Chemical environments of submarine hydrothermal systems
NASA Technical Reports Server (NTRS)
Shock, Everett L.
1992-01-01
Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal 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 hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal 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 hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems 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
Rare Earth Element Concentrations in Submarine Hydrothermal Fluids
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fowler, Andrew; Zierenberg, Robert
Rare earth element concentrations in submarine hydrothermal fluids from Alarcon Rise, East Pacific Rise, REE concentrations in submarine hydrothermal fluids from Pescadero Basin, Gulf of California, and the Cleft vent field, southern Juan de Fuca Ridge. Data are not corrected to zero Mg.
Hydrothermal mineralization along submarine rift zones, Hawaii
Hein, J.R.; Gibbs, A.E.; Clague, D.A.; Torresan, M.
1996-01-01
Describes mineralization of midplate submarine rift zones and hydrothermal manganese oxide mineralization of midplate volcanic edifices. Hydrothermal Mn oxides were recovered from submarine extensions of two Hawaiian rift zones, along Haleakala and Puna Ridges. These Mn oxides form two types of deposits, metallic stratiform layers in volcaniclastic rocks and cement for clastic rocks; both deposit types are composed of todorokite and birnessite. Unlike most other hydrothermal Mn oxide deposits, those from Hawaiian rift zones are enriched in the trace metals Zn, Co, Ba, Mo, Sr, V, and especially Ni. Metals are derived from three sources: mafic and ultramafic rocks leached by circulating hydrothermal fluids, clastic material (in Mn-cemented sandstone), and seawater that mixed with the hydrothermal fluids. Precipitation of Mn oxide below the seafloor is indicated by its occurrence as cement, growth textures that show mineralizing fluids were introduced from below, and pervasive replacement of original matrix of clastic rocks.Hydrothermal Mn oxides were recovered from submarine extensions of two Hawaiian rift zones, along Haleakala and Puna Ridges. These Mn oxides form two types of deposits, metallic stratiform layers in volcaniclastic rocks and cement for clastic rocks. Both deposit types are composed of todorokite and birnessite. This article describes in detail the specific characteristics of these Mn oxides.
ESR dating of submarine hydrothermal activities using barite in sulfide deposition
NASA Astrophysics Data System (ADS)
Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.
2012-12-01
The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much
Origin of Abiotic Methane in Submarine Hydrothermal Systems
NASA Astrophysics Data System (ADS)
Seewald, J. S.; German, C. R.; Grozeva, N. G.; Klein, F.; McDermott, J. M.; Ono, S.; Reeves, E. P.; Wang, D. T.
2018-05-01
Results of recent investigations into the chemical and isotopic composition of actively venting submarine hydrothermal fluids and volatile species trapped in fluid inclusions will be discussed in the context of processes responsible for abiotic CH4 formation.
Chemical environments of submarine hydrothermal systems. [supporting abiogenetic theory
NASA Technical Reports Server (NTRS)
Shock, Everett L.
1992-01-01
The paper synthesizes diverse information about the inorganic geochemistry of submarine hydrothermal systems, provides a description of the fundamental physical and chemical properties of these systems, 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 hydrothermal systems.
NASA Astrophysics Data System (ADS)
Stucker, Valerie K.; Walker, Sharon L.; de Ronde, Cornel E. J.; Caratori Tontini, Fabio; Tsuchida, Shinji
2017-10-01
The Hinepuia volcanic center is made up of two distinct edifices aligned northwest to southeast, with an active cone complex in the SE. Hinepuia is one of several active volcanoes in the northern segment of the Kermadec arc. Regional magnetic data show no evidence for large-scale hydrothermal alteration at Hinepuia, yet plume data confirm present-day hydrothermal discharge, suggesting that the hydrothermal system may be too young to have altered the host rocks with respect to measurable changes in magnetic signal. Gravity data are consistent with crustal thinning and shallow mantle under the volcanic center. Following the discovery of hydrothermal plumes over Hinepuia, the submersible Shinkai 6500 was used to explore the SE cone and sample hydrothermal fluids. The chemistry of hydrothermal fluids from submarine arc and backarc volcanoes is typically dominated by water-rock interactions and/or magmatic degassing. Chemical analyses of vent fluids show that Hinepuia does not quite fit either traditional model. Moreover, the Hinepuia samples fall between those typically ascribed to both end-member fluid types when plotted on a K-Mg-SO4 ternary diagram. Due to evidence of strong degassing, abundant native sulfur deposition, and H2S presence, the vent sampled at Hinepuia is ultimately classified as a magmatic-hydrothermal system with a water-rock influence. This vent is releasing water vapor and magmatic volatiles with a notable lack of salinity due to subcritical boiling and phase separation. Magmatic-hydrothermal fluid chemistry appears to be controlled by a combination of gas flux, phase separation processes, and volcano evolution and/or distance from the magma source.
Alteration of submarine volcanic rocks in oxygenated Archean oceans
NASA Astrophysics Data System (ADS)
Ohmoto, H.; Bevacqua, D.; Watanabe, Y.
2009-12-01
Most submarine volcanic rocks, including basalts in diverging plate boundaries and andesites/dacites in converging plate boundaries, have been altered by low-temperature seawater and/or hydrothermal fluids (up to ~400°C) under deep oceans; the hydrothermal fluids evolved from shallow/deep circulations of seawater through the underlying hot igneous rocks. Volcanogenic massive sulfide deposits (VMSDs) and banded iron formations (BIFs) were formed by mixing of submarine hydrothermal fluids with local seawater. Therefore, the behaviors of various elements, especially of redox-sensitive elements, in altered submarine volcanic rocks, VMSDs and BIFs can be used to decipher the chemical evolution of the oceans and atmosphere. We have investigated the mineralogy and geochemistry of >500 samples of basalts from a 260m-long drill core section of Hole #1 of the Archean Biosphere Drilling Project (ABDP #1) in the Pilbara Craton, Western Australia. The core section is comprised of ~160 m thick Marble Bar Chert/Jasper Unit (3.46 Ga) and underlying, inter-bedded, and overlying submarine basalts. Losses/gains of 65 elements were quantitatively evaluated on the basis of their concentration ratios against the least mobile elements (Ti, Zr and Nb). We have recognized that mineralogical and geochemical characteristics of many of these samples are essentially the same as those of hydrothermally-altered modern submarine basalts and also those of altered volcanic rocks that underlie Phanerozoic VMSDs. The similarities include, but are not restricted to: (1) the alteration mineralogy (chlorite ± sericite ± pyrophyllite ± carbonates ± hematite ± pyrite ± rutile); (2) the characteristics of whole-rock δ18O and δ34S values; (3) the ranges of depletion and enrichment of Si, Al, Mg, Ca, K, Na, Fe, Mn, and P; (4) the enrichment of Ba (as sulfate); (5) the increases in Fe3+/Fe2+ ratios; (6) the enrichment of U; (7) the depletion of Cr; and (8) the negative Ce anomalies. Literature data
The stability of amino acids at submarine hydrothermal vent temperatures
NASA Technical Reports Server (NTRS)
Bada, Jeffrey L.; Miller, Stanley L.; Zhao, Meixun
1995-01-01
It has been postulated that amino acid stability at hydrothermal vent temperatures is controlled by a metastable thermodynamic equilibrium rather than by kinetics. Experiments reported here demonstrate that the amino acids are irreversibly destroyed by heating at 240 C and that quasi-equilibrium calculations give misleading descriptions of the experimental observations. Equilibrium thermodynamic calculations are not applicable to organic compounds under high-temperature submarine vent conditions.
Near-Seafloor Magnetic Exploration of Submarine Hydrothermal Systems in the Kermadec Arc
NASA Astrophysics Data System (ADS)
Caratori Tontini, F.; de Ronde, C. E. J.; Tivey, M.; Kinsey, J. C.
2014-12-01
Magnetic data can provide important information about hydrothermal systems because hydrothermal alteration can drastically reduce the magnetization of the host volcanic rocks. Near-seafloor data (≤70 m altitude) are required to map hydrothermal systems 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 hydrothermal upflow zones and the structural control on the development of seafloor hydrothermal vent sites as well as being a tool for the discovery of previously unknown hydrothermal sites. Significant differences exist between the magnetic expressions of hydrothermal 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.
Kilias, Stephanos P.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N.; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J.; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael
2013-01-01
We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the hydrothermal vent field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor hydrothermal activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on hydrothermal ammonia and CO2. Our findings highlight that acidic shallow-submarine hydrothermal vents nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe3+-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe2+-oxidation, dependent on microbially produced nitrate. PMID:23939372
Schiffman, P.; Williams, A.E.; Evarts, R.C.
1984-01-01
The oxygen isotope compositions and metamorphic mineral assemblages of hydrothermally altered rocks from the Del Puerto ophiolite and overlying volcaniclastic sedimentary rocks at the base of the Great Valley sequence indicate that their alteration occurred in a submarine hydrothermal system. Whole rock ??18O compositions decrease progressively down section (with increasing metamorphic grade): +22.4??? (SMOW) to +13.8 for zeolite-bearing volcaniclastic sedimentary rocks overlying the ophiolite; +19.6 to +11.6 for pumpellyite-bearing metavolcanic rocks in the upper part of the ophiolite's volcanic member; +12.3 to +8.1 for epidote-bearing metavolcanic rocks in the lower part of the volcanic member; +8.5 to +5.7 for greenschist facies rocks from the ophiolite's plutonic member; +7.6 to +5.8 for amphibolite facies or unmetamorphosed rocks from the plutonic member. Modelling of fluid-rock interaction in the Del Puerto ophiolite indicates that the observed pattern of upward enrichment in whole rock ??18O can be best explained by isotopic exchange with discharging 18O-shifted seawater at fluid/rock mass ratios near 2 and temperatures below 500??C. 18O-depleted plutonic rocks necessarily produced during hydrothermal circulation were later removed as a result of tectonism. Submarine weathering and later burial metamorphism at the base of the Great Valley sequence cannot by itself have produced the zonation of hydrothermal minerals and the corresponding variations in oxygen isotope compositions. The pervasive zeolite and prehnite-pumpellyite facies mineral assemblages found in the Del Puerto ophiolite may reflect its origin near an island arc rather than deep ocean spreading center. ?? 1984.
NASA Astrophysics Data System (ADS)
Kiss, Gabriella B.; Zagyva, Tamás; Pásztor, Domokos; Zaccarini, Federica
2018-05-01
The Jurassic pillow basalt of the NE Hungarian Szarvaskő Unit is part of an incomplete ophiolitic sequence, formed in a back-arc- or marginal basin of Neotethyan origin. Different, often superimposing hydrothermal processes were studied aiming to characterise them and to discover their relationship with the geotectonic evolution of the region. Closely packed pillow, pillow-fragmented hyaloclastite breccia and transition to peperitic facies of a submarine lava flow were observed. The rocks underwent primary and cooling-related local submarine hydrothermal processes immediately after eruption at ridge setting. Physico-chemical data of this process and volcanic facies analyses revealed distal formation in the submarine lava flow. A superimposing, more extensive fluid circulation system resulted in intense alteration of basalt and in the formation of mostly sulphide-filled cavities. This lower temperature, but larger-scale process was similar to VMS systems and was related to ridge setting. As a peculiarity of the Szarvaskő Unit, locally basalt may be completely altered to a grossular-bearing mineral assemblage formed by rodingitisation s.l. This unique process observed in basalt happened in ridge setting/during spreading, in the absence of known large ultramafic blocks. Epigenetic veins formed also during Alpine regional metamorphism, related to subduction/obduction. The observed hydrothermal minerals represent different steps of the geotectonic evolution of the Szarvaskő Unit, from the ridge setting and spreading till the subduction/obduction. Hence, studying the superimposing alteration mineral assemblages can be a useful tool for reconstructing the tectonic history of an ophiolitic complex. Though the found mineral parageneses are often similar, careful study can help in distinguishing the processes and characterising their P, T, and X conditions.
van de Flierdt, T.; Frank, M.; Halliday, A.N.; Hein, J.R.; Hattendorf, B.; Gunther, D.; Kubik, P.W.
