kai; Su, Jianqiang; Jiao, Nianzhi</p> <p>2012-01-01</p> <p>To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span> off NE Taiwan’s coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white <span class="hlt">hydrothermal</span> vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different <span class="hlt">hydrothermal</span> plumes. The bacterial and archaeal communities from the white <span class="hlt">hydrothermal</span> plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow <span class="hlt">hydrothermal</span> plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH4) concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH4 was less tied to microbial processes in this shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We speculated that mixing between <span class="hlt">hydrothermal</span> fluids and the sea or meteoric water leads to distinctly different CH4 concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> off the coast of NE Taiwan. PMID:22970260</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-03pd2788.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-03pd2788.html"><span><span class="hlt">Endeavour</span> Return to Flight Maintenance</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2003-10-10</p> <p>(Clockwise from left), in the Orbiter Processing Facility, Tim Chastain, John Peterson and Sang Huynh, with United Space Alliance, work at removing the body flap actuator from the orbiter <span class="hlt">Endeavour</span>. The work is part of return to flight activities on the orbiter fleet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-03pd2787.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-03pd2787.html"><span><span class="hlt">Endeavour</span> Return to Flight Maintenance</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2003-10-10</p> <p>In the Orbiter Processing Facility, (from left) Tim Chastain, Sang Huynh and John Peterson, with United Space Alliance, work at removing the body flap actuator from the orbiter <span class="hlt">Endeavour</span>. The work is part of return to flight activities on the orbiter fleet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14504.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14504.html"><span>Opportunity Route to <span class="hlt">Endeavour</span> Crater</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-08-05</p> <p>The yellow line on this map shows where NASA Mars Rover Opportunity has driven from the place where it landed in January 2004, inside Eagle crater, at the upper left end of the track, to a point approaching the rim of <span class="hlt">Endeavour</span> crater.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813062W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813062W"><span>Geologic and hydrologic controls on the economic potential of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with upper crustal plutons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weis, Philipp; Driesner, Thomas; Scott, Samuel; Lecumberri-Sanchez, Pilar</p> <p>2016-04-01</p> <p>Heat and mass transport in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with upper crustal magmatic intrusions can result in resources with large economic potential (Kesler, 1994). Active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> can form high-enthalpy geothermal reservoirs with the possibility for renewable energy production. Fossil continental or submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may have formed ore deposits at variable crustal depths, which can be mined near today's surface with an economic profit. In both cases, only the right combination of first-order geologic and hydrologic controls may lead to the formation of a significant resource. To foster exploration for these <span class="hlt">hydrothermal</span> georesources, we need to improve our understanding of subsurface fluxes of mass and energy by combining numerical process modelling, observations at both active and fossil <span class="hlt">systems</span>, as well as knowledge of fluid and rock properties and their interactions in natural <span class="hlt">systems</span>. The presentation will highlight the role of non-linear fluid properties, phase separation, salt precipitation, fluid mixing, permeability structure, hydraulic fracturing and the transition from brittle to ductile rock behavior as major geologic and hydrologic controls on the formation of high-enthalpy and supercritical geothermal resources (Scott et al., 2015), and magmatic-<span class="hlt">hydrothermal</span> mineral resources, such as porphyry copper, massive sulfide and epithermal gold deposits (Lecumberri-Sanchez et al., 2015; Weis, 2015). References: Kesler, S. E., 1994: Mineral Resources, economics and the environment, New York, McMillan, 391. Lecumberri-Sanchez, P., Steele-MacInnis, M., Weis, P., Driesner, T., Bodnar, R.J. (2015): Salt precipitation in magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with upper crustal plutons. Geology, v. 43, p. 1063-1066, doi:10.1130/G37163.1 Scott, S., Driesner, T., Weis, P. (2015): Geologic controls on supercritical geothermal resources above magmatic intrusions. Nature Communications, 6:7837 doi: 10.1038/ncomms8837 Weis, P. (2015): The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017M%26PS...52..351S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017M%26PS...52..351S"><span>Evidence for a spatially extensive <span class="hlt">hydrothermal</span> <span class="hlt">system</span> at the Ries impact structure, Germany</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sapers, H. M.; Osinski, G. R.; Flemming, R. L.; Buitenhuis, E.; Banerjee, N. R.; Tornabene, L. L.; Blain, S.; Hainge, J.</p> <p>2017-02-01</p> <p>The 15 Ma, 26 km diameter Ries impact structure in south-central Germany was one of the first terrestrial impact structures where evidence of impact-associated <span class="hlt">hydrothermal</span> alteration was recognized. Previous studies suggested that pervasive, high-temperature <span class="hlt">hydrothermal</span> activity was restricted to the area within the "inner ring" (i.e., the crater-fill impactite units). Here we present mineralogical evidence for localized <span class="hlt">hydrothermal</span> activity in the ejecta beyond the crater rim in two previously unstudied settings: a pervasively altered lens of suevite ejecta directly overlying the Bunte Breccia at the Aumühle quarry; and suevite ejecta at depth overlain by 20 m of lacustrine sediments sampled by the Wörnitzostheim 1965 drill core. A comprehensive set of X-ray diffraction analyses indicates five distinct alteration regimes (1) surficial ambient weathering characterized by smectite and a minor illitic component; (2) locally restricted <span class="hlt">hydrothermal</span> activity characterized by an illitic component and minor smectite; (3) <span class="hlt">hydrothermal</span> activity at depth characterized by smectite, a minor illitic component, and calcite; (4) <span class="hlt">hydrothermal</span> activity at depth characterized by smectite, a minor illitic component, calcite, zeolites, and clinochlore; and (5) pervasive <span class="hlt">hydrothermal</span> activity at depth characterized by smectite, a minor illitic component, and minor clinochlore. These data spatially extend the Ries postimpact <span class="hlt">hydrothermal</span> <span class="hlt">system</span> suggesting a much more extensive, complex, and dynamic <span class="hlt">system</span> than previously thought. Constraining the mineralogical alteration regimes at the Ries impact structure may also further our understanding of impact-associated phyllosilicate formation on Mars with implications for climate models and habitability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JVGR..160...23M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JVGR..160...23M"><span>Textural and mineralogical changes associated with the incipient <span class="hlt">hydrothermal</span> alteration of glassy dacite at the submarine PACMANUS <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, eastern Manus Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Monecke, T.; Giorgetti, G.; Scholtysek, O.; Kleeberg, R.; Götze, J.; Hannington, M. D.; Petersen, S.</p> <p>2007-02-01</p> <p>Variably altered dacite from the PACMANUS vent field in the eastern Manus back-arc basin, Papua New Guinea, was studied to determine the textural and mineralogical characteristics of <span class="hlt">hydrothermal</span> alteration taking place in the immediate subsurface of this modern seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Detailed textural investigations show that fluid flow through the glassy dacite has been strongly controlled by the primary volcanic textures. Quench fractures and networks of interconnected perlitic cracks linking vesicles provided pathways for <span class="hlt">hydrothermal</span> fluids flowing up to the seafloor. <span class="hlt">Hydrothermal</span> alteration along these pathways resulted in the formation of pseudoclastic textures. Textural evidence suggests that alteration of the glassy dacite has not been sustained. The samples have been affected by incipient <span class="hlt">hydrothermal</span> alteration that is typically not preserved in ancient volcanic-rock-hosted massive sulfide deposits. Interaction of the glassy dacite with <span class="hlt">hydrothermal</span> fluids primarily resulted in the conversion of volcanic glass to dioctahedral smectite. Only minor amounts of trioctahedral smectite were formed. Destruction of the volcanic glass and the formation of smectite caused pronounced changes in the chemistry of the dacite samples, in particular a decrease in the SiO 2 whole-rock content and the Na 2O/K 2O ratio. The two alkali elements behaved differently during <span class="hlt">hydrothermal</span> alteration due to preferential incorporation of K into the interlayer position of the newly formed dioctahedral smectite. Smectite formation occurred under rock-dominated conditions although the addition of Mg was required to form trioctahedral smectite from the silicic volcanic glass. Primary plagioclase was resistant to <span class="hlt">hydrothermal</span> alteration highlighting the fact that the destruction of volcanic glass and feldspar are not necessarily contemporaneous in massive sulfide forming <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Incipient alteration of the glassy dacite close to the seafloor occurred at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6614I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6614I"><span>Hydrogeological structure of a seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span> related to backarc rifting in a continental margin setting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishibashi, Jun-ichiro</p> <p>2016-04-01</p> <p>Seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the Okinawa Trough backarc basin are considered as related to backarc rifting in a continental margin setting. Since the seafloor is dominantly covered with felsic volcaniclastic material and/or terrigenous sediment, <span class="hlt">hydrothermal</span> circulation is expected to be distributed within sediment layers of significantly high porosity. Deep drilling through an active <span class="hlt">hydrothermal</span> field at the Iheya North Knoll in the middle Okinawa Trough during IODP Expedition 331 provided a unique opportunity to directly access the subseafloor. While sedimentation along the slopes of the knoll was dominated by volcanic clasts of tubular pumice, intense <span class="hlt">hydrothermal</span> alteration was recognized in the vicinity of the <span class="hlt">hydrothermal</span> center even at very shallow depths. Detailed mineralogical and geochemical studies of <span class="hlt">hydrothermal</span> clay minerals in the altered sediment suggest that the prevalent alteration is attributed to laterally extensive fluid intrusion and occupation within the sediment layer. Onboard measurements of physical properties of the obtained sediment revealed drastic changes of the porosity caused by <span class="hlt">hydrothermal</span> interactions. While unaltered sediment showed porosity higher than 70%, the porosity drastically decreased in the layer of anhydrite formation. On the other hand, the porosity remained high (~50%) in the layer of only chlorite alteration. Cap rock formation caused by anhydrite precipitation would inhibit the ascent of high temperature fluids to the seafloor. Moreover, an interbedded nature of pelagic mud units and matrix-free pumice deposits may prompt formation of a tightly layered architecture of aquifers and aquicludes. This sediment architecture should be highly conducive to lateral flow pseudo-parallel to the surface topography. Occurrence of sphalerite-rich sulfides was recognized as associated with detrital and altered sediment, suggesting mineralization related to subsurface chemical processes. Moreover, the vertical profiles of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22928928','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22928928"><span>Microbial community structure across fluid gradients in the Juan de Fuca Ridge <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Rika E; Beltrán, Mónica Torres; Hallam, Steven J; Baross, John A</p> <p>2013-02-01</p> <p>Physical and chemical gradients are dominant factors in shaping <span class="hlt">hydrothermal</span> vent microbial ecology, where archaeal and bacterial habitats encompass a range between hot, reduced <span class="hlt">hydrothermal</span> fluid and cold, oxidized seawater. To determine the impact of these fluid gradients on microbial communities inhabiting these <span class="hlt">systems</span>, we surveyed bacterial and archaeal community structure among and between <span class="hlt">hydrothermal</span> plumes, diffuse flow fluids, and background seawater in several <span class="hlt">hydrothermal</span> vent sites on the Juan de Fuca Ridge using 16S rRNA gene diversity screening (clone libraries and terminal restriction length polymorphisms) and quantitative polymerase chain reaction methods. Community structure was similar between <span class="hlt">hydrothermal</span> plumes and background seawater, where a number of taxa usually associated with low-oxygen zones were observed, whereas high-temperature diffuse fluids exhibited a distinct phylogenetic profile. SUP05 and Arctic96BD-19 sulfur-oxidizing bacteria were prevalent in all three mixing regimes where they exhibited overlapping but not identical abundance patterns. Taken together, these results indicate conserved patterns of redox-driven niche partitioning between <span class="hlt">hydrothermal</span> mixing regimes and microbial communities associated with sinking particles and oxygen-deficient waters. Moreover, the prevalence of SUP05 and Arctic96BD-19 in plume and diffuse flow fluids indicates a more cosmopolitan role for these groups in the ecology and biogeochemistry of the dark ocean. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGP11A..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGP11A..01S"><span>The magnetic signature of ultramafic-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szitkar, F.; Dyment, J.; Honsho, C.; Horen, H.; Fouquet, Y.</p> <p>2013-12-01</p> <p>While the magnetic response of basalt-hosted <span class="hlt">hydrothermal</span> sites is well known, that of ultramafic-hosted <span class="hlt">hydrothermal</span> sites (UMHS) remains poorly documented. Here we present the magnetic signature of three of the six UMHS investigated to date on the Mid-Atlantic Ridge, i.e. sites Rainbow, Ashadze (1 and 2), and Logachev. Two magnetic signatures are observed. Sites Rainbow and Ashadze 1 are both characterized by a positive reduced-to-the-pole magnetic anomaly, i.e. a positive magnetization contrast. Conversely, sites Ashadze 2 and Logachev do not exhibit any clear magnetic signature. Rock-magnetic measurements on samples from site Rainbow reveal a strong magnetization (~30 A/m adding induced and remanent contributions) borne by sulfide-impregnated serpentinites; the magnetic carrier being magnetite. This observation can be explained by three (non exclusive) processes: (1) higher temperature serpentinization at the site resulting in the formation of more abundant / more strongly magnetized magnetite; (2) the reducing <span class="hlt">hydrothermal</span> fluid protecting magnetite at the site from the oxidation which otherwise affects magnetite in contact with seawater; and (3) the formation of primary (<span class="hlt">hydrothermal</span>) magnetite. We apply a new inversion method developed by Honsho et al. (2012) to the high-resolution magnetic anomalies acquired 10 m above seafloor at sites Rainbow and Ashadze 1. This method uses the Akaike Bayesian Information Criterion (ABIC) and takes full advantage of the near-seafloor measurements, avoiding the upward-continuation (i.e. loss of resolution) of other inversion schemes. This inversion reveals a difference in the intensity of equivalent magnetization obtained assuming a 100 m thick magnetic layer, ~30 A/m at site Rainbow and only 8A/m at site Ashadze, suggesting a thinner or less magnetized source for the latter. <span class="hlt">Hydrothermal</span> sites at Ashadze 2 and Logachev are much smaller (of the order of 10 m) than the previous ones (several 100 m). These sites, known as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS21C1526C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS21C1526C"><span>Investigation of Icelandic rift zones reveals systematic changes in <span class="hlt">hydrothermal</span> outflow in concert with seismic and magmatic events: Implications for investigation of Mid-Ocean Ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Curewitz, D.; Karson, J. A.</p> <p>2010-12-01</p> <p>Co-registration of several generations of geological data was carried out for <span class="hlt">hydrothermal</span> fields along active rift zones of the Iceland plate boundary zone. Significant short- and long-term changes in vent locations, flow rates and styles, and fluid characteristics over short periods take place in concert with recorded earthquakes, dike intrusions, and fissure eruptions. Higher resolution, more detailed analysis of the Icelandic <span class="hlt">hydrothermal</span> sites will inform investigation of similar data from mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> along the RIDGE 2000 focus sites. Initial results from the Hengill and Krafla geothermal areas covering a time-span of nearly 40 years at ~10 year intervals reveal limited changes in the surface expression of fault populations, with the exception of local fault and fracture <span class="hlt">systems</span>. The location and population density of individual vents and groups of vents underwent significant changes over the same time period, with either vents shifting location, or new vents opening and old vents closing. Registration of changes in vent fluid temperatures, vent field ground temperatures, fluid flow rates, and vent eruptive styles reveal changes in <span class="hlt">hydrothermal</span> flow systematics in concert with the observed changes in vent location and vent population density. Significant local seismic and volcanological events (earthquakes, earthquake swarms, dike intrusions, eruptions, inflation/deflation) that are potential triggers for the observed changes take place in intervening years between production of successive maps. Changes in modeled stress intensities and local fracture/fault density and geometry associated with these tectono-magmatic events correspond well to inferred locations of increased or decreased shallow permeability thought to control <span class="hlt">hydrothermal</span> outflow behavior. Recent seismic events are strongly linked to well-mapped changes in fracture/fault population and <span class="hlt">hydrothermal</span> flow behavior in the Hveragerdi region, near Hengill, and provide higher</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3130K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3130K"><span>Volcano-<span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> of the Central and Northern Kuril Island Arc - a Review</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalacheva, E.; Taran, Y.; Voloshina, E.; Ptashinsky, L.</p> <p>2015-12-01</p> <p>More than 20 active volcanoes with historical eruptions are known on 17 islands composing the Central and Northern part of the Kurilian Arc. Six islands - Paramushir, Shiashkotan, Rasshua, Ushishir, Ketoy and Simushir - are characterized by <span class="hlt">hydrothermal</span> activity, complementary to the fumarolic activity in their craters. There are several types of volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the islands. At Paramushir, Shiashkotan and Ketoy the thermal manifestations are acidic to ultra-acidic water discharges associated with <span class="hlt">hydrothermal</span> aquifers inside volcano edifices and formed as the result of the absorption of magmatic gases by ground waters. A closest known analogue of such activity is Satsuma-Iwojima volcano-island at the Ryukyu Arc. Another type of <span class="hlt">hydrothermal</span> activity are wide spread coastal hot springs (Shiashkotan, Rasshua), situated as a rule within tide zones and formed by mixing of the heated seawater with cold groundwater or, in opposite, by mixing of the steam- or conductively heated groundwater with seawater. This type of thermal manifestation is similar to that reported for other volcanic islands of the world (Satsuma Iwojima, Monserrat, Ischia, Socorro). Ushishir volcano-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> is formed by the absorption of magmatic gases by seawater. Only Ketoy Island hosts a permanent acidic crater lake. At Ebeko volcano (Paramushir) rapidly disappearing small acidic lakes (formed after phreatic eruptions) have been reported. The main <span class="hlt">hydrothermal</span> manifestation of Simushir is the Zavaritsky caldera lake with numerous coastal thermal springs and weak steam vents. The last time measured temperatures of fumaroles at the islands are: >500ºC at Pallas Peak (Ketoy), 480ºC at Kuntamintar volcano (Shiashkotan), variable and fast changing temperatures from 120º C to 500ºC at Ebeko volcano (Paramushir), 150ºC in the Rasshua crater, and > 300ºC in the Chirpoy crater (Black Brothers islands). The magmatic and rock-forming solute output by the Kurilian volcano-<span class="hlt">hydrothermal</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IJAsB...9..137L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IJAsB...9..137L"><span>Putative fossil life in a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of the Dellen impact structure, Sweden</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lindgren, Paula; Ivarsson, Magnus; Neubeck, Anna; Broman, Curt; Henkel, Herbert; Holm, Nils G.</p> <p>2010-07-01</p> <p>Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are commonly proposed as good candidates for hosting primitive life on early Earth and Mars. However, evidence of fossil microbial colonization in impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is rarely reported in the literature. Here we present the occurrence of putative fossil microorganisms in a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of the 89 Ma Dellen impact structure, Sweden. We found the putative fossilized microorganisms hosted in a fine-grained matrix of <span class="hlt">hydrothermal</span> alteration minerals set in interlinked fractures of an impact breccia. The putative fossils appear as semi-straight to twirled filaments, with a thickness of 1-2 μm, and a length between 10 and 100 μm. They have an internal structure with segmentation, and branching of filaments occurs frequently. Their composition varies between an outer and an inner layer of a filament, where the inner layer is more iron rich. Our results indicate that <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in impact craters could potentially be capable of supporting microbial life. This could have played an important role for the evolution of life on early Earth and Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201104290005HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201104290005HQ.html"><span>Space Shuttle <span class="hlt">Endeavour</span> STS-134</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-04-29</p> <p>Water pours out of the 290-foot-high tower that holds 300,000 gallons of water used for sound suppression during shuttle launches on launch pad 39a shortly after the rollback of the Rotating Service Structure (RSS) from the space shuttle <span class="hlt">Endeavour</span>, Thursday, April 28, 2011, at Kennedy Space Center in Cape Canaveral, Fla. During the 14-day mission, <span class="hlt">Endeavour</span> and the STS-134 crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. Launch is targeted for Friday, April 29 at 3:47 p.m. EDT. Photo credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Sci...336..570S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Sci...336..570S"><span>Ancient Impact and Aqueous Processes at <span class="hlt">Endeavour</span> Crater, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Squyres, S. W.; Arvidson, R. E.; Bell, J. F.; Calef, F.; Clark, B. C.; Cohen, B. A.; Crumpler, L. A.; de Souza, P. A.; Farrand, W. H.; Gellert, R.; Grant, J.; Herkenhoff, K. E.; Hurowitz, J. A.; Johnson, J. R.; Jolliff, B. L.; Knoll, A. H.; Li, R.; McLennan, S. M.; Ming, D. W.; Mittlefehldt, D. W.; Parker, T. J.; Paulsen, G.; Rice, M. S.; Ruff, S. W.; Schröder, C.; Yen, A. S.; Zacny, K.</p> <p>2012-05-01</p> <p>The rover Opportunity has investigated the rim of <span class="hlt">Endeavour</span> Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest <span class="hlt">hydrothermal</span> alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks adjacent to the crater rim. The gypsum was precipitated from low-temperature aqueous fluids flowing upward from the ancient materials of the rim, leading temporarily to potentially habitable conditions and providing some of the waters involved in formation of the ubiquitous sulfate-rich sandstones of the Meridiani region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22556248','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22556248"><span>Ancient impact and aqueous processes at <span class="hlt">Endeavour</span> Crater, Mars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Squyres, S W; Arvidson, R E; Bell, J F; Calef, F; Clark, B C; Cohen, B A; Crumpler, L A; de Souza, P A; Farrand, W H; Gellert, R; Grant, J; Herkenhoff, K E; Hurowitz, J A; Johnson, J R; Jolliff, B L; Knoll, A H; Li, R; McLennan, S M; Ming, D W; Mittlefehldt, D W; Parker, T J; Paulsen, G; Rice, M S; Ruff, S W; Schröder, C; Yen, A S; Zacny, K</p> <p>2012-05-04</p> <p>The rover Opportunity has investigated the rim of <span class="hlt">Endeavour</span> Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest <span class="hlt">hydrothermal</span> alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks adjacent to the crater rim. The gypsum was precipitated from low-temperature aqueous fluids flowing upward from the ancient materials of the rim, leading temporarily to potentially habitable conditions and providing some of the waters involved in formation of the ubiquitous sulfate-rich sandstones of the Meridiani region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70047182','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70047182"><span>Ancient impact and aqueous processes at <span class="hlt">Endeavour</span> Crater, Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Squyres, S. W.; Arvidson, R. E.; Bell, J.F.; Calef, F.J.; Clark, B. C.; Cohen, B. A.; Crumpler, L.A.; de Souza, P. A.; Farrand, W. H.; Gellert, Ralf; Grant, J.; Herkenhoff, K. E.; Hurowitz, J.A.; Johnson, J. R.; Jolliff, B.L.; Knoll, A.H.; Li, R.; McLennan, S.M.; Ming, D. W.; Mittlefehldt, D. W.; Parker, T.J.; Paulsen, G.; Rice, M.S.; Ruff, S.W.; Schröder, C.; Yen, A. S.; Zacny, K.</p> <p>2012-01-01</p> <p>The rover Opportunity has investigated the rim of <span class="hlt">Endeavour</span> Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest <span class="hlt">hydrothermal</span> alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks adjacent to the crater rim. The gypsum was precipitated from low-temperature aqueous fluids flowing upward from the ancient materials of the rim, leading temporarily to potentially habitable conditions and providing some of the waters involved in formation of the ubiquitous sulfate-rich sandstones of the Meridiani region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeCoA.190...35G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeCoA.190...35G"><span>Molecular evidence for abiotic sulfurization of dissolved organic matter in marine shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez-Saez, Gonzalo V.; Niggemann, Jutta; Dittmar, Thorsten; Pohlabeln, Anika M.; Lang, Susan Q.; Noowong, Ann; Pichler, Thomas; Wörmer, Lars; Bühring, Solveig I.</p> <p>2016-10-01</p> <p>Shallow submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are extreme environments with strong redox gradients at the interface of hot, reduced fluids and cold, oxygenated seawater. <span class="hlt">Hydrothermal</span> fluids are often depleted in sulfate when compared to surrounding seawater and can contain high concentrations of hydrogen sulfide (H2S). It is well known that sulfur in its various oxidation states plays an important role in processing and transformation of organic matter. However, the formation and the reactivity of dissolved organic sulfur (DOS) in the water column at <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are so far not well understood. We investigated DOS dynamics and its relation to the physicochemical environment by studying the molecular composition of dissolved organic matter (DOM) in three contrasting shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> off Milos (Eastern Mediterranean), Dominica (Caribbean Sea) and Iceland (North Atlantic). We used ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to characterize the DOM on a molecular level. The molecular information was complemented with general geochemical data, quantitative dissolved organic carbon (DOC) and DOS analyses as well as isotopic measurements (δ2H, δ18O and F14C). In contrast to the predominantly meteoric fluids from Dominica and Iceland, <span class="hlt">hydrothermal</span> fluids from Milos were mainly fed by recirculating seawater. The <span class="hlt">hydrothermal</span> fluids from Milos were enriched in H2S and DOS, as indicated by high DOS/DOC ratios and by the fact that >90% of all assigned DOM formulas that were exclusively present in the fluids contained sulfur. In all three <span class="hlt">systems</span>, DOS from <span class="hlt">hydrothermal</span> fluids had on average lower O/C ratios (0.26-0.34) than surrounding surface seawater DOS (0.45-0.52), suggesting shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> as a source of reduced DOS, which will likely get oxidized upon contact with oxygenated seawater. Evaluation of hypothetical sulfurization reactions suggests DOM reduction and sulfurization during seawater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B22B..02A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B22B..02A"><span>Evolutionary strategies of cells and viruses in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> revealed through comparative metagenomics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, R.; Sogin, M. L.; Baross, J. A.</p> <p>2013-12-01</p> <p>The deep-sea <span class="hlt">hydrothermal</span> vent habitat hosts a diverse community of archaea and bacteria that withstand extreme fluctuations in environmental conditions. Abundant viruses in these <span class="hlt">systems</span> must also withstand these environmental extremes, and a high proportion of viruses in these <span class="hlt">systems</span> are lysogenic. Comparative analysis of a cellular and viral metagenome from a diffuse flow <span class="hlt">hydrothermal</span> vent has provided insights into the evolutionary strategies of both cells and viruses in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. We detected numerous mobile elements in the viral and cellular gene pools as well as a large number of prophage in the cellular fraction. We show that the <span class="hlt">hydrothermal</span> vent viral gene pool is relatively enriched in genes related to energy metabolism, a feature that is unique to the <span class="hlt">hydrothermal</span> vent viral gene pool compared to viral gene pools from other environments, indicating a potential for integrated prophage to enhance host metabolic flexibility. We also detected stronger purifying selection in the viral versus cellular gene pool, indicating selection pressures that promote prolonged viral integration in the host. Our results support the hypothesis that viruses enhance host genomic plasticity and adaptability in this extreme and dynamic environment. Finally, we will discuss general implications of this work for understanding the viral impact on biogeochemical cycles and evolutionary trajectories of microbial populations in the deep subsurface biosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20529945','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20529945"><span>Mineral-microbe interactions in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: a challenge for Raman spectroscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Breier, J A; White, S N; German, C R</p> <p>2010-07-13</p> <p>In deep-sea <span class="hlt">hydrothermal</span> environments, steep chemical and thermal gradients, rapid and turbulent mixing and biologic processes produce a multitude of diverse mineral phases and foster the growth of a variety of chemosynthetic micro-organisms. Many of these microbial species are associated with specific mineral phases, and the interaction of mineral and microbial processes are of only recently recognized importance in several areas of <span class="hlt">hydrothermal</span> research. Many submarine <span class="hlt">hydrothermal</span> mineral phases form during kinetically limited reactions and are either metastable or are only thermodynamically stable under in situ conditions. Laser Raman spectroscopy is well suited to mineral speciation measurements in the deep sea in many ways, and sea-going Raman <span class="hlt">systems</span> have been built and used to make a variety of in situ measurements. However, the full potential of this technique for <span class="hlt">hydrothermal</span> science has yet to be realized. In this focused review, we summarize both the need for in situ mineral speciation measurements in <span class="hlt">hydrothermal</span> research and the development of sea-going Raman <span class="hlt">systems</span> to date; we describe the rationale for further development of a small, low-cost sea-going Raman <span class="hlt">system</span> optimized for mineral identification that incorporates a fluorescence-minimizing design; and we present three experimental applications that such a tool would enable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011321','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011321"><span>Nontronite from a low-temperature <span class="hlt">hydrothermal</span> <span class="hlt">system</span> on the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Murnane, R.; Clague, D.A.</p> <p>1983-01-01</p> <p>A deposit of Fe-rich, Al-poor, <span class="hlt">hydrothermal</span> nontronite was recovered from the Juan de Fuca Ridge. Analyses show the deposit to be mineralogically and chemically similar to nontronite described at other oceanic localities. The deposit is located near the tip of a propagating segment of the Juan de Fuca Ridge. Rare earth elements and Sr isotopes indicate that the nontronite precipitated from seawater. A formation temperature of 57??C is suggested by oxygen isotopic composition. The low-temperature nontronite deposits apparently form from newly established <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with the propagating rift segment. More mature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> that deposit sulfide on the seafloor may develop from these low-temperature <span class="hlt">systems</span>. ?? 1983.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/887500','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/887500"><span>Conceptual geologic model and native state model of the Roosevelt Hot Springs <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faulder, D.D.</p> <p>1991-01-01</p> <p>A conceptual geologic model of the Roosevelt Hot Springs <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was developed by a review of the available literature. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> consists of a meteoric recharge area in the Mineral Mountains, fluid circulation paths to depth, a heat source, and an outflow plume. A conceptual model based on the available data can be simulated in the native state using parameters that fall within observed ranges. The model temperatures, recharge rates, and fluid travel times are sensitive to the permeability in the Mineral Mountains. The simulation results suggests the presence of a magma chamber at depth as the likely heat source. A two-dimensional study of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> can be used to establish boundary conditions for further study of the geothermal reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5909343','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5909343"><span>Conceptual geologic model and native state model of the Roosevelt Hot Springs <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faulder, D.D.</p> <p>1991-01-01</p> <p>A conceptual geologic model of the Roosevelt Hot Springs <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was developed by a review of the available literature. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> consists of a meteoric recharge area in the Mineral Mountains, fluid circulation paths to depth, a heat source, and an outflow plume. A conceptual model based on the available data can be simulated in the native state using parameters that fall within observed ranges. The model temperatures, recharge rates, and fluid travel times are sensitive to the permeability in the Mineral Mountains. The simulation results suggests the presence of a magma chamber at depth as the likely heat source. A two-dimensional study of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> can be used to establish boundary conditions for further study of the geothermal reservoir. 33 refs., 9 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5641454','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5641454"><span><span class="hlt">Hydrothermal</span> industrialization electric-power <span class="hlt">systems</span> development. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1982-03-01</p> <p>The nature of <span class="hlt">hydrothermal</span> resources, their associated temperatures, geographic locations, and developable capacity are described. The parties involved in development, required activities and phases of development, regulatory and permitting requirements, environmental considerations, and time required to complete development activities ae examined in detail. These activities are put in proper perspective by detailing development costs. A profile of the geothermal industry is presented by detailing the participants and their operating characteristics. The current development status of geothermal energy in the US is detailed. The work on market penetration is summarized briefly. Detailed development information is presented for 56 high temperature sites. (MHR)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.2261E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.2261E"><span>Exploring an active <span class="hlt">hydrothermal</span> <span class="hlt">system</span> - An analogue study from the Swiss Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Egli, Daniel; Herwegh, Marco; Berger, Alfons; Baron, Ludovic</p> <p>2016-04-01</p> <p>Understanding the detailed flow paths in <span class="hlt">hydrothermal</span> reservoirs is crucial for successful exploration of naturally porous and permeable rock masses for energy production. However, due to the common inaccessibility of active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of suitable depth, e.g. in the northern Alpine foreland of the European Alps, direct observations are normally impossible and the knowledge about such <span class="hlt">systems</span> is still insufficient. For that reason, a known fault-bound <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the crystalline basement of the Aar Massif serves as an analogue for potential geothermal reservoirs in the deep crystalline subsurface of the northern Alpine foreland. During summer 2015, a 125 m hole has been drilled across this active <span class="hlt">hydrothermal</span> zone on the Grimsel Pass for in-situ characterization of its structural, petrophysical, mechanical as well as geophysical parameters. With this information, this project aims at improving the knowledge of natural <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> as a potentially exploitable energy source. The investigated <span class="hlt">system</span> is characterized by a central breccia zone surrounded by different types of cataclasites and localized high strain zones. The surrounding includes different altered and deformed granitoid host rocks. In this study, we focus on the ductile and brittle deformation (shear zones, fractures, joints) that provides the main fluid pathways. Their spatial distribution around a central water-bearing breccia zone as well as their continuity and permeability provide constraints on the water flow paths in such structurally controlled <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. The aim will be the connection of detailed structural data with petrophysical parameters such as porosities and permeabilities. The drillcore shows the high variability of deformation structures and related fluid pathways at different scales (millimeter-decameter) demonstrating the urgent need for an improved understanding of the link between mechanical evolution, associated deformation structures as well</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P33A4027G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P33A4027G"><span>Degradation of <span class="hlt">Endeavour</span> crater, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grant, J. A., III; Crumpler, L. S.; Parker, T. J.; Golombek, M. P.</p> <p>2014-12-01</p> <p>The Opportunity rover is traversing the western rim segments of the 22 km diameter <span class="hlt">Endeavour</span> crater in Meridiani Planum, with resultant data enabling evaluation of the craters's degradation state. The crater is Noachian in age, complex in morphology, and largely buried by younger sulfate-rich rocks. Nevertheless, exposed rim segments dubbed Cape York (CY) and Solander Point/Murray Ridge (S/M) ~1500 m to the south reveal breccias interpreted as remnants of the ejecta deposit (Shoemaker Formation or SF) that at CY overlie the pre-impact country rocks (Matijevic Formation or MF). At CY, relief is ~10 m and consists of 6-7 m of SF over at least several m of MF. By contrast, the MF/SF contact is not visible at S/M despite outcrops some 20 m below and 60 m above the elevation of the contact at CY. This implies some structural offset between the rim segments and suggests up to 70 m section is preserved at S/M. The lack of information about the orientation of the SF at S/M makes the true thickness difficult to establish, though it appears to be 10's of m more than at CY. Comparison to similar sized, fresh, complex craters on Mars and the Moon suggests there was originally 100-200 m of ejecta at <span class="hlt">Endeavour</span>'s rim. Ejecta comprise only 20-25% of the rim relief around lunar craters of similar size, thereby implying an original rim height of up to 500-1000 m at <span class="hlt">Endeavour</span>. If accurate, then ~400-800 m of the rim remains buried; the higher end of this range is close to the 800-900 m section interpreted elsewhere. If 200 m ejecta were present, then CY and S/M experienced ~190 m and over 100 m erosional lowering, respectively. If 100 m ejecta were present then rim lowering was ~90 m and 10's of m, respectively. Such differences between rim segments likely relate to changing efficiency of responsible processes and/or varying characteristics of the rocks and indicate portions of <span class="hlt">Endeavour</span> crater experienced significant degradation. A paucity of exposed debris shed from SF and MT</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994Geo....22...75W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994Geo....22...75W"><span>Mineralogy at the magma-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> interface in andesite volcanoes, New Zealand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wood, C. Peter</p> <p>1994-01-01</p> <p>Ejecta from phreatomagmatic eruptions of Ruapehu and White Island andesite volcanoes in New Zealand provide insight into the mineralogical reactions that occur when magma invades a vent-hosted <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. At the surface and in ejected blocks from shallow depths, <span class="hlt">hydrothermal</span> alteration mineralogies are dominated by silica polymorphs, anhydrite, natroalunite, and pyrite. Blocks from greater depths are composed mainly of cristobalite, anhydrite, halite, and magnetite. Where altered material was heated to magmatic temperatures, thermal decomposition reactions produced mullite, wollastonite, and indialite. Some ejected breccias contain osumilite, cordierite, sanidine, and hypersthene, indicative of reactions occurring near the osumilite-cordierite phase boundary at >800 °C and water pressure <0.2 kbar. Hedenbergite, wollastonite, andradite, and magnetite are found in rare skarn fragments, possibly formed by metasomatism of silica-poor, sulfate-rich <span class="hlt">hydrothermal</span> deposits. High- temperature parageneses of these types have not been reported before in shallow, acidic volcano-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. However, they may be typical of the magma- <span class="hlt">hydrothermal</span> contact zone at many andesite volcanoes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/624049','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/624049"><span>CO{sub 2} supply from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shitashima, Kiminori</p> <p>1998-07-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are aimed as an on-site field analysis on the behavior and diffusion of CO{sub 2} in deep ocean. Through ocean ridge volcanism, a large amount of elements including carbon as a form of CO{sub 2} are supplied to deep ocean. <span class="hlt">Hydrothermal</span> vent fluids at highly enriched in CO{sub 2} and show low pH ({approximately} pH 3) relative to seawater. Total carbonate, total CO{sub 2} in seawater, and pH were determined in samples at <span class="hlt">hydrothermal</span> active area in S-EPR. The concentration of total carbonate and pH in the <span class="hlt">hydrothermal</span> fluid samples ranged from 16 to 5 mM and from 3.1 to 7.6, respectively. The <span class="hlt">hydrothermal</span> fluids discharged from the vents were rapidly diluted with ambient seawater, therefore total carbonate concentration and pH value in the plume waters become close to that of ambient seawater near the vents. The positive anomaly of total carbonate and negative anomaly of pH associated with <span class="hlt">hydrothermal</span> plumes were observed on the seafloor along S-EPR axis. The diffusion of total carbonate plumes both westward and eastward in the bottom water along 15{degree}S across the S-EPR were also detected, but pH anomalies were not obtained in the plume. These suggest the possibility of discharging of CO{sub 2} through <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to the ocean. Recent estimation of CO{sub 2} fluxes to the ocean through MOR was calculated at 0.7--15 {times} 10{sup 12} mol C year{sup {minus}1}. These values are 3--4 orders of magnitude smaller than the annual CO{sub 2} fluxes through terrestrial and marine respiration, therefore the importance of CO{sub 2} input from MOR on oceanic carbon cycle is thus minimal on shorter-term time scale. However, the CO{sub 2} input from MOR is significant at 10{sup 6}--10{sup 7} years scales, and CO{sub 2} concentration in <span class="hlt">hydrothermal</span> fluids at hotspot and back-arc basin is 10--100 times higher than that of MOR. The flux of CO{sub 2} from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to the ocean may be significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSCT51A..