2004-01-01
Secular variations in the Pb isotopic composition of a mixed hydrogenous-hydrothermal ferromanganese crust from the Bauer Basin in the eastern Equatorial Pacific provide clear evidence for changes in hydrothermal contributions during the past 7 Myr. The nearby Galapagos Rise spreading center provided a strong hydrothermal flux prior to 6.5 Ma. After 6.5 Ma, the Pb became stepwise more radiogenic and more similar to Equatorial Pacific seawater, reflecting the westward shift of spreading to the presently active East Pacific Rise (EPR). A second, previously unrecognized enhanced hydrothermal period occurred between 4.4 and 2.9 Ma, which reflects either off-axis hydrothermal activity in the Bauer Basin or a late-stage pulse of hydrothermal Pb from the then active, but waning Galapagos Rise spreading center. Hafnium isotope time-series of the same mixed hydrogenous-hydrothermal crust show invariant values over the past 7 Myr. Hafnium isotope ratios, as well as Nd isotope ratios obtained for this crust, are identical to that of hydrogenous Equatorial Pacific deep water crusts and clearly indicate that hydrothermal Hf, similar to Nd, does not travel far from submarine vents. Therefore, we suggest that hydrothermal Hf fluxes do not contribute significantly to the global marine Hf budget. ?? 2004 Elsevier B.V. All rights reserved.
Submarine hydrothermal metamorphism of the Del Puerto ophiolite, California.
Evarts, R.C.; Schiffman, P.
1983-01-01
Metamorphic zonation overprinted on the volcanic member and overlying volcanogenic sediments of the ophiolite complex increases downward in grade and is characterized by the sequential appearance with depth of zeolites, ferric pumpellyite and pistacitic epidote. Metamorphic assemblages of the plutonic member of the complex are characterized by the presence of calcic amphibole. The overprinting represents the effects of hydrothermal metamorphism resulting from the massive interaction between hot igneous rocks and convecting sea-water in a submarine environment. A thermal gradient of 100oC/km is postulated to account for the zonal recrystallization effects in the volcanic member. The diversity and sporadic distribution of mineral assemblages in the amphibole zone are considered due to the limited availability of H2O in the deeper part of the complex. Details of the zonation and representative microprobe analyses are tabulated.-M.S.
Modeling microbial reaction rates in a submarine hydrothermal vent chimney wall
NASA Astrophysics Data System (ADS)
LaRowe, Douglas E.; Dale, Andrew W.; Aguilera, David R.; L'Heureux, Ivan; Amend, Jan P.; Regnier, Pierre
2014-01-01
The fluids emanating from active submarine hydrothermal vent chimneys provide a window into subseafloor processes and, through mixing with seawater, are responsible for steep thermal and compositional gradients that provide the energetic basis for diverse biological communities. Although several models have been developed to better understand the dynamic interplay of seawater, hydrothermal fluid, minerals and microorganisms inside chimney walls, none provide a fully integrated approach to quantifying the biogeochemistry of these hydrothermal systems. In an effort to remedy this, a fully coupled biogeochemical reaction-transport model of a hydrothermal vent chimney has been developed that explicitly quantifies the rates of microbial catalysis while taking into account geochemical processes such as fluid flow, solute transport and oxidation-reduction reactions associated with fluid mixing as a function of temperature. The metabolisms included in the reaction network are methanogenesis, aerobic oxidation of hydrogen, sulfide and methane and sulfate reduction by hydrogen and methane. Model results indicate that microbial catalysis is generally fastest in the hottest habitable portion of the vent chimney (77-102 °C), and methane and sulfide oxidation peak near the seawater-side of the chimney. The fastest metabolisms are aerobic oxidation of H2 and sulfide and reduction of sulfate by H2 with maximum rates of 140, 900 and 800 pmol cm-3 d-1, respectively. The maximum rate of hydrogenotrophic methanogenesis is just under 0.03 pmol cm-3 d-1, the slowest of the metabolisms considered. Due to thermodynamic inhibition, there is no anaerobic oxidation of methane by sulfate (AOM). These simulations are consistent with vent chimney metabolic activity inferred from phylogenetic data reported in the literature. The model developed here provides a quantitative approach to describing the rates of biogeochemical transformations in hydrothermal systems and can be used to constrain the
An authoritative global database for active submarine hydrothermal vent fields
NASA Astrophysics Data System (ADS)
Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew
2013-11-01
The InterRidge Vents Database is available online as the authoritative reference for locations of active submarine hydrothermal vent fields. Here we describe the revision of the database to an open source content management system and conduct a meta-analysis of the global distribution of known active vent fields. The number of known active vent fields has almost doubled in the past decade (521 as of year 2009), with about half visually confirmed and others inferred active from physical and chemical clues. Although previously known mainly from mid-ocean ridges (MORs), active vent fields at MORs now comprise only half of the total known, with about a quarter each now known at volcanic arcs and back-arc spreading centers. Discoveries in arc and back-arc settings resulted in an increase in known vent fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. The purpose of the database now extends beyond academic research and education and into marine policy and management, with at least 18% of known vent fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.
Quéméneur, Marianne; Bes, Méline; Postec, Anne; Mei, Nan; Hamelin, Jérôme; Monnin, Christophe; Chavagnac, Valérie; Payri, Claude; Pelletier, Bernard; Guentas-Dombrowsky, Linda; Gérard, Martine; Pisapia, Céline; Gérard, Emmanuelle; Ménez, Bénédicte; Ollivier, Bernard; Erauso, Gaël
2014-12-01
The shallow submarine hydrothermal field of the Prony Bay (New Caledonia) discharges hydrogen- and methane-rich fluids with low salinity, temperature (< 40°C) and high pH (11) produced by the serpentinization reactions of the ultramafic basement into the lagoon seawater. They are responsible for the formation of carbonate chimneys at the lagoon seafloor. Capillary electrophoresis single-strand conformation polymorphism fingerprinting, quantitative polymerase chain reaction and sequence analysis of 16S rRNA genes revealed changes in microbial community structure, abundance and diversity depending on the location, water depth, and structure of the carbonate chimneys. The low archaeal diversity was dominated by few uncultured Methanosarcinales similar to those found in other serpentinization-driven submarine and subterrestrial ecosystems (e.g. Lost City, The Cedars). The most abundant and diverse bacterial communities were mainly composed of Chloroflexi, Deinococcus-Thermus, Firmicutes and Proteobacteria. Functional gene analysis revealed similar abundance and diversity of both Methanosarcinales methanoarchaea, and Desulfovibrionales and Desulfobacterales sulfate-reducers in the studied sites. Molecular studies suggest that redox reactions involving hydrogen, methane and sulfur compounds (e.g. sulfate) are the energy driving forces of the microbial communities inhabiting the Prony hydrothermal system.
NASA Astrophysics Data System (ADS)
Valsami-Jones, E.; Baltatzis, E.; Bailey, E. H.; Boyce, A. J.; Alexander, J. L.; Magganas, A.; Anderson, L.; Waldron, S.; Ragnarsdottir, K. V.
2005-10-01
Geothermal activity in the Aegean island of Milos (Greece), associated with island-arc volcanism, is abundant both on-and off-shore. Hydrothermal fluids venting from several sites, mainly shallow submarine (up to 10 m), but also just above seawater level in one locality, were sampled over four summer field seasons. Some of the discharging fluids are associated with the formation of hydrothermal edifices. Overall, the main characteristics of the hydrothermal fluids are low pH and variable chlorinity. The lowest recorded pH was 1.7, and chlorinity ranged from 0.1 to 2.5 times that of seawater. The highest fluid temperatures recorded on site were 115 °C. Two main types of fluids were identified: low-chlorinity fluids containing low concentrations of alkalis (potassium, lithium, sodium) and calcium, and high concentrations of silica and sulphate; and high-chlorinity fluids containing high concentrations of alkalis and calcium, and lower concentrations of silica and sulphate. The type locality of the high-chlorinity fluids is shallow submarine in Palaeochori, near the east end of the south coast of the island, whereas the type locality of the low-chlorinity fluids is a cave to the west of Palaeochori. The two fluid types are therefore often referred to as "submarine" and "cave" fluids respectively. Both fluid types had low magnesium and high metal concentrations but were otherwise consistently different from each other. The low-chlorinity fluids had the highest cobalt, nickel, aluminium, iron and chromium (up to 1.6 μM, 3.6 μM, 1586 μM, 936 μM and 3.0 μM, respectively) and the high-chlorinity fluids had the highest zinc, cadmium, manganese and lead (up to 4.1 μM, 1.0 μM, 230 μM and 32 μM, respectively). Geochemical modelling suggests that metals in the former are likely to have been transported as sulphate species or free ions and in the latter as chloride species or free ions. Isotopic values for both water types range between δD -12 to 33‰ and δ 18O 1
Hydrothermal Venting at Kick'Em Jenny Submarine Volcano (West Indies)
NASA Astrophysics Data System (ADS)
Carey, S.; Croff Bell, K. L.; Dondin, F. J. Y.; Roman, C.; Smart, C.; Lilley, M. D.; Lupton, J. E.; Ballard, R. D.
2014-12-01
Kick'em Jenny is a frequently-erupting, shallow submarine volcano located ~8 km off the northwest coast of Grenada in the West Indies. The last eruption took place in 2001 but did not breach the sea surface. Focused and diffuse hydrothermal venting is taking place mainly within a small (~100 x 100 m) depression within the 300 m diameter crater of the volcano at depths of about 265 meters. Near the center of the depression clear fluids are being discharged from a focused mound-like vent at a maximum temperature of 180o C with the simultaneous discharge of numerous bubble streams. The gas consists of 93-96% CO2 with trace amounts of methane and hydrogen. A sulfur component likely contributes 1-4% of the gas total. Gas flux measurements on individual bubble streams ranged from 10 to 100 kg of CO2 per day. Diffuse venting with temperatures 5 to 35o C above ambient occurs throughout the depression and over large areas of the main crater. These zones are extensively colonized by reddish-yellow bacterial mats with the production of loose Fe-oxyhydroxides largely as a surface coating and in some cases, as fragile spires up to several meters in height. A high-resolution photo mosaic of the crater depression was constructed using the remotely operated vehicle Hercules on cruise NA039 of the E/V Nautilus. The image revealed prominent fluid flow patterns descending the sides of the depression towards the base. We speculate that the negatively buoyant fluid flow may be the result of second boiling of hydrothermal fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature. Increased density may also be the result of high dissolved CO2 content of the fluids, although we were not able to measure this directly. The low amount of sulphide mineralization on the crater floor suggests that deposition may be occurring mostly subsurface, in accord with models of second boiling mineralization from other hydrothermal vent systems.