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSCT51A..07G"><span>Sources and Fate of Dissolved Organic Sulfur at the Redox Interface of Marine Shallow <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez-Saez, G. V.; Niggemann, J.; Dittmar, T.; Pohlabeln, A. M.; Lang, S. Q.; Noowong, A.; Pichler, T.; Wörmer, L.; Bühring, S. I.</p> <p>2016-02-01</p> <p>Shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are extreme environments with strong redox gradients at the interface of hot, reduced fluids and cold, oxygenated seawater. <span class="hlt">Hydrothermal</span> fluids are often depleted in sulfate and can contain high concentrations of hydrogen sulfide (H2S). It is well known that sulfur plays an important role in processing and transformation of organic matter. However, the formation and the reactivity of dissolved organic sulfur (DOS) in the water column at <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are not well understood. We investigated DOS dynamics by studying the molecular composition of DOM in three contrasting <span class="hlt">systems</span> off Milos (Aegean Sea), Dominica (Lesser Antilles) and Iceland (North Atlantic). We used ultra-high resolution mass spectrometry (FTICR-MS) to characterize the DOM on a molecular level. The molecular information was complemented with geochemical data, quantitative DOC and DOS analyses and isotopic measurements (δ2H, δ18O, F14C). In contrast to the predominantly meteoric fluids from Dominica and Iceland, fluids from Milos were mainly fed by recirculating seawater. Milos <span class="hlt">hydrothermal</span> fluids were enriched in H2S and DOS, as indicated by high DOS/DOC ratios and by the fact that 93% of all assigned DOM molecular formulas exclusively present in the fluids contained sulfur. In all three <span class="hlt">systems</span>, DOS from the fluids had on average lower O/C ratios (0.31-0.33) than surrounding seawater DOS (0.47-0.49), suggesting shallow <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> as a marine source of reduced DOS, which will likely get oxidized upon contact with oxygenated seawater. Evaluation of hypothetical pathways suggested DOM reduction and sulfurization during seawater recirculation in Milos. The four most effective pathways were those exchanging an O atom by one S atom in the formula or the equivalent +H2S reaction. In conclusion, our study reveals novel insights about DOS dynamics in marine <span class="hlt">hydrothermal</span> environments and provides a conceptual framework for molecular-scale mechanisms in organic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPI....43.1915S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPI....43.1915S"><span>The Ries Post-Impact <span class="hlt">Hydrothermal</span> <span class="hlt">System</span>: Spatial and Temporal Mineralogical Variation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sapers, H. M.; Osinski, G. R.; Buitenhuis, E.; Banerjee, N. R.; Flemming, R. L.; Hainge, J.; Blain, S.</p> <p>2012-03-01</p> <p>Mineralogical data from surficial suevite, Nördlingen, and Wörnitzostheim drill cores used to assess the extent of the Ries post-impact <span class="hlt">hydrothermal</span> <span class="hlt">system</span> suggest that the <span class="hlt">system</span> outside the crater rim is more extensive than previously reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.T31A0489T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.T31A0489T"><span>Heat Flux From the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, W. J.; McDuff, R. E.; Stahr, F. R.; Yoerger, D. R.; Jakuba, M.</p> <p>2005-12-01</p> <p>The very essence of a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is transfer of heat by a convecting fluid, yet the flux of heat remains a poorly known quantity. Past studies of heat flux consisted primarily of point measurements of temperature and fluid flow at individual vent sites and inventories of the neutrally buoyant plume above the field. In 2000 the Flow Mow project used the Autonomous Benthic Explorer (ABE) to determine heat flux from Main <span class="hlt">Endeavour</span> Field (MEF) on the Juan de Fuca Ridge by intersecting the stems of rising buoyant plumes. ABE carries instruments to measure conductivity, temperature and depth, and a MAVS current meter to determine the vertical velocity of the fluid, after correcting for vehicle motion. Complementary work on horizontal fluxes suggests that the vertical flux measured by ABE includes both the primary high buoyancy focused "smoker" sources and also entrained diffuse flow. In 2004, ABE was again used to determine heat flux not only from MEF, but also from the other four fields in the <span class="hlt">Endeavour</span> Segment RIDGE 2000 Integrated Study Site. In this four year interval the flux of heat from MEF has declined by approximately a factor of two. The High Rise vent field has the greatest heat flux, followed by MEF, then Mothra, Salty Dawg and Sasquatch (of order 500, 300, 100, 50 MW respectively; heat flux at Sasquatch was below detection).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.8069L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.8069L"><span>Application of Hyperspectral Methods in <span class="hlt">Hydrothermal</span> Mineral <span class="hlt">System</span> Studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laukamp, Carsten; Cudahy, Thomas; Gessner, Klaus; Haest, Maarten; Cacetta, Mike; Rodger, Andrew; Jones, Mal; Thomas, Matilda</p> <p>2010-05-01</p> <p> hyperspectral mineral mapping of contaminating, carbonate- or clay-rich zones helped to better constrain the ore zones and the genesis of the mineral <span class="hlt">system</span>. Airborne hyperspectral data covering about 2500 km2 were obtained from the Eastern Goldfields Superterrane (Yilgarn Craton, Western Australia), which is highly prospective for Archean Au as well as komatiite associated Fe-Ni sulphide mineralisation. In this project hyperspectral airborne data allowed not only the remote mapping of mafic and ultramafic rocks, which are among the main host rocks for Archean Au deposits in the study area, but also the remote mapping of <span class="hlt">hydrothermal</span> alteration patterns and various geochemical signatures related to the structurally controlled Au mineralisation down to a 4.5 m pixel size. We can reconstruct fluid pathways and their intersections with steep physicochemical gradients, where Au deposition presumably took place, by combining hyperspectral remote sensing with hyperspectral drill core data in 3D mineral maps. White mica mineral maps as well as mineral maps based on the abundance and composition of MgOH and FeOH bearing silicates are the main products for a semi-quantitative assessment of the key alteration minerals in this project. In the southern Selwyn Range, Mount Isa Inlier, Queensland, hyperspectral mineral maps, such as "ferric oxide abundance", "white mica abundance" and "white mica composition", were integrated with geophysical datasets (total magnetic intensity, ternary radiometric imagery). The integration of the datasets enabled us to construct a comprehensive fluid flow model contributing to our understanding of iron-oxide Cu-Au deposits in this region, identifying the source, pathway and depositional sites, which are in good accordance with known deposits. 3D mineral maps derived from hyperspectral methods can distinctly improve our understanding of mineral <span class="hlt">systems</span>. The advantages of hyperspectral techniques over conventional exploration methods include: (1) the fast and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V23B0614G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V23B0614G"><span>The Sasquatch <span class="hlt">Hydrothermal</span> Field: Linkages Between Seismic Activity, <span class="hlt">Hydrothermal</span> Flow, and Geology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glickson, D. A.; Kelley, D. S.; Delaney, J. R.</p> <p>2006-12-01</p> <p>The Sasquatch <span class="hlt">Hydrothermal</span> Field is the most northern known vent field along the central <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge, located 6 km north of the Main <span class="hlt">Endeavour</span> Field (MEF) near 47° 59.8'N, 129° 4.0'W. It was discovered in 2000, after two large earthquake swarms in June 1999 and January 2000 caused increased venting temperatures in the MEF and significant changes in volatile composition along the entire axis [Johnson et al., 2000; Lilley et al., 2003; Proskurowski et al., 2004]. From 2004-2006, Sasquatch and the surrounding axial valley were comprehensively mapped with SM2000 multibeam sonar <span class="hlt">system</span> and Imagenex scanning sonar at a resolution of 1-5 m. These data were combined with visual imagery from Alvin and ROV dives to define the eruptive, <span class="hlt">hydrothermal</span>, and tectonic characteristics of the field and distal areas. Based on multibeam sonar results, bathymetric relief of the segment near Sasquatch is subdued. The broad axial valley is split by a central high that rises 30-40 m above the surrounding seafloor. Simple pattern analysis of the valley shows two fundamentally different regions, distinguished by low and high local variance. Areas of low variance correspond to a collapse/drainback landscape characterized by ropy sheet flow, basalt pillars, and bathtub rings capped by intact and drained lobate flows. Areas of high variance generally correspond to three types of ridge structures: 1) faulted basalt ridges composed of truncated pillow basalt, rare massive flows, and widespread pillow talus; 2) constructional basalt ridges composed of intact pillow flow fronts; and 3) extinct sulfide ridges covered by varying amounts of sulfide talus and oxidized <span class="hlt">hydrothermal</span> sediment. Sasquatch is located in a depression among truncated pillow ridges, and is comprised of ~10, 1-6 m high, fragile sulfide chimneys that vent fluids up to 289°C. The active field extends only ~25 x 25 m, although a linear, N-S trending ridge of nearly continuous extinct sulfide</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V11E2546M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V11E2546M"><span>Cabled-observatory Regional Circulation Moorings on the <span class="hlt">Endeavour</span> segment of the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mihaly, S. F.</p> <p>2011-12-01</p> <p>In September of 2010, one of four moorings was deployed on the <span class="hlt">Endeavour</span> node of the NEPTUNE Canada cabled-observatory network. The installation included the laying of a 7km cable from the node to the mooring site in the axial valley about 3km north of the Main <span class="hlt">Endeavour</span> Vent Field over extraordinary bathymetry. This September, three more cables and secondary junction boxes will be deployed to support the three additional moorings that complete the regional circulation array. The cable-laying is facilitated by the Canadian Scientific Submersible Facility's ROV ROPOS and a remotely operated cable-laying <span class="hlt">system</span>, whereas the actual deployment of the moorings is a two ship operation. The CCGS John P. Tully lowers the mooring anchor first, while the RV Thomas G. Thompson supports the ROV operations which navigate the mooring to underwater mateable cable end. Precise navigation is needed because there are few areas suitable for placement of the junction boxes. Scientifically, the moorings are designed and located to best constrain the <span class="hlt">hydrothermally</span> driven circulation within the rift valley, the regional circulation can then be used as a proxy measurement for <span class="hlt">hydrothermal</span> fluxes. Each mooring carries a current meter/ ctd pair at 4, 50, 125, and 200m, with an upward looking ADCP at 250m. The northern moorings are located between the Hi-Rise and Salty Dawg fields about 700m apart in the ~1km wide rift valley and the southern moorings are located south of the Mothra vent field. Here we present initial results from the four mooring array.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B21B0892W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B21B0892W"><span>Organic Acids as Hetrotrophic Energy Sources in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Windman, T. O.; Zolotova, N.; Shock, E.</p> <p>2004-12-01</p> <p>Many thermophilic microbes are heterotrophs, but little is known about the organic compounds present in <span class="hlt">hydrothermal</span> ecosystems. More is known about what these organisms will metabolize in lab experiments than what they do metabolize in nature. In an effort to bridge this gap, we have begun to incorporate organic analyses into ongoing research on Yellowstone <span class="hlt">hydrothermal</span> ecosystems. After filtering at least a liter of hot spring water to minimize contamination, samples were collected into sixty-milliliter serum vials containing ultra-pure phosphoric acid, sodium hydroxide, or benzalkonium chloride. Approximately 80 sites were sampled spanning temperatures from 60 to 90°C and pH values from 2 to 9. Analytical data for organic acid anions (including formate, acetate, lactate, and succinate) were obtained by ion chromatography. Preliminary results indicate that concentrations of organic acids anions range from 5 to 300 ppb. These results can be used with other field and lab data (sulfate, sulfide, nitrate, ammonia, bicarbonate, pH, hydrogen) in thermodynamic calculations to evaluate the amounts of energy available in heterotrophic reactions. Preliminary results of such calculations show that sulfate reduction to sulfide coupled to succinate oxidation to bicarbonate yields about 6 kcal per mole of electrons transferred. When formate oxidation to bicarbonate or hydrogen oxidation to water is coupled to sulfate reduction there is less energy available by approximately a factor of two. A comparison with nitrate reduction to ammonia involving succinate and/or formate oxidation reveals several similarities. Using formate to reduce nitrate can yield about as much energy as nitrate reduction with hydrogen (typically 12 to 14 kcal per mole of electrons transferred), but using succinate can yield more than twice as much energy. In fact, reduction of nitrate with succinate can provide more energy than any of the inorganic nitrate reduction reactions involving sulfur, iron</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1615834R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1615834R"><span>Propidium Monoazide-based Method for Identifying Phylogenetic Association of Necromass Near <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramírez, Gustavo; Edwards, Katrina</p> <p>2014-05-01</p> <p>Black Smoker <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are geologically driven <span class="hlt">systems</span> located near subduction zones and spreading centers associated with plate margins. The high temperature and low pH of fluids that are often associated with basalt-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> select for unique microbial communities primarily comprised of prokaryotes capable of S and Fe cycling. High temperature fluids, where temperatures exceed 300° C, are likely to have a lethal effect on transient deep water planktonic communities and, over long temporal scales, may influence the molecular composition of pelleted necromass aggregates near the chimney <span class="hlt">system</span>. We have developed a method for discriminative sequencing permitting intra vs. extracellular 16S rDNA sequencing to reveal community differences between biologically-relevant and necromass-associated DNA. This method has only recently been applied to marine environments and, here, we propose its use as relevant tool for studying the molecular ecology of high temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, as physical drivers of massive transient community die offs and associated detrital 16S rDNA community shifts. Ultimately, we aim to understand the fraction of 16S rDNA communities that do not represent living taxa, or the information-containing fraction of total necromass pool, to better frame ecological hypotheses regarding environmental biogeochemical cycling in <span class="hlt">hydrothermal</span> <span class="hlt">system</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V21D..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V21D..04S"><span>Radiogenic Isotope Constraints on Fluid Sources in the Yellowstone <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scott, S. R.; Sims, K. W. W.; Role, A.; Shock, E.; Boyd, E. S.</p> <p>2015-12-01</p> <p>For decades, researchers in Yellowstone National Park (YNP) have used major and trace element and light stable isotope geochemistry to evaluate fluid sources and geochemical reactions in the Yellowstone <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. However, the results can be affected by mixing, boiling and vapor-phase separation. We present new strontium (Sr), neodymium (Nd), and lead (Pb) isotopic data from <span class="hlt">hydrothermal</span> waters and fumarole condensates that allow us to evaluate fluid sources independent of near-surface mixing and boiling. Our sample set was selected to explore the range of fluid compositions found in the Yellowstone <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, including waters/fluids that are thought to be exclusively meteoric, exclusively from the deep <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, and those which are a mixture of these end members and/or that have been influenced by various <span class="hlt">hydrothermal</span> processes such as boiling or gas/water interaction. We have identified at least three isotopic endmembers that persist in various features throughout the YNP <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The first endmember has relatively unradiogenic Pb with Sr, Nd, and Pb isotopic compositions that are consistent with Yellowstone basalts and rhyolites. This endmember is typified by low pH features. We interpret this fluid as surface water and shallow groundwater that has interacted with volcanic rocks associated with the YNP magmatic <span class="hlt">system</span>, with the acidity derived from oxidation of volcanic gases. The second endmember has relatively radiogenic Pb, radiogenic Sr, and unradiogenic Nd. This endmember is typified by neutral pH features and near neutral fumarole condensates. We interpret this endmember to represent the hypothesized deep <span class="hlt">hydrothermal</span> reservoir that interacts with and reflects the isotopic composition of the host rock. The third endmember contains radiogenic Pb, unradiogenic Nd, and unradiogenic Sr. We observe this endmember in neutral features, which are interpreted as <span class="hlt">hydrothermal</span> waters (shallow, deep, or mixtures) that have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0302395&hterms=see+one+side+moon+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Donly%2Bsee%2Bone%2Bside%2Bmoon%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0302395&hterms=see+one+side+moon+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Donly%2Bsee%2Bone%2Bside%2Bmoon%2Bearth"><span><span class="hlt">Endeavour</span> Back Dropped By the Earth's Horizon</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>This STS-113 photograph shows an incredible view of the Space Shuttle <span class="hlt">Endeavour</span>'s payload bay. The blackness of space, Earth's moon (upper right frame), and a thin slice of Earth's horizon which runs vertically across the photograph, form the back drop for this photograph. The remote manipulator <span class="hlt">system</span> (RMS) robotic arm is visible in lower right frame. The 16th American assembly flight and 112th overall American flight to the International Space Station (ISS) launched on November 23, 2002 from Kennedy's launch pad 39A aboard the Space Shuttle Orbiter <span class="hlt">Endeavour</span> STS-113. Mission objectives included the installation and activation of the Port 1 Integrated Truss Assembly (P1). The first major component installed on the left side of the Station, the P1 truss provides three additional External Thermal Control <span class="hlt">System</span> radiators. Weighing in at 27,506 pounds, the P1 truss is 45 feet (13.7 meters) long, 15 feet (4.6 meters) wide, and 13 feet (4 meters) high. Three space walks, aided by the use of the Robotic Manipulator <span class="hlt">Systems</span> of both the Shuttle and the Station, were performed in the installation of P1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70041332','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70041332"><span>Identifying bubble collapse in a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> using hiddden Markov models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dawson, Phillip B.; Benitez, M.C.; Lowenstern, Jacob B.; Chouet, Bernard A.</p> <p>2012-01-01</p> <p>Beginning in July 2003 and lasting through September 2003, the Norris Geyser Basin in Yellowstone National Park exhibited an unusual increase in ground temperature and <span class="hlt">hydrothermal</span> activity. Using hidden Markov model theory, we identify over five million high-frequency (>15 Hz) seismic events observed at a temporary seismic station deployed in the basin in response to the increase in <span class="hlt">hydrothermal</span> activity. The source of these seismic events is constrained to within ~100 m of the station, and produced ~3500–5500 events per hour with mean durations of ~0.35–0.45 s. The seismic event rate, air temperature, hydrologic temperatures, and surficial water flow of the geyser basin exhibited a marked diurnal pattern that was closely associated with solar thermal radiance. We interpret the source of the seismicity to be due to the collapse of small steam bubbles in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, with the rate of collapse being controlled by surficial temperatures and daytime evaporation rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1281062','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1281062"><span><span class="hlt">System</span> and process for efficient separation of biocrudes and water in a <span class="hlt">hydrothermal</span> liquefaction <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.; Oyler, James R.; Rotness, Jr, Leslie J.; Schmidt, Andrew J.; Zacher, Alan H.</p> <p>2016-08-02</p> <p>A <span class="hlt">system</span> and process are described for clean separation of biocrudes and water by-products from <span class="hlt">hydrothermal</span> liquefaction (HTL) product mixtures of organic and biomass-containing feedstocks at elevated temperatures and pressures. Inorganic compound solids are removed prior to separation of biocrude and water by-product fractions to minimize formation of emulsions that impede separation. Separation may be performed at higher temperatures that reduce heat loss and need to cool product mixtures to ambient. The present invention thus achieves separation efficiencies not achieved in conventional HTL processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s89e5274.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s89e5274.html"><span>Wolf on <span class="hlt">Endeavour</span> with hardware</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1998-03-04</p> <p>S89-E-5274 (26 Jan 1998) --- This Electronic Still Camera (ESC) image shows astronaut David A. Wolf, mission specialist and cosmonaut guest researcher, holding a pen light in his teeth to get better lighting in this piece of equipment, he is working on onboard the Space Shuttle <span class="hlt">Endeavour</span>. Wolf is being replaced by astronaut Andrew S. W. Thomas as the cosmonaut guest researcher onboard Russia's Mir Space Station. Thomas will be the last American astronaut to serve onboard the Mir. This ESC view was taken on January 26, 1998, at 14:28:06 GMT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12712202','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12712202"><span>Magmatic events can produce rapid changes in <span class="hlt">hydrothermal</span> vent chemistry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lilley, Marvin D; Butterfield, David A; Lupton, John E; Olson, Eric J</p> <p>2003-04-24</p> <p>The <span class="hlt">Endeavour</span> segment of the Juan de Fuca ridge is host to one of the most vigorous <span class="hlt">hydrothermal</span> areas found on the global mid-ocean-ridge <span class="hlt">system</span>, with five separate vent fields located within 15 km along the top of the ridge segment. Over the past decade, the largest of these vent fields, the 'Main <span class="hlt">Endeavour</span> Field', has exhibited a constant spatial gradient in temperature and chloride concentration in its vent fluids, apparently driven by differences in the nature and extent of subsurface phase separation. This stable situation was disturbed on 8 June 1999 by an earthquake swarm. Owing to the nature of the seismic signals and the lack of new lava flows observed in the area during subsequent dives of the Alvin and Jason submersibles (August-September 1999), the event was interpreted to be tectonic in nature. Here we show that chemical data from <span class="hlt">hydrothermal</span> fluid samples collected in September 1999 and June 2000 strongly suggest that the event was instead volcanic in origin. Volatile data from this event and an earlier one at 9 degrees N on the East Pacific Rise show that such magmatic events can have profound and rapid effects on fluid-mineral equilibria, phase separation, 3He/heat ratios and fluxes of volatiles from submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010044700&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010044700&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhydrothermal"><span>Availability of Heat to Drive <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> in Large Martian Impact Craters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thorsos, I. E.; Newsom, H. E.; Davies, A. G.</p> <p>2001-01-01</p> <p>The central uplift in large craters on Mars can provide a substantial source of heat, equivalent to heat produced by the impact melt sheet. The heat generated in large impacts could play a significant role in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JVGR..189..172M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JVGR..189..172M"><span><span class="hlt">Hydrothermal</span> alteration in the Reykjanes geothermal <span class="hlt">system</span>: Insights from Iceland deep drilling program well RN-17</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marks, Naomi; Schiffman, Peter; Zierenberg, Robert A.; Franzson, Hjalti; Fridleifsson, Gudmundur Ó.</p> <p>2010-01-01</p> <p>The Reykjanes geothermal <span class="hlt">system</span> is a seawater-recharged <span class="hlt">hydrothermal</span> <span class="hlt">system</span> that appears to be analogous to seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in terms of host rock type and low water/rock alteration. The similarities make the Reykjanes <span class="hlt">system</span> a useful proxy for seafloor vents. At some time during the Pleistocene, the <span class="hlt">system</span> was dominated by meteoric water recharge, and fluid composition at Reykjanes has evolved through time as a result of changing proportions of meteoric water influx as well as differing pressure and temperature conditions. The purpose of this study is to characterize secondary mineralization, degree of metasomatic alteration, and bulk composition of cuttings from well RN-17 from the Reykjanes geothermal <span class="hlt">system</span>. The basaltic host rock includes hyaloclastite, breccia, tuff, extrusive basalt, diabase, as well as a marine sedimentary sequence. The progressive <span class="hlt">hydrothermal</span> alteration sequence observed with increasing depth results from reaction of geothermal fluids with the basaltic host rock. An assemblage of greenschist facies alteration minerals, including actinolite, prehnite, epidote and garnet, occurs at depths as shallow as 350 m; these minerals are commonly found in Icelandic geothermal <span class="hlt">systems</span> at temperatures above 250 °C (Bird and Spieler, 2004). This requires hydrostatic pressures that exceed the present-day depth to boiling point curve, and therefore must record alteration at higher fluid pressures, perhaps as a result of Pleistocene glaciation. Major, minor, and trace element profiles of the cuttings indicate transitional MORB to OIB composition with limited metasomatic shifts in easily mobilized elements. Changes in MgO, K 2O and loss on ignition indicate that metasomatism is strongly correlated with protolith properties. The textures of alteration minerals reveal alteration style to be strongly dependent on protolith as well. Hyaloclastites are intensely altered with calc-silicate alteration assemblages comprising calcic <span class="hlt">hydrothermal</span></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MinDe..52..383B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MinDe..52..383B"><span>A Palaeoproterozoic multi-stage <span class="hlt">hydrothermal</span> alteration <span class="hlt">system</span> at Nalunaq gold deposit, South Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bell, Robin-Marie; Kolb, Jochen; Waight, Tod Earle; Bagas, Leon; Thomsen, Tonny B.</p> <p>2017-03-01</p> <p>Nalunaq is an orogenic, high gold grade deposit situated on the Nanortalik Peninsula, South Greenland. Mineralisation is hosted in shear zone-controlled quartz veins, located in fine- and medium-grained amphibolite. The deposit was the site of Greenland's only operating metalliferous mine until its closure in 2014, having produced 10.67 t of gold. This study uses a combination of field investigation, petrography and U/Pb zircon and titanite geochronology to define a multi-stage <span class="hlt">hydrothermal</span> alteration <span class="hlt">system</span> at Nalunaq. A clinopyroxene-plagioclase-garnet(-sulphide) alteration zone (CPGZ) developed in the Nanortalik Peninsula, close to regional peak metamorphism and prior to gold-quartz vein formation. The ca. 1783-1762-Ma gold-quartz veins are hosted in reactivated shear zones with a <span class="hlt">hydrothermal</span> alteration halo of biotite-arsenopyrite-sericite-actinolite-pyrrhotite(-chlorite-plagioclase-löllingite-tourmaline-titanite), which is best developed in areas of exceptionally high gold grades. Aplite dykes dated to ca. 1762 Ma cross-cut the gold-quartz veins, providing a minimum age for mineralisation. A <span class="hlt">hydrothermal</span> calcite-titanite alteration assemblage is dated to ca. 1766 Ma; however, this alteration is highly isolated, and as a result, its field relationships are poorly constrained. The <span class="hlt">hydrothermal</span> alteration and mineralisation is cut by several generations of ca. 1745-Ma biotite granodiorite accompanied by brittle deformation. A ca. 1745-Ma lower greenschist facies <span class="hlt">hydrothermal</span> epidote-calcite-zoisite alteration assemblage with numerous accessory minerals forms halos surrounding the late-stage fractures. The contrasting <span class="hlt">hydrothermal</span> alteration styles at Nalunaq indicate a complex history of exhumation from amphibolite facies conditions to lower greenschist facies conditions in an orogenic belt which resembles modern Phanerozoic orogens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MinDe.tmp...36B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MinDe.tmp...36B"><span>A Palaeoproterozoic multi-stage <span class="hlt">hydrothermal</span> alteration <span class="hlt">system</span> at Nalunaq gold deposit, South Greenland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bell, Robin-Marie; Kolb, Jochen; Waight, Tod Earle; Bagas, Leon; Thomsen, Tonny B.</p> <p>2016-07-01</p> <p>Nalunaq is an orogenic, high gold grade deposit situated on the Nanortalik Peninsula, South Greenland. Mineralisation is hosted in shear zone-controlled quartz veins, located in fine- and medium-grained amphibolite. The deposit was the site of Greenland's only operating metalliferous mine until its closure in 2014, having produced 10.67 t of gold. This study uses a combination of field investigation, petrography and U/Pb zircon and titanite geochronology to define a multi-stage <span class="hlt">hydrothermal</span> alteration <span class="hlt">system</span> at Nalunaq. A clinopyroxene-plagioclase-garnet(-sulphide) alteration zone (CPGZ) developed in the Nanortalik Peninsula, close to regional peak metamorphism and prior to gold-quartz vein formation. The ca. 1783-1762-Ma gold-quartz veins are hosted in reactivated shear zones with a <span class="hlt">hydrothermal</span> alteration halo of biotite-arsenopyrite-sericite-actinolite-pyrrhotite(-chlorite-plagioclase-löllingite-tourmaline-titanite), which is best developed in areas of exceptionally high gold grades. Aplite dykes dated to ca. 1762 Ma cross-cut the gold-quartz veins, providing a minimum age for mineralisation. A <span class="hlt">hydrothermal</span> calcite-titanite alteration assemblage is dated to ca. 1766 Ma; however, this alteration is highly isolated, and as a result, its field relationships are poorly constrained. The <span class="hlt">hydrothermal</span> alteration and mineralisation is cut by several generations of ca. 1745-Ma biotite granodiorite accompanied by brittle deformation. A ca. 1745-Ma lower greenschist facies <span class="hlt">hydrothermal</span> epidote-calcite-zoisite alteration assemblage with numerous accessory minerals forms halos surrounding the late-stage fractures. The contrasting <span class="hlt">hydrothermal</span> alteration styles at Nalunaq indicate a complex history of exhumation from amphibolite facies conditions to lower greenschist facies conditions in an orogenic belt which resembles modern Phanerozoic orogens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080013258','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080013258"><span>Detection of Abiotic Methane in Terrestrial Continental <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span>: Implications for Methane on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Socki, Richard A.; Niles, Paul B.; Gibson, Everett K., Jr.; Romanek, Christopher S.; Zhang, Chuanlun L.; Bissada, Kadry K.</p> <p>2008-01-01</p> <p>The recent detection of methane in the Martian atmosphere and the possibility that its origin could be attributed to biological activity, have highlighted the importance of understanding the mechanisms of methane formation and its usefulness as a biomarker. Much debate has centered on the source of the methane in <span class="hlt">hydrothermal</span> fluids, whether it is formed biologically by microorganisms, diagenetically through the decomposition of sedimentary organic matter, or inorganically via reduction of CO2 at high temperatures. Ongoing research has now shown that much of the methane present in sea-floor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is probably formed through inorganic CO2 reduction processes at very high temperatures (greater than 400 C). Experimental results have indicated that methane might form inorganically at temperatures lower still, however these results remain controversial. Currently, methane in continental <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is thought to be formed mainly through the breakdown of sedimentary organic matter and carbon isotope equilibrium between CO2 and CH4 is thought to be rarely present if at all. Based on isotopic measurements of CO2 and CH4 in two continental <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, we suggest that carbon isotope equilibration exists at temperatures as low as 155 C. This would indicate that methane is forming through abiotic CO2 reduction at lower temperatures than previously thought and could bolster arguments for an abiotic origin of the methane detected in the martian atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512385H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512385H"><span>Numerical 3D models support two distinct <span class="hlt">hydrothermal</span> circulation <span class="hlt">systems</span> at fast spreading ridges</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hasenclever, Jörg; Theissen-Krah, Sonja; Rüpke, Lars</p> <p>2013-04-01</p> <p>We present 3D numerical calculations of <span class="hlt">hydrothermal</span> fluid flow at fast spreading ridges. The setup of the 3D models is based our previous 2D studies, in which we have coupled numerical models for crustal accretion and <span class="hlt">hydrothermal</span> fluid flow. One result of these calculations is a crustal permeability field that leads to a thermal structure in the crust that matches seismic tomography data of the East Pacific Rise (EPR). The 1000°C isotherm obtained from the 2D results is now used as the lower boundary of the 3D model domain, while the upper boundary is a smoothed bathymetry of the EPR. The same permeability field as in the 2D models is used, with the highest permeability at the ridge axis and a decrease with both depth and distance to the ridge. Permeability is also reduced linearly between 600 and 1000°C. Using a newly developed parallel finite element code written in Matlab that solves for thermal evolution, fluid pressure and Darcy flow, we simulate the flow patterns of <span class="hlt">hydrothermal</span> circulation in a segment of 5000m along-axis, 10000m across-axis and up to 5000m depth. We observe two distinct <span class="hlt">hydrothermal</span> circulation <span class="hlt">systems</span>: An on-axis <span class="hlt">system</span> forming a series of vents with a spacing ranging from 100 to 500m that is recharged by nearby (100-200m) downflows on both sides of the ridge axis. Simultaneously a second <span class="hlt">system</span> with much broader extensions both laterally and vertically exists off-axis. It is recharged by fluids intruding between 1500m to 5000m off-axis and sampling both upper and lower crust. These fluids are channeled in the deepest and hottest regions with high permeability and migrate up-slope following the 600°C isotherm until reaching the edge of the melt lens. Depending on the width of the melt lens these off-axis fluids either merge with the on-axis <span class="hlt">hydrothermal</span> <span class="hlt">system</span> or form separate vents. We observe separate off-axis vent fields if the magma lens half-width exceeds 1000m and confluence of both <span class="hlt">systems</span> for half-widths smaller than 500m. For</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11539452','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11539452"><span>Aqueous high-temperature and high-pressure organic geochemistry of <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Simoneit, B R</p> <p>1993-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> associated with oceanic spreading centers are now recognized as relatively common phenomena, and the organic chemical alterations occurring there are rapid and efficient. In the marine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at water depths > 1.5 km, the conditions driving chemical reactions are high temperatures (up to >400 degrees C), confining pressures (>150 bar), and other parameters such as pH, Eh, and mineralogy in an aqueous open flow medium. Continental <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may also be of interest, as, for example, in failed or dormant rifts and regions around piercement volcanoes. Organic matter alteration by reductive reactions to petroleum hydrocarbons occurs in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> over a wide temperature window (approximately 60 to >400 degrees C), under elevated pressure, and in a brief geological time (years to hundreds of years). The products are rapidly moved as bulk phase or in fluids from the regions at higher temperatures to areas at lower temperatures, where the high molecular weight material separates from the bulk. These conditions are conducive to organic chemistry which yields concurrent products by primarily reduction (due to mineral buffering), oxidation (high thermal stress), and synthesis reactions. This chemistry is just beginning to be elucidated by the geochemical community, but there are various industrial applications which provide useful preliminary insight. Therefore, the behavior of organic matter (inclusive of methane to high molecular weight compounds > C40) in warm to supercritical water needs to be characterized to understand the implications of this novel phenomenon in geological and geochemical processes, and the chemistry occurring over the full temperature spectrum of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is of relevance to origins of life research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts061-53-026.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts061-53-026.html"><span>View of HST as it approaches <span class="hlt">Endeavour</span>, taken from aft flight deck window</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1993-12-04</p> <p>STS061-53-026 (4 Dec 1993) --- One of the Space Shuttle <span class="hlt">Endeavour</span>'s aft flight deck windows frames this view of the Hubble Space Telescope (HST) as it approaches the <span class="hlt">Endeavour</span>. Backdropped against western Australia, the Remote Manipulator <span class="hlt">System</span> (RMS) arm awaits the arrival of the telescope. Once berthed in <span class="hlt">Endeavour</span>'s cargo bay, HST underwent five days of servicing provided by four space walking crew members. Shark Bay (upper left) and Perth (lower left) are visible in the frame.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1210070Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1210070Z"><span>Taal volcanic <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (Philippines) inferred by electromagnetic and other geophysical methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zlotnicki, Jacques; Toutain, Jean Paul; Sasai, Yoichi; Villacorte, Egardo; Bernard, Alain; Fauquet, Frederic; Nagao, Toshiyatsu</p> <p>2010-05-01</p> <p>On volcanoes which display <span class="hlt">hydrothermal</span>/magmatic unrests, Electromagnetic (EM) methods can be combined with geochemical (GC) and thermal methods. The integration of these methods allows to image in detail <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, to find out possible scenarios of volcanic unrest, and to monitor the on-going activity with knowledge on the sources of heat, gas and fluid transfers. Since the 1990's the volcano shows recurrent periods of seismic activity, ground deformation, <span class="hlt">hydrothermal</span> activity, and surface activity (geysers). Combined EM and GC methods noticeably contribute to map in detail the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> and to analyse the sources of the activity: - Total magnetic field mapping evidences demagnetised zones over the two main areas forming the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (in the northern part of Main crater (MC)). These low magnetized areas are ascribed to thermal sources located at some hundreds metres of depth, - Self-potential surveys, delineate the contours of the fluids-heat transfer, and the northern and southern structural discontinuities enclosing the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, - Ground temperature gradient measurements evidence the distinctive heat transfer modes, from low fluxes related to soil temperature dominated by solar input to extremely high temperature gradients of 1200 °C m-1 or to more related to magmatic fluids. - Ground temperature and surface temperature of central acidic lake calculated by Thermal Aster imaging highlight the location of the most active ground fissures, outcrops and diffuse areas. Higher and larger anomalies are observed in the northern part of MC. A rough estimation of the thermal discharge in the northern part of the volcano gives 17 MW. - CO2 concentrations and fluxes from soil supply inform on fluids origin and on local processes operating along active fractures. Much higher carbon dioxide fluxes at MC sites confirm that the source of Taal activity is presently located in the northern part of the crater. - Heat and fluids release</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-033.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-033.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-033 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-034.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-034.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-034 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-041.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-041.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-041 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-053.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-053.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-053 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-035.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-035.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-035 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-040.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-040.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-040 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-048.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-048.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-048 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-057.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-057.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-057 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-032.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-032.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-032 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts130-s-054.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts130-s-054.html"><span><span class="hlt">Endeavour</span> Launches on STS-130 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-02-08</p> <p>STS130-S-054 (8 Feb. 2010) --- Against a black night sky, space shuttle <span class="hlt">Endeavour</span> and its six-member STS-130 crew head toward Earth orbit and rendezvous with the International Space Station. Liftoff was at 4:14 a.m. (EST) on Feb. 8, 2010 from launch pad 39A at NASA's Kennedy Space Center. Onboard are NASA astronauts George Zamka, commander; Terry Virts, pilot; Robert Behnken, Kathryn Hire, Nicholas Patrick and Stephen Robinson, all mission specialists. This was the second launch attempt for <span class="hlt">Endeavour</span>'s STS-130 crew and the final scheduled space shuttle night launch. The first attempt on Feb. 7 was scrubbed due to unfavorable weather. The primary payload for the STS-130 mission to the International Space Station is the Tranquility node, a pressurized module that will provide additional room for crew members and many of the station's life support and environmental control <span class="hlt">systems</span>. Attached to one end of Tranquility is the Cupola module, a unique work area with six windows on its sides and one on top. The Cupola resembles a circular bay window and will provide a vastly improved view of the station's exterior. The multi-directional view will allow the crew to monitor spacewalks and docking operations, as well as provide a spectacular view of Earth and other celestial objects. The module was built in Turin, Italy, by Thales Alenia Space for the European Space Agency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P41A3881M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P41A3881M"><span>Aqueous Alteration of <span class="hlt">Endeavour</span> Crater Rim Apron Rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ming, D. W.; Mittlefehldt, D. W.; Gellert, R.; Clark, B. C.; Morris, R. V.; Yen, A. S.; Arvidson, R. E.; Crumpler, L. S.; Farrand, W. H.; Grant, J. A., III; Jolliff, B. L.; Parker, T. J.; Peretyazhko, T.</p> <p>2014-12-01</p> <p>Mars Exploration Rover Opportunity is exploring Noachian age rocks of the rim of 22 km diameter <span class="hlt">Endeavour</span> crater. Overlying the pre-impact lithologies and rim breccias is a thin apron of fine-grained sediments, the Grasberg fm, forming annuli on the lower slopes of rim segments. Hesperian Burns fm sandstones overly the Grasberg fm. Grasberg rocks have major element compositions that are distinct from Burns fm sandstones, especially when comparing interior compositions exposed by the Rock Abrasion Tool. Grasberg rocks are also different from <span class="hlt">Endeavour</span> rim breccias, but have general compositional similarities to them. Grasberg sediments are plausibly fine-grained materials derived from the impact breccias. Veins of CaSO4 transect Grasberg fm rocks demonstrating post-formation aqueous alteration. Minor/trace elements show variations consistent with mobilization by aqueous fluids. Grasberg fm rocks have low Mn and high Fe/Mn ratios compared to the other lithologies. Manganese likely was mobilized and removed from the Grasberg host rock by redox reactions. We posit that Fe2+ from acidic solutions associated with formation of the Burns sulfate-rich sandstones acted as an electron donor to reduce more oxidized Mn to Mn2+. The Fe contents of Grasberg rocks are slightly higher than in other rocks suggesting precipitation of Fe phases in Grasberg materials. Pancam spectra show that Grasberg rocks have a higher fraction of ferric oxide minerals than other <span class="hlt">Endeavour</span> rim rocks. Solutions transported Mn2+ into the <span class="hlt">Endeavour</span> rim materials and oxidized and/or precipitated it in them. Grasberg has higher contents of the mobile elements K, Zn, Cl, and Br compared to the rim materials. Similar enrichments of mobile elements were measured by the Spirit APXS on West Spur and around Home Plate in Gusev crater. Enhancements in these elements are attributed to interactions of <span class="hlt">hydrothermal</span> acidic fluids with the host rocks. Interactions of fluids with the Grasberg fm postdate the genesis</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140013102','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140013102"><span>Aqueous Alteration of <span class="hlt">Endeavour</span> Crater Rim Apron Rocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mittlefehldt, David W.; Ming, Douglas W.; Gellert, Ralf; Clark, Benton C.; Morris, Richard V.; Yen, Albert S.; Arvidson, Raymond E.; Crumpler, Larry S.; Farrand, William H.; Grant, John A.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20140013102'); toggleEditAbsImage('author_20140013102_show'); toggleEditAbsImage('author_20140013102_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20140013102_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20140013102_hide"></p> <p>2014-01-01</p> <p>Mars Exploration Rover Opportunity is exploring Noachian age rocks of the rim of 22 km diameter <span class="hlt">Endeavour</span> crater. Overlying the pre-impact lithologies and rim breccias is a thin apron of fine-grained sediments, the Grasberg fm, forming annuli on the lower slopes of rim segments. Hesperian Burns fm sandstones overly the Grasberg fm. Grasberg rocks have major element compositions that are distinct from Burns fm sandstones, especially when comparing interior compositions exposed by the Rock Abrasion Tool. Grasberg rocks are also different from <span class="hlt">Endeavour</span> rim breccias, but have general compositional similarities to them. Grasberg sediments are plausibly fine-grained materials derived from the impact breccias. Veins of CaSO4 transect Grasberg fm rocks demonstrating post-formation aqueous alteration. Minor/trace elements show variations consistent with mobilization by aqueous fluids. Grasberg fm rocks have low Mn and high Fe/Mn ratios compared to the other lithologies. Manganese likely was mobilized and removed from the Grasberg host rock by redox reactions. We posit that Fe2+ from acidic solutions associated with formation of the Burns sulfate-rich sandstones acted as an electron donor to reduce more oxidized Mn to Mn2+. The Fe contents of Grasberg rocks are slightly higher than in other rocks suggesting precipitation of Fe phases in Grasberg materials. Pancam spectra show that Grasberg rocks have a higher fraction of ferric oxide minerals than other <span class="hlt">Endeavour</span> rim rocks. Solutions transported Mn2+ into the <span class="hlt">Endeavour</span> rim materials and oxidized and/or precipitated it in them. Grasberg has higher contents of the mobile elements K, Zn, Cl, and Br compared to the rim materials. Similar enrichments of mobile elements were measured by the Spirit APXS on West Spur and around Home Plate in Gusev crater. Enhancements in these elements are attributed to interactions of <span class="hlt">hydrothermal</span> acidic fluids with the host rocks. Interactions of fluids with the Grasberg fm postdate the genesis</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.398..113A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.398..113A"><span>Microbial sulfate reduction within the Iheya North subseafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span> constrained by quadruple sulfur isotopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aoyama, Shinnosuke; Nishizawa, Manabu; Takai, Ken; Ueno, Yuichiro</p> <p>2014-07-01</p> <p>Subseafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> may host spatially extended and numerically abundant microbial communities sustained by sulfate reduction as one of the important terminal electron accepting metabolisms. In order to estimate microbial sulfate reduction in a subseafloor <span class="hlt">hydrothermal</span> regime, we analyzed sulfur isotopes (S32/S33/S34/S36) of pore-water sulfate and mineralized sulfide in the upper 100 m of sedimentary sequences at the Iheya North <span class="hlt">hydrothermal</span> field in the Okinawa Trough recovered in Integrated Ocean Drilling Program Expedition 331 (IODP Exp 331). On the basis of the pore water chemistry and temperature profiles, the subseafloor environment is divided into three hydrogeologic units. In the topmost Unit-1, relatively fresh seawater is recharged, and the bottommost Unit-3 is characterized by predominance of endmember-like high-temperature <span class="hlt">hydrothermal</span> fluid (>300 °C) underlying the impermeable cap rock layers. Intermediate Unit-2 is subject to mixing between the <span class="hlt">hydrothermal</span> fluid and seawater. The δ34S values of sulfate in the Unit-2 mixing zone were found to be more 34S-enriched than the values expected from simple mixing model of seawater sulfate in the Unit-1 with the <span class="hlt">hydrothermal</span> fluid in the Unit-3. The observed SSO434-enrichment and sulfate concentration [SO2-4]-depletion suggest sulfate reduction is taking place below the seafloor. Based on our model calculation, the isotope discrimination (ε34) is estimated to be -21‰. This large isotope discrimination together with slight Δ33S‧ enrichment and Δ36S‧ depletion reveals that sulfate reduction is caused by microbial processes but not by thermochemical processes. In addition, our numerical simulation points out that sulfate may be reduced prior to presently undergoing mixing with high-temperature fluid, probably within the seawater recharge zone. Despite the abundant input of <span class="hlt">hydrothermal</span> H2S, mineralized sulfide below 10 m seafloor (mbsf) shows characteristic sulfur isotopic signatures that</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25575309','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25575309"><span>Energy landscapes shape microbial communities in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the Arctic Mid-Ocean Ridge.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dahle, Håkon; Økland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H</p> <p>2015-07-01</p> <p>Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> through an investigation of two geochemically different basalt-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki's Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and <span class="hlt">hydrothermal</span> fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of <span class="hlt">hydrothermal</span> chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478700','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4478700"><span>Energy landscapes shape microbial communities in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the Arctic Mid-Ocean Ridge</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dahle, Håkon; Økland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H</p> <p>2015-01-01</p> <p>Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> through an investigation of two geochemically different basalt-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki's Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and <span class="hlt">hydrothermal</span> fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of <span class="hlt">hydrothermal</span> chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition. PMID:25575309</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.3511E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.3511E"><span>Fracture distribution and porosity in a fault-bound <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (Grimsel Pass, Swiss Alps)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Egli, Daniel; Küng, Sulamith; Baumann, Rahel; Berger, Alfons; Baron, Ludovic; Herwegh, Marco</p> <p>2017-04-01</p> <p>The spatial distribution, orientation and continuity of brittle and ductile structures strongly control fluid pathways in a rock mass by joining existing pores and creating new pore space (fractures, joints) but can also act as seals to fluid flow (e.g. ductile shear zones, clay-rich fault gouges). In long-lived <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, permeability and the related fluid flow paths are therefore dynamic in space and time. Understanding the evolution and behaviour of naturally porous and permeable rock masses is critical for the successful exploration and sustainable exploitation of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and can advance methods for planning and implementation of enhanced geothermal <span class="hlt">systems</span>. This study focuses on an active fault-bound <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the crystalline basement of the Aar Massif (<span class="hlt">hydrothermal</span> field Grimsel Pass, Swiss Alps) that has been exhumed from few kilometres depth and which documents at least 3 Ma of <span class="hlt">hydrothermal</span> activity. The explored rock unit of the Aar massif is part of the External Crystalline Massifs that hosts a multitude of thermal springs on its southern border in the Swiss Rhône valley and furthermore represents the exhumed equivalent of potentially exploitable geothermal reservoirs in the deep crystalline subsurface of the northern Alpine foreland basin. This study combines structural data collected from a 125 m long drillhole across the <span class="hlt">hydrothermal</span> zone, the corresponding drill core and surface mapping. Different methods are applied to estimate the porosity and the structural evolution with regard to porosity, permeability and fracture distribution. Analyses are carried out from the micrometre to decametre scale with main focus on the flow path evolution with time. This includes a large variety of porosity-types including fracture-porosity with up to cm-sized aperture down to grain-scale porosity. Main rock types are granitoid host rocks, mylonites, paleo-breccia and recent breccias. The porosity of the host rock as well as the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28484442','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28484442"><span>Relative Importance of Chemoautotrophy for Primary Production in a Light Exposed Marine Shallow <span class="hlt">Hydrothermal</span> <span class="hlt">System</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gomez-Saez, Gonzalo V; Pop Ristova, Petra; Sievert, Stefan M; Elvert, Marcus; Hinrichs, Kai-Uwe; Bühring, Solveig I</p> <p>2017-01-01</p> <p>The unique geochemistry of marine shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> promotes the establishment of diverse microbial communities with a range of metabolic pathways. In contrast to deep-sea vents, shallow-water vents not only support chemosynthesis, but also phototrophic primary production due to the availability of light. However, comprehensive studies targeting the predominant biogeochemical processes are rare, and consequently a holistic understanding of the functioning of these ecosystems is currently lacking. To this end, we combined stable isotope probing of lipid biomarkers with an analysis of the bacterial communities to investigate if chemoautotrophy, in parallel to photoautotrophy, plays an important role in autotrophic carbon fixation and to identify the key players. The study was carried out at a marine shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">system</span> located at 5 m water depth off Dominica Island (Lesser Antilles), characterized by up to 55°C warm <span class="hlt">hydrothermal</span> fluids that contain high amounts of dissolved Fe(2+). Analysis of the bacterial diversity revealed Anaerolineae of the Chloroflexi as the most abundant bacterial class. Furthermore, the presence of key players involved in iron cycling generally known from deep-sea <span class="hlt">hydrothermal</span> vents (e.g., Zetaproteobacteria and Geothermobacter), supported the importance of iron-driven redox processes in this <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Uptake of (13)C-bicarbonate into bacterial fatty acids under light and dark conditions revealed active photo- and chemoautotrophic communities, with chemoautotrophy accounting for up to 65% of the observed autotrophic carbon fixation. Relatively increased (13)C-incorporation in the dark allowed the classification of aiC15:0, C15:0, and iC16:0 as potential lipid biomarkers for bacterial chemoautotrophy in this ecosystem. Highest total (13)C-incorporation into fatty acids took place at the sediment surface, but chemosynthesis was found to be active down to 8 cm sediment depth. In conclusion, this study</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5399606','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5399606"><span>Relative Importance of Chemoautotrophy for Primary Production in a Light Exposed Marine Shallow <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gomez-Saez, Gonzalo V.; Pop Ristova, Petra; Sievert, Stefan M.; Elvert, Marcus; Hinrichs, Kai-Uwe; Bühring, Solveig I.</p> <p>2017-01-01</p> <p>The unique geochemistry of marine shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> promotes the establishment of diverse microbial communities with a range of metabolic pathways. In contrast to deep-sea vents, shallow-water vents not only support chemosynthesis, but also phototrophic primary production due to the availability of light. However, comprehensive studies targeting the predominant biogeochemical processes are rare, and consequently a holistic understanding of the functioning of these ecosystems is currently lacking. To this end, we combined stable isotope probing of lipid biomarkers with an analysis of the bacterial communities to investigate if chemoautotrophy, in parallel to photoautotrophy, plays an important role in autotrophic carbon fixation and to identify the key players. The study was carried out at a marine shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">system</span> located at 5 m water depth off Dominica Island (Lesser Antilles), characterized by up to 55°C warm <span class="hlt">hydrothermal</span> fluids that contain high amounts of dissolved Fe2+. Analysis of the bacterial diversity revealed Anaerolineae of the Chloroflexi as the most abundant bacterial class. Furthermore, the presence of key players involved in iron cycling generally known from deep-sea <span class="hlt">hydrothermal</span> vents (e.g., Zetaproteobacteria and Geothermobacter), supported the importance of iron-driven redox processes in this <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Uptake of 13C-bicarbonate into bacterial fatty acids under light and dark conditions revealed active photo- and chemoautotrophic communities, with chemoautotrophy accounting for up to 65% of the observed autotrophic carbon fixation. Relatively increased 13C-incorporation in the dark allowed the classification of aiC15:0, C15:0, and iC16:0 as potential lipid biomarkers for bacterial chemoautotrophy in this ecosystem. Highest total 13C-incorporation into fatty acids took place at the sediment surface, but chemosynthesis was found to be active down to 8 cm sediment depth. In conclusion, this study</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS41C1743W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS41C1743W"><span>A sampling <span class="hlt">system</span> for collecting gas-tight time-series <span class="hlt">hydrothermal</span> fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, S.; Yang, C.; Ding, K.</p> <p>2012-12-01</p> <p>It is known that the <span class="hlt">hydrothermal</span> venting has temporal variations associated with tectonic and geochemical processes. To date, the methods for long-term monitoring of the seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are rare. A new sampling <span class="hlt">system</span> has been designed to be deployed at seafloor for long term to collect gas-tight time-series samples from <span class="hlt">hydrothermal</span> vents. Based on the modular design principle, the sampling <span class="hlt">system</span> is currently composed of a control module and six sampling modules, which is convenient to be upgraded by adding more sampling modules if needed. The control module consists of a rechargeable battery pack and a circuit board with functions of sampling control, temperature measurement, data storage and communication. Each sampling module has an independent sampling valve, a valve actuator and a sampling cylinder. The sampling cylinder consists of a sample chamber and an accumulator chamber. Compressed nitrogen gas is used to maintain the sample at in-situ pressure. A prototype of the sampling <span class="hlt">system</span> has been constructed and tested. First, the instrument was tested in a high-pressure vessel at a pressure of 40 MPa. Six sampling modules were successfully triggered and water samples were collected and kept at in-situ pressure after experiment. Besides, the instrument was field tested at the shallow <span class="hlt">hydrothermal</span> field near off Kueishantao islet (24°51'N, 121°55'E), which is located offshore of northeastern Taiwan, from May 25 to May 28, 2011. The sampling <span class="hlt">system</span> worked at an automatic mode. Each sampling module was triggered according to the preset time. Time-series <span class="hlt">hydrothermal</span> fluids have been collected from a shallow <span class="hlt">hydrothermal</span> vent with a depth of 16 m. The preliminary tests indicated the success of the design and construction of the prototype of the sampling <span class="hlt">system</span>. Currently, the sampling <span class="hlt">system</span> is being upgraded by integration of a DC-DC power conversion and serial-to-Ethernet conversion module, so that it can utilize the continuous power supply and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRB..116.4104J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRB..116.4104J"><span>Geophysical characterization of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and intrusive bodies, El Chichón volcano (Mexico)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jutzeler, Martin; Varley, Nick; Roach, Michael</p> <p>2011-04-01</p> <p>The 1982 explosive eruptions of El Chichón volcano (Chiapas, Mexico) destroyed the inner dome and created a 1-km-wide and 180-m-deep crater within the somma crater. A shallow <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was exposed to the surface of the new crater floor and is characterized by an acid crater lake, a geyser-like Cl-rich spring (soap pool), and numerous fumarole fields. Multiple geophysical surveys were performed to define the internal structure of the volcanic edifice and its <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We carried out a high-resolution ground-based geomagnetic survey in the 1982 crater and its surroundings and 38 very low frequency (VLF) transects around the crater lake. A 3-D inversion of the ground-based magnetic data set highlighted three high-susceptibility isosurfaces, interpreted as highly magnetized bodies beneath the 1982 crater floor. Inversion of a digitized regional aeromagnetic map highlighted four major deeply rooted cryptodomes, corresponding to major topographic highs and massive lava dome outcrops outside and on the somma rim. The intracrater magnetic bodies correspond closely to the active <span class="hlt">hydrothermal</span> vents and their modeled maximum basal depth matches the elevation of the springs on the flanks of the volcano. Position, dip, and vertical extent of active and extinct <span class="hlt">hydrothermal</span> vents identified by VLF-EM surveys match the magnetic data set. We interpret the shallow lake spring <span class="hlt">hydrothermal</span> <span class="hlt">system</span> to be mostly associated with buried remnants of the 550 BP dome, but the Cl-rich soap pool may be connected to a small intrusion emplaced at shallow depth during the 1982 eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1975/0056/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1975/0056/report.pdf"><span>Preliminary hydrogeologic appraisal of selected <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in northern and central Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Olmsted, F.H.; Glancy, P.A.; Harrill, J.R.; Rush, F.E.; Van Denburgh, A.S.</p> <p>1975-01-01</p> <p>Several <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in northern and central Nevada were explored in a hydrogeologic reconnaissance. The <span class="hlt">systems</span> studied comprise those at Stillwater and Soda Lakes-Upsal Hogback in the Carson Desert, Gerlach, Fly Ranch-Granite Range, and Double Hot Springs in the Black Rock Desert, Brady's Hot Springs, Leach Hot Springs in Grass Valley, Buffalo Valley Hot Springs, and Sulphur Hot Springs in Ruby Valley. The investigation focused on (1) delineating of areas of high heat flow associated with rising thermal ground water, (2) determining the nature of the discharge parts of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, (3) estimating heat discharge from the <span class="hlt">systems</span>, (4) estimating water discharge from the <span class="hlt">systems</span>, (5) obtaining rough estimates of, conductive heat flow outside areas of <span class="hlt">hydrothermal</span> discharge, and (6) evaluating several investigative techniques that would yield the required information quickly and at relatively low cost. The most useful techniques were shallow test drilling to obtain geologic, hydraulic, and thermal data and hydrogeologic mapping of the discharge areas. The <span class="hlt">systems</span> studied are in the north-central part of the Basin and Range province. Exposed volcanic rocks of latest Tertiary and Quaternary age are chiefly basaltic. Basaltic terranes are generally regarded as less favorable for geothermal resources than terranes that contain large volumes of young volcanic mocks of felsic to intermediate composition. Most of the known <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are associated with Basin and Range faults which are caused by crustal extension across the province. An area of high heat flow centered at Battle Mountain and possibly other areas of high heat flow may be related to crustal heat sources. However, some of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> studied appear to be related to deep circulation of meteoric water in areas of 'normal' regional heat flow rather than to shallow-crustal heat sources. Discharge temperatures of thermal springs in the region range from slightly above mean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26154881','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26154881"><span>RNA Oligomerization in Laboratory Analogues of Alkaline <span class="hlt">Hydrothermal</span> Vent <span class="hlt">Systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burcar, Bradley T; Barge, Laura M; Trail, Dustin; Watson, E Bruce; Russell, Michael J; McGown, Linda B</p> <p>2015-07-01</p> <p>Discovering pathways leading to long-chain RNA formation under feasible prebiotic conditions is an essential step toward demonstrating the viability of the RNA World hypothesis. Intensive research efforts have provided evidence of RNA oligomerization by using circular ribonucleotides, imidazole-activated ribonucleotides with montmorillonite catalyst, and ribonucleotides in the presence of lipids. Additionally, mineral surfaces such as borates, apatite, and calcite have been shown to catalyze the formation of small organic compounds from inorganic precursors (Cleaves, 2008 ), pointing to possible geological sites for the origins of life. Indeed, the catalytic properties of these particular minerals provide compelling evidence for alkaline <span class="hlt">hydrothermal</span> vents as a potential site for the origins of life since, at these vents, large metal-rich chimney structures can form that have been shown to be energetically favorable to diverse forms of life. Here, we test the ability of iron- and sulfur-rich chimneys to support RNA oligomerization reactions using imidazole-activated and non-activated ribonucleotides. The chimneys were synthesized in the laboratory in aqueous "ocean" solutions under conditions consistent with current understanding of early Earth. Effects of elemental composition, pH, inclusion of catalytic montmorillonite clay, doping of chimneys with small organic compounds, and in situ ribonucleotide activation on RNA polymerization were investigated. These experiments, under certain conditions, showed successful dimerization by using unmodified ribonucleotides, with the generation of RNA oligomers up to 4 units in length when imidazole-activated ribonucleotides were used instead. Elemental analysis of the chimney precipitates and the reaction solutions showed that most of the metal cations that were determined were preferentially partitioned into the chimneys.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3139K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3139K"><span>Delineating Spatial Patterns in the Yellowstone <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> using Geothermometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>King, J.; Hurwitz, S.; Lowenstern, J. B.</p> <p>2015-12-01</p> <p>Yellowstone National Park is unmatched with regard to its quantity of active <span class="hlt">hydrothermal</span> features. Origins of thermal waters in its geyser basins have been traced to mixing of a deep parent water with meteoric waters in shallow local reservoirs (Fournier, 1989). A mineral-solution equilibrium model was developed to calculate water-rock chemical re-equilibration temperatures in these shallow reservoirs. We use the GeoT program, which uses water composition data as input to calculate saturation indices of selected minerals; the "best-clustering" minerals are then statistically determined to infer reservoir temperatures (Spycher et al., 2013). We develop the method using water composition data from Heart Lake Geyser Basin (HLGB), for which both chemical and isotopic geothermometers predict a reservoir water temperature of 205°C ± 10°C (Lowenstern et al., 2012), and minerals found in drill cores in Yellowstone's geyser basins. We test the model for sensitivity to major element composition, pH, Total Inorganic Carbon (TIC) and selected minerals to optimize model parameters. Calculated temperatures are most accurate at pH values below 9.0, and closely match the equilibrium saturation indices of quartz, stilbite, microcline, and albite. The model is optimized with a TIC concentration that is consistent with the mass of diffuse CO2 flux in HLGB (Lowenstern et al., 2012). We then use water compositions from other thermal basins in Yellowstone in search of spatial variations in reservoir temperatures. We then compare the calculated temperatures with various SiO2 and cation geothermometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70024124','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70024124"><span>Helium and carbon gas geochemistry of pore fluids from the sediment-rich <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in Escanaba Trough</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ishibashi, J.-I.; Sato, M.; Sano, Y.; Wakita, H.; Gamo, T.; Shanks, Wayne C.</p> <p>2002-01-01</p> <p>Ocean Drilling Program (ODP) Leg 169, which was conducted in 1996 provided an opportunity to study the gas geochemistry in the deeper part of the sediment-rich <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in Escanaba Trough. Gas void samples obtained from the core liner were analyzed and their results were compared with analytical data of vent fluid samples collected by a submersible dive program in 1988. The gas geochemistry of the pore fluids consisted mostly of a <span class="hlt">hydrothermal</span> component and was basically the same as that of the vent fluids. The He isotope ratios (R/RA = 5.6-6.6) indicated a significant mantle He contribution and the C isotopic compositions of the hydrocarbons [??13C(CH4) = -43???, ??13C(C2H6) = -20???] were characterized as a thermogenic origin caused by <span class="hlt">hydrothermal</span> activity. On the other hand, the pore fluids in sedimentary layers away from the <span class="hlt">hydrothermal</span> fields showed profiles which reflected lateral migration of the <span class="hlt">hydrothermal</span> hydrocarbons and abundant biogenic CH4. Helium and C isotope systematics were shown to represent a <span class="hlt">hydrothermal</span> component and useful as indicators for their distribution beneath the seafloor. Similarities in He and hydrocarbon signatures to that of the Escanaba Trough <span class="hlt">hydrothermal</span> <span class="hlt">system</span> were found in some terrestrial natural gases, which suggested that seafloor <span class="hlt">hydrothermal</span> activity in sediment-rich environments would be one of the possible petroleum hydrocarbon generation scenarios in unconventional geological settings. ?? 2002 Elsevier Science Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986JGR....91.1867H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986JGR....91.1867H"><span><span class="hlt">Hydrothermal</span> alteration in the Baca Geothermal <span class="hlt">System</span>, Redondo Dome, Valles Caldera, New Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hulen, Jeffrey B.; Nielson, Dennis L.</p> <p>1986-02-01</p> <p>Thermal fluids circulating in the active <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of the resurgent Redondo dome of the Valles caldera have interacted with their diverse host rocks to produce well-zoned alteration assemblages, which not only help locate permeable fluid channels but also provide insight into the <span class="hlt">system</span>'s thermal history. The alteration shows that fluid flow has been confined principally to steeply dipping normal faults and subsidiary fractures as well as thin stratigraphic aquifers. Permeability along many of these channels has been reduced or locally eliminated by <span class="hlt">hydrothermal</span> self-sealing. Alteration from the surface through the base of the Miocene Paliza Canyon Formation is of three distinctive types: argillic, propylitic, and phyllic. Argillic alteration forms a blanket above the deep water table in formerly permeable nonwelded tuffs. Beneath the argillic zone, pervasive propylitic alteration is weakly developed in felsic host rocks but locally intense in deep intermediate composition volcanics. Strong phyllic alteration is commonly but not invariably associated with major active thermal fluid channels. Phyllic zones yielding no fluid were clearly once permeable but now are <span class="hlt">hydrothermally</span> sealed. High-temperature alteration phases at Baca are presently found at much lower temperatures. We suggest either that isotherms have collapsed due to gradual cooling of the <span class="hlt">system</span>, that they have retreated without overall heat loss due to uplift of the Redondo dome, that the <span class="hlt">system</span> has shifted laterally, or that it has contracted due to a drop in the water table. The deepest Well (B-12, 3423 m) in the dome may have penetrated through the base of the active <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Below a depth of 2440 m in this well, <span class="hlt">hydrothermal</span> veining largely disappears, and the rocks resemble those developed by isochemical thermal metamorphism. The transition is reflected by temperature logs, which show a conductive thermal gradient below 2440 m. This depth may mark the dome's neutral plane</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616710Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616710Y"><span>Dynamic drivers of a shallow-water <span class="hlt">hydrothermal</span> vent ecogeochemical <span class="hlt">system</span> (Milos, Eastern Mediterranean)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yücel, Mustafa; Sievert, Stefan; Giovanelli, Donato; Foustoukos, Dionysis; DeForce, Emelia; Thomas, François; Vetriani, Constantino; Le Bris, Nadine</p> <p>2014-05-01</p> <p>Shallow-water <span class="hlt">hydrothermal</span> vents share many characteristics with their deep-sea analogs. However, despite ease of access, much less is known about the dynamics of these <span class="hlt">systems</span>. Here, we report on the spatial and temporal chemical variability of a shallow-water vent <span class="hlt">system</span> at Paleochori Bay, Milos Island, Greece, and on the bacterial and archaeal diversity of associated sandy sediments. Our multi-analyte voltammetric profiles of dissolved O2 and <span class="hlt">hydrothermal</span> tracers (e.g. Fe2+, FeSaq, Mn2+) on sediment cores taken along a transect in <span class="hlt">hydrothermally</span> affected sediments indicate three different areas: the central vent area (highest temperature) with a deeper penetration of oxygen into the sediment, and a lack of dissolved Fe2+ and Mn2+; a middle area (0.5 m away) rich in dissolved Fe2+ and Mn2+ (exceeding 2 mM) and high free sulfide with potential for microbial sulfide oxidation as suggested by the presence of white mats at the sediment surface; and, finally, an outer rim area (1-1.5 m away) with lower concentrations of Fe2+ and Mn2+ and higher signals of FeSaq, indicating an aged <span class="hlt">hydrothermal</span> fluid contribution. In addition, high-frequency temperature series and continuous in situ H2S measurements with voltammetric sensors over a 6-day time period at a distance 0.5 m away from the vent center showed substantial temporal variability in temperature (32 to 46 ºC ) and total sulfide (488 to 1329 µM) in the upper sediment layer. Analysis of these data suggests that tides, winds, and abrupt geodynamic events generate intermittent mixing conditions lasting for several hours to days. Despite substantial variability, the concentration of sulfide available for chemoautotrophic microbes remained high. These findings are consistent with the predominance of Epsilonproteobacteria in the <span class="hlt">hydrothermally</span> influenced sediments Diversity and metagenomic analyses on sediments and biofilm collected along a transect from the center to the outer rim of the vent provide further insights on</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JVGR..173..217F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JVGR..173..217F"><span>Chemical transport in geothermal <span class="hlt">systems</span> in Iceland: Evidence from <span class="hlt">hydrothermal</span> alteration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Franzson, Hjalti; Zierenberg, Robert; Schiffman, Peter</p> <p>2008-06-01</p> <p>This study focuses on the chemical changes in basaltic rocks in fossil low- and high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in Iceland. The method used takes into account the amount of dilution caused by vesicle and vein fillings in the rocks. The amount of dilution allows a calculation of the primary concentration of the immobile element Zr, and by multiplying the composition of the altered rock by the ratio of Zr (protolith)/Zr (altered rock) one can compute the mass addition caused by the dilution of the void fillings, and also make a direct comparison with the likely protoliths from the same areas. The samples were divided into three groups; two from Tertiary fossil high-temperature <span class="hlt">systems</span> (Hafnarfjall, Geitafell), and the third group from a low temperature, zeolite-altered plateau basalt succession. The results show that <span class="hlt">hydrothermally</span> altered rocks are enriched in Si, Al, Fe, Mg and Mn, and that Na, K and Ca are mobile but show either depletion or enrichment. The elements that are immobile include Zr, Y, Nb and probably Ti. The two high-temperature <span class="hlt">systems</span> show quite similar chemical alteration trends, an observation which may apply to Icelandic fresh water high-temperature <span class="hlt">systems</span> in general. The geochemical data show that the major changes in the altered rocks from Icelandic geothermal <span class="hlt">systems</span> may be attributed to addition of elements during deposition of pore-filling alteration minerals. A comparison with seawater-dominated basalt-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> shows much greater mass flux within the seawater <span class="hlt">systems</span>, even though both <span class="hlt">systems</span> have similar alteration assemblages. The secondary mineral assemblages seem to be controlled predominantly by the thermal stability of the alteration phases and secondarily by the composition of the <span class="hlt">hydrothermal</span> fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814058D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814058D"><span>Dynamic typology of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: competing effects of advection, dispersion and reactivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dolejs, David</p> <p>2016-04-01</p> <p>Genetic interpretation <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> relies on recognition of (i) <span class="hlt">hydrothermal</span> fluid source, (ii) fluid migration pathways, and (iii) deposition site identified by <span class="hlt">hydrothermal</span> alteration and/or mineralization. Frequently, only the last object is of interest or accessible to direct observation, but constraints on the fluid source (volume) and pathways can be obtained from evaluation of the time-integrated fluid flux during <span class="hlt">hydrothermal</span> event. Successful interpretation of the petrological record, that is, progress of alteration reactions, relies on identification of individual contributions arising from solute advection (to the deposition site), its lateral dispersion, and reaction efficiency. Although these terms are all applicable in a mass-conservation relationship within the framework of the transport theory, they are rarely considered simultaneously and their relative magnitudes evaluated. These phenomena operate on variable length and time scales, and may in turn provide insight into the <span class="hlt">system</span> dynamics such as flow, diffusion and reaction rates, or continuous vs. episodic behavior of <span class="hlt">hydrothermal</span> events. In addition, here we demonstrate that they also affect estimate of the net fluid flux, frequently by several orders of magnitude. The extent of alteration and mineralization reactions between the <span class="hlt">hydrothermal</span> fluid and the host environment is determined by: (i) temperature, pressure or any other gradients across the mineralization site, (ii) magnitude of disequilibrium at inflow to the mineralization site, which is related to physico-chemical gradient between the fluid source and the mineralization site, and (iii) chemical redistribution (dispersion) within the mineralization site. We introduce quantitative mass-transport descriptors - Péclet and Damköhler II numbers - to introduce division into dispersion-dominated, advection-dominated and reaction-constrained <span class="hlt">systems</span>. Dispersive <span class="hlt">systems</span> are characterized by lateral solute redistribution, driven by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.B31A0955A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.B31A0955A"><span>Microbial arsenic oxidation in a shallow marine <span class="hlt">hydrothermal</span> vent <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amend, J. P.; Meyer-Dombard, D. R.; Pichler, T.; Price, R.; Herndon, E.; Hsia, N.</p> <p>2005-12-01</p> <p>The toxic effects of arsenic are well documented, but this Group V element can also serve as an energy source to a diverse group of microorganisms. Most of the attention has been on arsenate (AsV) reduction, but the focus is shifting to include arsenite (AsIII) oxidation and subsequent immobilization through coprecipitation with iron (oxy)hydroxides. The shallow marine <span class="hlt">hydrothermal</span> fluids near Ambitle Island, Papua New Guinea are characterized by arsenite concentrations of up to 1,000 μg/L. Directly proximal to the vent orifices, arsenate coprecipitates with 2-line ferrihydrite, coating rocks and corals in red and green biofilms up to 1 cm thick. DNA extracted from these coatings was amplified with archaeal- and bacterial-specific primers, and the 16S rRNA gene was sequenced. Both biofilm samples revealed archaeal communities exclusively composed of uncultured Crenarchaea. The bacterial members are primarily gamma Proteobacteria and Planctomycetes in the red biofilm, but 60% of the community in the green biofilm affiliate with the alpha Proteobacteria and candidate group OP11; there is minimal overlap in bacterial phylotypes between the two coatings. Slurries from these coatings were also used to inoculate geochemically designed growth media supplemented with various redox couples, including aerobic and anaerobic As(III) oxidation. On a medium targeting anaerobic, chemolithoautotrophic arsenic oxidation coupled to ferric iron reduction at 50 °C, predominantly rod-shaped organisms (~5×105 cells/ml) were enriched. In contrast, on an aerobic arsenic oxidation medium, coccoid-shaped organisms (~3×106 cells/ml) were enriched. The respective thermophilic microbial communities may be taking advantage of overall metabolisms represented by H3AsO3(aq) + 2FeOOH(s) + 3H+ = H2AsO4- + 2Fe2+ + 3H2O (1) and H3AsO3(aq) + 1/2O2(aq) = H2AsO4- + H+. (2) To date, no arsenite oxidizers are known to use ferric iron as a terminal electron acceptor (reaction 1). However, this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGP13A1136C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGP13A1136C"><span>Magnetic mapping of submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> at Marsili and Palinuro volcanoes from deep-towed magnetometer data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caratori Tontini, F.; Bortoluzzi, G.; Carmisciano, C.; Cocchi, L.; de Ronde, C. E.; Ligi, M.; Muccini, F.