NASA Astrophysics Data System (ADS)
Tassi, Franco; Capaccioni, Bruno; Vaselli, Orlando
2014-05-01
The November 2002 submarine gas blast at Panarea Island (Sicily, southern Italy) was an unexpected reactivation event able to locally affect this hydrothermal-magmatic system whose the youngest eruptive products were dated at 20,000 ± 2000 years BP. The presence of magmatic gases (SO2 and HF) in the fumarolic gas discharges after the violent exhalative event was indicative of a magmatic input that temporary displaced the hydrothermal system. A few months later these acidic gases were indeed not detected in any of the studied fumaroles. Nevertheless, new geochemical data obtained by periodical sampling up to June 2013 suggest that the chemical-physical conditions of the hydrothermal-magmatic system at Panarea were not completely restored with respect to the geochemical data obtained in the early nineties. Thus, the 2002 gas burst has unequivocally caused a permanent modification to the fluid circulation system feeding the submarine fumaroles. In addition, strong compositional differences were observed by the 46 gases collected in 2012-2013 from submarine fumaroles located in different sites of the studied area, allowing to distinguish three different groups of fumaroles: A) H2- and CO-rich gases, which also show relatively low Ar concentrations, B) H2S-rich gases, having variable CO/CH4 ratios, and C) Ar-rich gases, having relatively low H2 concentrations. Gases from group A are distributed along NW- and NE-trending fault systems, whereas those of groups B and C discharge at increasing distance from the intersection of the two fault systems, indicating a spatial and compositional control by the local tectonic setting. The H2/CO ratios of groups A and B gases are significantly lower than those measured prior to 2012. This would imply an increase of gas pressure at depth, possibly caused by continuous addition of gas and energy from the magmatic source to the hydrothermal reservoir. Continuation of this process may lead to the occurrence of gas burst events in the
Organic matter in hydrothermal metal ores and hydrothermal fluids
Orem, W.H.; Spiker, E. C.; Kotra, R.K.
1990-01-01
Massive polymetallic sulfides are currently being deposited around active submarine hydrothermal vents associated with spreading centers. Chemoautolithotrophic bacteria are responsible for the high production of organic matter also associated with modern submarine hydrothermal activity. Thus, there is a significant potential for organic matter/metal interactions in these systems. We have studied modern and ancient hydrothermal metal ores and modern hydrothermal fluids in order to establish the amounts and origin of the organic matter associated with the metal ores. Twenty-six samples from modern and ancient hydrothermal systems were surveyed for their total organic C contents. Organic C values ranged from 0.01% to nearly 4.0% in these samples. Metal ores from modern and ancient sediment-covered hydrothermal systems had higher organic C values than those from modern and ancient hydrothermal systems lacking appreciable sedimentary cover. One massive pyrite sample from the Galapagos spreading center (3% organic C) had stable isotope values of -27.4% (??13C) and 2.1% (??15N), similar to those in benthic siphonophors from active vents and distinct from seep sea sedimentary organic matter. This result coupled with other analyses (e.g. 13C NMR, pyrolysis/GC, SEM) of this and other samples suggests that much of the organic matter may originate from chemoautolithotrophic bacteria at the vents. However, the organic matter in hydrothermal metal ores from sediment covered vents probably arises from complex sedimentary organic matter by hydrothermal pyrolysis. The dissolved organic C concentrations of hydrothermal fluids from one site (Juan de Fuca Ridge) were found to be the same as that of background seawater. This result may indicate that dissolved organic C is effectively scavenged from hydrothermal fluids by biological activity or by co-precipitation with metal ores. ?? 1990.
NASA Astrophysics Data System (ADS)
Iizasa, Kokichi; Asada, Akira; Mizuno, Katsunori; Katase, Fuyuki; Lee, Sangkyun; Kojima, Mitsuhiro; Ogawa, Nobuhiro
2018-04-01
Sulfide deposits with extremely high Au concentrations (up to 275 ppm; avg. 102 ppm, n = 15), high Au/Ag ratios (0.24, n = 15), and low Cu/(Cu + Zn) ratios (0.03, n = 15) were discovered in 2015 in active hydrothermal fields at a water depth of 760 m in a basalt-dominated submarine caldera in the Izu-Ogasawara frontal arc, Japan. Native gold grains occur in massive sulfide fragments, concretions, and metalliferous sediments from a sulfide mound (40 m across and 20 m high) with up to 30-m-high black smoker chimneys. Tiny native gold grains up to 14 μm in diameter are mainly present in sulfide fallouts from chimney orifices and plumes. Larger native gold grains up to 150 μm long occur mostly as discrete particles and/or with amorphous silica and sulfides. The larger gold grains are interpreted to represent direct precipitation from Au-bearing hydrothermal fluids circulating in and/or beneath the unconsolidated sulfide mound deposits. Sulfur isotope compositions from a limited number of sulfide separates (n = 4) range from 4.3 to 5.8‰ δ34S, similar to the quaternary volcanic rocks of the arc. Barite separates have values of 22.2 and 23.1‰, close to modern seawater values, and indicate probable seawater sulfate origin. The Cu, Zn, and Pb concentrations in bulk samples of sulfide-rich rocks are similar to those of volcanogenic massive sulfides formed in continental crustal environments. The gold is interpreted to have formed by low-temperature hydrothermal activity, perhaps genetically different from systems with documented magmatic contributions or from seafloor hydrothermal systems in other island arc settings. Its presence suggests that basalt-dominated submarine calderas situated on relatively thick continental crust in an intraoceanic arc setting such as the Higashi-Aogashima knoll caldera may be perspective for gold mineralization.
NASA Astrophysics Data System (ADS)
Araoka, Daisuke; Nishio, Yoshiro; Gamo, Toshitaka; Yamaoka, Kyoko; Kawahata, Hodaka
2016-10-01
The Li concentration and isotopic composition (δ7Li) in submarine vent fluids are important for oceanic Li budget and potentially useful for investigating hydrothermal systems deep under the seafloor because hydrothermal vent fluids are highly enriched in Li relative to seawater. Although Li isotopic geochemistry has been studied at mid-ocean-ridge (MOR) hydrothermal 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 hydrothermal systems in the western Pacific and examined Li behavior during high-temperature water-rock interactions in different geological settings. In sediment-starved hydrothermal systems (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 hydrothermal 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 hydrothermal fluid-sediment interactions associated with the thickness of the marine sediment overlying these hydrothermal sites.
Bacterial diversity in Fe-rich hydrothermal sediments at two South Tonga Arc submarine volcanoes.
Forget, N L; Murdock, S A; Juniper, S K
2010-12-01
Seafloor iron oxide deposits are a common feature of submarine hydrothermal systems. Morphological study of these deposits has led investigators to suggest a microbiological role in their formation, through the oxidation of reduced Fe in hydrothermal fluids. Fe-oxidizing bacteria, including the recently described Zetaproteobacteria, have been isolated from a few of these deposits but generally little is known about the microbial diversity associated with this habitat. In this study, we characterized bacterial diversity in two Fe oxide samples collected on the seafloor of Volcanoes 1 and 19 on the South Tonga Arc. We were particularly interested in confirming the presence of Zetaproteobacteria at these two sites and in documenting the diversity of groups other than Fe oxidizers. Our results (small subunit rRNA gene sequence data) showed a surprisingly high bacterial diversity, with 150 operational taxonomic units belonging to 19 distinct taxonomic groups. Both samples were dominated by Zetaproteobacteria Fe oxidizers. This group was most abundant at Volcano 1, where sediments were richer in Fe and contained more crystalline forms of Fe oxides. Other groups of bacteria found at these two sites include known S- and a few N-metabolizing bacteria, all ubiquitous in marine environments. The low similarity of our clones with the GenBank database suggests that new species and perhaps new families were recovered. The results of this study suggest that Fe-rich hydrothermal sediments, while dominated by Fe oxidizers, can be exploited by a variety of autotrophic and heterotrophic micro-organisms. © 2010 Blackwell Publishing Ltd.
NASA Astrophysics Data System (ADS)
Kobayashi, Kensei; Kurihara, Hironari; Hirako, Tomoaki; Obayashi, Yumiko; Kaneko, Takeo; Takano, Yoshinori; Yoshimura, Yoshitaka
Since late 1970's a great number of submarine hydrothermal systems (SHSs) has been dis-covered, and they are considered possible sites of chemical evolution and generation of life on the Earth since their discovery in late 1970s. A number of experiments simulating the con-ditions of SHSs were conducted, and abiotic production and polymerization of amino acids were reported. Free amino acids were frequently used as starting materials to examine possible organic reactions in the simulation experiments. In our early studies, not free amino acids but complex amino acids precursors with large molecular weights were formed abiotically from simulated primitive Earth atmosphere (a mixture of CO, N2 and H2 O) (Takano et al., 2004). Such complex organics (hereafter referred as to CNWs) should have been delivered to SHSs in Primitive Ocean, where they were subjected to further alteration. We examined possible alteration of the complex organics in high-temperature high-pressure environments by the su-percritical water flow reactor (SCWFR) (Islam et al.. 2003) and an autoclave. CNWs were quite hydrophilic compounds whose molecular weights were ca. 3000. After heating 573 K for 2 min in the SCWFR, aggregates of organics were formed, which were separated from aque-ous solution with a Nucleopore filter (pore size: 200 nm). We propose the following scenario of chemical evolution: (1) Complex organics including amino acid precursors were formed in primitive atmosphere and/or extraterrestrial environments, (ii) they were delivered to primor-dial SHSs, (iii) hydrothermal alteration occurred in SHSs to give organic aggregates, (iv) quite primitive molecular systems with subtle biological functions were generated in the competition among such aggregates. References: Islam, Md. N., Kaneko, T., and Kobayashi, K (2003). Reactions of Amino Acids with a Newly ConstructedSupercritical Water Flow Reactor Simulating Submarine Hydrothermal Systems. Bull. Chem. Soc. Jpn., 76, 1171. Takano, Y
NASA Astrophysics Data System (ADS)
Keith, Manuel; Haase, Karsten M.; Klemd, Reiner; Smith, Daniel J.; Schwarz-Schampera, Ulrich; Bach, Wolfgang
2018-05-01
Most magmatic-hydrothermal Cu deposits are genetically linked to arc magmas. However, most continental or oceanic arc magmas are barren, and hence new methods have to be developed to distinguish between barren and mineralised arc systems. Source composition, melting conditions, the timing of S saturation and an initial chalcophile element-enrichment represent important parameters that control the potential of a subduction setting to host an economically valuable deposit. Brothers volcano in the Kermadec island arc is one of the best-studied examples of arc-related submarine magmatic-hydrothermal activity. This study, for the first time, compares the chemical and mineralogical composition of the Brothers seafloor massive sulphides and the associated dacitic to rhyolitic lavas that host the hydrothermal system. Incompatible trace element ratios, such as La/Sm and Ce/Pb, indicate that the basaltic melts from L'Esperance volcano may represent a parental analogue to the more evolved Brothers lavas. Copper-rich magmatic sulphides (Cu > 2 wt%) identified in fresh volcanic glass and phenocryst phases, such as clinopyroxene, plagioclase and Fe-Ti oxide suggest that the surrounding lavas that host the Brothers hydrothermal system represent a potential Cu source for the sulphide ores at the seafloor. Thermodynamic calculations reveal that the Brothers melts reached volatile saturation during their evolution. Melt inclusion data and the occurrence of sulphides along vesicle margins indicate that an exsolving volatile phase extracted Cu from the silicate melt and probably contributed it to the overlying hydrothermal system. Hence, the formation of the Cu-rich seafloor massive sulphides (up to 35.6 wt%) is probably due to the contribution of Cu from a bimodal source including wall rock leaching and magmatic degassing, in a mineralisation style that is hybrid between Cyprus-type volcanic-hosted massive sulphide and subaerial epithermal-porphyry deposits.