</p> <p>2013-12-01</p> <p>We collected near-bottom magnetic data at Marsili and Palinuro volcanoes in the Southern Tyrrhenian Sea, by adding a magnetometer to a deep-towed sidescan sonar. Equivalent magnetization maps obtained by inversion of the recorded magnetic anomalies are analyzed to map alteration zones related to <span class="hlt">hydrothermal</span> processes and are correlated with water-column and seafloor observations of <span class="hlt">hydrothermal</span> activity. At Marsili volcano, we found a large elliptical area of low magnetization, confirming the existence of a large <span class="hlt">hydrothermal</span> <span class="hlt">system</span> located in proximity of the top cone, above the magma chamber. Palinuro volcano is characterized by <span class="hlt">hydrothermal</span> venting located along the caldera walls, where the corresponding ring faults may provide preferred pathways for the upflow of the <span class="hlt">hydrothermal</span> fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213320S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213320S"><span><span class="hlt">Hydrothermal</span> alteration in Lesser Antilles volcanoes: a study of trace element and U-Th isotope redistribution in active- and paleo- <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of Guadeloupe and Montserrat</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salaun, Anne; Villemant, Benoît.; Gerard, Martine; Komorowski, Jean-Christophe; Manhes, Gérard</p> <p>2010-05-01</p> <p><span class="hlt">Hydrothermally</span> altered material have been collected in active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and in debris avalanche deposits (DAD) that have sampled different region of the paleo-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> of La Soufrière of Guadeloupe and Soufriere Hills volcanoes. A detailed analysis of the mineralogy, the trace element (REE, U, Th, 1st transition series) composition and the U-Th isotopes disequilibrium of this altered material has been performed. These results are discussed in terms of relative element mobility and associated mineralogical assemblages in function of the progressive alteration stages of the andesitic material. Andesitic products that have been affected by shallow <span class="hlt">hydrothermal</span> alteration are complex assemblages of volcanic material (glass, phenocrysts and xenocrysts with complex magmatic histories) of different ages and lithologies. In DAD, this altered material has been more or less deeply reworked during transport. This material has eventually been exposed to later meteoritic or fumarollic alteration. Since REE and other incompatible elements (Th, U, Hf, Zr) are mainly concentrated in the groundmass of andesitic magmas, composition variations of these elements in altered material mainly traces the transformation of volcanic glass into smectite. This transformation is accompanied during the first stages of <span class="hlt">hydrothermal</span> alteration, (1) by a massive loss of alkaline and 1st transition series elements, (2) by a large REE fractionation, characterized by a low LREE mobility and a progressive HREE depletion with alteration degree, and (3) by a large U depletion relative to Th. LREE, Hf and Zr are not significantly modified by these alteration processes except that their absolute concentrations are generally increased in altered material by mass balance effects. U is generally redistributed over relatively short distances (maximum few centimetres) and is sometimes re-concentrated by adsorption on silica polymorphs or magnetites. Meteoric and low temperatures</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JVGR..325...15S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JVGR..325...15S"><span>Resistivity structure and geochemistry of the Jigokudani Valley <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, Mt. Tateyama, Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seki, Kaori; Kanda, Wataru; Tanbo, Toshiya; Ohba, Takeshi; Ogawa, Yasuo; Takakura, Shinichi; Nogami, Kenji; Ushioda, Masashi; Suzuki, Atsushi; Saito, Zenshiro; Matsunaga, Yasuo</p> <p>2016-10-01</p> <p>This study clarifies the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Jigokudani Valley near Mt. Tateyama volcano in Japan by using a combination of audio-frequency magnetotelluric (AMT) survey and hot-spring water analysis in order to assess the potential of future phreatic eruptions in the area. Repeated phreatic eruptions in the area about 40,000 years ago produced the current valley morphology, which is now an active solfatara field dotted with hot springs and fumaroles indicative of a well-developed <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. The three-dimensional (3D) resistivity structure of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was modeled by using the results of an AMT survey conducted at 25 locations across the valley in 2013-2014. The model suggests the presence of a near-surface highly conductive layer of < 50 m in thickness across the entire valley, which is interpreted as a cap rock layer. Immediately below the cap rock is a relatively resistive body interpreted as a gas reservoir. Field measurements of temperature, pH, and electrical conductivity (EC) were taken at various hot springs across the valley, and 12 samples of hot-spring waters were analyzed for major ion chemistry and H2O isotopic ratios. All hot-spring waters had low pH and could be categorized into three types on the basis of the Cl-/SO 42 - concentration ratio, with all falling largely on a mixing line between magmatic fluids and local meteoric water (LMW). The geochemical analysis suggests that the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> includes a two-phase zone of vapor-liquid. A comparison of the resistivity structure and the geochemically inferred structure suggests that a <span class="hlt">hydrothermal</span> reservoir is present at a depth of approximately 500 m, from which hot-spring water differentiates into the three observed types. The two-phase zone appears to be located immediately beneath the cap rock structure. These findings suggest that the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Jigokudani Valley exhibits a number of factors that could trigger a future phreatic eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19712334','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19712334"><span>Autotrophic ammonia oxidation in a deep-sea <span class="hlt">hydrothermal</span> plume.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lam, Phyllis; Cowen, James P; Jones, Ronald D</p> <p>2004-02-01</p> <p>Direct evidence for autotrophic ammonia oxidation is documented for the first time in a deep-sea <span class="hlt">hydrothermal</span> plume. Elevated NH(4) (+) concentrations of up to 341+/-136 nM were recorded in the plume core at Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge. This fueled autotrophic ammonia oxidation rates as high as 91 nM day(-1), or 92% of the total net NH(4) (+) removal. High abundance of ammonia-oxidizing bacteria was detected using fluorescence in situ hybridization. Ammonia-oxidizing bacteria within the plume core (1.0-1.4x10(4) cells ml(-1)) accounted for 7.0-7.5% of the total microbial community, and were at least as abundant as methanotrophs. Ammonia-oxidizing bacteria were a substantial component of the particle-associated communities (up to 51%), with a predominance of the r-strategist Nitrosomonas-like cells. In situ chemolithoautotrophic organic carbon production via ammonia oxidation may yield 3.9-18 mg C m(-2) day(-1) within the plume directly over Main <span class="hlt">Endeavour</span> Field. This rate was comparable to that determined for methane oxidation in a previous study, or at least four-fold greater than the flux of photosynthetic carbon reaching plume depths measured in another study. Hence, autotrophic ammonia oxidation in the neutrally buoyant <span class="hlt">hydrothermal</span> plume is significant to both carbon and nitrogen cycling in the deep-sea water column at <span class="hlt">Endeavour</span>, and represents another important link between seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and deep-sea biogeochemistry.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29007&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29007&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds"><span>Liftoff of STS-67 Space Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>Carrying a crew of seven and a complement of astronomic experiments, the Space Shuttle <span class="hlt">Endeavour</span> embarks on NASA's longest Shuttle flight to date. <span class="hlt">Endeavour</span>'s liftoff from Launch Pad 39A occurred at 1:38:13 a.m. (EST), March 2, 1995.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29005&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29005&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds"><span>Liftoff of STS-67 Space Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>Carrying a crew of seven and a compliment of astronomic experiments, the Space Shuttle <span class="hlt">Endeavour</span> embarks on NASA's longest Shuttle flight to date. <span class="hlt">Endeavour</span>'s liftoff from Launch Pad 39A occurred at 1:38:13 a.m. (EST), March 2, 1995.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29003&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS067%28S%29003&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ds"><span>Launch of STS-67 Space Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>Carrying a crew of seven and a complement of astronomic experiments, the Space Shuttle <span class="hlt">Endeavour</span> embarks on NASA's longest shuttle flight to date. <span class="hlt">Endeavour</span>'s liftoff from Launch Pad 39A occurred at 1:38:13 a.m. (EST), March 2, 1995. In this view the fence line near the launch pad is evident in the foreground.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29036&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29036&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds"><span>Liftoff of STS-59 Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1994-01-01</p> <p>The liftoff of the Space Shuttle <span class="hlt">Endeavour</span> is backdropped against a dawn sky at the Kennedy Space Center (KSC). The morning sky allows for a contrasting backdrop for the diamond shock effect of the thrust from <span class="hlt">Endeavour</span>'s main engines. Trees outline the lower portion of the view. Liftoff occurred at 7:05 a.m., April 9, 1994.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010012139&hterms=Docker&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DDocker','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010012139&hterms=Docker&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DDocker"><span>STS-49 <span class="hlt">Endeavour</span>/Intelsat Briefing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>Lak Virdee of Intelsat, summarizes Intelsat's role in the STS-49 <span class="hlt">Endeavour</span> mission. He discusses the reboost hardware, giving details on the capture arm and docker adapter assembly. He describes the rendezvous between Intelsat and the <span class="hlt">Endeavour</span> Orbiter. Mr. Virdee then answers questions from the press.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3129T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3129T"><span>Geochemistry of the Koshelev Volcano-<span class="hlt">Hydrothermal</span> <span class="hlt">System</span>, Southern Kamchatka, Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taran, Y.; Kalacheva, E.</p> <p>2015-12-01</p> <p>Koshelev is the southernmost volcano of the Kamchatkan volcanic front where magmatic plumbing <span class="hlt">systems</span> of the Kamchatkan subduction zone cross a thick layer of the oil-gas-bearing Neogene sedimentary strata of Western Kamchatka. The volcanic massive hosts a powerful <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, which has been drilled in early 1980s. Deep wells tapped a hot (ca. 300ºC) saline solution (up to 40 g/L of Cl), whereas the upper part of the <span class="hlt">system</span> is a typical steam cap with temperature close to 240ºC. Two <span class="hlt">hydrothermal</span> fields of the volcano (Upper and Lower) discharge saturated or super-heated (up to 150ºC) steam and are characterized by numerous hot pools and low flow-rate springs of steam-heated waters enriched in boron and ammonia. There is also a small lateral group of warm Na-Ca-Cl-SO4 springs (40ºC). We report here our data and review the literature geochemical data on the chemical and isotopic composition of waters and <span class="hlt">hydrothermal</span> vapours of the Koshelev <span class="hlt">system</span>. Data on the gas composition include He and C isotopes, as well as the chemical and isotopic composition of light hydrocarbons. Water geochemistry includes literature data on water isotopes of the deep brine and trace elements and REE of steam-heated waters. A conceptual model of the <span class="hlt">system</span> is presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3735525','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3735525"><span>Functional Metagenomic Investigations of Microbial Communities in a Shallow-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tang, Kai; Liu, Keshao; Jiao, Nianzhi; Zhang, Yao; Chen, Chen-Tung Arthur</p> <p>2013-01-01</p> <p>Little is known about the functional capability of microbial communities in shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> (water depth of <200 m). This study analyzed two high-throughput pyrosequencing metagenomic datasets from the vent and the surface water in the shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span> offshore NE Taiwan. This <span class="hlt">system</span> exhibited distinct geochemical parameters. Metagenomic data revealed that the vent and the surface water were predominated by Epsilonproteobacteria (Nautiliales-like organisms) and Gammaproteobacteria (Thiomicrospira-like organisms), respectively. A significant difference in microbial carbon fixation and sulfur metabolism was found between the vent and the surface water. The chemoautotrophic microorganisms in the vent and in the surface water might possess the reverse tricarboxylic acid cycle and the Calvin−Bassham−Benson cycle for carbon fixation in response to carbon dioxide highly enriched in the environment, which is possibly fueled by geochemical energy with sulfur and hydrogen. Comparative analyses of metagenomes showed that the shallow-sea metagenomes contained some genes similar to those present in other extreme environments. This study may serve as a basis for deeply understanding the genetic network and functional capability of the microbial members of shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. PMID:23940820</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/491864','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/491864"><span>Field-based tests of geochemical modeling codes: New Zealand <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.</p> <p>1993-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with predictions of fluid-solid equilibria made using geochemical modeling codes will determine how the codes can be used to predict the chemical and mineralogical response of the environment to nuclear waste emplacement. Field-based exercises allow us to test the models on time scales unattainable in the laboratory. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei and Kawerau geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/60846','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/60846"><span>Field-based tests of geochemical modeling codes using New Zealand <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bruton, C.J.; Glassley, W.E.; Bourcier, W.L.</p> <p>1994-06-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> in the Taupo Volcanic Zone, North Island, New Zealand are being used as field-based modeling exercises for the EQ3/6 geochemical modeling code package. Comparisons of the observed state and evolution of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> with predictions of fluid-solid equilibria made using geochemical modeling codes will determine how the codes can be used to predict the chemical and mineralogical response of the environment to nuclear waste emplacement. Field-based exercises allow us to test the models on time scales unattainable in the laboratory. Preliminary predictions of mineral assemblages in equilibrium with fluids sampled from wells in the Wairakei and Kawerau geothermal field suggest that affinity-temperature diagrams must be used in conjunction with EQ6 to minimize the effect of uncertainties in thermodynamic and kinetic data on code predictions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/815537','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/815537"><span>Using toughreact to model reactive fluid flow and geochemical transport in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten</p> <p>2003-07-31</p> <p>The interaction between <span class="hlt">hydrothermal</span> fluids and the rocks through which they migrate alters the earlier formed primary minerals and leads to the formation of secondary minerals, resulting in changes in the physical and chemical properties of the <span class="hlt">system</span>. We have developed a comprehensive numerical simulator, TOUGHREACT, which considers nonisothermal multi-component chemical transport in both liquid and gas phases. A variety of subsurface thermo-physical-chemical processes is considered under a wide range of conditions of pressure, temperature, water saturation, and ionic strength. The code can be applied to problems in fundamental analysis of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and in the exploration of geothermal reservoirs including chemical evolution, mineral alteration, mineral scaling, changes of porosity and permeability, and mineral recovery from geothermal fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/347708','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/347708"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> associated with the Kilauea East Rift Zone, Hawaii</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thomas, D.M.; Conrad, M.E.</p> <p>1997-12-31</p> <p>During the last twenty years drilling and fluid production on the Kilauea East Rift Zone (KERZ) has shown that an active <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is associated with much of the rift. Well logging and fluid geochemistry indicate that reservoir temperatures exceed 360 C but are highly variable. Although neither well testing nor pressure decline data have clearly demonstrated the lateral limits of the reservoir, divergent fluid compositions over short distances suggest that the larger <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is strongly compartmentalized across the rift zone. The chemical compositions of production fluids indicate that recharge is derived from ocean water and meteoric recharge and isotopic data suggest that the latter may be derived from subsurface inflow from the flanks of Mauna Loa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JVGR...65...51F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JVGR...65...51F"><span>Surficial extent and conceptual model of <span class="hlt">hydrothermal</span> <span class="hlt">system</span> at Mount Rainier, Washington</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frank, David</p> <p>1995-04-01</p> <p>A once massive <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was disgorged from the summit of Mount Rainier in a highly destructive manner about 5000 years ago. Today, <span class="hlt">hydrothermal</span> processes are depositing clayey alteration products that have the potential to reset the stage for similar events in the future. Areas of active <span class="hlt">hydrothermal</span> alteration occur in three representative settings: (1) An extensive area (greater than 12,000 m 2) of heated ground and slightly acidic boiling-point fumaroles at 76-82 °C at East and West Craters on the volcano's summit, where alteration products include smectite, halloysite and disordered kaolinite, cristobalite, tridymite, opal, alunite, gibbsite, and calcite. (2) A small area (less than 500 m 2) of heated ground and sub-boiling-point fumaroles at 55-60 °C on the upper flank at Disappointment Cleaver with smectite alteration and chalcedony, tridymite, and opal-A encrustations. Similar areas probably occur at Willis Wall, Sunset Amphitheater, and the South Tahoma and Kautz headwalls. (3) Sulfate- and carbon dioxide-enriched thermal springs at 9-24 °C on the lower flank of the volcano in valley walls beside the Winthrop and Paradise Glaciers, where calcite, opal-A, and gypsum are being deposited. In addition, chloride- and carbon dioxide-enriched thermal springs issue from thin sediments that overlie Tertiary rocks at, or somewhat beyond, the base of the volcanic edifice in valley bottoms of the Nisqually and Ohanapecosh Rivers. Maximum spring temperatures of 19-25 °C and 38-50 °C, respectively, and extensive travertine deposits have developed in these more distant localities. The heat flow, distribution of thermal activity, and nature of alteration minerals and fluids suggest a conceptual model of a narrow, central <span class="hlt">hydrothermal</span> <span class="hlt">system</span> within Mount Rainier, with steam-heated snowmelt at the summit craters and localized leakage of steam-heated fluids within 2 km of the summit. The lateral extent of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is marked by discharge of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=demand+AND+driven&pg=4&id=EJ1063820','ERIC'); return false;" href="https://eric.ed.gov/?q=demand+AND+driven&pg=4&id=EJ1063820"><span>All above Average: Secondary School Improvement as an Impossible <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Taylor, Phil</p> <p>2015-01-01</p> <p>This article argues that secondary school improvement in England, when viewed as a <span class="hlt">system</span>, has become an impossible <span class="hlt">endeavour</span>. This arises from the conflation of improvement with effectiveness, judged by a narrow range of outcome measures and driven by demands that all schools should somehow be above average. The expectation of comparable…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-s123e009806.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-s123e009806.html"><span>Shuttle <span class="hlt">Endeavour</span> returns home after the STS-123 Mission</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2008-03-24</p> <p>S123-E-009806 (24 March 2008) --- Backdropped by a large area of white clouds, Space Shuttle <span class="hlt">Endeavour</span>'s vertical stabilizer and orbital maneuvering <span class="hlt">system</span> pods are featured in this image photographed by a STS-123 crew member while docked with the International Space Station.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714343J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714343J"><span>Seismic tomography and dynamics of geothermal and natural <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the south of Bandung, Indonesia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jousset, Philippe; Sule, Rachmat; Diningrat, Wahyuddin; Syahbana, Devy; Schuck, Nicole; Akbar, Fanini; Kusnadi, Yosep; Hendryana, Andri; Nugraha, Andri; Ryannugroho, Riskiray; Jaya, Makki; Erbas, Kemal; Bruhn, David; Pratomo, Bambang</p> <p>2015-04-01</p> <p>The structure and the dynamics of geothermal reservoirs and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> allows us to better assess geothermal resources in the south of Bandung. A large variety of intense surface manifestations like geysers, hot-steaming grounds, hot water pools, and active volcanoes suggest an intimate coupling between volcanic, tectonic and <span class="hlt">hydrothermal</span> processes in this area. We deployed a geophysical network around geothermal areas starting with a network of 30 seismic stations including high-dynamic broadband Güralp and Trillium sensors (0.008 - 100 Hz) and 4 short-period (1 Hz) sensors from October 2012 to December 2013. We extended the network in June 2013 with 16 short-period seismometers. Finally, we deployed a geodetic network including a continuously recording gravity meter, a GPS station and tilt-meters. We describe the set-up of the seismic and geodetic networks and we discuss observations and results. The earthquakes locations were estimated using a non-linear algorithm, and revealed at least 3 seismic clusters. We perform joint inversion of hypo-center and velocity tomography and we look at seismic focal mechanisms. We develop seismic ambient noise tomography. We discuss the resulting seismic pattern within the area and relate the structure to the distribution of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. We aim at searching possible structural and dynamical links between different <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. In addition, we discuss possible dynamical implications of this complex volcanic <span class="hlt">systems</span> from temporal variations of inferred parameters. The integration of those results allows us achieving a better understanding of the structures and the dynamics of those geothermal reservoirs. This approach contributes to the sustainable and optimal exploitation of the geothermal resource in Indonesia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T31G..04W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T31G..04W"><span>Interactions between phase separation, mineral precipitation, and permeability variations in saline magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weis, P.</p> <p>2016-12-01</p> <p>Fluid flow through permeable rocks in saline magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is influenced by non-linear fluid and rock properties as well as physical and chemical fluid-rock interactions. The same processes are of critical importance to a variety of different disciplines of Earth sciences such as volcanology, geothermal energy, hydrogeology and economic geology, and progress in understanding the relative importance of the interactions between different processes requires multi-method approaches investigating both active and fossil <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Observations and model results suggest that many of these <span class="hlt">systems</span> are highly dynamic and have a potential for self-organization, optimizing heat and mass transport by fluids in the upper crust. For example, numerical simulations in combination with oxygen isotopes of vein quartz suggest that ore precipitation in porphyry copper deposits occurs at the hydrological interface between a dynamic plume of ascending magmatic fluids and meteoric water convection, which is controlled by the transition from ductile to brittle rock behavior. With increasing ductile behavior, we infer that locally host rock permeability is reduced and the regional stress state is relaxed, resulting in fluid pressure build-up to near-lithostatic values with continued fluid expulsion, which eventually leads to episodic brittle failure of otherwise nominally ductile rocks. Sharp pressure drops and phase separation at this hydrological front can lead to saturation in solid halite, which is indicated to be a ubiquitous feature in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with upper crustal plutons both by fluid inclusion studies and numerical simulations. Precipitation of solid halite can also lead to permeability reduction and evoke pulsating fluid migration. The presentation will show analytical and numerical results describing the role of non-linear fluid properties, phase separation, salt precipitation, fluid mixing, hydraulic fracturing and the brittle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70018464','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70018464"><span>Hydrogen isotope systematics of phase separation in submarine <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: Experimental calibration and theoretical models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Berndt, M.E.; Seal, R.R.; Shanks, Wayne C.; Seyfried, W.E.</p> <p>1996-01-01</p> <p>Hydrogen isotope fractionation factors were measured for coexisting brines and vapors formed by phase separation of NaCl/H2O fluids at temperatures ranging from 399-450??C and pressures from 277-397 bars. It was found that brines are depleted in D compared to coexisting vapors at all conditions studied. The magnitude of hydrogen isotope fractionation is dependent on the relative amounts of Cl in the two phases and can be empirically correlated to pressure using the following relationship: 1000 ln ??(vap-brine) = 2.54(??0.83) + 2.87(??0.69) x log (??P), where ??(vap-brine) is the fractionation factor and ??P is a pressure term representing distance from the critical curve in the NaCl/H2O <span class="hlt">system</span>. The effect of phase separation on hydrogen isotope distribution in subseafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> depends on a number of factors, including whether phase separation is induced by heating at depth or by decompression of <span class="hlt">hydrothermal</span> fluids ascending to the seafloor. Phase separation in most subseafloor <span class="hlt">systems</span> appears to be a simple process driven by heating of seawater to conditions within the two-phase region, followed by segregation and entrainment of brine or vapor into a seawater dominated <span class="hlt">system</span>. Resulting vent fluids exhibit large ranges in Cl concentration with no measurable effect on ??D. Possible exceptions to this include <span class="hlt">hydrothermal</span> fluids venting at Axial and 9??N on the East Pacific Rise. High ??D values of low Cl fluids venting at Axial are consistent with phase separation taking place at relatively shallow levels in the oceanic crust while negative ??D values in some low Cl fluids venting at 9??N suggest involvement of a magmatic fluid component or phase separation of D-depleted brines derived during previous <span class="hlt">hydrothermal</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7255691','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7255691"><span>Experimental and theoretical investigation of the production of HCl and some metal chlorides in magmatic/<span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1990-01-01</p> <p><span class="hlt">Hydrothermal</span> experiments on the partitioning of HCl and copper chloride in the <span class="hlt">system</span> silicate melt-hydrosaline liquid-aqueous vapor are described. Modelling of the aqueous phase evolution process is discussed. (MHR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B13A0179B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B13A0179B"><span>Current Research at the <span class="hlt">Endeavour</span> Ridge 2000 Integrated Studies Site</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butterfield, D. A.; Kelley, D. S.; Ridge 2000 Community, R.</p> <p>2004-12-01</p> <p> investigations at MEF, Mothra, Sasquatch, and Middle Valley, collecting fluid, particle, and animal samples for culture and phylogenetic analysis. al Tiburon continued in late August/September with detailed petrological sampling. A Keck-sponsored al Thompson/ROPOS cruise in September continued work on chemical/physical sensor deployments and time-series chemical and microbial sampling. A graduate student workshop at Friday Harbor beginning October 2004 will analyze the first year of data from the seismic network and begin to correlate seismic activity with <span class="hlt">hydrothermal</span> activity. The <span class="hlt">Endeavour</span> ISS is still in a phase of data collection and sensor development, but moving toward data integration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5139708','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5139708"><span>Comparative assessment of five potential sites for <span class="hlt">hydrothermal</span>-magma <span class="hlt">systems</span>: energy transport</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hardee, H.C.</p> <p>1980-09-01</p> <p>A comparative assessment of five sites is being prepared as part of a Continental Scientific Drilling Program (CSDP) review of thermal regimes for the purpose of scoping areas for future research and drilling activities. This background report: discusses the various energy transport processes likely to be encountered in a <span class="hlt">hydrothermal</span>-magma <span class="hlt">system</span>, reviews related literature, discusses research and field data needs, and reviews the sites from an energy transport viewpoint. At least three major zones exist in the magma-<span class="hlt">hydrothermal</span> transport <span class="hlt">system</span>: the magma zone, the <span class="hlt">hydrothermal</span> zone, and the transition zone between the two. Major energy transport questions relate to the nature and existence of these zones and their evolution with time. Additional energy transport questions are concerned with the possible existence of critical state and super-critical state permeable convection in deep geothermal <span class="hlt">systems</span>. A review of thermal transport models emphasizes the fact that present transport models and computational techniques far outweigh the scarcity and quality of deep field data.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V21A4731T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V21A4731T"><span>A Blind <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> in an Ocean Island Environment: Humu'ula Saddle, Hawaii Island</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, D. M.; Wallin, E.; Lautze, N. C.; Lienert, B. R.; Pierce, H. A.</p> <p>2014-12-01</p> <p>A recently drilled groundwater investigation borehole, drilled to a depth of 1760 m in the Humu'ula Saddle of Hawaii Island, encountered an unexpectedly high temperature gradient of more than 160 ̊C/km. Although prior MT surveys across the region identified conductive formations of modest extent in the region, there were few surface manifestations of geologic structures likely to host a geothermal <span class="hlt">system</span> and no evidence of an active, extensive <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Cores recovered from the borehole showed the presence of intrusive formations and moderate <span class="hlt">hydrothermal</span> alteration at depth with progressive infilling of fractures and vesicles with depth and temperature. Independent modeling of gravity data (Flinders et al., 2013) suggests the presence of a broad intrusive complex within the region that is consistent with the borehole's confirmation of a high-elevation (~1400 m amsl) regional water table. A subsequent MT survey covering much of the western Saddle region has confirmed the presence of highly conductive conditions, consistent with thermal activity, to depths of 4 km and greater. Light stable isotope data for the borehole fluids indicate that the regional water table is derived from recharge from the upper elevations of Mauna Kea; major element chemistry indicates that formation temperatures exceed 200 ̊C. A conceptual model of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, along with isotopic and fluid chemistry of the thermal fluids will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.441...26F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.441...26F"><span>Origin of magnetic highs at ultramafic hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: Insights from the Yokoniwa site of Central Indian Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujii, Masakazu; Okino, Kyoko; Sato, Taichi; Sato, Hiroshi; Nakamura, Kentaro</p> <p>2016-05-01</p> <p>High-resolution vector magnetic measurements were performed on an inactive ultramafic-hosted <span class="hlt">hydrothermal</span> vent field, called Yokoniwa <span class="hlt">Hydrothermal</span> Field (YHF), using a deep-sea manned submersible Shinkai6500 and an autonomous underwater vehicle r2D4. The YHF has developed at a non-transform offset massif of the Central Indian Ridge. Dead chimneys were widely observed around the YHF along with a very weak venting of low-temperature fluids so that <span class="hlt">hydrothermal</span> activity of the YHF was almost finished. The distribution of crustal magnetization from the magnetic anomaly revealed that the YHF is associated with enhanced magnetization, as seen at the ultramafic-hosted Rainbow and Ashadze-1 <span class="hlt">hydrothermal</span> sites of the Mid-Atlantic Ridge. The results of rock magnetic analysis on seafloor rock samples (including basalt, dolerite, gabbro, serpentinized peridotite, and <span class="hlt">hydrothermal</span> sulfide) showed that only highly serpentinized peridotite carries high magnetic susceptibility and that the natural remanent magnetization intensity can explain the high magnetization of Yokoniwa. These observations reflect abundant and strongly magnetized magnetite grains within the highly serpentinized peridotite. Comparisons with the Rainbow and Ashadze-1 suggest that in ultramafic-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, strongly magnetized magnetite and pyrrhotite form during the progression of <span class="hlt">hydrothermal</span> alteration of peridotite. After the completion of serpentinization and production of hydrogen, pyrrhotites convert into pyrite or nonmagnetic iron sulfides, which considerably reduces their levels of magnetization. Our results revealed origins of the magnetic high and the development of subsurface chemical processes in ultramafic-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. Furthermore, the results highlight the use of near-seafloor magnetic field measurements as a powerful tool for detecting and characterizing seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6832174','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6832174"><span>Comparative assessment of five potential sites for <span class="hlt">hydrothermal</span>-magma <span class="hlt">systems</span>: summary</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Luth, W.C.; Hardee, H.C.</p> <p>1980-11-01</p> <p>A comparative assessment of five potential <span class="hlt">hydrothermal</span>-magma sites for this facet of the Thermal Regimes part of the CSDP has been prepared for the DOE Office of Basic Energy Sciences. The five sites are: The Geysers-Clear Lake, CA, Long Valley, CA, Rio Grande Rift, NM, Roosevelt Hot Springs, UT, and Salton Trough, CA. This site assessment study has drawn together background information (geology, geochemistry, geophysics, and energy transport) on the five sites as a preliminary stage to site selection. Criteria for site selection are that potential sites have identifiable, or likely, <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and associated magma sources, and the important scientific questions can be identified and answered by deep scientific holes. Recommendations were made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS11A0338B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS11A0338B"><span>The Third Dimension of an Active Back-arc <span class="hlt">Hydrothermal</span> <span class="hlt">System</span>: ODP Leg 193 at PACMANUS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Binns, R.; Barriga, F.; Miller, D.</p> <p>2001-12-01</p> <p>This first sub-seafloor examination of an active <span class="hlt">hydrothermal</span> <span class="hlt">system</span> hosted by felsic volcanics, at a convergent margin, obtained drill core from a high-T "smoker" site (penetrated to sim200 mbsf) and a low-T site of diffuse venting (~400mbsf). We aimed to delineate the lateral and vertical variability in mineralisation and alteration patterns, so as to understand links between volcanological, structural and <span class="hlt">hydrothermal</span> phenomena and the sources of fluids, and to establish the nature and extent of microbial activity within the <span class="hlt">system</span>. Technological breakthroughs included deployment of a new hard-rock re-entry <span class="hlt">system</span>, and direct comparison in a hardrock environment of structural images obtained by wireline methods and logging-while-drilling. The PACMANUS <span class="hlt">hydrothermal</span> site, at the 1700m-deep crest of a 500m-high layered sequence of dacitic lavas, is notable for baritic massive sulfide chimneys rich in Cu, Zn, Au and Ag. Below an extensive cap 5-40m thick of fresh dacite-rhyodacite, we found unexpectedly pervasive <span class="hlt">hydrothermal</span> alteration of vesicular and flow-banded precursors, accompanied by variably intense fracturing and anhydrite-pyrite veining. Within what appears one major <span class="hlt">hydrothermal</span> event affecting the entire drilled sequence, there is much overprinting and repetition of distinctly allochemical argillaceous (illite-chlorite), acid-sulfate (pyrophyllite-anhydrite) and siliceous assemblages. The alteration profiles include a transition from metastable cristobalite to quartz at depth, and are similar under low-T and high-T vent sites but are vertically condensed in a manner suggesting higher thermal gradients beneath the latter. The altered rocks are surprisingly porous (average 25%). Retention of intergranular pore spaces and open vesicles at depth implies elevated <span class="hlt">hydrothermal</span> pressures, whereas evidence from fluid inclusions and <span class="hlt">hydrothermal</span> brecciation denotes local or sporadic phase separation. A maximum measured temperature of 313 degC measured 8 days</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4117188','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4117188"><span>Biosphere frontiers of subsurface life in the sedimented <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Guaymas Basin</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Teske, Andreas; Callaghan, Amy V.; LaRowe, Douglas E.</p> <p>2014-01-01</p> <p>Temperature is one of the key constraints on the spatial extent, physiological and phylogenetic diversity, and biogeochemical function of subsurface life. A model <span class="hlt">system</span> to explore these interrelationships should offer a suitable range of geochemical regimes, carbon substrates and temperature gradients under which microbial life can generate energy and sustain itself. In this theory and hypothesis article, we make the case for the <span class="hlt">hydrothermally</span> heated sediments of Guaymas Basin in the Gulf of California as a suitable model <span class="hlt">system</span> where extensive temperature and geochemical gradients create distinct niches for active microbial populations in the <span class="hlt">hydrothermally</span> influenced sedimentary subsurface that in turn intercept and process <span class="hlt">hydrothermally</span> generated carbon sources. We synthesize the evidence for high-temperature microbial methane cycling and sulfate reduction at Guaymas Basin – with an eye on sulfate-dependent oxidation of abundant alkanes – and demonstrate the energetic feasibility of these latter types of deep subsurface life in previously drilled Guaymas Basin locations of Deep-Sea Drilling Project 64. PMID:25132832</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V41B1389T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41B1389T"><span><span class="hlt">Hydrothermal</span> circulation <span class="hlt">system</span> in the central Mariana illustrated by Magnetometoric Resistivity experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tada, N.; Seama, N.; Goto, T.; Kido, M.</p> <p>2004-12-01</p> <p><span class="hlt">Hydrothermal</span> vent fields are known to exist on the spreading axis, where sea water penetrates into the crust and upwells through the <span class="hlt">hydrothermal</span> vents. Understanding of the <span class="hlt">hydrothermal</span> circulation <span class="hlt">system</span> is extremely important to reveal the cooling process of the oceanic crust. The thermal structure beneath the <span class="hlt">hydrothermal</span> vent reflects the extent of underground activity and the convection scale of the hot water. Temperature in the crust can be estimated from the electrical conductivity because the conductivity depends on the water volume, the salinity concentration and the temperature of the sea water in the crust. The Alice Spring Field (18 o12.9'N, 144 o42.5'E and 3600m deep), on the spreading axis in the central Mariana Back-Arc Basin, is a suitable site for this purpose. <span class="hlt">Hydrothermal</span> vent in this field was firstly discovered by Alvin in 1987 (Hawkins et al., 1990). Shinkai6500 also confirmed the <span class="hlt">hydrothermal</span> activity in 1992 and 1996 (Gamou et al., 1994; Fujikura et al., 1997). In November, 2002, we conducted Magnetometric Resistivity (MMR) survey using R/V Kairei, JAMSTEC in this field. In the MMR method, controlled electric current was applied from a pair of electrodes; one is just beneath the sea surface and the other is close to the seafloor. To record electoromagnetic responses of the crust to the inputed current, we deployed six ocean bottom electromagnetometers (OBEMs), which can measure 3-components of magnetic and electric fields simultaneously. Measurements were conducted at 34 sites around the field, each of which consists of 30 minutes stacking for repeated current signals to keep better S/N ratio. Apparent resistivity is given by a function of amplitudes of magnetic field variation and source-receiver distance. We recovered the data from four OBEMs (two were on the spreading axis and other two were off axis). The plot of magnetic amplitudes to source-receiver distances shows different trend between OBEMs on-axis and off-axis. Therefore, we</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.T11C1268L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.T11C1268L"><span>Gas Chemistry of <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> of the Explorer Ridge, NE Pacific Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lupton, J.; Lilley, M.; Baker, E.; Butterfield, D.; Embley, R.; Silvers, B.; Resing, J.; Olson, E.; Evans, L.; Lebon, G.; Greene, R.</p> <p>2002-12-01</p> <p>In June-August, 2002, a 2-leg expedition aboard the R/V Thompson completed an extensive survey of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of the Explorer Ridge. The first part of the expedition employed hydrographic casts to detect <span class="hlt">hydrothermal</span> activity via the presence of water-column plumes. A total of 29 casts were completed, 17 conventional vertical casts and 11 tow-yos, covering the entire length of the Explorer Ridge from 49.5°N to 50.3°N. A total of 288 discrete samples were collected for shorebased analysis of helium isotopes. Preliminary results based on shipboard analysis of CTD data indicated that the strong <span class="hlt">hydrothermal</span> venting was confined to the Magic Mountain area of the Explorer Ridge at 49.76°N, 130.26°W, where strong temperature and light attenuation signals were detected. However, it is possible that the water-column helium isotope results, when available, will indicate other areas of <span class="hlt">hydrothermal</span> activity. In the second phase of the exploration, a series of submersible dives were conducted using the Canadian ROV ROPOS. The ROPOS dives were concentrated on the <span class="hlt">hydrothermal</span> sites of the Magic Mountain area, which are concentrated along a 400-m long zone on the eastern shoulder of the axial valley. A suite of vent fluid samples was collected for analysis of gas chemistry using either discrete titanium gas-tight samplers or using the NOAA <span class="hlt">hydrothermal</span> fluid sampler (HFS). A total of 11 discrete vent fluid samples were collected for gas chemistry at 7 different vents ranging in temperature from 162°C to 313°C. All of the vents sampled were very gas-rich, with total gas contents ranging from 0.3 ccSTP/g up to 1.4 ccSTP/g at Record Breaker Vent (313°C). Results for vent fluid concentrations of 3He, 4He, Ne, H2, CH4, and CO2 will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999GeCoA..63..627D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999GeCoA..63..627D"><span>Yttrium and rare earth elements in fluids from various deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Douville, Eric; Bienvenu, Philippe; Charlou, Jean Luc; Donval, Jean Pierre; Fouquet, Yves; Appriou, Pierre; Gamo, Toshitaka</p> <p>1999-03-01</p> <p>Rare earth element (REE) and yttrium (Y) concentrations were measured in fluids collected from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> including the Mid-Atlantic Ridge (MAR), i.e., Menez Gwen, Lucky Strike, TAG, and Snakepit; the East Pacific Rise (EPR), i.e., 13°N and 17-19°S; and the Lau (Vai Lili) and Manus (Vienna Woods, PacManus, Desmos) Back-Arc Basins (BAB) in the South-West Pacific. In most fluids, Y is trivalent and behaves like Ho. Chondrite normalized Y-REE (Y-REE N) concentrations of fluids from MAR, EPR, and two BAB sites, i.e., Vai Lili and Vienna Woods, showed common patterns with LREE enrichment and positive Eu anomalies. REE analysis of plagioclase collected at Lucky Strike strengthens the idea that fluid REE contents, are controlled by plagioclase phenocrysts. Other processes, however, such as REE complexation by ligands (Cl -, F - SO 42-), secondary phase precipitation, and phase separation modify REE distributions in deep-sea <span class="hlt">hydrothermal</span> fluids. REE speciation calculations suggest that aqueous REE are mainly complexed by Cl - ions in hot acidic fluids from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. REE concentrations in the fluid phases are, therefore, influenced by temperature, pH, and duration of rock-fluid interaction. Unusual Y-REE N patterns found in the PacManus fluids are characterized by depleted LREE and a positive Eu anomaly. The Demos fluid sample shows a flat Y-REE N pattern, which increases regularly from LREE to HREE with no Eu anomaly. These Manus Basin fluids also have an unusual major element chemistry with relatively high Mg, SO 4, H 2S, and F contents, which may be due to the incorporation of magmatic fluids into heated seawater during <span class="hlt">hydrothermal</span> circulation. REE distribution in PacManus fluids may stem from a subseafloor barite precipitation and the REE in Demos fluids are likely influenced by the presence of sulfate ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/890518','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/890518"><span>Deep Borehole Measurements for Characterizing the Magma/<span class="hlt">Hydrothermal</span> <span class="hlt">System</span> at Long Valley Caldera, CA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Carrrigan, Charles R.