NASA Astrophysics Data System (ADS)
Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.
2016-05-01
The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d-1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.
Santana-Casiano, J M; Fraile-Nuez, E; González-Dávila, M; Baker, E T; Resing, J A; Walker, S L
2016-05-09
The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 10(5) ± 1.1 10(5 )kg d(-1) which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.
Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.
2016-01-01
The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d−1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%. PMID:27157062
de Wit, Maarten J.; Furnes, Harald
2016-01-01
Estimates of ocean temperatures on Earth 3.5 billion years ago (Ga) range between 26° and 85°C. We present new data from 3.47- to 3.43-Ga volcanic rocks and cherts in South Africa suggesting that these temperatures reflect mixing of hot hydrothermal fluids with cold marine and terrestrial waters. We describe fossil hydrothermal pipes that formed at ~200°C on the sea floor >2 km below sea level. This ocean floor was uplifted tectonically to sea level where a subaerial hydrothermal system was active at 30° to 270°C. We also describe shallow-water glacial diamictites and diagenetic sulfate mineral growth in abyssal muds. These new observations reveal that both hydrothermal systems operated in relatively cold environments and that Earth’s surface temperatures in the early Archean were similar to those in more recent times. PMID:26933677
NASA Astrophysics Data System (ADS)
Carey, Steven; Olsen, Rene; Bell, Katherine L. C.; Ballard, Robert; Dondin, Frederic; Roman, Chris; Smart, Clara; Lilley, Marvin; Lupton, John; Seibel, Brad; Cornell, Winton; Moyer, Craig
2016-03-01
Kick'em Jenny is a frequently erupting, shallow submarine volcano located 7.5 km off the northern coast of Grenada in the Lesser Antilles subduction zone. Focused and diffuse hydrothermal venting is taking place mainly within a small (˜70 × 110 m) depression within the 300 m diameter crater of the volcano at depths of about 265 m. Much of the crater is blanketed with a layer of fine-grained tephra that has undergone hydrothermal alteration. Clear fluids and gas are being discharged near the center of the depression from mound-like vents at a maximum temperature of 180°C. The gas consists of 93-96% CO2 with trace amounts of methane and hydrogen. Gas flux measurements of individual bubble streams range from 10 to 100 kg of CO2 per day. Diffuse venting with temperatures 5-35°C above ambient occurs throughout the depression and over large areas of the main crater. These zones are colonized by reddish-yellow bacteria with the production of Fe-oxyhydroxides as surface coatings, fragile spires up to several meters in height, and elongated mounds up to tens of centimeters thick. A high-resolution photomosaic of the inner crater depression shows fluid flow patterns descending the sides of the depression toward the crater floor. We suggest that the negatively buoyant fluid flow is the result of phase separation of hydrothermal fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature.
NASA Astrophysics Data System (ADS)
Jackson, M. D.; Couper, S.; Li, Y.; Stan, C. V.; Tamura, N.; Stefansson, A.; Moore, J. G.; Wenk, H. R.
2016-12-01
Basaltic tephra at Surtsey volcano, produced by 1963-1967 eruptions in the offshore SE Icelandic rift zone, record the complex interplay of factors that determine rates of palagonitization and crystallization of authigenic minerals in seafloor basalts worldwide. We investigate how formation of nanocrystalline clay mineral in fresh sideromelane glass influenced crystallization of mineral cements in submarine tuff from a 181 m core drilled in 1979. Synchrotron-based microdiffraction and microfluorescence maps (2x5 µm X-ray beam spot size) at beamline 12.3.2, Advanced Light Source, SEM-EDS compositional analyses, and fluid geochemical models compare processes in lapilli-sized glass fragments, vitric cementing matrix, and fine ash accretions. In lapilli at 137.9 m (100°C), nanocrystalline clay mineral in gel-palagonite has asymetric 14.9-12.6 Å (001) reflections, with Fe and Ti enrichment relative to Si, Al and Ca, compared with adjacent sideromelane. Neighboring fibro-palagonite has symmetric (001) and greater Fe and Ti enrichment. Al-tobermorite, a rare calcium-silicate-hydrate, crystallized in nearby vesicles. The 11.30-11.49 Å (002) interlayer and Ca/(Si+Al) ratio of 0.9-1.0 record release of Si, Al, and Ca in a chemical system relatively isolated from submarine hydrothermal fluid flow. In vitric matrix relatively open to fluid flow, however, phillipsite zeolite cement predominates. Al-tobermorite formed at 88.45 m (130°C) and 102.6 m (140°C), but is associated with fibro-palagonite and analcite, reflecting more rapid palagonitization, and changing cation solubility and pH at higher temperature. Tubular palagonite microstructures show nanocrystalline clay mineral with (001) preferred orientations that wrap around relict microchannels, produced perhaps through biogenic activity. Nanocrystalline clay mineral d-spacings suggest similarities with nontronite, but zeolite in palagonite diffraction patterns and 6-9 wt% MgO suggest a polycrystalline composite with
Campbell, Barbara J.; Smith, Julie L.; Hanson, Thomas E.; Klotz, Martin G.; Stein, Lisa Y.; Lee, Charles K.; Wu, Dongying; Robinson, Jeffrey M.; Khouri, Hoda M.; Eisen, Jonathan A.; Cary, S. Craig
2009-01-01
Submarine hydrothermal vents are model systems for the Archaean Earth environment, and some sites maintain conditions that may have favored the formation and evolution of cellular life. Vents are typified by rapid fluctuations in temperature and redox potential that impose a strong selective pressure on resident microbial communities. Nautilia profundicola strain Am-H is a moderately thermophilic, deeply-branching Epsilonproteobacterium found free-living at hydrothermal vents and is a member of the microbial mass on the dorsal surface of vent polychaete, Alvinella pompejana. Analysis of the 1.7-Mbp genome of N. profundicola uncovered adaptations to the vent environment—some unique and some shared with other Epsilonproteobacterial genomes. The major findings included: (1) a diverse suite of hydrogenases coupled to a relatively simple electron transport chain, (2) numerous stress response systems, (3) a novel predicted nitrate assimilation pathway with hydroxylamine as a key intermediate, and (4) a gene (rgy) encoding the hallmark protein for hyperthermophilic growth, reverse gyrase. Additional experiments indicated that expression of rgy in strain Am-H was induced over 100-fold with a 20°C increase above the optimal growth temperature of this bacterium and that closely related rgy genes are present and expressed in bacterial communities residing in geographically distinct thermophilic environments. N. profundicola, therefore, is a model Epsilonproteobacterium that contains all the genes necessary for life in the extreme conditions widely believed to reflect those in the Archaean biosphere—anaerobic, sulfur, H2- and CO2-rich, with fluctuating redox potentials and temperatures. In addition, reverse gyrase appears to be an important and common adaptation for mesophiles and moderate thermophiles that inhabit ecological niches characterized by rapid and frequent temperature fluctuations and, as such, can no longer be considered a unique feature of hyperthermophiles
NASA Astrophysics Data System (ADS)
Rodriguez-Losada, Jose A.; Eff-Darwich, Antonio; Hernandez, Luis E.; Viñas, Ronaldo; Pérez, Nemesio; Hernandez, Pedro; Melián, Gladys; Martinez-Frías, Jesús; Romero-Ruiz, M. Carmen; Coello-Bravo, Juan Jesús
2015-02-01
This paper describes the main physical, petrological and geochemical features of the floating fragments that were emitted in the initial stages of the 2011-2012 submarine eruption off the coast of the Canarian island of El Hierro, located 380 km from the Northwest African Coast. It attempts to assess the potential of radiometric analyses to discern the intriguing origin of the floating fragments and the differences between their constituent parts. In this regard, the material that conforms the core of the fragments contains the largest concentration of uranium (U) ever found in volcanic rocks of the Canary Islands. This enrichment in U is not found in the content of thorium (Th), hence the floating fragments have an unusual U/Th ratio, namely equal to or larger than 3. Although the origin of this material is under discussion, it is proposed that the enrichment in U is the result of hydrothermal processes.
Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken
2012-01-01
Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205
Hydrothermal Synthesis and Photocatalytic Property of β-Ga2O3 Nanorods
NASA Astrophysics Data System (ADS)
Reddy, L. Sivananda; Ko, Yeong Hwan; Yu, Jae Su
2015-09-01
Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.
Hydrothermal Synthesis and Photocatalytic Property of β-Ga2O3 Nanorods.
Reddy, L Sivananda; Ko, Yeong Hwan; Yu, Jae Su
2015-12-01
Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.
Wang, Yan; Sun, Xiao-ming; Xu, Li; Liang, Ye-heng; Wu, Zhong-wei; Fu, Yu; Huang, Yi
2015-03-01
In this study, we analyze element geochemistry of submarine basalt in situ, which is sampled in hydrothermal areas from ultraslow spreading Southwest Indian Ridge, including the fresh basalt rocks (B19-9, B15-13) and altered basalt (B5-2). And we can confirm that altered mineral in B5-2 is celadonite by microscope and Raman Spectrum. Furthermore, amygdaloidal celadonites are analyzed by electron microprobe (EPMA) and EDS-line scanning. The results show that K-contents decrease and Na-contents increase from the core to the edge in these altered minerals, indicating the transition from celadonite to saponite. Celadonite is an altered minerals, forming in low temperature (< 50 degrees C) and oxidizing condition, while saponite form in low water/rock and more reducing condition. As a result, the transition from celadonite to saponite suggests environment change from oxidizing to reducing condition. Using the result of EPMA as internal standard, we can analyze rare earth elements (REE) in altered mineral in situ. Most of result show positive Eu anomaly (Δ(Eu)), indicating hydrothermal fluid transform from oxidizing to reducing, and reducing fluid rework on the early altered minerals. Comparison with REE in matrix feldspar both in altered and unaltered zoning, we find that reducing fluid can leach REE from the matrix feldspar, leading to lower total REE concentrations and positive Eu anomaly. So leaching process play an important role in hydrothermal system.
Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise
German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M. V.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J. M.; de Lépinay, B. Mercier; Nakamura, K.; Seewald, J. S.; Smith, J. L.; Sylva, S. P.; Van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.
2010-01-01
Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the ∼110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at ∼5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity—all in close proximity. PMID:20660317
Wen, Hsin-Yi; Sano, Yuji; Takahata, Naoto; Tomonaga, Yama; Ishida, Akizumi; Tanaka, Kentaro; Kagoshima, Takanori; Shirai, Kotaro; Ishibashi, Jun-ichiro; Yokose, Hisayoshi; Tsunogai, Urumu; Yang, Tsanyao F.
2016-01-01
Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The 3He flux and methane flux in the investigated area are estimated to be (0.99–2.6) × 104 atoms/cm2/sec and 6–60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin. PMID:27671524
Wen, Hsin-Yi; Sano, Yuji; Takahata, Naoto; Tomonaga, Yama; Ishida, Akizumi; Tanaka, Kentaro; Kagoshima, Takanori; Shirai, Kotaro; Ishibashi, Jun-Ichiro; Yokose, Hisayoshi; Tsunogai, Urumu; Yang, Tsanyao F
2016-09-27
Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The 3 He flux and methane flux in the investigated area are estimated to be (0.99-2.6) × 10 4 atoms/cm 2 /sec and 6-60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin.
600 kyr of Hydrothermal Activity on the Cleft Segment of the Juan de Fuca Ridge
NASA Astrophysics Data System (ADS)
Middleton, J. L.; Mukhopadhyay, S.; Langmuir, C. H.; Costa, K.; McManus, J. F.; Katz, R. F.; Huybers, P. J.; Winckler, G.; Li, Y.
2017-12-01
Pressure fluctuations caused by glacially driven variations in sea level may modulate magmatic and hydrothermal output at submarine volcanic centers, with falling sea level driving increased volcanic activity. In turn, glacially paced changes in submarine volcanism could induce globally synchronous variations in the delivery of bioavailable iron and CO2 from mid-ocean ridges and thus provide solid-Earth feedbacks into the climate system. While evaluation of submarine volcanic output on orbital-timescales is technically challenging, near-ridge sediment cores hosting hydrothermal plume precipitates provide continuous, spatially integrated, and datable records to investigate the long-term behavior of hydrothermal systems. We will present new sedimentary records of hydrothermal variability spanning the past 600 kyr on the Cleft Segment of the Juan de Fuca Ridge in the Northeast Pacific. As an intermediate spreading-rate ridge, the Juan de Fuca Ridge is hypothesized to be particularly sensitive to sea level forcing at the Milankovitch frequencies of Pleistocene glacial cycles. Thus, the new records can be used to examine the connection between sea level and hydrothermal activity over multiple glacial cycles. Hydrothermal input is determined from iron and copper, with a titanium-based correction for lithogenic contributions. Sedimentary fluxes are then constrained using excess thorium-230 and extraterrestrial helium-3 as constant flux proxies. Preliminary results indicate 10-fold changes in hydrothermal iron and copper fluxes over the past 600 kyr and suggest a quasiperiodic variability in hydrothermal deposition on 100 to 120 kyr cycles. Comparison of the Juan de Fuca record with model predictions for an intermediate spreading ridge forced by Pleistocene glacial cycles finds frequent coincidence between predicted positive anomalies in magmatic output and observed peaks in hydrothermal deposition. This work encourages the continued exploration of the relationship between
“Edifice Rex” Sulfide Recovery Project: Analysis of submarine hydrothermal, microbial habitat
NASA Astrophysics Data System (ADS)
Delaney, John R.; Kelley, Deborah S.; Mathez, Edmond A.; Yoerger, Dana R.; Baross, John; Schrenk, Matt O.; Tivey, Margaret K.; Kaye, Jonathan; Robigou, Veronique
Recent scientific developments place inquiries about submarine volcanic systems in a broad planetary context. Among these is the discovery that submarine eruptions are intimately linked with massive effusions of microbes and their products from below the sea floor [Holden et al., 1998]. This material includes microbes that only grow at temperatures tens of degrees higher than the temperatures of the vent fluids from which they were sampled. Such results lend support for the existence of a potentially extensive, but currently unexplored sub-sea floor microbial biosphere associated with active submarine volcanoes [Deming and Baross, 1993; Delaney et al., 1998; Summit and Baross, 1998].
Yu, Mingzhe; Draskovic, Thomas I; Wu, Yiying
2014-06-02
The delafossite CuGaO2 is an important p-type transparent conducting oxide for both fundamental science and industrial applications. An emerging application is for p-type dye-sensitized solar cells. Obtaining delafossite CuGaO2 nanoparticles is challenging but desirable for efficient dye loading. In this work, the phase formation and crystal growth mechanism of delafossite CuGaO2 under low-temperature (<250 °C) hydrothermal conditions are systematically studied. The stabilization of Cu(I) cations in aqueous solution and the controlling of the hydrolysis of Ga(III) species are two crucial factors that determine the phase formation. The oriented attachment (OA) growth is proposed as the crystal growth mechanism to explain the formation of large CuGaO2 nanoplates. Importantly, by suppressing this OA process, delafossite CuGaO2 nanoparticles that are 20 nm in size were successfully synthesized for the first time. Moreover, considering the structural and chemical similarities between the Cu-based delafossite series compounds, the understanding of the hydrothermal chemistry and crystallization mechanism of CuGaO2 should also benefit syntheses of other similar delafossites such as CuAlO2 and CuScO2.
Evidence for early life in Earth's oldest hydrothermal vent precipitates.
Dodd, Matthew S; Papineau, Dominic; Grenne, Tor; Slack, John F; Rittner, Martin; Pirajno, Franco; O'Neil, Jonathan; Little, Crispin T S
2017-03-01
Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite-haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago.
Beyond the vent: New perspectives on hydrothermal plumes and pelagic biology
NASA Astrophysics Data System (ADS)
Phillips, Brennan T.
2017-03-01
Submarine hydrothermal vent fields introduce buoyant plumes of chemically altered seawater to the deep-sea water column. Chemoautotrophic microbes exploit this energy source, facilitating seafloor-based primary production that evidence suggests may transfer to pelagic consumers. While most hydrothermal plumes have relatively small volumes, there are recent examples of large-scale plume events associated with periods of eruptive activity, which have had a pronounced effect on water-column biology. This correlation suggests that hydrothermal plumes may have influenced basin-scale ocean chemistry during periods of increased submarine volcanism during the Phanerozoic eon. This paper synthesizes a growing body of scientific evidence supporting the hypothesis that hydrothermal plumes are the energetic basis of unique deep-sea pelagic food webs. While many important questions remain concerning the biology of hydrothermal plumes, this discussion is not present in ongoing management efforts related to seafloor massive sulfide (SMS) mining. Increased research efforts, focused on high-resolution surveys of midwater biology relative to plume structures, are recommended to establish baseline conditions and monitor the impact of future mining-based disturbances to the pelagic biosphere.
NASA Astrophysics Data System (ADS)
Weiland, C.; Chadwick, W. W.; Embley, R. W.
2001-12-01
To help visualize the submarine volcanic landscape at NOAA's New Millennium Observatory (NeMO), we have created the NeMO Explorer web site: http://www.pmel.noaa.gov/vents/nemo/explorer.html. This web site takes visitors a mile down beneath the ocean surface to explore Axial Seamount, an active submarine volcano 300 miles off the Oregon coast. We use virtual reality to put visitors in a photorealistic 3-D model of the seafloor that lets them view hydrothermal vents and fresh lava flows as if they were really on the seafloor. At each of six virtual sites there is an animated tour and a 360o panorama in which users can view the volcanic landscape and see biological communities within a spatially accurate context. From the six sites there are hyperlinks to 50 video clips taken by a remotely operated vehicle. Each virtual site concentrates on a different topic, including the dynamics of the 1998 eruption at Axial volcano (Rumbleometer), high-temperature hydrothermal vents (CASM and ASHES), diffuse hydrothermal venting (Marker33), subsurface microbial blooms (The Pit), and the boundary between old and new lavas (Castle vent). In addition to exploring the region geographically, visitors can also explore the web site via geological concepts. The concepts gallery lets you quickly find information about mid-ocean ridges, hydrothermal vents, vent fauna, lava morphology, and more. Of particular interest is an animation of the January 1998 eruption, which shows the rapid inflation (by over 3 m) and draining of the sheet flow. For more info see Fox et al., Nature, v.412, p.727, 2001. This project was funded by NOAA's High Performance Computing and Communication (HPCC) and Vents Programs. Our goal is to present a representative portion of the vast collection of NOAA's multimedia imagery to the public in a way that is easy to use and understand. These data are particularly challenging to present because of their high data rates and low contextual information. The 3-D models create
Evidence for early life in Earth’s oldest hydrothermal vent precipitates
Dodd, Matthew S.; Papineau, Dominic; Grenne, Tor; Slack, John F.; Rittner, Martin; Pirajno, Franco; O’Neil, Jonathan; Little, Crispin T.S.
2017-01-01
Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite–haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago.
Submarine thermal springs on the Galapagos Rift
Corliss, J.B.; Dymond, J.; Gordon, L.I.; Edmond, J.M.; Von Herzen, R. P.; Ballard, Richard D.; Green, K.; Williams, D.; Bainbridge, A.; Crane, K.; Van Andel, T. H.
1979-01-01
The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis
NASA Astrophysics Data System (ADS)
Tanaka, A.; Abe, G.; Yamaguchi, K. E.
2014-12-01
Recent studies have shown that submarine hydrothermal system supports diverse microbial life. Bio-essential metals supporting such microbial communities were released from basalts by high-temperature water-rock interaction in deeper part of the oceanic crust and carried by submarine fluid flow. Its total quantity in global hydrothermal settings has been estimated to be on the order of ~1019 g/yr, which is surprisingly on the same order of the total river flows (Urabe et al., 2011). Therefore, it is important to explore how submarine river system works, i.e., to understand mechanism and extent of elemental transport, which should lead to understanding of the roles of hydrothermal circulation in oceanic crust in controlling elemental budget in the global ocean and geochemical conditions to support deep hot biosphere. We performed REE analysis of marine sediments influenced by submarine hydrothermal activity in Mid-Okinawa Trough. The sediment samples used in this study are from IODP site at Iheya North region and JADE site at Izena region. The samples show alternation between volcanic and clastic sediments. Hydrothermal fluids of this area contain elevated concentrations of volatile components such as H2, CO2, CH4, NH4+, and H2S, supporting diverse chemoautotrophic microbial community (Nakagawa et al., 2005). The purpose of this study is to examine the effect of hydrothermal activity on the REE signature of the sediments. Chondrite-normalized REE patterns of the samples show relative enrichment of light over heavy REEs, weak positive Ce anomalies, and variable degrees of negative Eu anomalies. The REE patterns suggest the sediments source was mainly basalt, suggesting insignificant input of continental materials. Negative Eu anomalies found in the IODP site become more pronounced with increasing depth, suggesting progressive increase of hydrothermal alteration where Eu was reductively dissolved into fluids by decomposition of feldspars. Contrary, at the JADE site
Chemical Fluxes from a Recently Erupted Submarine Volcano on the Mariana Arc
NASA Astrophysics Data System (ADS)
Buck, N. J.; Resing, J. A.; Lupton, J. E.; Larson, B. I.; Walker, S. L.; Baker, E. T.
2016-12-01
While hydrothermal circulation is paramount to the geochemical budget for a wide array of elements, relatively few flux estimates exist in the literature. To date most studies have concentrated on constraining global and vent-field scale inputs originating from ocean spreading ridges. The goal of this study is to directly measure the chemical flux from an active submarine volcano injecting hydrothermal fluids into the surface ocean. Ahyi Seamount, a submarine intraoceanic arc volcano located in the Northern Mariana Islands, has a summit depth <100 m and erupted in May 2014. In November 2014 a hydrothermal plume originating from Ahyi was sampled aboard the R/V Roger Revelle during the Submarine Ring of Fire 2014 Ironman Expedition. Shipboard hull mounted Acoustic Doppler Current Profile data was collected to provide current vector measurements to be used in combination with continuous and discrete CTD data. Towed CTD sections were conducted perpendicular to the current direction - a sampling strategy that optimizes chemical flux estimate calculations by reducing complexities introduced by temporal variability in the speed and direction of plume dispersion. The Ahyi plume had a significant optical backscatter signal accompanied by evidence of reduced chemical species and a lowered pH. It was sampled for He isotopes, CH4, H2, H2S, total CO2, nutrients, TSM and total and dissolved Fe and Mn. Laboratory analyses found enriched concentrations of H2, 3He, CO2 and Fe, consistent with a recent eruption. Preliminary flux calculations estimate a Fe input of 16 mmol s-1. This indicates shallow submarine arc volcanoes are capable of supplying appreciable quantities of Fe into the surface ocean. Further laboratory analyses and calculations to characterize and constrain the fluxes of other chemical constituents are underway.