</p> <p>1989-03-21</p> <p>The Magma Energy Program of the Geothermal Technology Division is scheduled to begin drilling a deep (6 km) exploration well in Long Valley Caldera, California in 1989. The drilling site is near the center of the caldera which is associated with numerous shallow (5-7 km) geophysical anomalies. This deep well will present an unparalleled opportunity to test and validate geophysical techniques for locating magma as well as a test of the theory that magma is still present at drillable depths within the central portion of the caldera. If, indeed, drilling indicates magma, the geothermal community will then be afforded the unique possibility of examining the coupling between magmatic and <span class="hlt">hydrothermal</span> regimes in a major volcanic <span class="hlt">system</span>. Goals of planned seismic experiments that involve the well include the investigation of local crustal structure down to depths of 10 km as well as the determination of mechanisms for local seismicity and deformation. Borehole electrical and electromagnetic surveys will increase the volume and depth of rock investigated by the well through consideration of the conductive structure of the <span class="hlt">hydrothermal</span> and underlying regimes. Currently active processes involving magma injection will be studied through observation of changes in pore pressure and strain. Measurements of in situ stress from recovered cores and hydraulic fracture tests will be used in conjunction with uplift data to determine those models for magmatic injection and inflation that are most applicable. Finally, studies of the thermal regime will be directed toward elucidating the coupling between the magmatic source region and the more shallow <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the caldera fill. To achieve this will require careful logging of borehole fluid temperature and chemistry. In addition, studies of rock/fluid interactions through core and fluid samples will allow physical characterization of the transition zone between <span class="hlt">hydrothermal</span> and magmatic regimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.2084J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.2084J"><span>Sulfide geochronology along the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jamieson, John W.; Hannington, Mark D.; Clague, David A.; Kelley, Deborah S.; Delaney, John R.; Holden, James F.; Tivey, Margaret K.; Kimpe, Linda E.</p> <p>2013-07-01</p> <p>Forty-nine <span class="hlt">hydrothermal</span> sulfide-sulfate rock samples from the <span class="hlt">Endeavour</span> Segment of the Juan de Fuca Ridge, northeastern Pacific Ocean, were dated by measuring the decay of 226Ra (half-life of 1600 years) in <span class="hlt">hydrothermal</span> barite to provide a history of <span class="hlt">hydrothermal</span> venting at the site over the past 6000 years. This dating method is effective for samples ranging in age from ˜200 to 20,000 years old and effectively bridges an age gap between shorter- and longer-lived U-series dating techniques for <span class="hlt">hydrothermal</span> deposits. Results show that <span class="hlt">hydrothermal</span> venting at the active High Rise, Sasquatch, and Main <span class="hlt">Endeavour</span> fields began at least 850, 1450, and 2300 years ago, respectively. Barite ages of other inactive deposits on the axial valley floor are between ˜1200 and ˜2200 years old, indicating past widespread <span class="hlt">hydrothermal</span> venting outside of the currently active vent fields. Samples from the half-graben on the eastern slope of the axial valley range in age from ˜1700 to ˜2925 years, and a single sample from outside the axial valley, near the westernmost valley fault scarp is ˜5850 ± 205 years old. The spatial relationship between <span class="hlt">hydrothermal</span> venting and normal faulting suggests a temporal relationship, with progressive younging of sulfide deposits from the edges of the axial valley toward the center of the rift. These relationships are consistent with the inward migration of normal faulting toward the center of the valley over time and a minimum age of onset of <span class="hlt">hydrothermal</span> activity in this region of 5850 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5419S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5419S"><span>Post-impact <span class="hlt">hydrothermal</span> <span class="hlt">system</span> geochemistry and mineralogy: Rochechouart impact structure, France.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simpson, Sarah</p> <p>2014-05-01</p> <p>Hypervelocity impacts generate extreme temperatures and pressures in target rocks and may permanently alter them. The process of cratering is at the forefront of research involving the study of the evolution and origin of life, both on Mars and Earth, as conditions may be favourable for <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> to form. Of the 170 known impact structures on Earth, over one-third are known to contain fossil <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> [1]. The introduction of water to a <span class="hlt">system</span>, when coupled with even small amounts of heat, has the potential to completely alter the target or host rock geochemistry. Often, the mineral assemblages produced in these environments are unique, and are useful indicators of post-impact conditions. The Rochechouart impact structure in South-Central France is dated to 201 ± 2 Ma into a primarily granitic target [2]. Much of the original morphological features have been eroded and very little of the allochthonous impactites remain. This has, however, allowed researchers to study the shock effects on the lower and central areas of the structure, as well as any subsequent <span class="hlt">hydrothermal</span> activity. Previous work has focused on detailed classification of the target and autochthonous and allochthonous impactites [3, 4], identification of the projectile [5], and dating the structure using Ar-isotope techniques [2]. Authors have also noted geochemical evidence of K-metasomatism, which is pronounced throughout all lithologies as enrichment in K2O and depletion in CaO and Na2O [3, 4, 5]. This indicates a pervasive <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, whose effects throughout the structure have yet to be studied in detail, particularly in those parts at and below the transient floor. The purpose of this study is to classify the mineralogical and geochemical effects of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Samples were collected via permission from the Réserve Naturelle de l'Astroblème de Rochechouart-Chassenon [6]. Sample selection was based on the presence of secondary mineralization in hand</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V34B..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V34B..03B"><span>Sulfur Lakes and Sulfur-rich Volcanic <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> on the Mariana Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butterfield, D. A.; Resing, J. A.; Chadwick, W. W.; Embley, R. W.; Lupton, J. E.; Nakamura, K.; Lilley, M. D.; Huber, J. A.</p> <p>2007-12-01</p> <p>During the Submarine Ring of Fire expeditions in 2004 and 2006, and the Natsushima NT-05-18 expedition in 2005 we investigated and sampled <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on ten submarine volcanoes in the Mariana arc between 13.5 and 23.1 degrees N. The high volatile content of the volcanic arc environment is evident in the CO2 and SO2 dominated fluids sampled and differentiates volcanic arc <span class="hlt">hydrothermal</span> chemistry from more rock- buffered mid-ocean ridge <span class="hlt">systems</span>. Sulfur-dominated sites appear to be common on submarine arc volcanoes at water depths shallower than 700 meters. At NW Rota-1 volcano, there is clear evidence of ongoing eruptive activity producing clouds of particulate and molten sulfur as well as mm to m-size glassy volcanic ejecta. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> at NW Rota-1 represents a direct connection to a sub-seafloor magma body, and is one of the only known sites in the world where we can directly sample the solid, liquid and gaseous products of a submarine magmatic <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Fluids (30 to 260 deg C) sampled directly from an eruptive vent have pH as low as 1.0, with a high content of particulate sulfur, excess sulfurous and sulfuric acid, and very low H2S content. Fluids percolating through volcaniclastic sand adjacent to the vent reached 100 deg C and had higher silica, slightly higher pH, and millimolar levels of H2S. The chemistry of both types of fluids is indicative of input of volcanic SO2 and incomplete disproportionation into sulfuric acid and either H2S (in volcaniclastic sands) or elemental sulfur (in the eruptive vent). Highly acidic aqueous fluids attack the basaltic substrate, and carry high levels of iron and aluminum. Daikoku (21.3°N) and Nikko (23.1°N) submarine volcanoes both host active molten sulfur ponds and a wide variety of sulfur flows and deposits. The remarkable molten sulfur pools (~180-200°C) occur without widespread focused venting of hot water and may be maintained by active magmatic degassing of hot CO2/SO2-rich gases</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V52B..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V52B..06G"><span><span class="hlt">Hydrothermal</span> REE and Zr Ore Forming Processes in Peralkaline Granitic <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gysi, A. P.</p> <p>2015-12-01</p> <p>Anorogenic peralkaline igneous <span class="hlt">systems</span> display extreme enrichment of REE and Zr with a <span class="hlt">hydrothermal</span> overprint leading to post-magmatic metal mobilization. Strange Lake in Canada, for example, is a mid-Proterozoic peralkaline granitic intrusion and host to a world-class REE-Zr deposit with >50 Mt ore (>1.5 wt.% REE and >3 wt.% Zr). In contrast to porphyry <span class="hlt">systems</span>, peralkaline <span class="hlt">systems</span> are poorly understood and <span class="hlt">hydrothermal</span> metal mobilization models are only in the early stage of their development. This is partly due to the paucity of thermodynamic data for REE-bearing minerals and aqueous species, and the complexity of the <span class="hlt">hydrothermal</span> fluids (enrichment of F, P and Cl), which make it difficult to develop thermodynamic models of metal partitioning. This study aims to show the link between alteration stages and metal mobilization using Strange Lake as a natural laboratory and combine these observations with numerical modeling. Four types of alteration were recognized at Strange Lake: i) alkali (i.e. K and Na) metasomatism related to interaction with NaCl-bearing orthomagmatic fluids, ii) acidic alteration by HCl-HF-bearing fluids originating from the pegmatites followed by iii) aegirinization of the border of the pegmatites and surrounding granites and by iv) pervasive Ca-F-metasomatism. The acidic alteration accounts for most of the <span class="hlt">hydrothermal</span> metal mobilization in and outward from the pegmatites, whereas the Ca-F-metasomatism led to metal deposition and resulted from interaction of an acidic F-rich fluid with a Ca-bearing fluid. Numerical simulations of fluid-rock reactions with saline HCl-HF-bearing fluids at 400 °C to 250 °C indicate that temperature, availability of F/Cl and pH limit the mobility of Zr and REE. Fluids with pH <2 led to the formation of quartz and fluorite in the core of the pegmatites and to an increase in the stability of REE chloride species favorable for REE mobilization. The mobilization of Zr was favored at low temperature with the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V32B..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V32B..06C"><span><span class="hlt">Hydrothermal</span> mineralogy and fluid inclusions chemistry to understand the roots of active geothermal <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chambefort, I. S.; Dilles, J. H.; Heinrich, C.</p> <p>2013-12-01</p> <p>An integrated study to link magmatic textures, magmatic mineral compositions, <span class="hlt">hydrothermal</span> alteration zoning, <span class="hlt">hydrothermal</span> mineral chemistry, and fluid inclusion compositions has been undertaken to link an intrusive complex and its degassing alteration halo with their surface equivalent in an active geothermal <span class="hlt">system</span>. Ngatamariki geothermal <span class="hlt">system</span>, New Zealand, presents a unique feature in the Taupo Volcanic Zone (TVZ). Drilling intercepted an intrusive complex with a high temperature alteration halo similarly to what is observed in magmatic-derived ore deposits. Thus it presents the perfect opportunity to study the magmatic-<span class="hlt">hydrothermal</span> transition of the TVZ by characterizing the nature of the deep magmatic fluids link to the heat source of the world known geothermal fields. The record of magmatic-<span class="hlt">hydrothermal</span> fluid-rock interactions preserved at Ngatamariki may be analogous of processes presently occurring at depth beneath TVZ geothermal <span class="hlt">systems</span>. The intrusive complex consists of over 5 km3 of tonalite, diorite, basalt and aplitic dykes. Evidence of undercooling subsolidus magmatic textures such as myrmekite and skeletal overgrowth are commonly observed and often linked to volatile loss. The fluids released during the crystallization of the intrusive complex are interpreted to be at the origin of the surrounding high temperature alteration halo. Advanced argillic to potassic alteration and high temperature acidic assemblage is associated with high-temperature quartz veining at depth and vuggy silica at the paleo-surface. Major element compositions of the white micas associated with the high temperature halo show a transition from, muscovite to phengite, muscovitic illite away from the intrusion, with a transition to pyrophyllite and/ or topaz, and andalusite characteristic of more acidic conditions. Abundant high-density (up to 59 wt% NaCl eq and homogenization temperatures of 550 degree Celsius and above) coexist with low-density vapor fluid inclusions. This</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012514','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012514"><span>A review of numerical simulation of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Mercer, J.W.; Faust, C.R.</p> <p>1979-01-01</p> <p>Many advances in simulating single and two-phase fluid flow and heat transport in porous media have recently been made in conjunction with geothermal energy research. These numerical models reproduce <span class="hlt">system</span> thermal and pressure behaviour and can be used for other heat-transport problems, such as high-level radioactive waste disposal and heat-storage projects. -Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JIEIB..98...35J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JIEIB..98...35J"><span>Group Search Optimization for Fixed Head <span class="hlt">Hydrothermal</span> Power <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jena, Chitralekha; Basu, Mousumi</p> <p>2017-02-01</p> <p>This paper presents group search optimization for optimal scheduling of thermal plants in coordination with fixed head hydro units. Numerical results for two test <span class="hlt">systems</span> have been presented to demonstrate the performance of the proposed method. Results obtained from the proposed group search optimization method have been compared with those obtained from differential evolution and evolutionary programming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JIEIB.tmp....3J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JIEIB.tmp....3J"><span>Group Search Optimization for Fixed Head <span class="hlt">Hydrothermal</span> Power <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jena, Chitralekha; Basu, Mousumi</p> <p>2016-05-01</p> <p>This paper presents group search optimization for optimal scheduling of thermal plants in coordination with fixed head hydro units. Numerical results for two test <span class="hlt">systems</span> have been presented to demonstrate the performance of the proposed method. Results obtained from the proposed group search optimization method have been compared with those obtained from differential evolution and evolutionary programming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatCo...610150H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatCo...610150H"><span>Talc-dominated seafloor deposits reveal a new class of <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodgkinson, Matthew R. S.; Webber, Alexander P.; Roberts, Stephen; Mills, Rachel A.; Connelly, Douglas P.; Murton, Bramley J.</p> <p>2015-12-01</p> <p>The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, <span class="hlt">hydrothermal</span> precipitates at the VDVF comprise 85-90% by volume of the magnesium silicate mineral, talc. <span class="hlt">Hydrothermal</span> fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215 °C with low metal concentrations, intermediate pH (5.8) and high concentrations (667 mmol kg-1) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487+/-101 MW, comparable to the most powerful magma-driven <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4703833','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4703833"><span>Talc-dominated seafloor deposits reveal a new class of <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hodgkinson, Matthew R. S.; Webber, Alexander P.; Roberts, Stephen; Mills, Rachel A.; Connelly, Douglas P.; Murton, Bramley J.</p> <p>2015-01-01</p> <p>The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, <span class="hlt">hydrothermal</span> precipitates at the VDVF comprise 85–90% by volume of the magnesium silicate mineral, talc. <span class="hlt">Hydrothermal</span> fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215 °C with low metal concentrations, intermediate pH (5.8) and high concentrations (667 mmol kg−1) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487±101 MW, comparable to the most powerful magma-driven <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models. PMID:26694142</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26694142','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26694142"><span>Talc-dominated seafloor deposits reveal a new class of <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hodgkinson, Matthew R S; Webber, Alexander P; Roberts, Stephen; Mills, Rachel A; Connelly, Douglas P; Murton, Bramley J</p> <p>2015-12-22</p> <p>The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, <span class="hlt">hydrothermal</span> precipitates at the VDVF comprise 85-90% by volume of the magnesium silicate mineral, talc. <span class="hlt">Hydrothermal</span> fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215 °C with low metal concentrations, intermediate pH (5.8) and high concentrations (667 mmol kg(-1)) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487±101 MW, comparable to the most powerful magma-driven <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032253','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032253"><span>Identifying bubble collapse in a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> using hidden Markov models</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dawson, P.B.; Benitez, M.C.; Lowenstern, J. B.; Chouet, B.A.</p> <p>2012-01-01</p> <p>Beginning in July 2003 and lasting through September 2003, the Norris Geyser Basin in Yellowstone National Park exhibited an unusual increase in ground temperature and <span class="hlt">hydrothermal</span> activity. Using hidden Markov model theory, we identify over five million high-frequency (>15Hz) seismic events observed at a temporary seismic station deployed in the basin in response to the increase in <span class="hlt">hydrothermal</span> activity. The source of these seismic events is constrained to within ???100 m of the station, and produced ???3500-5500 events per hour with mean durations of ???0.35-0.45s. The seismic event rate, air temperature, hydrologic temperatures, and surficial water flow of the geyser basin exhibited a marked diurnal pattern that was closely associated with solar thermal radiance. We interpret the source of the seismicity to be due to the collapse of small steam bubbles in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, with the rate of collapse being controlled by surficial temperatures and daytime evaporation rates. copyright 2012 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1861c0033B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1861c0033B"><span><span class="hlt">Hydrothermal</span> <span class="hlt">system</span> of the Papandayan Volcano from temperature, self-potential (SP) and geochemical measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrdina, Svetlana; Revil, André; Gunawan, Hendra; Saing, Ugan B.; Grandis, Hendra</p> <p>2017-07-01</p> <p>Papandayan volcano in West Java, Indonesia, is characterized by intense <span class="hlt">hydrothermal</span> activities manifested by numerous fumaroles at three craters or kawah, i.e. Mas, Manuk and Baru. The latter was created after November 2002 phreatic eruption. Since 2011, numerous volcano-tectonic B events are encountered and the volcano was set on alert status on several occasions. The purpose of the present study is to delineate the structure of the summital <span class="hlt">hydrothermal</span> <span class="hlt">system</span> from Self-Potential (SP), soil temperature and gas concentrations in the soil (CO2, SO2 and H2S) data. This combination of geophysical and geochemical methods allows identification of the weak permeable zones serving as preferential pathways for <span class="hlt">hydrothermal</span> circulation and potential candidates to future landslides or flank collapses. This study is an on-going collaborative research project and we plan to conduct electrical resistivity tomography (ERT) and also Induced-Polarization (IP) surveys. Additional data would allow the 3D imaging of the studied area. The IP parameters will be used to characterise and to quantify the degree of alteration of the volcanic rocks as has been shown very recently in the laboratory studies. There are also rocks and soil samples that will undergo laboratory analyses at ISTerre for IP and complex resistivity parameters at the sample scale that will help to interpret the survey results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V53A1745J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V53A1745J"><span>Fossil Magmatic-<span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> in Pleistocene Brokeoff Volcano, Lassen Volcanic National Park, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>John, D. A.; Breit, G. N.; Lee, R. G.; Dilles, J. H.; Muffler, L. P.; Clynne, M. A.</p> <p>2006-12-01</p> <p>The mineralogy, distribution, and isotopic composition of altered rocks exposed in the core of Brokeoff Volcano are attributed to two fossil magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span> that are partly masked by younger alteration related to modern hot springs. Brokeoff Volcano was a large andesitic volcano (~600 to 400 ka) that preceded formation of Lassen Peak and the Lassen dome field. The two centers of fossil <span class="hlt">hydrothermal</span> activity are about 1 km apart and are identified here as the Brokeoff Mountain (BM) and Mt. Diller (MD) <span class="hlt">systems</span>. The BM <span class="hlt">system</span>, centered about 1 km NE of Brokeoff Mountain, covers about 1.5 km2 extending 2.5 km west from Diamond Peak, through Sulphur Works, to west of the ridge between Brokeoff Mountain and Mt. Diller. Alteration affected mostly andesite lavas and breccias of the Mill Canyon sequence (~600-475 ka). Core alteration extends westward and upward from an altered andesite plug exposed west of Sulphur Works. It consists of narrow, west-trending, brecciated vuggy silica ledges as long as 600 m surrounded by zones of variable thickness (<1 to 30 m) composed of alunite, kaolinite, pyrophyllite, dickite, topaz, pyrite, and a range of silica minerals. Farther outward from the advanced argillic alteration are broader zones of propylitic (chlorite-calcite-illite-pyrite) and smectite-pyrite alteration. Initial S-O isotopic data indicate that alunite formed by high-temperature disproportionation of magmatic SO2. The ~3 km2 MD <span class="hlt">system</span>, centered about 1 km SE of Mt. Diller, extends 3 km ESE to near Bumpass Hell. Lavas and breccias of the Mill Canyon sequence and the Mt. Diller sequence (ca. 400 ka) have been <span class="hlt">hydrothermally</span> altered. Although the center of the MD <span class="hlt">system</span> is largely obscured by landslides and by superimposed steam-heated acid leaching related to present-day <span class="hlt">hydrothermal</span> activity, recognized core alteration consists of pyrite-rich quartz-dickite and quartz-kaolinite breccias; pyrite content locally exceeds 50%. Only minor amounts of alunite and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5707K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5707K"><span>Geochemistry and solute fluxes from volcano-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Ketoy, Kuril Island arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalacheva, Elena; Taran, Yuri; Voloshina, Ekaterina; Tarasov, Kirill; Kotenko, Tatiana</p> <p>2017-04-01</p> <p>Ketoy is a volcanic island in the middle of the Kuril Island arc. With an area of ˜70 km2 it consists of two volcanic structures of different ages. The younger Pallas cone (960 m asl) is characterized by a strong fumarolic activity with maximum temperature of 720˚ C (August 2016) and hosts a cold acid crater lake in the summit crater. The older Ketoy cone (1172 m) at the NE of the island is cut by the erosion crater that open to the east and known as a canyon of Gorchichny Stream. There is a strong <span class="hlt">hydrothermal</span> activity within the canyon with boiling springs and steam vents. We present our data obtained during the fieldwork in August 2016 on the chemical (major and trace elements including REE) and isotopic (H, O, C, S) composition of thermal fluids from both Gorchichny canyon and thermal fields on the slopes of the Pallas cone. Thermal field of the Gorchichny Stream discharges acid Ca-SO4 and near neutral unusual, Cl-poor, Na-Ca-SO4 hot-to-boiling waters with TDS 2-3 g/L. Thermal field of the summit plateau at the base of the Pallas cone discharges acid Ca-SO4 warm water that can be the seepage from the crater lake. Isotopic compositions of thermal waters are close to the meteoric water line but with a clear positive shift in both δ18O and δD with a trend directed to the isotopic composition of condensates of fumarolic gases of the Pallas cone. For the first time the outflow rates of the draining streams have been measured and <span class="hlt">hydrothermal</span> solute fluxes from the volcano-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> have been estimated. The total <span class="hlt">hydrothermal</span> flux of chloride and sulfate from Ketoy Island is estimated as 8.5 t/d of Cl and 30 t/d of SO4. This work was supported by the RSF grant #15-17-20011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.V34B..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.V34B..01P"><span>Drilling of Submarine Shallow-water <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> in Volcanic Arcs of the Tyrrhenian Sea, Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petersen, S.; Augustin, N.; de Benedetti, A.; Esposito, A.; Gaertner, A.; Gemmell, B.; Gibson, H.; He, G.; Huegler, M.; Kleeberg, R.; Kuever, J.; Kummer, N. A.; Lackschewitz, K.; Lappe, F.; Monecke, T.; Perrin, K.; Peters, M.; Sharpe, R.; Simpson, K.; Smith, D.; Wan, B.</p> <p>2007-12-01</p> <p>Seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> related to volcanic arcs are known from several localities in the Tyrrhenian Sea in water depths ranging from 650 m (Palinuro Seamount) to less than 50 m (Panarea). At Palinuro Seamount 13 holes (<5m) were drilled using Rockdrill 1 of the British Geological Survey 1 into the heavily sediment-covered deposit recovering 11 m of semi-massive to massive sulfides. Maximum recovery within a single core was 4.8 m of massive sulfides/sulfates with abundant late native sulfur overprint. The deposit is open to all sides and to depth since all drill holes ended in mineralization. Metal enrichment at the top of the deposit is evident in some cores with polymetallic (Zn, Pb, Ag) sulfides overlying more massive and dense pyritic ore. The massive sulfide mineralization at Palinuro Seamount contains a number of unusual minerals, including enargite, tennantite, luzonite, and Ag-sulfosalts, that are not commonly encountered in mid-ocean ridge massive sulfides. In analogy to epithermal deposits forming on land, the occurrence of these minerals suggests a high sulfidation state of the <span class="hlt">hydrothermal</span> fluids during deposition implying that the mineralizing fluids were acidic and oxidizing rather than near-neutral and reducing as those forming typical base metal rich massive sulfides along mid-ocean ridges. Oxidizing conditions during sulfide deposition can probably be related to the presence of magmatic volatiles in the mineralizing fluids that may be derived from a degassing magma chamber. Elevated temperatures within sediment cores and TV-grab stations (up to 60°C) indicate present day <span class="hlt">hydrothermal</span> fluid flow. This is also indicated by the presence of small tube-worm bushes present on top the sediment. A number of drill holes were placed around the known phreatic gas-rich vents of Panarea and recovered intense clay-alteration in some holes as well as abundant massive anhydrite/gypsum with only trace sulfides along a structural depression suggesting the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003TrGeo...6..181G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003TrGeo...6..181G"><span><span class="hlt">Hydrothermal</span> Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>German, C. R.; von Damm, K. L.</p> <p>2003-12-01</p> <p>What is <span class="hlt">Hydrothermal</span> Circulation?<span class="hlt">Hydrothermal</span> circulation occurs when seawater percolates downward through fractured ocean crust along the volcanic mid-ocean ridge (MOR) <span class="hlt">system</span>. The seawater is first heated and then undergoes chemical modification through reaction with the host rock as it continues downward, reaching maximum temperatures that can exceed 400 °C. At these temperatures the fluids become extremely buoyant and rise rapidly back to the seafloor where they are expelled into the overlying water column. Seafloor <span class="hlt">hydrothermal</span> circulation plays a significant role in the cycling of energy and mass between the solid earth and the oceans; the first identification of submarine <span class="hlt">hydrothermal</span> venting and their accompanying chemosynthetically based communities in the late 1970s remains one of the most exciting discoveries in modern science. The existence of some form of <span class="hlt">hydrothermal</span> circulation had been predicted almost as soon as the significance of ridges themselves was first recognized, with the emergence of plate tectonic theory. Magma wells up from the Earth's interior along "spreading centers" or "MORs" to produce fresh ocean crust at a rate of ˜20 km3 yr-1, forming new seafloor at a rate of ˜3.3 km2 yr-1 (Parsons, 1981; White et al., 1992). The young oceanic lithosphere formed in this way cools as it moves away from the ridge crest. Although much of this cooling occurs by upward conduction of heat through the lithosphere, early heat-flow studies quickly established that a significant proportion of the total heat flux must also occur via some additional convective process (Figure 1), i.e., through circulation of cold seawater within the upper ocean crust (Anderson and Silbeck, 1981). (2K)Figure 1. Oceanic heat flow versus age of ocean crust. Data from the Pacific, Atlantic, and Indian oceans, averaged over 2 Ma intervals (circles) depart from the theoretical cooling curve (solid line) indicating convective cooling of young ocean crust by circulating seawater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=9WlakQkH2wk','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=9WlakQkH2wk"><span>Shuttle <span class="hlt">Endeavour</span> Flyover of Los Angeles Landmarks</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>Space shuttle <span class="hlt">Endeavour</span> atop NASA's Shuttle Carrier Aircraft flew over many Los Angeles area landmarks on its final ferry flight Sept. 21, 2012, including the Coliseum, the Hollywood Sign, Griffith...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=Vhxj4fegSA4','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=Vhxj4fegSA4"><span><span class="hlt">Endeavour</span> Begins Ferry Flight to LA</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>Space shuttle <span class="hlt">Endeavour</span> and the Shuttle Carrier Aircraft took off Wednesday morning, Sept. 19, from NASA's Kennedy Space Center in Florida to begin the first leg of a mission to deliver the retired...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14508.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14508.html"><span>West Rim of <span class="hlt">Endeavour</span> Crater on Mars</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-08-10</p> <p>A portion of the west rim of <span class="hlt">Endeavour</span> crater sweeps southward in this color view from NASA Mars Exploration Rover Opportunity. The rover first destination on the rim, called Spirit Point in tribute to Opportunity now-inactive twin, Spirit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=aGeZixp264E','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=aGeZixp264E"><span><span class="hlt">Endeavour</span> Mated to SCA Time-Lapse</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p></p> <p>At the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida, space shuttle <span class="hlt">Endeavour</span> is mounted atop NASA's Shuttle Carrier Aircraft, or SCA, in preparation for its ferry flight to Ca...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA13084.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA13084.html"><span><span class="hlt">Endeavour</span> on the Horizon Context View</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2010-04-30</p> <p>This image uses a view from the navigation camera on NASA Mars Exploration Rover Opportunity to show context for a horizon shot by the rover narrower-angle panoramic camera of the rim of <span class="hlt">Endeavour</span> crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H32F..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H32F..01W"><span>The Interplay Between Saline Fluid Flow and Dynamic Permeability in Magmatic-<span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weis, P.</p> <p>2014-12-01</p> <p>Magmatic-<span class="hlt">hydrothermal</span> ore deposits document the interplay between saline fluid flow and rock permeability. Numerical simulations of multi-phase flow of variably miscible, compressible H20-NaCl fluids in concert with a dynamic permeability model can reproduce characteristics of porphyry copper and epithermal gold <span class="hlt">systems</span>. This dynamic permeability model incorporates depth-dependent permeability profiles characteristic for tectonically active crust as well as pressure- and temperature-dependent relationships describing hydraulic fracturing and the transition from brittle to ductile rock behavior. In response to focused expulsion of magmatic fluids from a crystallizing upper crustal magma chamber, the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> self-organizes into a hydrological divide, separating an inner part dominated by ascending magmatic fluids under near-lithostatic pressures from a surrounding outer part dominated by convection of colder meteoric fluids under near-hydrostatic pressures. This hydrological divide also provides a mechanism to transport magmatic salt through the crust, and prevents the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> to become "clogged" by precipitation of solid halite due to depressurization of saline, high-temperature magmatic fluids. The same physical processes at similar permeability ranges, crustal depths and flow rates are relevant for a number of active <span class="hlt">systems</span>, including geothermal resources and excess degassing at volcanos. The simulations further suggest that the described mechanism can separate the base of free convection in high-enthalpy geothermal <span class="hlt">systems</span> from the magma chamber as a driving heat source by several kilometers in the vertical direction in tectonic settings with hydrous magmatism. This hydrology would be in contrast to settings with anhydrous magmatism, where the base of the geothermal <span class="hlt">systems</span> may be closer to the magma chamber.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhDT........18G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhDT........18G"><span>From Magma Formation to <span class="hlt">Hydrothermal</span> Alteration: an Integrated Study of the Martian Crust Using Thermodynamic Modeling of Geochemical <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Griffith, Laura Lee</p> <p></p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">systems</span> have undoubtedly occurred on Mars. These <span class="hlt">systems</span> are of interest for a number of reasons. <span class="hlt">Hydrothermal</span> alteration of host rocks can have effects on the atmosphere of the planet, the volatile budget, local hydrologic patterns, the rheology of the rocks, their ability to resist weathering, and even lower the melting temperature of crustal rocks. In addition, there is a connection between <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and the origin of life on earth that raises questions about life on Mars. The approach taken used theoretical geochemical modeling techniques to model hypothetical <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on Mars. The initial phase of the research involved understanding terrestrial <span class="hlt">systems</span> that were used as analogs for Martian <span class="hlt">systems</span>. Compositions of Icelandic host rocks were used as input for extensive modeling calculations. These calculations investigated the roles of initial rock composition, fluid temperature, partial pressure of carbon dioxide in the fluid, water to rock ratio, and oxygen fugacity of the fluid on alteration assemblages. The second phase utilized the data available on the SNC meteorites (they are suspected to come from Mars) as the basis for <span class="hlt">hydrothermal</span> <span class="hlt">system</span> modeling. The focus of this investigation was the variability of alteration assemblages that could be produced from the SNC meteorites. The final investigation broadened the scope of possible substrates for <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> by using theoretical geochemical modeling of igneous processes to produce likely Martial crustal rock compositions from a possible Martial mantle composition. A variety of variables (depth of initial melting, amount of initial melt, cooling rate during ascent, and depth of final emplacement) were examined to determine their effects on compositions of the calculated melts. Several rock compositions produced by the igneous modeling were used as input for <span class="hlt">hydrothermal</span> modeling calculations. These calculations examined possible differences in alteration</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25244359','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25244359"><span>Identification and activity of acetate-assimilating bacteria in diffuse fluids venting from two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Winkel, Matthias; Pjevac, Petra; Kleiner, Manuel; Littmann, Sten; Meyerdierks, Anke; Amann, Rudolf; Mußmann, Marc</p> <p>2014-12-01</p> <p>Diffuse <span class="hlt">hydrothermal</span> fluids often contain organic compounds such as hydrocarbons, lipids, and organic acids. Microorganisms consuming these compounds at <span class="hlt">hydrothermal</span> sites are so far only known from cultivation-dependent studies. To identify potential heterotrophs without prior cultivation, we combined microbial community analysis with short-term incubations using (13)C-labeled acetate at two distinct <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. We followed cell growth and assimilation of (13)C into single cells by nanoSIMS combined with fluorescence in situ hybridization (FISH). In 55 °C-fluids from the Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">system</span>/Mid-Atlantic Ridge, a novel epsilonproteobacterial group accounted for nearly all assimilation of acetate, representing the first aerobic acetate-consuming member of the Nautiliales. In contrast, Gammaproteobacteria dominated the (13) C-acetate assimilation in incubations of 37 °C-fluids from the back-arc <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the Manus Basin/Papua New Guinea. Here, 16S rRNA gene sequences were mostly related to mesophilic Marinobacter, reflecting the high content of seawater in these fluids. The rapid growth of microorganisms upon acetate addition suggests that acetate consumers in diffuse fluids are copiotrophic opportunists, which quickly exploit their energy sources, whenever available under the spatially and temporally highly fluctuating conditions. Our data provide first insights into the heterotrophic microbial community, catalyzing an under-investigated part of microbial carbon cycling at <span class="hlt">hydrothermal</span> vents. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930034010&hterms=organic+synthesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dorganic%2Bsynthesis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930034010&hterms=organic+synthesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dorganic%2Bsynthesis"><span><span class="hlt">Hydrothermal</span> organic synthesis experiments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shock, Everett L.</p> <p>1992-01-01</p> <p>Ways in which heat is useful in organic synthesis experiments are described, and experiments on the <span class="hlt">hydrothermal</span> destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under <span class="hlt">hydrothermal</span> conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> have not yet been conducted with the aim of testing the hypothesis of <span class="hlt">hydrothermal</span> organic <span class="hlt">systems</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6579B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6579B"><span>Silicon isotopes fractionation in meteoric chemical weathering and <span class="hlt">hydrothermal</span> alteration <span class="hlt">systems</span> of volcanic rocks (Mayotte)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basile-Doelsch, Isabelle; Puyraveau, Romain-Arnaud; Guihou, Abel; Haurine, Frederic; Deschamps, Pierre; rad, Setareh; Nehlig, Pierre</p> <p>2017-04-01</p> <p>Low temperature chemical weathering fractionates silicon (Si) isotopes while forming secondary silicates. The Si fractionation ranges of high temperature secondary phyllosilicates formed in <span class="hlt">hydrothermal</span> alteration environments have not been investigated to date. Several parameters, including temperature, reaction rates, pH, ionic concentrations in solution, precipitation/dissolution series or kinetic versus equilibrium regime are not the same in <span class="hlt">hydrothermal</span> alteration and surface weathering <span class="hlt">systems</span> and may lead to different fractionation factors. In this work, we analyzed Si isotopes in these two types of alteration conditions in two profiles sampled on the volcanic island of Mayotte. In both profiles, Si-bearing secondary mineral was kaolinite. Both profiles showed 30Si depletion as a function of the degree of alteration but each with a distinct pattern. In the meteoric weathering profile, from the bottom to the top, a gradual decrease of the δ30Si from parent rock (-0.29 ± 0.13 ‰) towards the most weathered product (-2.05 ± 0.13 ‰) was observed. In the <span class="hlt">hydrothermal</span> alteration profile, in which meteoric weathering was also superimposed at the top of the profile, an abrupt transition of the δ30Si was measured at the interface between parent-rock (-0.21 ± 0.11 ‰) and the altered products, with a minimum value of -3.06 ± 0.16 ‰˙ At the scale of Si-bearing secondary minerals, in the chemical weathering <span class="hlt">system</span>, a Δ30Sikaol-parentrock of -1.9 ‰ was observed, in agreement with results in the literature. A low temperature kinetic fractionation 30ɛ of -2.29 ‰ was calculated using a simple steady state model. However, an unexpected Δ30Sikaol-parentrock of -2.85 ‰ was measured in the <span class="hlt">hydrothermal</span> alteration site, pointing to possible mechanisms linked to dissolution/precipitation series and/or to ionic composition of the solution as the main controlling factors of fractionation in <span class="hlt">hydrothermal</span> conditions. At the scale of the profiles, both δ30Si</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70018270','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70018270"><span>Emerald mineralization and metasomatism of amphibolite, khaltaro granitic pegmatite - <span class="hlt">Hydrothermal</span> vein <span class="hlt">system</span>, Haramosh Mountains, Northern Pakistan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Laurs, B.M.; Dilles, J.H.; Snee, L.W.</p> <p>1996-01-01</p> <p> single fluid of magmatic origin with ??18OH2O = 8??? produced the pegmatite-vein <span class="hlt">system</span> and <span class="hlt">hydrothermal</span> alteration at temperatures between 550 and 400??C. The formation of emerald results from introduction of HF-rich magmatic-<span class="hlt">hydrothermal</span> fluids into the amphibolite, which caused hydrogen ion metasomatism and released Cr and Fe into the pegmatite-vein <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53C1050D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53C1050D"><span>Application of AUVs in the Exploration for and Characterization of Arc Volcano Seafloor <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Ronde, C. E. J.; Walker, S. L.; Caratori Tontini, F.; Baker, E. T.; Embley, R. W.; Yoerger, D.