Organic synthesis during fluid mixing in hydrothermal systems
NASA Astrophysics Data System (ADS)
Shock, Everett L.; Schulte, Mitchell D.
1998-12-01
Hydrothermal circulation can lead to fluid mixing on any planet with liquid water and a source of heat. Aqueous fluids with differing compositions, especially different oxidation states, are likely to be far from thermodynamic equilibrium when they mix, and provide a source of free energy that can drive organic synthesis from CO2 and H2, and/or supply a source of geochemical energy to chemolithoautotrophic organisms. Results are presented that quantify the potential for organic synthesis during unbuffered fluid mixing in present submarine hydrothermal systems, as well as hypothetical systems that may have existed on the early Earth and Mars. Dissolved hydrogen, present in submarine hydrothermal fluids owing to the high-temperature reduction of H2O as seawater reacts with oceanic crustal rocks, provides the reduction potential and the thermodynamic drive for organic synthesis from CO2 (or bicarbonate) as hydrothermal fluids mix with seawater. The potential for organic synthesis is a strong function of the H2 content of the hydrothermal fluid, which is, in turn, a function of the prevailing oxidation state controlled by the composition of the rock that hosts the hydrothermal system. Hydrothermal fluids with initial oxidation states at or below those set by the fayalite-magnetite-quartz mineral assemblage show the greatest potential for driving organic synthesis. These calculations show that it is thermodynamically possible for 100% of the carbon in the mixed fluid to be reduced to a mixture of carboxylic acids, alcohols, and ketones in the range 250-50°C as cold seawater mixes with the hydrothermal fluid. As the temperature drops, larger organic molecules are favored, which implies that fluid mixing could drive the geochemical equivalent of a metabolic system. This enormous reduction potential probably drives a large portion of the primary productivity around present seafloor hydrothermal vents and would have been present in hydrothermal systems on the early Earth
Diverse styles of submarine venting on the ultra-slow spreading Mid-Cayman Rise (Invited)
NASA Astrophysics Data System (ADS)
German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J.; Mercier de Lepinay, B. F.; Nakamura, K.; Seewald, J.; Smith, J.; Sylva, S.; van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.
2010-12-01
Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global Mid Ocean Ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultra-slow spreading ridges which were the last to be demonstrated to host high-temperature venting, but may host systems particularly relevant to pre-biotic chemistry and the origins of life. Here we report first evidence for diverse and very deep hydrothermal vents along the ~110 km long, ultra-slow spreading Mid-Cayman Rise collected using a combination of CTD-rosette operations and dives of the Hybrid Remotely Operated Vehicle (HROV) Nereus in 2009 followed by shore based work-up of samples for geochemical and microbiological analyses. Our data indicate that the Mid-Cayman Rise hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultra-mafic systems and, at ~5000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent-types identified here and their relative geographic isolation make the Mid-Cayman Rise unique in the oceans. These new sites offer prospects for: an expanded range of vent-fluid compositions; varieties of abiotic organic chemical synthesis and extremophile microorganisms; and unparalleled faunal biodiversity - all in close proximity.
Schrenk, Matthew O; Kelley, Deborah S; Bolton, Sheryl A; Baross, John A
2004-10-01
The recently discovered Lost City Hydrothermal Field (LCHF) represents a new type of submarine hydrothermal system driven primarily by exothermic serpentinization reactions in ultramafic oceanic crust. Highly reducing, alkaline hydrothermal environments at the LCHF produce considerable quantities of hydrogen, methane and organic molecules through chemo- and biosynthetic reactions. Here, we report the first analyses of microbial communities inhabiting carbonate chimneys awash in warm, high pH fluids at the LCHF and the predominance of a single group of methane-metabolizing Archaea. The predominant phylotype, related to the Methanosarcinales, formed tens of micrometre-thick biofilms in regions adjacent to hydrothermal flow. Exterior portions of active structures harboured a diverse microbial community composed primarily of filamentous Eubacteria that resembled sulphide-oxidizing species. Inactive samples, away from regions of hydrothermal flow, contained phylotypes related to pelagic microorganisms. The abundance of organisms linked to the volatile chemistry at the LCHF hints that similar metabolic processes may operate in the subseafloor. These results expand the range of known geological settings that support biological activity to include submarine hydrothermal systems that are not dependent upon magmatic heat sources.
Energetics of amino acid synthesis in hydrothermal ecosystems
NASA Technical Reports Server (NTRS)
Amend, J. P.; Shock, E. L.
1998-01-01
Thermodynamic calculations showed that the autotrophic synthesis of all 20 protein-forming amino acids was energetically favored in hot (100 degrees C), moderately reduced, submarine hydrothermal solutions relative to the synthesis in cold (18 degrees C), oxidized, surface seawater. The net synthesis reactions of 11 amino acids were exergonic in the hydrothermal solution, but all were endergonic in surface seawater. The synthesis of the requisite amino acids of nine thermophilic and hyperthermophilic proteins in a 100 degreesC hydrothermal solution yielded between 600 and 8000 kilojoules per mole of protein, which is energy that is available to drive the intracellular synthesis of enzymes and other biopolymers in hyperthermophiles thriving in these ecosystems.
Hydrothermal exploration and astrobiology: oases for life in distant oceans?
NASA Astrophysics Data System (ADS)
German, Christopher R.
2004-04-01
High-temperature submarine hydrothermal fields on Earth's mid-ocean ridges play host to exotic ecosystems with fauna previously unknown to science. Because these systems draw significant energy from chemosynthesis rather than photosynthesis, it has been postulated that the study of such systems could have relevance to the origins of life and, hence, astrobiology. A major flaw to that argument, however, is that modern basalt-hosted submarine vents are too oxidizing and lack the abundant free hydrogen required to drive abiotic organic synthesis and/or the energy yielding reactions that the most primitive anaerobic thermophiles isolated from submarine vent-sites apparently require. Here, however, the progress over the past decade in which systematic search strategies have been used to identify previously overlooked venting on the slow-spreading Mid-Atlantic Ridge and the ultra-slow spreading Arctic and SW Indian Ridges is described. Preliminary identification of fault-controlled venting in a number of these sites has led to the discovery of at least two high-temperature hydrothermal fields hosted in ultramafic rocks which emit complex organic molecules in their greater than 360 °C vent-fluids. Whether these concentrations represent de novo organic synthesis within the hydrothermal cell remains open to debate but it is probable that many more such sites exist throughout the Atlantic, Arctic and SW Indian Oceans. One particularly intriguing example is the Gakkel Ridge, which crosses the floor of the Arctic Ocean. On-going collaborations between oceanographers and astrobiologists are actively seeking to develop a new class of free-swimming autonomous underwater vehicle, equipped with appropriate chemical sensors, to conduct long-range missions that will seek out, locate and investigate new sites of hydrothermal venting at the bottom of this, and other, ice-covered oceans.
NASA Astrophysics Data System (ADS)
Zhang, J.; Yoshida, K.; Hagiwara, T.; Nagao, K.; Kusakabe, M.; Wang, B.; Chen, C. A.
2012-12-01
Most natural Shallow Water submarine Hydrothermal activates (SWH) along coastlines are related to hydrothermal eruptions involving heating of groundwater with the volcanic gas. These SWHs supply nutrients such as phosphorus and micro nutrients like iron to the euphotic zone, contributing to the overall natural fertility and primary productivity of coastal waters. However, SWHs also have a negative effect, dispersing toxic materials such as mercury and arsenic, and affecting the acidification of the surrounding waters. In this study, we evaluate the impact of "iron supply" and "ocean acidification" on the primary production in a coastal marine environment, at a SWH area discovered off Gueshandao Island, northeast Taiwan. In the past three years, expeditions were conducted and observations made around this SWH site. Divers, small boats and a research vessel (R/V OR1, Ocean University National Taiwan) were used to survey successively larger areas around the site. Some of the results obtained are as follows. Hydrothermal vents are located in a hilly terrain rich with hot spring water with gas erupting intermittently. There are two types of vents, roughly divided by color, yellow hot spring water with higher temperature >110 degC ejected from sulfur chimneys of various sizes, and colorless water with lower temperature ~80 degC ejected directly from the crevices of the andesitic bedrock. Natural sulfur solidifying in the mouth of a small chimney was captured by a video camera, and explosions were also observed at intervals of a few minutes. Sediment, sand and particles of sulfur were deposited on the sides to a radius of about 50 m condensing around the chimney. The bottom type changes from sand/particles to outcrop/rock away from the vents. Moreover, gas samples were collected from the vents; the ratios of gas concentrations (N2/Ar) and isotopic composition of noble gas (3He/4He) suggest that these volcanic gases are mantle-derived. Hydrothermal fluid with high p
Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents
NASA Astrophysics Data System (ADS)
Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua
2017-12-01
Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H2 and CO2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.
Prebiotic Synthesis of Glycine from Ethanolamine in Simulated Archean Alkaline Hydrothermal Vents.
Zhang, Xianlong; Tian, Ge; Gao, Jing; Han, Mei; Su, Rui; Wang, Yanxiang; Feng, Shouhua
2017-12-01
Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H 2 and CO 2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80-160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1-8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.
Miniature Robotic Submarine for Exploring Harsh Environments
NASA Technical Reports Server (NTRS)
Behar, Alberto; Bruhn, Fredrik; Carsey, Frank
2004-01-01
The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration -- especially, looking for signs of life -- in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine (see figure) that could launch itself or could be launched from another vehicle. Examples of environments that might be explored by use of the MASE include subglacial lakes, deep-ocean hydrothermal vents, acidic or alkaline lakes, brine lenses in permafrost, and ocean regions under Antarctic ice shelves.
NASA Astrophysics Data System (ADS)
Rubin, K. H.; Chadwick, W. C.; Embley, R. W.; Butterfield, D. A.
2018-05-01
Newly-discovered extensive explosive deep sea volcanism produces distinct stratovolcano structures and physical rock characteristics, and host primarily diffuse flow hydrothermal activity, unlike focused flow systems at effusive submarine volcanoes.
Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël
2015-01-01
Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.
Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël
2015-01-01
Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems. PMID:26379636
Pathways for abiotic organic synthesis at submarine hydrothermal fields.
McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P
2015-06-23
Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.
Pathways for abiotic organic synthesis at submarine hydrothermal fields
McDermott, Jill M.; Seewald, Jeffrey S.; German, Christopher R.; Sylva, Sean P.
2015-01-01
Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond. PMID:26056279
Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.
ERIC Educational Resources Information Center
National Oceanic and Atmospheric Administration (DOC), Rockville, MD.
This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent…
2009-02-01
21 ° N East Pacific Rise . In Hydrothermal Processes at Seafloor Spreading Centers (ed. P. Rona, K. Boström, L. Laubier, and K. L. Smith), pp... hydrothermal fluids ( 21 ° N East Pacific Rise ) are taken from Mitra et al (1994) and Klinkhammer et al. (1994). The chemical composition...Measures C. I., Walden B., and Weiss R. F. (1985) Chemistry of submarine hydrothermal solutions at 21 ° N , East
Thermodynamics of Strecker synthesis in hydrothermal systems
NASA Technical Reports Server (NTRS)
Schulte, Mitchell; Shock, Everett
1995-01-01
Submarine hydrothermal systems 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 hydrothermal 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 hydrothermal systems provide important clues for determining the potential of these and other systems as sites for the emergence of life.
Coupled cycling of Fe and organic carbon in submarine hydrothermal systems: Modelling approach
NASA Astrophysics Data System (ADS)
Legendre, Louis; German, Christopher R.; Sander, Sylvia G.; Niquil, Nathalie
2014-05-01
It has been recently proposed that hydrothermal plumes may be a significant source of dissolved Fe to the oceans. In order to assess this proposal, we investigated the fate of dissolved Fe released from hydrothermal systems to the overlying ocean using an approach that combined modelling and field values. We based our work on a consensus conceptual model developed by members of SCOR-InterRidge Working Group 135. The model was both complex enough to capture the main processes of dissolved Fe released from hydrothermal systems and chemical transformation in the hydrothermal plume, and simple enough to be parameterized with existing field data. It included the following flows: Fe, water and heat in the high temperature vent fluids, in the fluids diffusing around the vent, and in the entrained seawater in the buoyant plume; Fe precipitation in polymetallic sulphides near the vent; transport of Fe in the non-buoyant plume, and both its precipitation in particles onto the sea bottom away from the vent and dissolution into deep-sea waters. In other words, there were three Fe input flows into the buoyant hydrothermal plume (vent-fluids; entrained diffuse flow; entrained seawater) and three Fe output flows (sedimentation from the buoyant plume as polymetallic sulfides; sedimentation from the non-buoyant plume in particulate form; export to the deep ocean in dissolved or nanoparticulate form). The output flows balanced the input flows. We transformed the conceptual model into equations, and parameterized these with field data. To do so, we assumed that all hydrothermal systems, globally, can be represented by the circumstances that prevail at the EPR 9°50'N hydrothermal field, although we knew this assumption not to be accurate. We nevertheless achieved, by following this approach, two important goals, i.e. we could assemble into a coherent framework, for the first time, several discrete data sets acquired independently over decades of field work, and we could obtain model
The chemistry of hydrothermal magnetite: a review
Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John
2014-01-01
States and Indonesia, and (5) plutonic igneous rocks from the Henderson Climax-type Mo deposit, United States, and the un-mineralized Inner Zone Batholith granodiorite, Japan. These five settings represent a diverse suite of geological settings and cover a wide range of formation conditions. The main discriminator elements for magnetite are Mg, Al, Ti, V, Cr, Mn, Co, Ni, Zn, and Ga. These elements are commonly present at detectable levels (10 to > 1000 ppm) and display systematic variations. We propose a combination of Ni/(Cr + Mn) vs. Ti + V, Al + Mn vs. Ti + V, Ti/V and Sn/Ga discriminant plots and upper threshold concentrations to discriminate hydrothermal from igneous magnetite and to fingerprint different hydrothermal ore deposits. The overall trends in upper threshold values for the different settings can be summarized as follows: (I) BIF (hydrothermal) — low Al, Ti, V, Cr, Mn, Co, Ni, Zn, Ga and Sn; (II) Ag–Pb–Zn veins (hydrothermal) — high Mn and low Ga and Sn; (III) Mg-skarn (hydrothermal) — high Mg and Mn and low Al, Ti, Cr, Co, Ni and Ga; (IV) skarn (hydrothermal) — high Mg, Al, Cr, Mn, Co, Ni and Zn and low Sn; (V) porphyry (hydrothermal) — high Ti and V and low Sn; (VI) porphyry (igneous) — high Ti, V and Cr and low Mg; and (VII) Climax-Mo (igneous) — high Al, Ga and Sn and low Mg and Cr.
Frouin, Eléonore; Bes, Méline; Ollivier, Bernard; Quéméneur, Marianne; Postec, Anne; Debroas, Didier; Armougom, Fabrice; Erauso, Gaël
2018-01-01
The Bay of Prony, South of New Caledonia, represents a unique serpentinite-hosted hydrothermal field due to its coastal situation. It harbors both submarine and intertidal active sites, discharging hydrogen- and methane-rich alkaline fluids of low salinity and mild temperature through porous carbonate edifices. In this study, we have extensively investigated the bacterial and archaeal communities inhabiting the hydrothermal chimneys from one intertidal and three submarine sites by 16S rRNA gene amplicon sequencing. We show that the bacterial community of the intertidal site is clearly distinct from that of the submarine sites with species distribution patterns driven by only a few abundant populations, affiliated to the Chloroflexi and Proteobacteria phyla. In contrast, the distribution of archaeal taxa seems less site-dependent, as exemplified by the co-occurrence, in both submarine and intertidal sites, of two dominant phylotypes of Methanosarcinales previously thought to be restricted to serpentinizing systems, either marine (Lost City Hydrothermal Field) or terrestrial (The Cedars ultrabasic springs). Over 70% of the phylotypes were rare and included, among others, all those affiliated to candidate divisions. We finally compared the distribution of bacterial and archaeal phylotypes of Prony Hydrothermal Field with those of five previously studied serpentinizing systems of geographically distant sites. Although sensu stricto no core microbial community was identified, a few uncultivated lineages, notably within the archaeal order Methanosarcinales and the bacterial class Dehalococcoidia (the candidate division MSBL5) were exclusively found in a few serpentinizing systems while other operational taxonomic units belonging to the orders Clostridiales, Thermoanaerobacterales , or the genus Hydrogenophaga , were abundantly distributed in several sites. These lineages may represent taxonomic signatures of serpentinizing ecosystems. These findings extend our current
Heavy metals from Kueishantao shallow-sea hydrothermal vents, offshore northeast Taiwan
NASA Astrophysics Data System (ADS)
Chen, Xue-Gang; Lyu, Shuang-Shuang; Garbe-Schönberg, Dieter; Lebrato, Mario; Li, Xiaohu; Zhang, Hai-Yan; Zhang, Ping-Ping; Chen, Chen-Tung Arthur; Ye, Ying
2018-04-01
Shallow water hydrothermal vents are a source of heavy metals leading to their accumulation in marine organisms that manage to live under extreme environmental conditions. This is the case at Kueishantao (KST) shallow-sea vents system offshore northeast Taiwan, where the heavy metal distribution in vent fluids and ambient seawater is poorly understood. This shallow vent is an excellent natural laboratory to understand how heavy and volatile metals behave in the nearby water column and ecosystem. Here, we investigated the submarine venting of heavy metals from KST field and its impact on ambient surface seawater. The total heavy metal concentrations in the vent fluids and vertical plumes were 1-3 orders of magnitude higher than the overlying seawater values. When compared with deep-sea hydrothermal systems, the estimated KST end-member fluids exhibited much lower concentrations of transition metals (e.g., Fe and Mn) but comparable concentrations of toxic metals such as Pb and As. This may be attributed to the lower temperature of the KST reaction zone and transporting fluids. Most of the heavy metals (Fe, Mn, As, Y, and Ba) in the plumes and seawater mainly originated from hydrothermal venting, while Cd and Pb were largely contributed by external sources such as contaminated waters (anthropogenic origin). The spatial distribution of heavy metals in the surface seawater indicated that seafloor venting impacts ambient seawater. The measurable influence of KST hydrothermal activity, however, was quite localized and limited to an area of < 1 km2. The estimated annual fluxes of heavy metals emanating from the yellow KST hydrothermal vent were: 430-2600 kg Fe, 24-145 kg Mn, 5-32 kg Ba, 10-60 kg As, 0.3-1.9 kg Cd, and 2-10 kg Pb. This study provides important data on heavy metals from a shallow-sea hydrothermal field, and it helps to better understand the environmental impact of submarine shallow hydrothermal venting.
Bottom sediments and pore waters near a hydrothermal vent in Lake Baikal (Frolikha Bay)
Granina, L.Z.; Klerkx, J.; Callender, E.; Leermakers, M.; Golobokova, L.P.
2007-01-01
We discuss the redox environments and the compositions of bottom sediments and sedimentary pore waters in the region of a hydrothermal vent in Frolikha Bay, Lake Baikal. According to our results, the submarine vent and its companion nearby spring on land originate from a common source. The most convincing evidence for their relation comes from the proximity of stable oxygen and hydrogen isotope compositions in pore waters and in the spring water. The isotope composition indicates a meteoric origin of pore waters, but their major- and minor-element chemistry bears imprint of deep water which may seep through permeable faulted crust. Although pore waters near the submarine vent have a specific enrichment in major and minor constituents, hydrothermal discharge at the Baikal bottom causes a minor impact on the lake water chemistry, unlike the case of freshwater geothermal lakes in the East-African Rift and North America. ?? 2007.
NASA Astrophysics Data System (ADS)
Cui, Lu; Wang, Hong; Xin, Baifu; Mao, Guijie
2017-10-01
Ultrafine nanocrystals of γ-gallium oxide (γ-Ga2O3) were rapidly synthesized via microwave hydrothermal method at 140 °C, in which Ga(NO3)3 was used as the gallium source and urea was the precipitant. The samples were characterized by X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-Vis), transmission electron microscopy (TEM), nitrogen physisorption and photoluminescence spectroscopy (PL). The crystallite size of ultrafine spinel γ-Ga2O3 was in the range from 4 to 5 nm and the optical bandgap was 4.61 eV. To improve the crystallinity, the ultrafine γ-Ga2O3 nanocrystals were calcined at 300-700 °C further. The ultrafine γ-Ga2O3 calcined at 500 °C (calcined-γ-Ga2O3) still remained the metastable γ-phase with relatively high crystallinity and the crystallite size around 5-7 nm. Photocatalytic performances of the synthesized samples were also evaluated by the degradation of rhodamine B (RhB). Results revealed that the ultrafine γ-Ga2O3 and the calcined-γ-Ga2O3 samples exhibited high photocatalytic efficiencies of 68.2 and 90.7%, respectively.
Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc
NASA Astrophysics Data System (ADS)
Hanson, M.; Beaulieu, S.; Tunnicliffe, V.; Chadwick, W.; Breuer, E. R.
2015-12-01
In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 through 2010 and ceased as of 2014. In late 2009, NW Rota-1 experienced a massive landslide decimating the habitat on the southern side of the volcano. This presented an enormous natural disturbance to the community. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching specifically for larvae which have the potential to recolonize the sea floor after such a major disturbance. We focused on samples for which profiles with a MAPR sensor indicated hydrothermal plumes in the water column. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument also can act as sources for these planktonic, recolonizing larvae. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both
Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc
NASA Astrophysics Data System (ADS)
Beaulieu, S.; Hanson, M.; Tunnicliffe, V.; Chadwick, W. W., Jr.; Breuer, E. R.
2016-02-01
In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 and 2010 and ceased as of 2014. NW Rota-1 experienced a massive landslide in late 2009, decimating the habitat on the southern side of the volcano. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching for larvae which have the potential to recolonize the sea floor after such a major disturbance. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument may act as sources for these larvae, but connectivity in this region of complex topography is unknown. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both the zooplankton and benthic community composition in this area of the Monument.