</p> <p>2014-12-01</p> <p>The application of Autonomous Underwater Vehicles (AUVs) in the search for, and characterization of, seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with arc volcanoes has provided important information at a scale relevant to the study of these <span class="hlt">systems</span>. That is, 1-2 m resolution bathymetric mapping of the seafloor, when combined with high-resolution magnetic and water column measurements, enables the discharge of <span class="hlt">hydrothermal</span> vent fluids to be coupled with geological and structural features, and inferred upflow zones. Optimum altitude for the AUVs is ~70 m ensuring high resolution coverage of the area, maximum exposure to <span class="hlt">hydrothermal</span> venting, and efficency of survey. The Brothers caldera and Clark cone volcanoes of the Kermadec arc have been surveyed by ABE and Sentry. At Brothers, bathymetric mapping shows complex features on the caldera walls including embayment's, ridges extending orthogonal to the walls and the location of a dominant ring fault. Water column measurements made by light scattering, temperature, ORP and pH sensors confirmed the location of the known vent fields on the NW caldera wall and atop the two cones, and discovered a new field on the West caldera wall. Evidence for diffuse discharge was also seen on the rim of the NW caldera wall; conversely, there was little evidence for discharge over an inferred ancient vent site on the SE caldera wall. Magnetic measurements show a strong correlation between the boundaries of vent fields determined by water column measurements and observed from manned submersible and towed camera surveys, and donut-shaped zones of magnetic 'lows' that are focused along ring faults. A magnetic low was also observed to cover the SE caldera site. Similar surveys over the NW edifice of Clark volcano also show a strong correlation between active <span class="hlt">hydrothermal</span> venting and magnetic lows. Here, the survey revealed a pattern resembling Swiss cheese of magnetic lows, indicating more widespread permeability. Moreover, the magnetic survey</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17.3835A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17.3835A"><span>Lithium isotopic systematics of submarine vent fluids from arc and back-arc <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Araoka, Daisuke; Nishio, Yoshiro; Gamo, Toshitaka; Yamaoka, Kyoko; Kawahata, Hodaka</p> <p>2016-10-01</p> <p>The Li concentration and isotopic composition (δ7Li) in submarine vent fluids are important for oceanic Li budget and potentially useful for investigating <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> deep under the seafloor because <span class="hlt">hydrothermal</span> vent fluids are highly enriched in Li relative to seawater. Although Li isotopic geochemistry has been studied at mid-ocean-ridge (MOR) <span class="hlt">hydrothermal</span> sites, in arc and back-arc settings Li isotopic composition has not been systematically investigated. Here we determined the δ7Li and 87Sr/86Sr values of 11 end-member fluids from 5 arc and back-arc <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western Pacific and examined Li behavior during high-temperature water-rock interactions in different geological settings. In sediment-starved <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> (Manus Basin, Izu-Bonin Arc, Mariana Trough, and North Fiji Basin), the Li concentrations (0.23-1.30 mmol/kg) and δ7Li values (+4.3‰ to +7.2‰) of the end-member fluids are explained mainly by dissolution-precipitation model during high-temperature seawater-rock interactions at steady state. Low Li concentrations are attributable to temperature-related apportioning of Li in rock into the fluid phase and phase separation process. Small variation in Li among MOR sites is probably caused by low-temperature alteration process by diffusive <span class="hlt">hydrothermal</span> fluids under the seafloor. In contrast, the highest Li concentrations (3.40-5.98 mmol/kg) and lowest δ7Li values (+1.6‰ to +2.4‰) of end-member fluids from the Okinawa Trough demonstrate that the Li is predominantly derived from marine sediments. The variation of Li in sediment-hosted sites can be explained by the differences in degree of <span class="hlt">hydrothermal</span> fluid-sediment interactions associated with the thickness of the marine sediment overlying these <span class="hlt">hydrothermal</span> sites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/889743','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/889743"><span>Numerical Simulations of the <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> at Lassen Volcanic National Park</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sorey, Michael L.; Ingebritsen, Steven E.</p> <p>1983-12-15</p> <p>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the vicinity of Lassen Volcanic National Park contains a central region of fluid upflow in which steam and liquid phases separate, with steam rising through a parasitic vapor-dominated zone and liquid flowing laterally toward areas of hot spring discharge south of the Park. A simplified numerical model was used to simulate the 10,000-20,000 year evolution of this <span class="hlt">system</span> and to show that under certain circumstances fluid withdrawal from hot-water reservoirs south of the Park could significantly alter the discharge of steam from thermal areas within the Park.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993BVol...55..289S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993BVol...55..289S"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Volcan Puracé, Colombia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sturchio, Neil C.; Williams, Stanley N.; Sano, Yuji</p> <p>1993-05-01</p> <p>This paper presents chemical and isotopic data for thermal waters, gases and S deposits from Volcan Puracé (summit elevation ˜4600 m) in SW Colombia. Hot gas discharges from fumaroles in and around the summit crater, and thermal waters discharge from three areas on its flanks. The waters from all areas have δD values of-75±1, indicating a single recharge area at high elevation on the volcano. Aircorrected values of3He/4He in thermal waters range from 3.8 to 6.7 RA, and approach those for crater fumarole gas (6.1 7.1 RA), indicating widespread addition of magmatic volatiles. An economic S deposit (El Vinagre) is being mined in the Rio Vinagre fault zone at 3600 m elevation. Sulfur isotopic data are consistent with a magmatic origin for S species in thermal waters and gases, and for the S ore deposit. Isotopic equilibration between S species may have occurred at 220±40°C, which overlaps possible equilibration temperatures (170±40°C) determined by a variety of other geothermometers for neutral thermal waters. Apparent CH4-CO2 equilibration temperatures for gases from thermal springs (400±50°C) and crater fumaroles (520±60°C) reflect higher temperatures deeper in the <span class="hlt">system</span>. Hot magmatic gas ascending through the Rio Vinagre fault zone is though to have precipitated S and generated thermal waters by interaction with descending meteoric waters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997E%26PSL.153..239F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997E%26PSL.153..239F"><span>Tide-related variability of TAG <span class="hlt">hydrothermal</span> activity observed by deep-sea monitoring <span class="hlt">system</span> and OBSH</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujioka, Kantaro; Kobayashi, Kazuo; Kato, Kazuhiro; Aoki, Misumi; Mitsuzawa, Kyohiko; Kinoshita, Masataka; Nishizawa, Azusa</p> <p>1997-12-01</p> <p><span class="hlt">Hydrothermal</span> activities were monitored by an ocean bottom seismometer with hydrophone (OBSH) and a composite measuring <span class="hlt">system</span> (Manatee) including CTD, current meter, transmission meter and cameras at a small depression on the TAG <span class="hlt">hydrothermal</span> mound in the Mid-Atlantic Ridge. Low-frequency pressure pulses detected by the hydrophone with semi-diurnal periodicity seem to correspond to cycles of <span class="hlt">hydrothermal</span> upflow from a small and short-lived smoker vent close to the observing site. The peaks of pressure pulses are synchronous with the maximum gradient of areal strain decrease due to tidal load release. Microearthquakes with very near epicenters occur sporadically and do not appear to be directly correlatable to <span class="hlt">hydrothermal</span> venting. Temporal variations in bottom water temperature also have semi-diurnal periodicity but are more complicated than the pressure events. Temperatures may be affected both by upwelling of hot water and by lateral flow of the bottom current changing its directions with ocean tide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1988/4152/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1988/4152/report.pdf"><span>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in central Twin Falls County, Idaho</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lewis, R.E.; Young, H.W.</p> <p>1989-01-01</p> <p>Thermal water in Twin Fall County has been used for space heating, large-scale greenhouse operations, and aquaculture since the mid-1970's. More recently, increased utilization of the thermal water has caused aquifer pressures to decline. Near the city of Twin Falls, water levels in some formerly flowing thermal wells have declined to below land surface. The thermal water is principally in the silicic volcanic rocks of the Idavada Volcanics. Electrical resistivity soundings indicate that thickness of the rocks ranges from about 700 to 3,000 ft and averages about 2,000 ft. Temperatures of water sampled range from 26 C to nearly 50 C in wells completed in the upper part of the reservoir near Twin Falls. Water from deeper parts of the reservoir may be warmer than 50 C. Most of the thermal water is a sodium bicarbonate type. The maximum fluoride concentration was 22 mg/L. Chloride concentrations between about 50 and 150 mg/L are the result of mixing of deep water with shallower, cooler water that has been affected by percolation of irrigation water. Carbon-14 concentrations in selected thermal water samples indicate ages of 1,000 to 15,000 years. The water becomes progressively older northward along proposed groundwater flowpaths. On the basis of transit times in the <span class="hlt">system</span> of 10,000 to 15,000 years and the reservoir volume, recharge is estimated to be about 5 to 7 cu ft/sec. Net heat flux in the area is about 2.2 heat flow units.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5569857','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5569857"><span>Geophysical characteristics of the <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of Kilauea volcano, Hawaii</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kauahikaua, J. )</p> <p>1993-08-01</p> <p>Clues to the structure of Kilauea volcano can be obtained from spatial studies of gravity, magnetic, and seismic velocity variations. The rift zones and summit are underlain by dense, magnetic, and seismic velocity variations. The rift zones and summit are underlain by dense, magnetic, high P-wave-velocity rocks at depths of about 2 km less. The gravity and seismic velocity studies indicate that the rift structures are broad, extending farther to the north than to the south of the surface features. The magnetic data allow separation into a narrow, highly-magnetized, shallow zone and broad, flanking, magnetic lows. The patterns of gravity, magnetic variations, and seismicity document the southward migration of the upper east rift zone. Regional, hydrologic features of Kilauea can be determined from resistivity and self-potential studies. High-level groundwater exists beneath Kilauea summit to elevations of +800 m within a triangular area bounded by the west edge of the upper southwest rift zone, the east edge of the upper east rift zone, and the Koa'e fault <span class="hlt">system</span>. High-level groundwater is present within the east rift zone beyond the triangular summit area. Self-potential mapping shows that areas of local heat produce local fluid circulation in the unconfined aquifer (water table). Shallow seismicity and surface deformation indicate that magma is intruding and that fractures are forming beneath the rift zones and summit area. Heat flows of 370--820 mW/m[sup 2] are calculated from deep wells within the lower east rift zone. The estimated heat input rate for Kilauea of 9 gigawatts (GW) is at least 25 times higher than the conductive heat loss as estimated from the heat flow in wells extrapolated over the area of the summit caldera and rift zones. 115 refs., 13 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V11A3057S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V11A3057S"><span>Numerical Modeling of Brine Formation and Serpentinization at the Rainbow <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sekhar, P.; Lowell, R. P.</p> <p>2015-12-01</p> <p>The Rainbow <span class="hlt">hydrothermal</span> field on the Mid Atlantic Ridge is a high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">system</span> hosted in peridotite. The vent fluids are rich in methane and hydrogen suggesting that serpentinization is occurring at depth in the <span class="hlt">system</span>. Vent temperature of ~365°C, salinity of ~4.5 wt%, and heat output of ~500 MW suggest that Rainbow field is driven by a magmatic heat source and that phase separation is occurring at depth. To understand the origin of high salinity in the Rainbow <span class="hlt">hydrothermal</span> fluid, we construct a 2D numerical model of two-phase <span class="hlt">hydrothermal</span> circulation using the numerical simulator FISHES. This code uses the finite volume method to solve the conservation of mass, momentum, energy, and salt equations in a NaCl-H2O fluid. We simulate convection in an open top 2D box at a surface pressure of 23 MPa and seawater temperature of 10oC. The bottom and sides of the box are insulated and impermeable, and a fixed temperature distribution is maintained at the base to ensure phase separation. We first consider a homogeneous model with a permeability of 10-13 m2 and <span class="hlt">system</span> depths of 2 and 1 km, respectively. The brine-derived fluid from the deeper <span class="hlt">system</span> barely exceeds seawater, whereas the shallower <span class="hlt">system</span> produces a short pulse of 9.0 wt% for 5 years. We then consider 1 km deep <span class="hlt">systems</span> with a high permeability discharge zone of 5x10-13 m2 that corresponds to a fault zone, surrounded by recharge zones of 10-13, 10-14 and 10-15 m2, respectively. The model with recharge permeability of 10-14 m2 yields stable plumes that vent brine-derived fluid of 4.2 wt% for 150 years. Using the quasi- steady state of this model as a base, we estimate the rate of serpentinization along the fluid flow paths, and evolution of porosity and permeability. This analysis will indicate the extent to which serpentinization will affect the dynamics of the <span class="hlt">system</span> and will provide insight into methane flux in the Rainbow vent field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9613W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9613W"><span>Laboratory experiments and continuous fluid monitoring at Campi Flegrei to understand pressure transients in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woith, Heiko; Mangiacapra, Annarita; Chiodini, Giovanni; Pilz, Marco; Walter, Thomas</p> <p>2015-04-01</p> <p>The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> beneath Campi Flegrei is strongly affected by sub-surface processes as manifested by the existence of a geothermal "plume" below Solfatara (Bruno et al. 2007), associated with formation of new fumaroles and the spatial pattern of exhalation vents. Within the frame of MED-SUV (The MED-SUV project has received funding from the European Union Seventh Framework Programme (FP7) under Grant agreement no 308665), pressure tansients in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Campi Flegrei shall be studied using a combination of laboratory experiments and continuous pressure/temperature monitoring at fumaroles, mudpools, hot springs, and geothermal wells. Four groundwater monitoring sites were installed in September 2013: one in the Fangaia mud pool inside Solfatara and three within the geothermal area of Agnano, which is located roughly 3 km to the East of the Solfatara crater. In 2014 additional sensors were installed in Pisciarelli. Autonomous devices are being used to record the water level and water temperature at 10 minute intervals. Records reveal significant changes of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in September 2013 at the Agnano main spring during the night from 23 to 24 September. Both, the water level and the water temperature dropped significantly, confirmed by visual inspection of the spa operators. The pool of the main spring almost emptied and the flow rate was significantly reduced, implying a profound change in the <span class="hlt">system</span>. Similar water level drops occurred in the following months. Gas bubbles are likely to play a major role with respect to spatio-temporal variations in shallow fluid <span class="hlt">systems</span> below Solfatara. Thus, additional to the field measurements we investigate potential bubble-related mechanisms capable to increase fluid pressure. The BubbleLab at GFZ has been setup. We are able to simulate earthquake ground motions with a shaking table, track the size and velocity of rising bubbles via a camera <span class="hlt">system</span>, and quantify transients with a set of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26394465','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26394465"><span>[Chemical Potentials of <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> and Formation of Coupled Modular Metabolic Pathways].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marakushev, S A; Belonogova, O V</p> <p>2015-01-01</p> <p>According to Gibbs J.W. the number of independent components is the least number of those chemical constituents, by combining which the compositions of all possible phases in the <span class="hlt">system</span> can be obtained, and at the first stages of development of the primary metabolism of the three-component <span class="hlt">system</span> C-H-O different hydrocarbons and molecular hydrogen were used as an energy source for, it. In the Archean <span class="hlt">hydrothermal</span> conditions under the action of the phosphorus chemical potential the C-H-O <span class="hlt">system</span> was transformed into a four-component <span class="hlt">system</span> C-H-O-P setting up a gluconeogenic <span class="hlt">system</span>, which became the basis of power supply for a protometabolism, and formation of a new cycle of CO2 fixation (reductive pentose phosphate pathway). It is shown that parageneses (association) of certain substances permitted the modular constructions of the central metabolism of the <span class="hlt">system</span> C-H-O-P and the formed modules appear in association with each other in certain physicochemical <span class="hlt">hydrothermal</span> conditions. Malate, oxaloacetate, pyruvate and phosphoenolpyruvate exhibit a turnstile-like mechanism of switching reaction directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGP31B..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGP31B..01P"><span>Imaging the magmatic and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> of Long Valley Caldera, California with magnetotellurics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peacock, J.; Mangan, M.; McPhee, D.; Ponce, D. A.</p> <p>2015-12-01</p> <p>Long Valley Caldera (LVC) in Eastern California contains active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, areas of episodic seismicity, and areas of elevated gas emissions, all of which are related to a deeper magmatic <span class="hlt">system</span> that is not well characterized. To better image the Long Valley magmatic <span class="hlt">system</span>, 60 full-tensor broadband magnetotelluric (MT) stations were collected in LVC and modeled in three-dimensions to constrain the subsurface electrical resistivity structure down to 30 km. Three conductive zones are imaged in the preferred resistivity model. The most prominent conductive zone (<7 Ohm-m) is located 5 km beneath the resurgent dome (near the center of Long Valley Caldera), where it elongates in a north-south direction, and has westward connection to the surface close to well 44-16 near Deer Mountan. This conductive zone is interpreted to be an accumulation zone of <span class="hlt">hydrothermal</span> fluids originating from a deeper magmatic source. The shape of the conductive body suggests that the fluids pool under the resurgent dome and migrate westward, upwelling just south of well 44-16 to feed the near surface geothermal <span class="hlt">system</span>. A second conductive zone (<10 Ohm-m) is 4 km southeast of the resurgent dome and 5 km deep and coincident with the seismic swarm of 2014. This is another zone of fluid accumulation, where the source could be the fluid accumulation zone to the west or an independent deeper source. The third conductive anomaly (<10 Ohm-m) is a few kilometers south of the resurgent dome below a depth of 15 km, and collocated with a low p- and s-wave velocity zone, and directly beneath a GPS inflation area, all of which advocate for a magma mush zone of as much as 30% interstitial melt. The preferred resistivity model suggests an accumulation of <span class="hlt">hydrothermal</span> fluids 5 km below the resurgent dome that originates from a deeper magmatic source at 15 km depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18163870','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18163870"><span>Temporal changes in fluid chemistry and energy profiles in the vulcano island <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rogers, Karyn L; Amend, Jan P; Gurrieri, Sergio</p> <p>2007-12-01</p> <p>In June 2003, the geochemical composition of geothermal fluids was determined at 9 sites in the Vulcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, including sediment seeps, geothermal wells, and submarine vents. Compositional data were combined with standard state reaction properties to determine the overall Gibbs free energy (DeltaG(r) ) for 120 potential lithotrophic and heterotrophic reactions. Lithotrophic reactions in the H-O-N-S-C-Fe <span class="hlt">system</span> were considered, and exergonic reactions yielded up to 120 kJ per mole of electrons transferred. The potential for heterotrophy was characterized by energy yields from the complete oxidation of 6 carboxylic acids- formic, acetic, propanoic, lactic, pyruvic, and succinic-with the following redox pairs: O(2)/H(2)O, SO(4) (2)/H(2)S, NO(3) ()/NH(4) (+), S(0)/H(2)S, and Fe(3)O(4)/Fe(2+). Heterotrophic reactions yielded 6-111 kJ/mol e(). Energy yields from both lithotrophic and heterotrophic reactions were highly dependent on the terminal electron acceptor (TEA); reactions with O(2) yielded the most energy, followed by those with NO(3) (), Fe(III), SO(4) (2), and S(0). When only reactions with complete TEA reduction were included, the exergonic lithotrophic reactions followed a similar electron tower. Spatial variability in DeltaG(r) was significant for iron redox reactions, owing largely to the wide range in Fe(2+) and H(+) concentrations. Energy yields were compared to those obtained for samples collected in June 2001. The temporal variations in geochemical composition and energy yields observed in the Vulcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span> between 2001 and 2003 were moderate. The largest differences in DeltaG(r) over the 2 years were from iron redox reactions, due to temporal changes in the Fe(2+) and H(+) concentrations. The observed variations in fluid composition across the Vulcano <span class="hlt">hydrothermal</span> <span class="hlt">system</span> have the potential to influence not only microbial diversity but also the metabolic strategies of the resident microbial communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017161','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017161"><span>Mass transfer constraints on the chemical evolution of an active <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, Valles caldera, New Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>White, A.F.; Chuma, N.J.; Goff, F.</p> <p>1992-01-01</p> <p>Partial equilibrium conditions occur between fluids and secondary minerals in the Valles <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, contained principally in the Tertiary rhyolitic Bandelier Tuff. The mass transfer processes are governed by reactive phase compositions, surface areas, water-rock ratios, reaction rates, and fluid residence times. Experimental dissolution of the vitric phase of the tuff was congruent with respect to Cl in the solid and produced reaction rates which obeyed a general Arrhenius release rate between 250 and 300??C. The 18O differences between reacted and unreacted rock and fluids, and mass balances calculations involving Cl in the glass phase, produced comparable water-rock ratios of unity, confirming the importance of irreversible reaction of the vitric tuff. A fluid residence time of approximately 2 ?? 103 years, determined from fluid reservoir volume and discharge rates, is less than 0.2% of the total age of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> and denotes a geochemically and isotopically open <span class="hlt">system</span>. Mass transfer calculations generally replicated observed reservoir pH, Pco2, and PO2 conditions, cation concentrations, and the secondary mineral assemblage between 250 and 300??C. The only extraneous component required to maintain observed calcite saturation and high Pco2 pressures was carbon presumably derived from underlying Paleozoic limestones. Phase rule constraints indicate that Cl was the only incompatible aqueous component not controlled by mineral equilibrium. Concentrations of Cl in the reservoir directly reflect mass transport rates as evidenced by correlations between anomalously high Cl concentrations in the fluids and tuff in the Valles caldera relative to other <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in rhyolitic rocks. ?? 1992.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-04pd0344.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-04pd0344.html"><span>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (center) and Deputy Director Woodrow Whitlow Jr. (far left) look at the external tank door corrosion work being done on <span class="hlt">Endeavour</span>. Next to Whitlow is Bruce Buckingham, assistant to the deputy director. Providing information, at right, are Kathy Laufenberg, Orbiter Airframe Engineering ground area manager, and Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, both with United Space Alliance; and Joy Huff, with Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2004-02-25</p> <p>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (center) and Deputy Director Woodrow Whitlow Jr. (far left) look at the external tank door corrosion work being done on <span class="hlt">Endeavour</span>. Next to Whitlow is Bruce Buckingham, assistant to the deputy director. Providing information, at right, are Kathy Laufenberg, Orbiter Airframe Engineering ground area manager, and Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, both with United Space Alliance; and Joy Huff, with Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-KSC-04pd0346.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-KSC-04pd0346.html"><span>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (center) and Deputy Director Woodrow Whitlow Jr. (far left) look at the external tank door corrosion work being done on <span class="hlt">Endeavour</span>. Next to Whitlow is Bruce Buckingham, assistant to the deputy director. Providing information, at right, are Orbiter Airframe Engineering ground area manager, and Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, both with United Space Alliance; and Joy Huff, with KSC Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2004-02-25</p> <p>KENNEDY SPACE CENTER, FLA. - On a tour of the Orbiter Processing Facility, Center Director Jim Kennedy (center) and Deputy Director Woodrow Whitlow Jr. (far left) look at the external tank door corrosion work being done on <span class="hlt">Endeavour</span>. Next to Whitlow is Bruce Buckingham, assistant to the deputy director. Providing information, at right, are Orbiter Airframe Engineering ground area manager, and Tom Roberts, Airframe Engineering <span class="hlt">System</span> specialist, both with United Space Alliance; and Joy Huff, with KSC Space Shuttle Processing. <span class="hlt">Endeavour</span> is in its Orbiter Major Modification period, which began in December 2003.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6019861','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6019861"><span>Scientific drilling to study the roots of active <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> related to young magmatic intrusions. [Abstract only</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Muffler, L.J.P.</p> <p>1983-03-01</p> <p>At present, <span class="hlt">hydrothermal</span>-magma processes can be studied only inferentially, using observations on hot springs and volcanic rocks, data from shallow- and intermediate-depth drill holes, analogies with exhumed fossil <span class="hlt">systems</span>, and extrapolation of laboratory investigations. The Thermal Regimes Panel of the Continental Scientific Drilling Committee in a draft report concludes that an understanding of active <span class="hlt">hydrothermal</span>-magma <span class="hlt">systems</span> requires drill-hole investigations of deeper and hotter levels than have been drilled and studied to date. The Panel groups <span class="hlt">hydrothermal</span>-magma <span class="hlt">systems</span> in the United States into five classes: (1) dominantly andesitic centers, (2) spreading ridges, (3) basaltic fields, (4) evolved basaltic centers, and (5) silicic caldera complexes. Application of eight scientific criteria and three social criteria leads to the conclusion that silicic caldera complexes should be the first target of a focused drilling program to investigate the <span class="hlt">hydrothermal</span>-magma interface at depths of 5 to 7 km. Primary targets are the three young, silicic caldera <span class="hlt">systems</span> in the western conterminous United States: Yellowstone (Wyoming), Valles (New Mexico), and Long Valley (California). Scientific drilling of these active <span class="hlt">hydrothermal</span>-magma <span class="hlt">systems</span> complements scientific drilling proposed for fossil <span class="hlt">systems</span> such as Creede (Colorado). In addition, the roots of the Salton Sea geothermal <span class="hlt">system</span> (California) present an opportunity for add-on deep drilling and scientific experiments to supplement geothermal drilling by industry in this active spreading-ridge environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V52A..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V52A..01C"><span>Source Dynamics of Long-Period Seismicity in Volcanic and <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chouet, B. A.</p> <p>2006-12-01</p> <p>Long-period (LP) seismicity, including individual LP events and tremor, is widely observed in relation to magmatic and <span class="hlt">hydrothermal</span> activities in volcanic areas and is recognized as a precursory phenomenon for eruptive activity. The waveform of the LP event is characterized by simple decaying harmonic oscillations except for a brief interval at the event onset. This characteristic event signature is commonly interpreted as oscillations of a fluid-filled resonator in response to a time-localized excitation. By the same token, tremor may be viewed as oscillations of the same resonator in response to a sustained excitation. Because the properties of the resonator <span class="hlt">system</span> at the source of the LP event can be inferred from the complex frequencies of the decaying harmonic oscillations in the tail of the seismogram, these events are particularly important in the quantification of volcanic and <span class="hlt">hydrothermal</span> processes. The damped oscillations in the LP coda are characterized by two parameters, T and Q, where T is the period of the dominant mode of oscillation, and Q is the quality factor of the oscillatory <span class="hlt">system</span> representing the combined effects of radiation and intrinsic losses. Typical periods observed for LP events are in the range 0.2 - 2 s, while observed Q range from values near 1 to values larger than 100. Waveform inversions of LP signals carried out so far point to a crack geometry at the source of these events. Detailed investigations of the oscillating characteristics of LP sources based on the fluid-filled crack model suggest source dimensions ranging from tens to several hundred meters. Such studies further indicate that dusty gases and bubbly basalt are the most common types of fluids involved at the source of LP events in magmatic <span class="hlt">systems</span>, while misty gases, steam and bubbly water commonly represent LP events of <span class="hlt">hydrothermal</span> origin. Observations carried out in different volcanic settings point to a wide variety of LP excitation mechanisms. At Stromboli</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B11D0717H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B11D0717H"><span>Geophysical Characterization of the Borax Lake <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> in the Alvord Desert, Southeastern Oregon.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hess, S.; Paul, C.; Bradford, J.; Lyle, M.; Clement, W.; Liberty, L.; Myers, R.; Donaldson, P.</p> <p>2003-12-01</p> <p>We are conducting a detailed geophysical characterization of an active <span class="hlt">hydrothermal</span> <span class="hlt">system</span> as part of an interdisciplinary project aiming to study the link between the physical characteristics of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> and biota that occupy those <span class="hlt">systems</span>. The Borax Lake <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> (BLHS), consisting of Borax Lake and the surrounding hot springs, is located near the center of the Alvord Basin in southeastern Oregon. As a result of Basin and Range extension, the Alvord Basin is a north-south trending graben bounded by the Steens Mountains to the west and the Trout Creek Mountains to the east. We are using several geophysical techniques to generate both basin-wide and high-resolution local characterizations of the Alvord Basin and the BLHS. To date we have completed two scales of seismic reflection surveys: an east-west trending basin scale survey and a shallow (~10 - 300 m depth) 3D survey of the BLHS. The basin scale seismic survey consists of 11 km of 2D, 60 fold CMP data acquired with a 200 lb accelerated weight drop. We acquired the 3D survey of the BLHS using a 7.62x39 mm SKS rifle and 240 channel recording <span class="hlt">system</span>. The 3D patch covers ~ 90,000 sq. m with a maximum inline offset aperture of 225 m, crossline aperture of 75 m, and 360 degree azimuthal coverage. Additionally, we have completed a regional total-field magnetic survey for a large portion of the Alvord Basin and a 3D transient electromagnetic (TEM) survey of the BLHS. The 3D TEM survey covers the central portion of the 3D seismic survey. Initial results from the regional magnetic and seismic surveys indicate a mid-basin basement high. The basement high appears to correlate with the northeast trending BLHS. Additionally, the cross-basin seismic profile clearly shows that recent deformation has primarily been along an eastward dipping normal fault that bounds the basement high to the east. This suggests that both spatial and temporal characteristics of deformation control <span class="hlt">hydrothermal</span> activity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8179M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8179M"><span>Multifractal spatial organisation in <span class="hlt">hydrothermal</span> gold <span class="hlt">systems</span> of the Archaean Yilgarn craton, Western Australia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Munro, Mark; Ord, Alison; Hobbs, Bruce</p> <p>2015-04-01</p> <p>A range of factors controls the location of <span class="hlt">hydrothermal</span> alteration and gold mineralisation in the Earth's crust. These include the broad-scale lithospheric architecture, availability of fluid sources, fluid composition and pH, pressure-temperature conditions, microscopic to macroscopic structural development, the distribution of primary lithologies, and the extent of fluid-rock interactions. Consequently, the spatial distribution of alteration and mineralization in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is complex and often considered highly irregular. However, despite this, do they organize themselves in a configuration that can be documented and quantified? Wavelets, mathematical functions representing wave-like oscillations, are commonly used in digital signals analysis. Wavelet-based multifractal analysis involves incrementally scanning a wavelet across the dataset multiple times (varying its scale) and recording its degree of fit to the signal at each interval. This approach (the wavelet transform modulus maxima method) highlights patterns of self-similarity present in the dataset and addresses the range of scales over which these patterns replicate themselves (expressed by their range in 'fractal dimension'). Focusing on seven gold ore bodies in the Archaean Yilgarn craton of Western Australia, this study investigates whether different aspects of <span class="hlt">hydrothermal</span> gold <span class="hlt">systems</span> evolve to organize themselves spatially as multifractals. Four ore bodies were selected from the Sunrise Dam deposit (situated in the Laverton tectonic zone of the Kurnalpi terrane) in addition to the Imperial, Majestic and Salt Creek gold prospects, situated in the Yindarlgooda dome of the Mount Monger goldfield (approximately 40km due east of Kalgoorlie). The Vogue, GQ, Cosmo East and Astro ore bodies at Sunrise Dam were chosen because they exhibit different structural geometries and relationships between gold and associated host-rock alteration styles. Wavelet-based analysis was conducted on 0.5m and 1m</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LPICo1912.2083J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LPICo1912.2083J"><span>Organic Biomarker Preservation in Silica-Rich <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> with Implications to Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jahnke, L. L.; Parenteau, M. N.; Farmer, J. D.</p> <p>2016-05-01</p> <p>Microbial community structure and preservation of organic matter in siliceous <span class="hlt">hydrothermal</span> environments is a critical issue given the discovery of <span class="hlt">hydrothermal</span> vents and silica on Mars. Here we discuss preservation of cyanobacterial biomarker lipid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1305G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1305G"><span>Dual-scale <span class="hlt">hydrothermal</span> circulation inferred from detailed heat flow measurements in the Suiyo Seamount <span class="hlt">Hydrothermal</span> <span class="hlt">System</span>, Izu-Bonin Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomado, M.; Kinoshita, M.</p> <p>2002-12-01</p> <p><span class="hlt">Hydrothermal</span> activity within the caldera of Suiyo Seamount was investigated in detail using manned or remotely-operated submersibles, and by deep-tow imagery and seismic surveys. <span class="hlt">Hydrothermal</span> regime in the Suiyo-seamount is characterized by a geochemically uniform fluid, shallow reservoir depth, very permeable seafloor, and venting without creating big chimneys. Detailed heat flow surveys were carried out through four research cruises conducted in 2001-2002. Geothermal probes, called SAHF (Stand-Alone Heat Flow) meter, are 1m in length, and five thermistors are installed at 11-12 cm intervals. Heat flow is highest (> 10 W/m2) within the active area. These values were obtained close to black smokers, thus are affected by the venting or very shallow reservoirs. To the east, heat flow is uniform around 4 W/m2. Since there were no indications of discharge, this area is dominated by thermal conduction, and its heat source would be a <span class="hlt">hydrothermal</span> reservoir capped by some impermeable layer. To the west, we detected very low heat flow values of less than 0.3 W/m2, only several tens of meters away from the active area. A similar heat flow anomaly was detected in the TAG hyudrothermal mound of the Mid-Atlantic Ridge (Becker et al., 1996). We penetrated at 1-2 m away from two isolated active sulfide mounds. At both sites subbottom temperatures were about 40 degC at 10-20 cm depth, then they decreased to about 20 degC at 30-40cm. The temperature reversals suggest a meter-scale <span class="hlt">hydrothermal</span> circulation, where a hot fluid discharges as a branch flow from the main vent to the mound. An impermeable structure of the mound and a permeable sediment surrounding the mound would make this very local circulation possible. We suggest a dual scale <span class="hlt">hydrothermal</span> circulation <span class="hlt">system</span>, one with several meters scale, and the other with few tens of meters scale. The former would be driven by a suction created by discrete venting of high temperature fluid, and the latter is a regional</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H13G1444W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H13G1444W"><span>Implications of Chloride, Boron, and Lithium in <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> of Jamaica, WI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wishart, D.</p> <p>2012-12-01</p> <p>Chloride (Cl) often termed a "relatively conservative element" served as a very useful tracer (pathfinder element) in fluids from <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> by comparing its concentration to those of select ions in solution. The concentrations of major ions of three thermal spring water samples: Bath hot springs (BTHS and BTHN), Milk River (MKR), Windsor (WS) and a cold spring water sample-Salt River spring (SR) of Jamaica were plotted against the Cl concentration. Results of chemical analyses, graphical analyses, and hydrogeochemical modeling confirmed three water types: Na-Cl-SO4, Na-Cl, and Ca-Na-Cl. Whereas chloride concentrations at MKR, WS and SR strongly indicate the influence of sea water mixing, the concentrations at MKR and SR are spatially related to a major tectonic feature, the South Coast Fault Zone (SCFZ). A principal component analysis (PCA) performed for the water samples showed a direct correlation between the concentrations of chloride and other conservative elements: boron (B), lithium (Li), bromide (Br), strontium (Sr), arsenic (As), and cesium (Cs). Isotope results (δ18O, δ2H, 3H) of the water samples implied minimal shallow mixing with deep circulating thermal fluids at the Bath site and the predominance of mixing with deep-circulating brines at the WS, MKR, and SR sites. Ionic ratios (Cl/B, Br/Cl, Li/B, have provided further interesting results for these <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> including (1) a power series relationship between Li/B and SO4/Cl ratios; (2) the variation of B/Li versus Cl/SO4 concentrations with relatively prolonged water-rock contact time for these waters occurring at depth; and (3) low enthalpy. A discriminant analysis (DA) aided in the delineation of three independent <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> based on processes affecting the chemical compositions of the water samples. Calculated chloride convective heat fluxes range between compared to the boron flux range of 3.41 x 104 - 1.63 x 106 Calories/second.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993JVGR...56..401K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JVGR...56..401K"><span>Relations of ammonium minerals at several <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western U.S.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krohn, M. Dennis; Kendall, Carol; Evans, John R.; Fries, Terry L.</p> <p>1993-08-01</p> <p>Ammonium bound to silicate and sulfate minerals has recently been located at several major <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH 4 + by K + or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14‰ range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017337','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017337"><span>Relations of ammonium minerals at several <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western U.S.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Krohn, M.D.; Kendall, C.; Evans, J.R.; Fries, T.L.</p> <p>1993-01-01</p> <p>Ammonium bound to silicate and sulfate minerals has recently been located at several major <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH4+ by K+ or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14??? range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles. ?? 1993.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS41A0443C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS41A0443C"><span>Exploring the Oceans for New <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span>: Collecting Stamps in the New Millenium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Collier, R.; Lilley, M.; Cowen, J.</p> <p>2001-12-01</p> <p>Only a few years after helping to sample and characterize the first seafloor <span class="hlt">hydrothermal</span> vents, John Edmond frequently characterized continued vent exploration as "stamp collecting". But in fact, John was an avid explorer who helped expose the workings of the hydrosphere through observation. John showed us through his actions (if not always his words) that exploration, built on a strong scientific foundation, could lead to remarkable insights. The quest for new <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> still continues, often beginning with the characterization of <span class="hlt">hydrothermal</span> plumes in the water column. Although many of the tools and techniques are relatively well developed, the justification for this research and the modes of deployment have changed significantly. This presentation will summarize recent explorations of the Central Indian Ridge and southern East Pacific Rise, showing both the success of the primary goal -- to find new vents -- as well as the added value derived from the study of the <span class="hlt">hydrothermal</span> plumes themselves. In April, 2001, a study using the ROV Jason, deployed from the R/V Knorr (162-12), located and sampled new vent fields on the Central Indian Ridge (Van Dover et al., Science, 14 Sept., 2001). The primary goal of the expedition was to locate and characterize the vent communities as they may represent a unique connection between Atlantic and Pacific communities. The ship sailed with an interdisciplinary team ready to locate the vents and sample the biological community as well as their geological and geochemical environment within a single expedition. A series of nested CTD-transmissometer surveys, coupled with current measurements and chemical analyses for Fe, Mn, CH4, and H2 identified unequivocal <span class="hlt">hydrothermal</span> plumes and led to the discovery of a new vent field, named for John Edmond two weeks after he passed away in Boston. The combined application of physical, optical, and chemical properties allowed us to rapidly locate the vent within one hour of ROV</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGP13A1284D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGP13A1284D"><span><span class="hlt">Hydrothermal</span> <span class="hlt">System</span> of the Lastarria Volcano (Central Andes) Imaged by Magnetotellurics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diaz, D.</p> <p>2015-12-01</p> <p>Lazufre volcanic complex, located in the central Andes, is recently undergoing an episode of uplift, conforming one of the most extensive deforming volcanic <span class="hlt">systems</span> worldwide. Recent works have focused on the subsurface of this volcanic <span class="hlt">system</span> at different scales, using surface deformation data, seismic noise tomography and magnetotellurics. Here we image the electrical resistivity structure of the Lastarria volcano, one of the most important features in the Lazufre area, using broadband magnetotelluric data at 30 locations around the volcanic edifice. Results from 3-D modeling show a conductive zone at 6 km depth south of the Lastarria volcano interpreted as a magmatic heat source, which is connected to a shallower conductive area beneath the volcanic edifice and its close vicinity. This shallow highly conductive zone fits with geochemical analysis results of thermal fluid discharges, related to fumaroles present in this area, in terms of depth extent and possible temperatures of fluids, and presents also a good correlation with seismic tomography results. The horizontal extension of this shallow conductive zone, related to the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> of Lastarria, suggests that it has been draining one of the lagoons in the area (Laguna Azufrera), forming a sulfur rich area which can be observed at the southern side of this lagoon. Joint modeling of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> using magnetotellurics and seismic data is part of the current work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V53E2881U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V53E2881U"><span>Volcanic Seismicity of La Soufrière Volcano (Guadeloupe, FWI): Interaction with <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ucciani, G.; Nercessian, A.; Bouin, M.; Beauducel, F.</p> <p>2012-12-01</p> <p>Our goal of this study is to characterize, spatially and temporally the seismicity of the La Soufrière volcano (Guadeloupe, FWI) and investigate the relationship between this seismicity andthe dynamics of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. We examine a set of 1777 volcanic earthquakes recorded by the permanent seismological monitoring network operated by the Volcanic and Seismological Observatory of Guadeloupe (OVSG-IPGP). This seismicity appears to be generated in a volume located at shallow depths under the volcano (maximum depth is 4km). The Observatory has classified volcanic earthquakes in three large groups: Volcano Tectonic events [VA] (760 events), Nested Volcanic events [VE] (922 events) and Monochromatic Volcanic events [VM] (140 events). We investigate the waveform similarity between earthquakes belonging to the same group by cross-correlation of the P phases. Results show a low similarity rate among earthquakes of the same groupe demonstrating that a refined classification is needed, which is in good agreement with a seismicity generated in a fractured medium by overpressure in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. For VA and VE group, we use the similarity rates to distribute all events in different clusters by adjusting the selection threshold. With this method we show that both VA and VE events are present in all the clusters , and we conclude that similar seismic sources may generate this two types of events. For VM earthquakes, we observed different coda lengths and spectral features. To identify different clusters, we analyze these events with autoregressive method to determine resonance frequencies and factor Q. Based on results, we can infer that seismic events at La Soufrière volcano are related to two different source mechanisms: (1) fracturation processes of rocks and (2) resonance of cracks or conduits filled with <span class="hlt">hydrothermal</span> fluid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JVGR..138..139F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JVGR..138..139F"><span>Miocene fossil <span class="hlt">hydrothermal</span> <span class="hlt">system</span> associated with a volcanic complex in the Andes of central Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fuentes, Francisco; Aguirre, Luis; Vergara, Mario; Valdebenito, Leticia; Fonseca, Eugenia</p> <p>2004-11-01</p> <p>Cenozoic deposits in the Andes of central Chile have been affected by very low-grade burial metamorphism. At about 33°S in the Cuesta de Chacabuco area, approximately 53 km north of Santiago, two Oligocene and Miocene volcanic units form a ca. 1300-m-thick rock pile. The Miocene unit corresponds to a volcanic complex composed of two eroded stratovolcanoes. Secondary mineral assemblages in both units were studied petrographically and using X-ray diffraction and electron microprobe analyses. Most of the igneous minerals are wholly or partially preserved, and the ubiquitous secondary minerals are zeolites and mafic phyllosilicates. The alteration pattern observed is characterized by a lateral zonation in secondary mineralogy related to a lateral increase in temperature but not to stratigraphic depth. The following three zones were established, mainly based on the distribution of zeolites: zone I comprises heulandite, thomsonite, mesolite, stilbite and tri-smectite; zone II contains laumontite, yugawaralite, prehnite, epidote and chlorite; and zone III comprises wairakite, epidote, chlorite, diopside, biotite and titanite. For each zone, the following temperature ranges were estimated: zone I, 100-180 °C; zone II, 180-270 °C; and zone III, 245-310 °C. The alteration episode was characterized by a high Pfluid/ Ptotal ratio (ca. 1.0), although slightly variable, a high geothermal gradient of ca. 160 °C km -1 and fluid pressures below 500 bars. Although temperature was the main control on the mineral zonation, several interrelated parameters, mainly fluid composition, porosity and permeability, were also important. Hot, near neutral to slightly alkaline pH, alkali chloride <span class="hlt">hydrothermal</span> fluids with very low dissolved CO 2 contents deposited the secondary minerals. The alteration pattern is the result of depositing fluids in outflow regions from a <span class="hlt">hydrothermal</span> <span class="hlt">system</span> developed inside a volcanic complex during the Miocene. The <span class="hlt">hydrothermal</span> <span class="hlt">system</span> has been eroded to a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1978/1003/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1978/1003/report.pdf"><span>Methodology of determining the uncertainty in the accessible geothermal resource base of identified <span class="hlt">hydrothermal</span> convection <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nathenson, Manuel</p> <p>1978-01-01</p> <p>In order to quantify the uncertainty of estimates of the geothermal resource base in identified <span class="hlt">hydrothermal</span> convection <span class="hlt">systems</span>, a methodology is presented for combining estimates with uncertainties for temperature, area, and thickness of a geothermal reservoir into an estimate of the stored energy with uncertainty. Probability density functions for temperature, area, and thickness are assumed to be triangular in form. In order to calculate the probability distribution function for the stored energy in a single <span class="hlt">system</span> or in many <span class="hlt">systems</span>, a computer program for aggregating the input distribution functions using the Monte-Carlo method has been developed. To calculate the probability distribution of stored energy in a single <span class="hlt">system</span>, an analytical expression is also obtained that is useful for calibrating the Monte Carlo approximation. For the probability distributions of stored energy in a single and in many <span class="hlt">systems</span>, the central limit approximation is shown to give results ranging from good to poor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70030295','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70030295"><span>Tertiary tilting and dismemberment of the laramide arc and related <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>, Sierrita Mountain, Arizona</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stavast, W.J.A.; Butler, R.P.; Seedorff, E.; Barton, M.D.; Ferguson, C.A.</p> <p>2008-01-01</p> <p>Multiple lines of evidence, including new and published geologic mapping and paleomagnetic and geobarometric determinations, demonstrate that the rocks and large porphyry copper <span class="hlt">systems</span> of the Sierrita Mountains in southern Arizona were dismembered and tilted 50?? to 60?? to the south by Tertiary normal faulting. Repetition of geologic features and geobarometry indicate that the area is segmented into at least three major structural blocks, and the present surface corresponds to oblique sections through the Laramide plutonic-<span class="hlt">hydrothermal</span> complex, ranging in paleodepth from ???1 to ???12 km. These results add to an evolving view of a north-south extensional domain at high angles to much extension in the southern Basin and Range, contrast with earlier interpretations that the Laramide <span class="hlt">systems</span> are largely upright and dismembered by thrust faults, highlight the necessity of restoring Tertiary rotations before interpreting Laramide structural and <span class="hlt">hydrothermal</span> features, and add to the broader understanding of pluton emplacement and evolution of porphyry copper <span class="hlt">systems</span>. ?? 2008 Society of Economic Geologists, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21747174','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21747174"><span>Development of micro-flow <span class="hlt">hydrothermal</span> monitoring <span class="hlt">systems</span> and their applications to the origin of life study on Earth.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kawamura, Kunio</p> <p>2011-01-01</p> <p>Continuous extensive studies on thermophilic organisms have suggested that life emerged on <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> on primitive Earth. Thus, it is well known that <span class="hlt">hydrothermal</span> reactions are, therefore, very important to study fields deeply related to the origin-of-life study. Furthermore, the importance of <span class="hlt">hydrothermal</span> and solvothermal <span class="hlt">systems</span> is now realized in both fundamental and practical areas. Here, our recent investigations are described for the development of real-time and in situ monitoring <span class="hlt">systems</span> for <span class="hlt">hydrothermal</span> reactions. The <span class="hlt">systems</span> were primarily developed for the origin-of-life study, but it was also applicable to fundamental and practical areas. The present techniques are based on the concept that a sample solution is injected to a narrow tubing flow reactor at high temperatures, where the sample is rapidly heated up in a very short time by exposure at to a high-temperature narrow tubing flow reactor with a very short time scale. This enables millisecond to second time-scale monitoring in real time and/or in situ at temperatures of up to 400°C. By using these techniques, a series of studies on the <span class="hlt">hydrothermal</span> origin-of-life have been successfully carried out.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B11J0571L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B11J0571L"><span>Insight from Genomics on Biogeochemical Cycles in a Shallow-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, G. S.; Amend, J.</p> <p>2015-12-01</p> <p>Shallow-sea <span class="hlt">hydrothermal</span> ecosystems are dynamic, high-energy <span class="hlt">systems</span> influenced by sunlight and geothermal activity. They provide accessible opportunities for investigating thermophilic microbial biogeochemical cycles. In this study, we report biogeochemical data from a shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span> offshore Paleochori Bay, Milos, Greece, which is characterized by a central vent covered by white microbial mats with <span class="hlt">hydrothermally</span> influenced sediments extending into nearby sea grass area. Geochemical analysis and deep sequencing provide high-resolution information on the geochemical patterns, microbial diversity and metabolic potential in a two-meter transect. The venting fluid is elevated in temperature (~70oC), low in pH (~4), and enriched in reduced species. The geochemical pattern shows that the profile is affected by not only seawater dilution but also microbial regulation. The microbial community in the deepest section of vent core (10-12 cm) is largely dominated by thermophilic archaea, including a methanogen and a recently described Crenarcheon. Mid-core (6-8 cm), the microbial community in the venting area switches to the hydrogen utilizer Aquificae. Near the sediment-water interface, anaerobic Firmicutes and Actinobacteria dominate, both of which are commonly associated with subsurface and <span class="hlt">hydrothermal</span> sites. All other samples are dominated by diverse Proteobacteria. The sulfate profile is strongly correlated with the population size of delta- and episilon-proteobactia. The dramatic decrease in concentrations of As and Mn in pore fluids as a function of distance from the vent suggests that in addition to seawater dilution, microorganisms are likely transforming these and other ions through a combination of detoxification and catabolism. In addition, high concentrations of dissolved Fe are only measurable in the shallow sea grass area, suggesting that iron-transforming microorganisms are controlling Fe mobility, and promoting biomineralization. Taken</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812544B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812544B"><span>Resistivity structure of the Furnas <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (Azores archipelago, Portugal) from AMT and ERT imaging.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrdina, Svetlana; Vandemeulebrouck, Jean; Rath, Volker; Silva, Catarina; Hogg, Colin; Kiyan, Duygu; Viveiros, Fatima; Eleuterio, Joana; Gresse, Marceau</p> <p>2016-04-01</p> <p>The Furnas volcanic complex is located in the eastern part of the São Miguel Island and comprises a 5 km × 8 km summit depression filled by two nested calderas with several craters and a lake. Present-day volcanic activity of Furnas volcano is mostly located in the northern part of the caldera, within the Furnas village and north to Furnas Lake, where <span class="hlt">hydrothermal</span> manifestations are mainly fumarolic fields, steam vents, thermal springs, and intense soil diffuse degassing. Considering the Furnas volcano as a whole, the total integrated CO2 efflux is extremely high, with a total amount of CO2 close to 1000 ton per day (Viveiros et al., 2009). We present the first results of an electrical resistivity tomography (ERT), combined with audio-magneto-telluric (AMT) measurements aligned along two profiles inside the caldera. The purpose of this survey is to delimit the extent, the geometry, and the depth of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> and to correlate the deep resistivity structure with high resolution cartography of diffuse CO2 flux (Viveiros et al, 2015). The ERT and AMT methods are complementary in terms of resolution and penetration depth: ERT can image the structural details of shallow <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (down to 100 m in our study) while AMT can image at lower resolution deeper structures at the roots of a volcano (down to 4 km in our study). Our first independent 2D inversions of the ERT-AMT data show a good agreement between the surficial and deeper features. Below the main fumarole area we observe a low resistivity body (less than 1 Ohmm) which corresponds well to the high CO2 flux at the surface and is associated with an extended conductive body at larger depth. These results strongly suggest the presence of <span class="hlt">hydrothermal</span> waters at depth or/and the presence of altered clay-rich material. On a larger scale however, the geometry of the conducting zones differs slightly from what was expected from earlier surface studies, and may not be directly related to fault zones</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/355671','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/355671"><span>Yttrium and rare earth elements in fluids from various deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Douville, E. |; Appriou, P.; Bienvenu, P.; Charlou, J.L.; Donval, J.P.; Fouquet, Y.; Gamo, Toshitaka</p> <p>1999-03-01</p> <p>Rare earth element (REE) and yttrium (Y) concentrations were measured in fluids collected from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> including the Mid-Atlantic Ridge (MAR), i.e., Menez Gwen, Lucky Strike, TAG, and Snakepit; the East Pacific Rise (EPR), i.e., 13{degree}N and 17--19{degree}S; and the Lau (Vai Lili) and Manus (Vienna Woods, PacManus, Desmos) Back-arc Basins (BAB) in the South-West Pacific. In most fluids, Y is trivalent and behaves like Ho. Chondrite normalized Y-REE (Y-REE{sub N}) concentrations of fluids from MAR, EPR, and two BAB sites, i.e., Vai Lili and Vienna Woods, showed common patterns with LREE enrichment and positive Eu anomalies. REE analysis of plagioclase collected at Lucky Strike strengthens the idea that fluid REE contents, are controlled by plagioclase phenocrysts. Other processes, however, such as REE complexation by ligands (Cl{sup {minus}}, F{sup {minus}}, So{sub 4}{sup 2{minus}}), secondary phase precipitation, and phase separation modify REE distributions in deep-sea <span class="hlt">hydrothermal</span> fluids. REE speciation calculations suggest that aqueous REE are mainly complexed by Cl{sup {minus}} ions in hot acidic fluids from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. REE concentrations in the fluid phases are, therefore, influenced by temperature, pH, and duration of rock-fluid interaction. Unusual Y-REE{sub N} patterns found in the PacManus fluids are characterized by depleted LREE and a positive Eu anomaly. The Demos fluid sample shows a flat Y-REE{sub N} pattern, which increases regularly from LREE to HREE with no Eu anomaly. These Manus Basin fluids also have an unusual major element chemistry with relatively high Mg, So{sub 4}, H{sub 2}S, and F contents, which may be due to the incorporation of magmatic fluids into heated seawater during <span class="hlt">hydrothermal</span> circulation. REE distribution in PacManus fluids may stem from a subseafloor barite precipitation and the REE in Demos fluids are likely influenced by the presence of sulfate ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-S111E5026.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-S111E5026.html"><span>Bursch poses next to BPS installed in a slot on <span class="hlt">Endeavour</span>'s middeck for return on STS-111 UF-2</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2002-06-07</p> <p>STS111-E-5026 (7 June 2002) --- Astronaut Daniel W. Bursch, who has been aboard the International Space Station (ISS) for the past six months, wastes little time in going to work on board the Space Shuttle <span class="hlt">Endeavour</span> following linkup of the shuttle and station on June 7, 2002. Bursch, who will return home aboard <span class="hlt">Endeavour</span> in a few days, is pictured at the Biomass Production <span class="hlt">System</span> (BPS) on <span class="hlt">Endeavour</span>'s mid deck.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6026682','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6026682"><span>The boron isotope systematics of the Yellowstone National Park (Wyoming) <span class="hlt">hydrothermal</span> <span class="hlt">system</span>: A reconnaissance</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Palmer, M.R. ); Sturchio, N.C. )</p> <p>1990-10-01</p> <p>Boron concentrations and isotope compositions have been measured in fourteen hot spring waters, two drill hole waters, an unaltered rhyolite flow, and <span class="hlt">hydrothermally</span> altered rhyolite from the geothermal <span class="hlt">system</span> in Yellowstone National Park, Wyoming. The samples are representative of the major thermal areas within the park and span the range of fluid types. For the fluids, the B concentrations range from 0.043-2.69 mM/kg, and the {delta}{sup 11}B values range from {minus}9.3 to +4.4{per thousand}. There is no relationship between the dissolved B concentrations or isotope compositions with the concentration of any major element (other than Cl) or physical property. Each basin is characterized by a restricted range in B/Cl ratios and {delta}{sup 11}B values. Hot spring waters from the Norris Basin, Upper Geyser Basin, Calcite Springs, and Clearwater have {delta}{sup 11}B values close to that of unaltered rhyolite ({minus}5.2{per thousand}) and are interpreted to have derived their B from this source. Waters from Mammoth Hot Springs, Sheepeater, and Rainbow Springs have lower {delta}{sup 11}B values close to {minus}8{per thousand}. These lower values may reflect leaching of B from sedimentary rocks outside the Yellowstone caldera, but they are similar to the {delta}{sup 11}B value of <span class="hlt">hydrothermally</span> altered rhyolite ({minus}9.7{per thousand}). Hence, the light boron isotope compositions recorded in these hot spring waters may reflect leaching of previously deposited <span class="hlt">hydrothermal</span> minerals. Cooler springs along the Yellowstone River just outside the park boundary have lower B concentrations and higher {delta}{sup 11}B values that may reflect mixing with shallow meteoric water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990GeCoA..54.2811P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990GeCoA..54.2811P"><span>The boron isotope systematics of the Yellowstone National Park (Wyoming) <span class="hlt">hydrothermal</span> <span class="hlt">system</span>: A reconnaissance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Palmer, M. R.; Sturchio, N. C.</p> <p>1990-10-01</p> <p>Boron concentrations and isotope compositions have been measured in fourteen hot spring waters, two drill hole waters, an unaltered rhyolite flow, and <span class="hlt">hydrothermally</span> altered rhyolite from the geothermal <span class="hlt">system</span> in Yellowstone National Park, Wyoming. The samples are representative of the major thermal areas within the park and span the range of fluid types. For the fluids, the B concentrations range from 0.043-2.69 mM/kg, and the δ11B values range from -9.3 to +4.4%.. There is no relationship between the dissolved B concentrations or isotope compositions with the concentration of any major element (other than Cl) or physical property. Each basin is characterized by a restricted range in B/Cl ratios and δ11B values. Hot spring waters from the Morris Basin, Upper Geyser Basin, Calcite Springs, and Clearwater have δ11B values close to that of unaltered rhyolite (-5.2%.) and are interpreted to have derived their B from this source. Waters from Mammoth Hot Springs, Sheepeater, and Rainbow Springs have lower δ11B values close to -8%.. These lower values may reflect leaching of B from sedimentary rocks outside the Yellowstone caldera, but they are similar to the δ11B value of <span class="hlt">hydrothermally</span> altered rhyolite (-9.7%.). Hence, the light boron isotope compositions recorded in these hot spring waters may reflect leaching of previously deposited <span class="hlt">hydrothermal</span> minerals. Cooler springs along the Yellowstone River just outside the park boundary have lower B concentrations and higher δ11B values that may reflect mixing with shallow meteoric water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS059-05-007&hterms=red+shift&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dred%2Bshift','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS059-05-007&hterms=red+shift&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dred%2Bshift"><span>STS-59 red shift crew on <span class="hlt">Endeavour</span>'s middeck</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1994-01-01</p> <p>On <span class="hlt">Endeavour</span>'s middeck, the three sts-59 red shift crew members begin to organize what was believed to be among the longest mail messages in recent Shuttle history. With the picture held vertically, Astronaut Sidney M. Gutierrez, mission commander, is in upper right. Also seen are Astronauts Linda M. Godwin, payload commander, and Kevin P. Chilton, pilot. Though early Shuttle flights could brag of longer teleprinted messages, this Thermal Printing <span class="hlt">System</span>'s (TIPS) message from the ground competes with those of recent Shuttle flights.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1009306','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1009306"><span><span class="hlt">Hydrothermal</span> Processing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Elliott, Douglas C.</p> <p>2011-03-11</p> <p>This chapter is a contribution to a book on Thermochemical Conversion of Biomass being edited by Prof. Robert Brown of Iowa State University. It describes both <span class="hlt">hydrothermal</span> liquefaction and <span class="hlt">hydrothermal</span> gasification of biomass to fuels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23375572','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23375572"><span>Calibration of an acoustic <span class="hlt">system</span> for measuring 2-D temperature distribution around <span class="hlt">hydrothermal</span> vents.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fan, Wei; Chen, Chen-Tung Arthur; Chen, Ying</p> <p>2013-04-01</p> <p>One of the fundamental purposes of quantitative acoustic surveys of seafloor <span class="hlt">hydrothermal</span> vents is to measure their 2-D temperature distributions. Knowing the <span class="hlt">system</span> latencies and the acoustic center-to-center distances between the underwater transducers in an acoustic tomography <span class="hlt">system</span> is fundamental to the overall accuracy of the temperature reconstruction. However, commercial transducer sources typically do not supply the needed data. Here we present a novel calibration algorithm to automatically determine the <span class="hlt">system</span> latencies and the acoustic center-to-center distances. The possible <span class="hlt">system</span> latency error and the resulting temperature error are derived and analyzed. We have also developed the experimental setup for calibration. To validate the effectiveness of the proposed calibration method, an experimental study was performed on acoustic imaging of underwater temperature fields in Lake Qiezishan, located at Longling County, Yunnan Province, China. Using the calibrated data, the reconstructed temperature distributions closely resemble the actual distributions measured with thermocouples, thus confirming the effectiveness of our algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23093668','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23093668"><span>Early Solar <span class="hlt">System</span> <span class="hlt">hydrothermal</span> activity in chondritic asteroids on 1-10-year timescales.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dyl, Kathryn A; Bischoff, Addi; Ziegler, Karen; Young, Edward D; Wimmer, Karl; Bland, Phil A</p> <p>2012-11-06</p> <p>Chondritic meteorites are considered the most primitive remnants of planetesimals from the early Solar <span class="hlt">System</span>. As undifferentiated objects, they also display widespread evidence of water-rock interaction on the parent body. Understanding this history has implications for the formation of planetary bodies, the delivery of water to the inner Solar <span class="hlt">System</span>, and the formation of prebiotic molecules. The timescales of water-rock reactions in these early objects, however, are largely unknown. Here, we report evidence for short-lived water-rock reactions in the highly metamorphosed ordinary chondrite breccia Villalbeto de la Peña (L6). An exotic clast (d = 2cm) has coexisting variations in feldspar composition and oxygen isotope ratios that can only result from <span class="hlt">hydrothermal</span> conditions. The profiles were modeled at T = 800 °C and P(H(2)O) = 1 bar using modified grain-boundary diffusion parameters for oxygen self-diffusion and reaction rates of NaSiCa(-1)Al(-1) exchange in a fumarole. The geochemical data are consistent with <span class="hlt">hydrothermal</span> activity on the parent body lasting only 1-10 y. This result has wide-ranging implications for the geological history of chondritic asteroids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3494924','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3494924"><span>Early Solar <span class="hlt">System</span> <span class="hlt">hydrothermal</span> activity in chondritic asteroids on 1–10-year timescales</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dyl, Kathryn A.; Bischoff, Addi; Ziegler, Karen; Young, Edward D.; Wimmer, Karl; Bland, Phil A.</p> <p>2012-01-01</p> <p>Chondritic meteorites are considered the most primitive remnants of planetesimals from the early Solar <span class="hlt">System</span>. As undifferentiated objects, they also display widespread evidence of water–rock interaction on the parent body. Understanding this history has implications for the formation of planetary bodies, the delivery of water to the inner Solar <span class="hlt">System</span>, and the formation of prebiotic molecules. The timescales of water–rock reactions in these early objects, however, are largely unknown. Here, we report evidence for short-lived water–rock reactions in the highly metamorphosed ordinary chondrite breccia Villalbeto de la Peña (L6). An exotic clast (d = 2cm) has coexisting variations in feldspar composition and oxygen isotope ratios that can only result from <span class="hlt">hydrothermal</span> conditions. The profiles were modeled at T = 800 °C and P(H2O) = 1 bar using modified grain-boundary diffusion parameters for oxygen self-diffusion and reaction rates of NaSiCa-1Al-1 exchange in a fumarole. The geochemical data are consistent with <span class="hlt">hydrothermal</span> activity on the parent body lasting only 1–10 y. This result has wide-ranging implications for the geological history of chondritic asteroids. PMID:23093668</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Icar..226..487S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Icar..226..487S"><span>Alteration minerals in impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> - Exploring host rock variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwenzer, Susanne P.; Kring, David A.</p> <p>2013-09-01</p> <p>Impact-generated <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> have been previously linked to the alteration of Mars’ crust and the production of secondary mineral assemblages seen from orbit. The sensitivity of the resultant assemblages has not yet been evaluated as a function of precursor primary rock compositions. In this work, we use thermochemical modeling to explore the variety of minerals that could be produced by altering several known lithologies based on martian meteorite compositions. For a basaltic host rock lithology (Dhofar 378, Humphrey) the main alteration phases are feldspar, zeolite, pyroxene, chlorite, clay (nontronite, kaolinite), and hematite; for a lherzolithic host rock lithology (LEW 88516) the main alteration phases are amphibole, serpentine, chlorite, clay (nontronite, kaolinite), and hematite; and for an ultramafic host rock lithology (Chassigny) the main minerals are secondary olivine, serpentine, magnetite, quartz, and hematite. These assemblages and proportions of phases in each of those cases depend on W/R and temperature. Integrating geologic, hydrologic and alteration mineral evidence, we have developed a model to illustrate the distribution of alteration assemblages that occur in different levels of an impact structure. At the surface, hot, hydrous alteration affects the ejecta and melt sheet producing clay and chlorite. Deeper in the subsurface and depending on the permeability of the rock, a variety of minerals - smectite, chlorite, serpentine, amphiboles and hematite - are produced in a circulating <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. These modeled mineral distributions should assist with interpretation of orbital observations and help guide surface exploration by rovers and sample return assets.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JVGR..171..301P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JVGR..171..301P"><span>Evolution of the Vesuvius magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> before the 16 December 1631 eruption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Principe, Claudia; Marini, Luigi</p> <p>2008-04-01</p> <p>In a recently published manuscript [Guidoboni, E., Boschi, E., 2006. Vesuvius before the 1631 eruption, EOS, 87(40), 417 and 423]; [Guidoboni, E. (Ed.), 2006. Pirro Ligorio, Libro di diversi terremoti (1571), volume 28, codex Ja II 15, Archivio di Stato di Torino, Edizione Nazionale delle Opere di Pirro Ligorio, Roma, De Luca, 261 pp], Pirro Ligorio gives a detailed description of the phenomena occurring in the crater area of Vesuvius volcano, in 1570-1571 and previous years. Here, these phenomena are interpreted as the first clearly documented signals of unrest of this volcanic <span class="hlt">system</span> caused by the shallow emplacement of a magma batch and leading to the 1631 eruption. Our interpretation is mainly based on the present understanding of the fluid geochemistry of magmatic-<span class="hlt">hydrothermal</span> <span class="hlt">systems</span>. In this way, it is possible to conclude that: (i) incandescent rocks were present at the surface, with temperatures > 500 °C approximately and (ii) either a magmatic-dominated or a magmatic-<span class="hlt">hydrothermal</span>-type of conceptual geochemical model applies to Vesuvius in 1570-1571 and preceding years. The Ligorio's picture represents the first clear evidence that the magma involved in the 1631 eruption was present under the volcano more than sixty years before the eruption. Moreover, its emplacement produced a series of phenomena which were clearly observed although not understood at that time. A similar phenomenological pattern should be easily detected and correctly interpreted at present or in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33C2772M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33C2772M"><span>Changes in Vegetation Reflect Changes in the Mammoth Mountain and Long Valley Caldera <span class="hlt">Hydrothermal</span> <span class="hlt">System</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, F.; Diefenbach, A. K.; Evans, W.; Hurwitz, S.</p> <p>2013-12-01</p> <p>We examined aerial photographs of the area near Mammoth Lakes, CA taken from 1951 to the present, with the goal of determining if visible changes in vegetation might reflect changes in the upflow of gas or heat through the soil zone. Such changes could be related to magmatic intrusion, the development of geothermal resources, groundwater pumping, earthquakes, or to natural changes in the <span class="hlt">hydrothermal</span> flow <span class="hlt">system</span>. We examined the area near Horseshoe Lake at the southern base of Mammoth Mountain where diffuse emissions of carbon dioxide created extensive tree-kill in the 1990s. Analysis of photographs acquired in 1951 suggests that tree density in this area was lower than its surroundings at the time. Whether the low-density tree cover identified in the photographs indicates some lasting effects of a previous episode of tree mortality needs further investigation. We also examine possible effects of geothermal energy production at Casa Diablo that began operation in 1985 on vegetation along the western part of the resurgent dome of Long Valley Caldera. Previous studies have correlated tree-kill in this area with increased steam upflow from the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EP%26S...68..162T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EP%26S...68..162T"><span>Response of <span class="hlt">hydrothermal</span> <span class="hlt">system</span> to stress transients at Lassen Volcanic Center, California, inferred from seismic interferometry with ambient noise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taira, Taka'aki; Brenguier, Florent</p> <p>2016-10-01</p> <p>Time-lapse monitoring of seismic velocity at volcanic areas can provide unique insight into the property of <span class="hlt">hydrothermal</span> and magmatic fluids and their temporal variability. We established a quasi real-time velocity monitoring <span class="hlt">system</span> by using seismic interferometry with ambient noise to explore the temporal evolution of velocity in the Lassen Volcanic Center, Northern California. Our monitoring <span class="hlt">system</span> finds temporal variability of seismic velocity in response to stress changes imparted by an earthquake and by seasonal environmental changes. Dynamic stress changes from a magnitude 5.7 local earthquake induced a 0.1 % velocity reduction at a depth of about 1 km. The seismic velocity susceptibility defined as ratio of seismic velocity change to dynamic stress change is estimated to be about 0.006 MPa-1, which suggests the Lassen <span class="hlt">hydrothermal</span> <span class="hlt">system</span> is marked by high-pressurized <span class="hlt">hydrothermal</span> fluid. By combining geodetic measurements, our observation shows that the long-term seismic velocity fluctuation closely tracks snow-induced vertical deformation without time delay, which is most consistent with an hydrological load model (either elastic or poroelastic response) in which surface loading drives <span class="hlt">hydrothermal</span> fluid diffusion that leads to an increase of opening of cracks and subsequently reductions of seismic velocity. We infer that heated-<span class="hlt">hydrothermal</span> fluid in a vapor-dominated zone at a depth of 2-4 km range is responsible for the long-term variation in seismic velocity[Figure not available: see fulltext.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70016607','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70016607"><span><span class="hlt">Hydrothermal</span> ore-forming processes in the light of studies in rock- buffered <span class="hlt">systems</span>: II. Some general geologic applications</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hemley, J.J.; Hunt, J.P.</p> <p>1992-01-01</p> <p>The experimental metal solubilities for rock-buffered <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> provide important insights into the acquisition, transport, and deposition of metals in real <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> that produced base metal ore deposits. Water-rock reactions that determine pH, together with total chloride and changes in temperature and fluid pressure, play significant roles in controlling the solubility of metals and determining where metals are fixed to form ore deposits. Deposition of metals in <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> occurs where changes such as cooling, pH increase due to rock alteration, boiling, or fluid mixing cause the aqueous metal concentration to exceed saturation. Metal zoning results from deposition occurring at successive saturation surfaces. Zoning is not a reflection simply of relative solubility but of the manner of intersection of transport concentration paths with those surfaces. Saturation surfaces will tend to migrate outward and inward in prograde and retrograde time, respectively, controlled by either temperature or chemical variables. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13B0476L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13B0476L"><span>Microbial heterotrophy coupled to Fe-S-As cycling in a shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, G.; Amend, J.</p> <p>2013-12-01</p> <p>To date, there are only a few known heterotrophic arsenite oxidizers and arsenate reducers. They utilize organic compounds as their carbon source and/or as important electron donors in the transfer arsenic in high temperature environments. Arsenic in <span class="hlt">hydrothermal</span> vent <span class="hlt">systems</span> can be immobilized at low temperatures through (ad)sorption on iron oxide and other iron-bearing minerals. Interactions with sulfur species can also affect the redox state of arsenic species. A better understanding of microbially-catalyzed reactions involving carbon, arsenic, iron and sulfur would provide constraints on the mobility of arsenic in a wide variety of natural and engineered <span class="hlt">systems</span>. The aim of this study is to establish links between microbial distribution and in situ Fe-S-As cycling processes in a shallow-sea <span class="hlt">hydrothermal</span> vent <span class="hlt">system</span>. We investigated three shallow-sea <span class="hlt">hydrothermal</span> vents, Champagne Hot Spring (CHS), Soufriere Spring (SOU) and Portsmouth Spring (PM), located off the western coast of Dominica, Lesser Antilles. CHS and SOU are characterized by moderate temperatures (46oC and 55oC, respectively), and PM is substantially hotter (~90-111 oC). Two sediment cores (one close to and one far from the thermal source) were collected from CHS and from SOU. Porewaters in both background cores had low concentrations of arsenic (mostly As3+, to a lesser extent As5+, DMA, MMA) and ferrous iron. The arsenic concentrations (predominantly As3+) in the CHS high temperature core were 30-90 nM, tracking with dissolved iron. Similar to CHS, the arsenic concentration in the SOU high temperature core was dominated by As3+ and controlled by ferrous iron. However, the arsenic concentration at SOU is comparatively higher, up to 1.9 mM. At the hotter and deeper PM site, highly elevated arsenic levels (1-2.5 mM) were measured, values that are among the highest arsenic concentrations ever reported in a marine <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. Several autotrophic and heterotrophic media at two pHs (5.5 and 8</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V13C3161S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V13C3161S"><span>Sub-glacial Origin of the Hot Springs Bay Valley <span class="hlt">hydrothermal</span> <span class="hlt">System</span>, Akutan, Alaska</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stelling, P. L.; Tobin, B.; Knapp, P.</p> <p>2015-12-01</p> <p>Exploration for geothermal energy in Hot Springs Bay Valley (HSBV) on Akutan Island, Alaska, has revealed a rich <span class="hlt">hydrothermal</span> history, including what appears to be a stage of peak activity during a significant glacial period. Alteration mineralogy observed in 754 m of drill core recovered from the outflow zone is dominated by chlorite and includes minor smectite clays, a suite of zeolite species and several moderately high-temperature <span class="hlt">hydrothermal</span> minerals (epidote/clinozoisite, prehnite, adularia and wairakite). The latter minerals each have minimum formation temperatures exceeding 200 oC, and fluid inclusion results in related calcite crystals indicate temperatures of formation to be as high as 275 oC, some 100 oC hotter than the modern boiling point with depth (BPD) curve at that depth (>62 m). In order to maintain liquid temperatures this high, the pressure during mineralization must have been substantially greater (~680 bar), a pressure change equivalent to erosion of ~280 m of rock (ρ=2.5 g/cm3). Although glacial erosion rates are too low (0.034 mm/yr; Bekele et al., 2003) for this amount of erosion to occur in a single glaciation, glacial melting and ablation are substantially more rapid (~100 mm/yr; Bekele et al., 2003; Person et al., 2012). Thus, a more probable scenario than pure erosion is that peak <span class="hlt">hydrothermal</span> conditions occurred during a large glacial event, with the added pressure from the overlying ice allowing the high temperature minerals to form closer to the ground surface. Subsequent melting of the ice eroded upper tributary valleys and upper levels of the originally smectite-rich alteration assemblage, explaining the paucity of swelling clays in the region. We present mineralogical, fluid inclusion and geochronologic evidence to support these conclusions, and discuss the general implications of sub-glacial <span class="hlt">hydrothermal</span> <span class="hlt">system</span> formation and geothermal resource potential. References: Bekele, E., Rostron, B. and Person, M. (2003) Fluid pressure</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008MinDe..43..623H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008MinDe..43..623H"><span>Oxygen isotope mapping of the Archean Sturgeon Lake caldera complex and VMS-related <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, Northwestern Ontario, Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holk, Gregory J.; Taylor, Bruce E.; Galley, Alan G.</p> <p>2008-08-01</p> <p>The <span class="hlt">hydrothermal</span> and magmatic evolution of the Sturgeon Lake caldera complex is graphically documented by a regional-scale (525 km2) analysis of oxygen isotopes. Spatial variations in whole-rock oxygen isotope compositions provide a thermal map of the cumulative effects of multiple stages of <span class="hlt">hydrothermal</span> metasomatism before, during, and after volcanogenic massive sulfide (VMS) mineralization. There is a progressive, upward increase in δ18O from less than 2‰ to greater than 15‰ through a 5-km-thick section above the Biedelman Bay subvolcanic intrusive complex. This isotopic trend makes it clear that at least the earlier phases of this intrusive complex were coeval with the overlying VMS-hosting cauldron succession and provided thermal energy to drive a convective <span class="hlt">hydrothermal</span> circulation <span class="hlt">system</span>. The sharp contrast in δ18O values between late stage phases of the Biedelman Bay intrusion and immediate hanging wall strata indicates that the main phase of VMS-related <span class="hlt">hydrothermal</span> activity took place before late-stage resurgence in the cauldron-related magmatic activity. Mineralogical and isotopic evidence indicates the presence of both syn- and postmineralization <span class="hlt">hydrothermal</span> activity defined by the presence of widespread semiconformable and more restricted discordant alteration zones that affect the pre- and syncauldron strata. The semiconformable alteration zones formed during early stages of <span class="hlt">hydrothermal</span> circulation and are defined by widespread silicification and carbonatization in association with relatively high δ18O values. The discordant alteration assemblages, containing Al-silicate minerals with chloritoid and/or Fe-rich carbonate or chlorite, centered on synvolcanic faults represent restricted zones of both seawater inflow and <span class="hlt">hydrothermal</span> fluid upflow. A rapid increase in δ18O values (˜7-9‰) over a short distance (<200 m) suggests marked cooling of <span class="hlt">hydrothermal</span> fluid from ˜350°C to less than 130°C either just before or during discharge onto the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JVGR..282...19D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JVGR..282...19D"><span>Evolution of a dynamic paleo-<span class="hlt">hydrothermal</span> <span class="hlt">system</span> at Mangatete, Taupo Volcanic Zone, New Zealand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drake, Bryan D.; Campbell, Kathleen A.; Rowland, Julie V.; Guido, Diego M.; Browne, Patrick R. L.; Rae, Andrew</p> <p>2014-08-01</p> <p>Recent quarrying and active faulting at Mangatete, Taupo Volcanic Zone (TVZ), New Zealand, illuminate a rare spatial and temporal window on a dynamic Late Quaternary geothermal <span class="hlt">system</span>. Detailed geological mapping, stratigraphic logging, AMS 14C dating, and textural and mineralogical analyses were used to construct a complex history of <span class="hlt">hydrothermal</span>, volcanological and tectonic activity from ~ 36 to 2 ka. Extinct, surface <span class="hlt">hydrothermal</span> manifestations occur over a ~ 2 km2 area, and include in situ siliceous sinters distributed on normal fault terraces, an inferred <span class="hlt">hydrothermal</span> eruption breccia (HEB) containing acid-etched sinter blocks, another probable HEB that was bathed in silicifying thermal fluids, and sinter clasts that were entrained in a debris flow associated with a volcanic ash event. Preserved sinter textures typical of near-neutral pH, alkali chloride spring discharge channels, aprons, terraces and affiliated marshes comprise plant-rich, palisade, tufted bubble mat, and domal stromatolitic fabrics. In addition, a packed fragmental sinter facies is shown herein to constitute silicified microbial mats that were broken, transported and deposited as point bar deposits in thermal spring-fed streams. Moreover, four unusual siliceous sinter fabrics-vuggy, globular spongy, scalloped, and arcuate wavy layered-are interpreted to have formed from local acid-sulfate-chloride thermal springs, possibly associated with paleo-fumaroles. The reconstructed history of paleo-<span class="hlt">hydrothermal</span> activity indicates that the oldest sinters (~ 36 ka) at Mangatete developed in alkali chloride hot springs, but then underwent post-depositional alterion/overprinting by acid-sulfate steam condensate and were dismembered, possibly by a <span class="hlt">hydrothermal</span> eruption. Low pH hot-spring discharges forming the unusual, inferred acid sinter fabrics were localized in the same area. A shift in paleo-hydrology is evidenced by unaltered, alkali chloride sinters dated between ~ 22 and 3 ka. A cluster of sinter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss003e8301.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss003e8301.html"><span>View of the docking approach of <span class="hlt">Endeavour</span> taken during Expedition Three</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2001-12-07</p> <p>ISS003-E-8301 (7 December 2001) --- The Space Shuttle <span class="hlt">Endeavour</span>, controlled by the flight crew of STS-108, is backdropped against the blackness of space over Earth's horizon as it approaches the International Space Station (ISS). The Raffaello logistics module that is being brought up to the orbiting outpost is clearly visible in <span class="hlt">Endeavour</span>'s cargo bay. The Space Station Remote Manipulator <span class="hlt">System</span> (SSRMS) or Canadarm2 is visible at lower right. Among other activities the <span class="hlt">Endeavour</span>'s mission will include the change out of the station crews. The image was recorded with a digital still camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-iss003e8303.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-iss003e8303.html"><span>View of the docking approach of <span class="hlt">Endeavour</span> taken during Expedition Three</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2001-12-07</p> <p>ISS003-E-8303 (7 December 2001) --- The Space Shuttle <span class="hlt">Endeavour</span>, controlled by the flight crew of STS-108, is backdropped against the blackness of space over Earth's horizon as it approaches the International Space Station (ISS). The Raffaello logistics module that is being brought up to the orbiting outpost is clearly visible in <span class="hlt">Endeavour</span>'s cargo bay. The Space Station Remote Manipulator <span class="hlt">System</span> (SSRMS) or Canadarm2 is visible at lower right. Among other activities the <span class="hlt">Endeavour</span>'s mission will include the change out of the station crews. The image was recorded with a digital still camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS21C1518K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS21C1518K"><span>Heat and chemical flux variability within the Main <span class="hlt">Endeavour</span> Field, Juan de Fuca Ridge, from 2000, 2004</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kellogg, J. P.; McDuff, R. E.; Hautala, S. L.; Stahr, F.</p> <p>2010-12-01</p> <p>The Main <span class="hlt">Endeavour</span> Field (MEF) has had a split personality since it was discovered. The southern half of the field is regularly observed to be hotter and fresher than the northern half. Differences lessened after the 1999 earthquake event, but the thermal and chemical gradient remains. We examine CTD and MAVS current meter data collected during surveys, designed to intersect the rising <span class="hlt">hydrothermal</span> plume, conducted with the Autonomous Benthic Explorer (ABE) in 2000 and 2004. By taking subsets of the data over known clusters of structures within the field, we attribute fractional contributions to the whole field heat and salt fluxes. Preliminary findings indicate that North MEF contributes ~90% and ~100% of the heat from MEF in 2000 and 2004 respectively. It is clear from this that the majority of the MEF buoyancy flux is from North MEF even though the source fluids from South MEF are estimated to be initially more buoyant than those from North MEF. Within North MEF, ~2/3 of the heat comes from the Grotto, Dante, Lobo sulfide cluster and ~1/4 from the Hulk and Crypto cluster. These data, for the intra-field spatial scales of heat and salt flux, may allow us to infer mechanisms capable of altering the porous network of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-9264290&hterms=japanese+women&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Djapanese%2Bwomen','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-9264290&hterms=japanese+women&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Djapanese%2Bwomen"><span>Space Shuttle Orbiter <span class="hlt">Endeavour</span> STS-47 Launch</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1992-01-01</p> <p>A smooth countdown culminated in a picture-perfect launch as the Space Shuttle Orbiter <span class="hlt">Endeavour</span> (STS-47) climbed skyward atop a ladder of billowing smoke on September 12, 1992. The primary payload for the plarned seven-day flight was the Spacelab-J science laboratory. The second flight of <span class="hlt">Endeavour</span> marks a number of historic firsts: the first space flight of an African-American woman, the first Japanese citizen to fly on a Space Shuttle, and the first married couple to fly in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts059-s-036.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts059-s-036.html"><span>Liftoff of STS-59 Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1994-04-09</p> <p>STS059-S-036 (9 April 1994) --- The liftoff of the Space Shuttle <span class="hlt">Endeavour</span> is backdropped against a dawn sky at the Kennedy Space Center (KSC) as six NASA astronauts head for a week and a half in Earth orbit. The morning sky allows for a contrasting backdrop for the diamond shock effect of the thrust from <span class="hlt">Endeavour</span>'s main engines. Liftoff occurred at 7:05 a.m. (EDT), April 9, 1994. Onboard for the Space Radar Laboratory (SRL-1) mission were astronauts Sidney M. Gutierrez, Kevin P. Chilton, Jerome (Jay) Apt, Linda M. Godwin, Michael R. U. (Rich) Clifford and Thomas D. Jones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5141380','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5141380"><span>Stochastic optimization of a <span class="hlt">hydro-thermal</span> <span class="hlt">system</span> including network constraints</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gorenstin, B.G.; Campdonico, N.M.; Costa, J.P.; Pereira, M.V.F. )</p> <p>1992-05-01</p> <p>This paper describes a methodology for the optimal scheduling of <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> taking into account multiple hydro reservoir characteristics, inflow stochasticity and transmission network represented by a linearized power flow model. The solution algorithm is based on stochastic dual dynamic programming, which decomposes the multi-stage stochastic problem into several one stage subproblems. Each subproblem corresponds to a linearized optimal power flow with additional constraints represented the hydro reservoir equations and a piecewise linear approximation of the expected future cost function. Each subproblem is solved by a customized network flow/Dual Simplex algorithm which takes advantage of the network characteristics of the hydro reservoirs and of the transmission <span class="hlt">system</span>. The application of the methodology is illustrated in a case study with a Brazilian <span class="hlt">system</span> comprising 44 hydroplants, 11 thermal plants, 463 buses and 834 circuits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5739009','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5739009"><span>Implementation of network flow programming to the <span class="hlt">hydrothermal</span> coordination in an energy management <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chaoan Li; Jap, P.J.; Streiffert, D.L. )</p> <p>1993-08-01</p> <p><span class="hlt">Hydrothermal</span> Coordination (HTC), consisting of hydro optimization and thermal unit commitment, is a major function in a power <span class="hlt">system</span> for allocating its generating resources to achieve the <span class="hlt">system</span>'s maximum economy. This paper is divided into two major parts. In the first part the optimality conditions of an Incremental Network Flow Programming (INFP) is described. In the second part the implementation of INFP in an EMS <span class="hlt">system</span> and its interface with the existing Unit Commitment (UC) software is presented. Some new features are described in detail. The combined HTC and UC package has been delivered to a power utility, Tenaga National Berhad (TNB) in West malaysia. ESCA's internal tests and Factory Acceptance Tests have shown that NFP with a modified Superkilter algorithm is a powerful tool for hydro network flow optimization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.1931Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.1931Y"><span>Bacterial community under the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> on the Suiyo Seamount: A model for archean and exo-biota</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamagishi, A.</p> <p></p> <p>Microbial community in <span class="hlt">hydrothermal</span> area at seafloor has been analyzed by culture-independent methods. <span class="hlt">Hydrothermal</span> fluid from natural vents and vent chimneys have been analyzed by PCR (1-2). Hyperthermophilic microbes have been isolated from these environments (3-4). Though the analysis of these samples can provide the window to penetrate the microbial community under the seafloor, more direct analysis is desired for better understanding of the sub-seafloor microbial community In the ``Archaean Park Project'' supported by Special Coordination Fund, several holes were drilled and the holes were supported by casing pipes in the crater of the Suiyo seamount on the Izu-Bonin arc, West Pacific Ocean (about 1,400 m depth) in 2001 and 2002. <span class="hlt">Hydrothermal</span> fluids were sampled from cased holes. The fluids were filtered to collect the microbial cells. The DNA was extracted and used to amplify 16S rDNA fragments by PCR (polymerase chain reaction) using a bacteria and an archaea specific primer sets. The PCR fragments were cloned and sequenced. FISH analysis revealed from 6 x103 to 2.5 x 106 bactrerial cells/ml in these <span class="hlt">hydrothermal</span> fluids. PCR clone-analysis showed significant variation in bacterial sequences found in these samples. The species-patterns suggest that the contamination of ambient seawater to <span class="hlt">hydrothermal</span> fluid samples is negligible. Difference in the dominant species depending on the location was found, suggesting that the bacterial community at sub-sea floor is not monotonous but has gradual shift from the <span class="hlt">hydrothermal</span> center to peripheral area. The results suggest that there is chemo-autotrophic microbe-dependent biota under the <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. References 1) Takai et al. Genetics 152: 1285-1297 (1999) 2) Takai et al. Appl. Environ. Microbioi. 67: 3618-3629 (2001) 3) Summit et al. Proc. Natl. Acad. Sci. 98: 2158-2163 (2001) 4) Amend, J. P. and Shodk, E. L. FEMS Microbiol. Rev. 25: 175-243 (2002)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0302390&hterms=MBS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMBS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0302390&hterms=MBS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMBS"><span>STS-111 Onboard Photo of <span class="hlt">Endeavour</span> Docking With PMA-2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>The STS-111 mission, the 14th Shuttle mission to visit the International Space Station (ISS), was launched on June 5, 2002 aboard the Space Shuttle Orbiter <span class="hlt">Endeavour</span>. On board were the STS-111 and Expedition Five crew members. Astronauts Kerneth D. Cockrell, commander; Paul S. Lockhart, pilot, and mission specialists Franklin R. Chang-Diaz and Philippe Perrin were the STS-111 crew members. Expedition Five crew members included Cosmonaut Valeri G. Korzun, commander, Astronaut Peggy A. Whitson and Cosmonaut Sergei Y. Treschev, flight engineers. Three space walks enabled the STS-111 crew to accomplish mission objectives: The delivery and installation of the Mobile Remote Servicer Base <span class="hlt">System</span> (MBS), an important part of the Station's Mobile Servicing <span class="hlt">System</span> that allows the robotic arm to travel the length of the Station, which is necessary for future construction tasks; the replacement of a wrist roll joint on the Station's robotic arm; and the task of unloading supplies and science experiments from the Leonardo multipurpose Logistics Module, which made its third trip to the orbital outpost. In this photograph, the Space Shuttle <span class="hlt">Endeavour</span>, back dropped by the blackness of space, is docked to the pressurized Mating Adapter (PMA-2) at the forward end of the Destiny Laboratory on the ISS. <span class="hlt">Endeavour</span>'s robotic arm is in full view as it is stretched out with the S0 (S-zero) Truss at its end.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0302391&hterms=MBS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMBS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0302391&hterms=MBS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMBS"><span>STS-111 Onboard Photo of <span class="hlt">Endeavour</span> Docking With PMA-2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>The STS-111 mission, the 14th Shuttle mission to visit the International Space Station (ISS), was launched on June 5, 2002 aboard the Space Shuttle Orbiter <span class="hlt">Endeavour</span>. On board were the STS-111 and Expedition Five crew members. Astronauts Kerneth D. Cockrell, commander; Paul S. Lockhart, pilot, and mission specialists Franklin R. Chang-Diaz and Philippe Perrin were the STS-111 crew members. Expedition Five crew members included Cosmonaut Valeri G. Korzun, commander, Astronaut Peggy A. Whitson and Cosmonaut Sergei Y. Treschev, flight engineers. Three space walks enabled the STS-111 crew to accomplish the delivery and installation of the Mobile Remote Servicer Base <span class="hlt">System</span> (MBS), an important part of the Station's Mobile Servicing <span class="hlt">System</span> that allows the robotic arm to travel the length of the Station, which is necessary for future construction tasks; the replacement of a wrist roll joint on the Station's robotic arm; and the task of unloading supplies and science experiments from the Leonardo multipurpose Logistics Module, which made its third trip to the orbital outpost. In this photograph, the Space Shuttle <span class="hlt">Endeavour</span>, back dropped by the blackness of space, is docked to the pressurized Mating Adapter (PMA-2) at the forward end of the Destiny Laboratory on the ISS. A portion of the Canadarm2 is visible on the right and <span class="hlt">Endeavour</span>'s robotic arm is in full view as it is stretched out with the S0 (S-zero) Truss at its end.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4960541','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4960541"><span>Volcano electrical tomography unveils edifice collapse hazard linked to <span class="hlt">hydrothermal</span> <span class="hlt">system</span> structure and dynamics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rosas-Carbajal, Marina; Komorowski, Jean-Christophe; Nicollin, Florence; Gibert, Dominique</p> <p>2016-01-01</p> <p>Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edifice often located above a low-strength detachment plane. The volume of altered rock available for collapse, the dynamics of the <span class="hlt">hydrothermal</span> fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. Here we derive a high-resolution, three-dimensional electrical conductivity model of the La Soufrière de Guadeloupe volcano from extensive electrical tomography data. We identify several highly conductive regions in the lava dome that are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. We interpret this model together with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> dynamics on the hazards associated to collapse-prone altered volcanic edifices. PMID:27457494</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JVGR..286..303P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JVGR..286..303P"><span>Debris flow evolution and the activation of an explosive <span class="hlt">hydrothermal</span> <span class="hlt">system</span>; Te Maari, Tongariro, New Zealand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Procter, J. N.; Cronin, S. J.; Zernack, A. V.; Lube, G.; Stewart, R. B.; Nemeth, K.; Keys, H.</p> <p>2014-10-01</p> <p>Analysis of the pre- and post-eruption topography, together with observations of the avalanche deposition sequence, yields a triggering mechanism for the 6 August 2012 eruption of Upper Te Maari. The avalanche was composed of a wedge of c. 683 000-774 000 m3 of coarse breccia, spatter and clay-rich tuffs and diamictons which slid from the western flanks of the Upper Te Maari Crater, the failure plane is considered to be a <span class="hlt">hydrothermally</span> altered clay layer. This landslide led to a pressure drop of up to 0.5 MPa, enough to generate an explosive eruption from the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> below, which had been activated over the months earlier by additional heat and gas from a shallow intrusion. The landslide transformed after c. 700 m into a clay-rich cohesive debris flow, eroding soils from steep, narrow stretches of channel, before depositing on intermediate broad flatter reaches. After each erosive reach, the debris flow contained greater clay and mud contents and became more mobile. At c. 2 km flow distance, however, the unsaturated flow stopped, due to a lack of excess pore pressure. This volume controlled flow deposited thick, steep sided lobes behind an outer levee, accreting inward and upward to form a series of curved surface ridges.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27457494','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27457494"><span>Volcano electrical tomography unveils edifice collapse hazard linked to <span class="hlt">hydrothermal</span> <span class="hlt">system</span> structure and dynamics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rosas-Carbajal, Marina; Komorowski, Jean-Christophe; Nicollin, Florence; Gibert, Dominique</p> <p>2016-07-26</p> <p>Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edifice often located above a low-strength detachment plane. The volume of altered rock available for collapse, the dynamics of the <span class="hlt">hydrothermal</span> fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. Here we derive a high-resolution, three-dimensional electrical conductivity model of the La Soufrière de Guadeloupe volcano from extensive electrical tomography data. We identify several highly conductive regions in the lava dome that are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. We interpret this model together with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> dynamics on the hazards associated to collapse-prone altered volcanic edifices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ResPh...2...66H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ResPh...2...66H"><span><span class="hlt">Hydrothermal</span> synthesis of Eu3+ doped yttria nanoparticles using a supercritical flow reaction <span class="hlt">system</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hayashi, Hiromichi</p> <p>2012-01-01</p> <p>Highly crystalline Eu3+ doped yttria nanoparticle was synthesized by <span class="hlt">hydrothermal</span> reaction in supercritical water using a continuous flow reaction <span class="hlt">system</span> (FHT). The reactants of Y(NO3)3/Eu(NO3)3 mixed solution and KOH solution were used as starting materials and that was heated quickly up to 350-450 °C under the pressure of 30 MPa for 0.1-15 s as reaction time. The XRD results revealed that the crystal phase of as-prepared particles was YOOH and converted into cubic-phase Y2O3 after annealing above 550 °C. Primarily particle size of the YOOH was as small as less than 50 nm, keeping after annealing at 800 °C. Effects of reaction time, annealing temperature and Eu doping amount on photoluminescence were examined. The as-prepared particles exhibited red emission without annealing at high temperatures whereas photoluminescent intensity at 612 nm was increased with an increase in the annealing temperature. Photoluminescent intensity was increased with an increase in the Eu doping amount until 4 mol % and saturated at 8 mol %. The photoluminescent property was compared with reference samples via conventional co-precipitation (CP) and batchwise <span class="hlt">hydrothermal</span> (BHT) methods. The photoluminescent intensity for annealed samples increased in the order: FHT < BHT < CP owing to the increased particle size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6319993','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6319993"><span>Deep borehole measurements for characterizing the magma/<span class="hlt">hydrothermal</span> <span class="hlt">system</span> at Long Valley Caldera, CA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Carrigan, C.R.</p> <p>1989-01-01</p> <p>The Magma Energy Program of the Geothermal Technology Division is scheduled to begin drilling a deep (6 km) exploration well in long Valley Caldera, California in 1989. The drilling site is near the center of the caldera which is associated with numerous shallow (5-7 km) geophysical anomalies. This deep well will present an unparalleled opportunity to test and validate geophysical techniques for locating magma as well as a test of the theory that magma is still present at drillable depths within the central portion of the caldera. If, indeed, drilling indicates magma, the geothermal community will then be afforded the unique possibility of examining the coupling between magmatic and <span class="hlt">hydrothermal</span> regimes in a major volcanic <span class="hlt">system</span>. Goals of planned seismic experiments that involve the well include the investigation of local crystal structure down to depths of 10 km as well as the determination of mechanisms for local seismicity and deformation. Borehole electrical and electromagnetic surveys will increase the volume and depth of rock investigated by the well through consideration of the conductive structure of the <span class="hlt">hydrothermal</span> and underlying regimes. 9 refs., 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.7791J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.7791J"><span>Geophysical observations at natural and exploited <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in West Java, Indonesia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jousset, Philippe; Sule, Rachmat; Diningrat, Wahyuddin; Gassner, Alexandra; Guichard, Sebastien; Kamil Syahbana, Devy; Abkar, Fanani; Ryannugroho, Riskiray; Hendryana, Andri; Kusnadi, Yosep; Nugraha, Andri; Umar, Muksin; Jaya, Makky; Erbas, Kemal</p> <p>2014-05-01</p> <p>We assess geothermal resources from our understanding of the structure and the dynamics of geothermal reservoirs and <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the south of Bandung. The co-existence of a large variety of intense surface manifestations like geysers, hot-steaming grounds, hot water pools, and active volcanoes suggest an intimate coupling between volcanic, tectonic and <span class="hlt">hydrothermal</span> processes in this area. We deployed a multidisciplinary geophysical network around geothermal areas in the south of Bandung, West Java, Indonesia. We deployed a network of 30 broadband and 4 short-period (1 Hz) seismic stations with Güralp and Trillium sensors (0.008 - 100 Hz) from October 2012 until December 2013. We extended the network in June 2013 with 16 short-period seismometers. Finally, we deployed a geodetic network including a continuously recording gravity meter, a GPS station, clinometers. We describe the set-up of the seismic and geodetic networks and we discuss first observations and results. As a first estimation of this excellent data set, we performed preliminary location of earthquakes using a non-linear algorithm, which allows us to define at least 3 seismic clusters. We use this first estimate to perform joint inversion tomography of hypocenters and velocity model. We discuss the found seismic pattern within the area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...629899R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...629899R"><span>Volcano electrical tomography unveils edifice collapse hazard linked to <span class="hlt">hydrothermal</span> <span class="hlt">system</span> structure and dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosas-Carbajal, Marina; Komorowski, Jean-Christophe; Nicollin, Florence; Gibert, Dominique</p> <p>2016-07-01</p> <p>Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edifice often located above a low-strength detachment plane. The volume of altered rock available for collapse, the dynamics of the <span class="hlt">hydrothermal</span> fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. Here we derive a high-resolution, three-dimensional electrical conductivity model of the La Soufrière de Guadeloupe volcano from extensive electrical tomography data. We identify several highly conductive regions in the lava dome that are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. We interpret this model together with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> dynamics on the hazards associated to collapse-prone altered volcanic edifices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6240083','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6240083"><span><span class="hlt">Hydrothermal</span> flow regime and magmatic heat source of the Cerro Prieto geothermal <span class="hlt">system</span>, Baja California, Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Elders, W.A.; Bird, D.K.; Schiffman, P.; Williams, A.E.</p> <p>1984-01-01</p> <p>This detailed three-dimensional model of the natural flow regime of the Cerro Prieto geothermal field, before steam production began, is based on patterns of <span class="hlt">hydrothermal</span> mineral zones and light stable isotopic ratios observed in rock samples from more than 50 deep wells, together with temperature gradients, wireline logs and other data. At the level so far penetrated by drilling, this <span class="hlt">hydrothermal</span> <span class="hlt">system</span> was heated by a thermal plume of water close to boiling, inclined at 45/sup 0/, rising from the northeast and discharging to the west. To the east a zone of cold water recharge overlies the inclined thermal plume. Fission track annealing studies show the reservoir reached 170/sup 0/C only 10/sup 4/ years ago. Oxygen isotope exchange data indicate that a 12 km/sup 3/ volume of rock subsequently reacted with three times its volume of water hotter than 200/sup 0/C. Averaged over the duration of the heating event this would require a flow velocity through a typical cross-section of the reservoir of about 6 m/year. The heat in storage in that part of the reservoir hotter than 200/sup 0/C and shallower than 3 km depth is equivalent to that which would be released by the cooling of about 1 or 2 km/sup 3/ of basalt or gabbro magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.7953P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.7953P"><span>Three-dimensional electrical resistivity model of the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in Long Valley Caldera, California, from magnetotellurics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peacock, J. R.; Mangan, M. T.; McPhee, D.; Wannamaker, P. E.</p> <p>2016-08-01</p> <p>Though shallow flow of <span class="hlt">hydrothermal</span> fluids in Long Valley Caldera, California, has been well studied, neither the <span class="hlt">hydrothermal</span> source reservoir nor heat source has been well characterized. Here a grid of magnetotelluric data were collected around the Long Valley volcanic <span class="hlt">system</span> and modeled in 3-D. The preferred electrical resistivity model suggests that the source reservoir is a narrow east-west elongated body 4 km below the west moat. The heat source could be a zone of 2-5% partial melt 8 km below Deer Mountain. Additionally, a collection of hypersaline fluids, not connected to the shallow <span class="hlt">hydrothermal</span> <span class="hlt">system</span>, is found 3 km below the medial graben, which could originate from a zone of 5-10% partial melt 8 km below the south moat. Below Mammoth Mountain is a 3 km thick isolated body containing fluids and gases originating from an 8 km deep zone of 5-10% basaltic partial melt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V52A..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V52A..01S"><span>Ultramafic-hosted <span class="hlt">Hydrothermal</span> <span class="hlt">Systems</span> at Mid-Ocean Ridges: Serpentinization, Chloritization and Geochemical Controls on Mass-Transfer Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seyfried, W. E.; Pester, N. J.; Ding, K.</p> <p>2012-12-01</p> <p>Recent studies of seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> associated with the slow spreading Mid-Atlantic Ridge have provided a wealth of information on the complex interplay between tectonic and magmatic processes that ultimately govern the chemical and physical evolution of these <span class="hlt">systems</span>. The Lost City <span class="hlt">hydrothermal</span> field (LCHF)(30°N) and the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">system</span> (36°N), for example, provide contrasting styles of heat and mass transfer that result in very different constraints on the composition of <span class="hlt">hydrothermal</span> fluids. <span class="hlt">Hydrothermal</span> fluids were sampled and analyzed during a series of ROV (Jason II) supported dives in 2008 to these and related vent sites along the northern MAR. In addition to deployment of conventional vent fluid sampling devices, in-situ chemical sensor <span class="hlt">systems</span> were also used to better constrain pH and redox reactions. The general characteristics of the Lost City <span class="hlt">hydrothermal</span> field, which is offset approximately 15km from the MAR owing to tectonic effects imposed by the emplacement of the Atlantis Massif, have been extensively reviewed in recent years. Vent fluids issuing from this peridotite-hosted <span class="hlt">system</span> reveal temperatures of approximately 90-100°C, high concentrations of dissolved hydrogen and methane, and pH measured (25°C) values that exceed 10. The relatively low vent fluid temperatures notwithstanding, phase equilibria constraints imposed by dissolved Ca and sulfate suggest temperatures of approximately 200°C at depth, below the seafloor. New data for dissolved silica indicate a <span class="hlt">hydrothermal</span> "root zone" lacking brucite, but where fluid chemistry and pH is buffered by serpentine-diopside-fluid equilibria. Consistent with previously published strontium and boron isotope measurements, data reported here for trace alkali elements (Cs, Rb, Li) indicate high fluid/rock mass ratios. Variably low dissolved Fe concentrations are broadly consistent with constraints imposed by magnetite-fluid equilibria at the high measured dissolved H2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033475','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033475"><span>Diffuse flow <span class="hlt">hydrothermal</span> manganese mineralization along the active Mariana and southern Izu-Bonin arc <span class="hlt">system</span>, western Pacific</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hein, J.R.; Schulz, M.S.; Dunham, R.E.; Stern, R.J.; Bloomer, S.H.</p> <p>2008-01-01</p> <p>Abundant ferromanganese oxides were collected along 1200 km of the active Izu-Bonin-Mariana arc <span class="hlt">system</span>. Chemical compositions and mineralogy show that samples were collected from two deposit types: Fe-Mn crusts of mixed hydrogenetic/<span class="hlt">hydrothermal</span> origin and <span class="hlt">hydrothermal</span> Mn oxide deposits; this paper addresses only the second type. Mn oxides cement volcaniclastic and biogenic sandstone and breccia layers (Mn sandstone) and form discrete dense stratabound layers along bedding planes and within beds (stratabound Mn). The Mn oxide was deposited within coarse-grained sediments from diffuse flow <span class="hlt">systems</span> where precipitation occurred below the seafloor. Deposits were exposed at the seabed by faulting, mass wasting, and erosion. Scanning electron microscopy and microprobe analyses indicate the presence of both amorphous and crystalline 10 ?? and 7 ?? manganate minerals, the fundamental chemical difference being high water contents in the amorphous Mn oxides. Alternation of amorphous and crystalline laminae occurs in many samples, which likely resulted from initial rapid precipitation of amorphous Mn oxides from waxing pulses of <span class="hlt">hydrothermal</span> fluids followed by precipitation of slow forming crystallites during waning stages. The chemical composition is characteristic of a <span class="hlt">hydrothermal</span> origin including strong fractionation between Fe (mean 0.9 wt %) and Mn (mean 48 wt %) for the stratabound Mn, generally low trace metal contents, and very low rare earth element and platinum group element contents. However, Mo, Cd, Zn, Cu, Ni, and Co occur in high concentrations in some samples and may be good indicator elements for proximity to the heat source or to massive sulfide deposits. For the Mn sandstones, Fe (mean-8.4%) and Mn (12.4%) are not significantly fractionated because of high Fe contents in the volcaniclastic material. However, the proportion of <span class="hlt">hydrothermal</span> Fe (nondetrital Fe) to total Fe is remarkably constant (49-58%) for all the sample groups, regardless of the degree of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS21B0441J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS21B0441J"><span>Thermal Grid 2000/2001: An Examination of the Thermal Flux From a 3.5 km Length of the <span class="hlt">Endeavour</span> Segment, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, H. P.; Hautala, S. L.</p> <p>2001-12-01</p> <p>Two Thermal Grid cruises in 2000/2001 used the ROV Jason to quantify diffuse <span class="hlt">hydrothermal</span> venting over a 3.5 km along-strike length of the <span class="hlt">Endeavour</span> axial valley, an area that includes two large <span class="hlt">hydrothermal</span> fields (MEF and High Rise) and many smaller, isolated diffuse <span class="hlt">systems</span>. A systematic near-bottom survey was first made using ROV-mounted CTDs, particulate and O2 sensors, to identify sites of diffuse venting. We also deployed the ROV-mounted SM2000 scanning sonar during, and the data provided the highest resolution bathymetric map made to date, with sub-meter pixels and 10 cm vertical resolution. The SM2000 data was also used to produce AST (acoustic scintillation tomography) images, where the acoustic de-correlation between adjacent sonar pings identified areas of <span class="hlt">hydrothermal</span> fluid venting. In areas of high AST de-correlation (warm water vents), we deployed MAV current meters and thermistors to acquire data on vertical thermal flux over both long (9 month) and short (24 hr) intervals. Data from these cruises allows us to (a) determine vertical thermal flux through the seafloor in vent areas, (b) discover a large number of circular magnetization lows across the valley floor, which overlie active or extinct <span class="hlt">hydrothermal</span> vent fields, (c) collect temperature and ADCP data to measure seawater entrainment around a high temperature vent, (d) define regions of diffuse fluid vents with the AST method, (e) make long-term measurements of fluid flow variability due to crustal and tidal processes, and (f) use CTD and near-bottom magnetometer data in the discovery of several new and extinct <span class="hlt">hydrothermal</span> fields on west axial valley wall, providing new constraints regarding crustal fluid circulation. * including C. Jones, M.A. Tivey, M. Pruis, I. Garcia-Berdeal, L. Gilbert, J. Voight, W. Fredericks, T. Bjorkland, T. Kurokawa, M. Tsurumi, S. Bolton, L. Thomas, K. O'Connell, J. Turner, J. Howland and the entire Jason Group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007MinDe..42..423P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007MinDe..42..423P"><span>PGE fractionation in seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span>: examples from mafic- and ultramafic-hosted <span class="hlt">hydrothermal</span> fields at the slow-spreading Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pašava, Jan; Vymazalová, Anna; Petersen, Sven</p> <p>2007-04-01</p> <p>The distribution of platinum group elements (PGEs) in massive sulfides and hematite-magnetite±pyrite assemblages from the recently discovered basalt-hosted Turtle Pits <span class="hlt">hydrothermal</span> field and in massive sulfides from the ultramafic-hosted Logatchev vent field both on the Mid-Atlantic Ridge was studied and compared to that from selected ancient volcanic-hosted massive sulfide (VHMS) deposits. Cu-rich samples from black smoker chimneys of both vent fields are enriched in Pd and Rh (Pd up to 227 ppb and Rh up to 149 ppb) when compared to hematite-magnetite-rich samples from Turtle Pits (Pd up to 10 ppb, Rh up to 1.9 ppb). A significant positive correlation was established between Cu and Rh in sulfide samples from Turtle Pits. PGE chondrite-normalized patterns (with a positive Rh anomaly and Pd and Au enrichment), Pd/Pt and Pd/Au ratios close to global MORB, and high values of Pd/Ir and Pt/Ir ratios indicate mafic source rock and seawater involvement in the <span class="hlt">hydrothermal</span> <span class="hlt">system</span> at Turtle Pits. Similarly shaped PGE chondrite-normalized patterns and high values of Pd/Pt and Pd/Ir ratios in Cu-rich sulfides at Logatchev likely reflect a similar mechanism of PGE enrichment but with involvement of ultramafic source rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013OLEB...43...99C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013OLEB...43...99C"><span>Survivability and Abiotic Reactions of Selected Amino Acids in Different <span class="hlt">Hydrothermal</span> <span class="hlt">System</span> Simulators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chandru, Kuhan; Imai, Eiichi; Kaneko, Takeo; Obayashi, Yumiko; Kobayashi, Kensei</p> <p>2013-04-01</p> <p>We tested the stability and reaction of several amino acids using <span class="hlt">hydrothermal</span> <span class="hlt">system</span> simulators: an autoclave and two kinds of flow reactors at 200-250 °C. This study generally showed that there is a variation in the individual amino acids survivability in the simulators. This is mainly attributed to the following factors; heat time, cold quenching exposure, metal ions and also silica. We observed that, in a rapid heating flow reactor, high aggregation and/or condensation of amino acids could occur even during a heat exposure of 2 min. We also monitored their stability in a reflow-type of simulator for 120 min at 20 min intervals. The non-hydrolyzed and hydrolyzed samples for this <span class="hlt">system</span> showed a similar degradation only in the absence of metal ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS13A1712Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13A1712Y"><span>What is the constraint on formation of oil-starved <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> in the sediment-rich Okinawa Trough, southwestern Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamanaka, T.; Akashi, H.; Mitsunari, T.</p> <p>2012-12-01</p> <p>Petroleum generation associated with seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> was first identified at the Guaymas Basin, Gulf of California in 1978 (Simoneit et al., 1979). Since the first discovery, <span class="hlt">hydrothermal</span> petroleums have been discovered at other seafloor <span class="hlt">hydrothermal</span> fields, Escanaba Trough, Middle Valley, and the Red Sea, where thick sedimentary layer overlay the active spreading center. Simoneit (1990) suggested that <span class="hlt">hydrothermal</span> petroleum can be occurred any <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> as a result of interaction between hot <span class="hlt">hydrothermal</span> fluid and organic mater in the sedimentary layer. In the middle Okinawa Trough, where typical sediment-hosted <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> distribute, occurrence of <span class="hlt">hydrothermal</span> petroleum has not been found. In 2010 IODP Exp. 331 had been performed, and then five sites were drilled at the Iheya North <span class="hlt">hydrothermal</span> <span class="hlt">system</span>. However, <span class="hlt">hydrothermal</span> petroleum generation has not been reported even at that time. On the other hand, significant <span class="hlt">hydrothermal</span> petroleum generation has been observed at a shallow-seafloor <span class="hlt">hydrothermal</span> <span class="hlt">system</span> in the Kagoshima Bay, north extension of Okinawa Trough (Yamanaka et al., 1999). It is an interesting subject why <span class="hlt">hydrothermal</span> petroleum can not be found in the Okinawa Trough. So we considered what is the most critical constraint on occurrence of <span class="hlt">hydrothermal</span> petroleum based on comparison with the well known <span class="hlt">hydrothermal</span> fields occurred <span class="hlt">hydrothermal</span> petroleum. Three major control factors for petroleum generation at seafloor <span class="hlt">hydrothermal</span> <span class="hlt">systems</span> are expected; (i) temperature, (ii) elapsed time, (iii) type of sediment. High temperature is essential for maturation of organic matter, but under extremely high temperature condition pyrolysis to gaseous hydrocarbon and other low-molecular weight product may be prevailed. Dissolved organic matter (DOM) and methane concentrations may reflect the temperature condition, because methane generation may continue under extreme condition but DOM, especially low-molecular weight organic acid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14759.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14759.html"><span>Approaching <span class="hlt">Endeavour</span> Crater, Sol 2,680</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-10-10</p> <p>This image from the navigation camera on NASA Mars Exploration Rover Opportunity shows the view ahead on the day before the rover reached the rim of <span class="hlt">Endeavour</span> crater. It was taken during the 2,680th Martian day, or sol, of the rover work on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-STS126-S-041.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-STS126-S-041.html"><span>STS-126 Space Shuttle <span class="hlt">Endeavour</span> Launch</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2008-11-14</p> <p>The Moon is seen rising behind the Space Shuttle <span class="hlt">Endeavour</span> (STS-126) on pad 39a Friday, November 14, 2008, at the Kennedy Space Center in Cape Canaveral, Fla. The Shuttle lifted off from launch pad 39A at 7:55 p.m. EST. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-sts061-93-031.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-sts061-93-031.html"><span>Hubble Space Telescope approaches Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>1993-12-04</p> <p>STS061-93-031 (4 Dec 1993) --- Part of the vast Indian Ocean forms the backdrop for this scene of the Hubble Space Telescope (HST) as it approaches the Space Shuttle <span class="hlt">Endeavour</span>. Denham Sound and Shark Bay, on Australia's west coast, are just below the waiting mechanical arm at lower right corner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29034&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29034&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds"><span>Liftoff of STS-59 Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1994-01-01</p> <p>The liftoff of the Space Shuttle <span class="hlt">Endeavour</span> is backdropped against a dawn sky at the Kennedy Space Center (KSC). Trees and water from a nearby marsh outline the lower portion of the view. Liftoff occurred at 7:05 a.m., April 9, 1994.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29066&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=STS059%28S%29066&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ds"><span>Liftoff of STS-59 Shuttle <span class="hlt">Endeavour</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1994-01-01</p> <p>The liftoff of the Space Shuttle <span class="hlt">Endeavour</span> is backdropped against clouds at the Kennedy Space Center (KSC). Liftoff occurred at 7:05 a.m., April 9, 1994. The air-to-air view was photographed from the Shuttle Training Aircraft (STA) piloted by astronaut Robert L. Gibson.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14135.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14135.html"><span>Eagle to <span class="hlt">Endeavour</span>: Opportunity Path, Sol 2609</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-06-08</p> <p>The yellow line on this map shows where NASA Mars Rover Opportunity has driven from the place where it landed in January 2004, inside Eagle crater, upper left end of track, to a point about 2.2 miles away from reaching the rim of <span class="hlt">Endeavour</span> crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14505.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14505.html"><span>Opportunity Route to <span class="hlt">Endeavour</span> Crater Wide View</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-08-05</p> <p>The yellow line on this map shows where NASA Mars Rover Opportunity has driven from the place where it landed in January 2004, inside Eagle crater, at the upper left end of the track, to a point approaching the rim of <span class="hlt">Endeavour</span> crater.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" oncl