NASA Astrophysics Data System (ADS)
Dann, Jesse
2001-08-01
Komatiites of the 3.5-Ga Komati Formation are ultramafic lavas (>23% MgO) erupted in a submarine, lava plain environment. Newly discovered vesicular komatiites have vesicular upper crusts disrupted by synvolcanic structures that are similar to inflation-related structures of modern lava flows. Detailed outcrop maps reveal flows with upper vesicular zones, 2-15 m thick, which were (1) rotated by differential inflation, (2) intruded by dikes from the interior of the flow, (3) extended, forming a flooded graben, and/or (4) entirely engulfed. The largest inflated structure is a tumulus with 20 m of surface relief, which was covered by a compound flow unit of spinifex flow lobes. The lava that inflated and rotated the upper vesicular crust did not vesiculate, but crystallized as a thick spinifex zone with fist-size skeletal olivine. Instead of representing rapidly cooled lava, the spinifex zone cooled slowly beneath an insulating upper crust during inflation. Overpressure of the inflating lava may have inhibited vesiculation. This work describes the oldest vesicular komatiites known, illustrates the first field evidence for inflated structures in komatiite flows, proposes a new factor in the development of spinifex zones, and concludes that the inflation model is useful for understanding the evolution of komatiite submarine flow fields.
NASA Astrophysics Data System (ADS)
Ko, Rong-Ming; Wang, Shui-Jinn; Chen, Ching-Yi; Wu, Cheng-Han; Lin, Yan-Ru; Lo, Hsin-Ming
2017-04-01
The hydrothermal growth (HTG) of crystalline n-ZnO films on both the nonpatterned and patterned p-GaN epilayers with a honeycomb array of etched holes is demonstrated, and its application in n-ZnO/p-GaN heterojunction light-emitting diodes (HJ-LEDs) is reported. The results reveal that an HTG n-ZnO film on a patterned p-GaN layer exhibits a high-quality single crystal with FWHMs of 0.463 and 0.983° obtained from a ω-rocking curve and a ϕ-scan pattern, respectively, which are much better than those obtained on a nonpatterned p-GaN layer. In addition, the n-ZnO/patterned p-GaN HJ-LED exhibited a much better rectifying diode behavior owing to having a higher n-ZnO film crystallinity quality and an improved interface with the p-GaN layer. Strong violet and violet-blue lights emitted from the n-ZnO/patterned p-GaN HJ-LED at around 405, 412, and 430 nm were analyzed.
NASA Astrophysics Data System (ADS)
Chen, Xue-Gang; Lyu, Shuang-Shuang; Zhang, Ping-Ping; Yu, Ming-Zhen; Chen, Chen-Tung Arthur; Chen, Yun-Jie; Li, Xiaohu; Jin, Aimin; Zhang, Hai-Yan; Duan, Wei; Ye, Ying
2018-03-01
The chemical compositions of gas discharges from the Kueishantao (KST) hydrothermal field changed dramatically from 2000 to 2014. In this study, we established a gas mixing model for the KST gases. The N2, Ar, and CO2 contents were mixed from a magmatic endmember with CO2 of about 990 mmol/mol, a hydrothermal and an atmospheric endmember enriched in N2 and Ar. More than 71% KST gas components were mantle-derived/magmatic. The calculated endmember N2/Ar ratio and Ar contents of the hydrothermal endmember (percolated fluid) are about 140 and 5.28-5.52 mmol/mol, respectively. This relatively elevated N2/Ar ratio was probably caused by the thermogenic addition of N2. The log(CH4/CO2) values of the KST gas samples correlate well with the mixing temperature that estimated from the mixing ratio between the percolated fluid and the magmatic endmember. It is indicated that the KST CH4 and CO2 may have attained chemical equilibrium. The temporal variations of the KST gas compositions are determined by the mixing ratio, which is dependent on the magmatic activity underneath the KST field. With the decreasing of magmatic activity since 2005, the proportion of the hydrothermal endmember increased, along with the increasing of N2, Ar, and CH4 contents. This study proposed an effective model to quantitatively assess the sources of gas components discharged from submarine hydrothermal vents. In addition, it is suggested that the mixing between a magmatic and a hydrothermal endmember may play an important role in the concentrations of CO2 and CH4 in hydrothermal gas discharges.
Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system.
Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai
2016-06-17
Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.
Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system
Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valèrie; Nomikou, Paraskevi; Polymenakou, Paraskevi N.; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai
2016-01-01
Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10−6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano. PMID:27311383
2015-06-15
What would a submarine to explore the liquid methane seas of Saturn's Moon Titan look like? This video shows one submarine concept that would explore both the shoreline and the depths of this strange world that has methane rain, rivers and seas! The design was developed for the NASA Innovative Advanced Concepts (NIAC) Program, by NASA Glenn's COMPASS Team, and technologists and scientists from the Applied Physics Lab and submarine designers from the Applied Research Lab.
Extraterrestrial Impact Episodes and Archaean to Early Proterozoic (3.8 2.4 Ga) Habitats of Life
NASA Astrophysics Data System (ADS)
Glikson, Andrew
development of sulphate-reducing microbes around anoxic submarine fumarole ("black smoker") environments; (3) ~2.63-2.47 Ga - impact-triggered tsunami effects in oxygenated carbonate-dominated epicontinental and intracratonic environments (Hamersley and Transvaal basins); (4) in at least three instances onset of ferruginous sedimentation closely following major impact events, possibly signifying hydrothermal Fe-enrichment related to impact-triggered volcanic activity. Due to limitations on the phylogenic speciation of Precambrian stromatolite and bacterial populations, major impact-extinction-radiation relations are identified only from the late Proterozoic, beginning with the ~0.
The hydrothermal exploration system on the 'Qianlong2' AUV
NASA Astrophysics Data System (ADS)
Tao, W.; Tao, C.; Jinhui, Z.; Cai, L.; Guoyin, Z.
2016-12-01
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 hydrothermal 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 hydrothermal exploration system 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 hydrothermal vents. Taking one dive as an example, we systemically showed the process about how to analyse hydrothermal survey data and acquire the location results of hydrothermal 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.
NASA Astrophysics Data System (ADS)
Watanabe, Y.; Ohmoto, H.
2010-12-01
As part of the Archean Biosphere Drilling Project (ABDP), we have determined the multiple sulfur isotope ratios and examined the mineralogical and geochemical characteristics of the sulfur-bearing minerals (e.g., pyrite, sphalerite, barite) and the host rocks (e.g., major and trace element chemistry; Corg, Ccarb and S contents; δ13Corg and δ13Ccarb) of >100 samples of sedimentary rocks from five ABDP drill cores in the Pilbara Craton, Western Australia. The total ranges of Δ33S and δ34S values of the studied samples are -0.9 to +1.2‰ and -4 to +8‰, respectively. We have found that the Δ33S and δ34S relationships show unique values depending on their depositional environment: (1) Pyrites in the 3.46 Ga Marble Bar Chert Member (ABDP #1), which were formed by submarine hydrothermal fluids, show no AIF-S (anomalously fractionated sulfur isotope) signatures: Δ33S = -0.08 to +0.08‰ and δ34S = -3.3 to +0.6‰ (n = 5). This indicates that the H2S presented in the submarine hydrothermal fluid, which was partly generated through seawater sulfate reduction by Fe2+, did not possess AIF-S signatures. (2) Pyrites in organic C-poor lacustrine shales of the 2.76 Ga Hardey Formation (ABDP #3) also show no or very little AIF-S signatures: Δ33S = -0.38 to +0.25‰ and δ34S = -2.7 to +1.9‰ (n = 18). (3) Pyrites in organic C-poor marine shales of the 2.92 Ga Mosquito Creek Formation (ABDP#5) show no or small negative AIF-S signatures: Δ33S = -0.59 to 0.19 ‰ and all positive δ34S = +1.4 to +7.7‰ (n = 24). (4) Pyrites in organic C-rich (> 1 wt%) and hydrothermally altered marine shales in the 3.46 Ga Panorama Formation (ABDP #2) show constant and small positive AIF-S signatures (+0.44 to +0.61‰) and the smallest variation in δ34S (-1.1 to +1.6‰) (n = 35). In contrast, pyrites in organic C-rich shales in the 2.72 Ga Mt. Roe Basalt show negative Δ33S = -0.50 to -0.10‰ and δ34S = -3.7 to 1.8‰ (n = 10). (5) Pyrites in stromatolitic carbonates of the 2.7 Ga
Ancient hydrothermal ecosystems on earth: a new palaeobiological frontier.
Walter, M R
1996-01-01
Thermal springs are common in the oceans and on land. Early in the history of the Earth they would have been even more abundant, because of a higher heat flow. A thermophilic lifestyle has been proposed for the common ancestor of extant life, and hydrothermal ecosystems can be expected to have existed on Earth since life arose. Though there has been a great deal of recent research on this topic by biologists, palaeobiologists have done little to explore ancient high temperature environments. Exploration geologists and miners have long known the importance of hydrothermal systems, as they are sources for much of our gold, silver, copper, lead and zinc. Such systems are particularly abundant in Archaean and Proterozoic successions. Despite the rarity of systematic searches of these by palaeobiologists, already 12 fossiliferous Phanerozoic deposits are known. Five are 'black smoker' type submarine deposits that formed in the deep ocean and preserve a vent fauna like that in the modern oceans; the oldest is Devonian. Three are from shallow marine deposits of Carboniferous age. As well as 'worm tubes', several of these contain morphological or isotopic evidence of microbial life. The oldest well established fossiliferous submarine thermal spring deposit is Cambro-Ordovician; microorganisms of at least three or four types are preserved in this. One example each of Carboniferous and Jurassic sub-lacustrine fossiliferous thermal springs are known. There are two convincing examples of fossiliferous subaerial hydrothermal deposits. Both are Devonian. Several known Proterozoic and Archaean deposits are likely to preserve a substantial palaeobiological record, and all the indications are that there must be numerous deposits suitable for study. Already it is demonstrable that in ancient thermal spring deposits there is a record of microbial communities preserved as stromatolites, microfossils, isotope distribution patterns and hydrocarbon biomarkers.
From GaN to ZnGa(2)O(4) through a low-temperature process: nanotube and heterostructure arrays.
Lu, Ming-Yen; Zhou, Xiang; Chiu, Cheng-Yao; Crawford, Samuel; Gradečak, Silvija
2014-01-22
We demonstrate a method to synthesize GaN-ZnGa2O4 core-shell nanowire and ZnGa2O4 nanotube arrays by a low-temperature hydrothermal process using GaN nanowires as templates. Transmission electron microscopy and X-ray photoelectron spectroscopy results show that a ZnGa2O4 shell forms on the surface of GaN nanowires and that the shell thickness is controlled by the time of the hydrothermal process and thus the concentration of Zn ions in the solution. Furthermore, ZnGa2O4 nanotube arrays were obtained by depleting the GaN core from GaN-ZnGa2O4 core-shell nanowire arrays during the reaction and subsequent etching with HCl. The GaN-ZnGa2O4 core-shell nanowires exhibit photoluminescence peaks centered at 2.60 and 2.90 eV attributed to the ZnGa2O4 shell, as well as peaks centered at 3.35 and 3.50 eV corresponding to the GaN core. We also demonstrate the synthesis of GaN-ZnGa2O4 heterojunction nanowires by a selective formation process as a simple route toward development of heterojunction nanodevices for optoelectronic applications.
NASA Astrophysics Data System (ADS)
Kolesnik, O. N.; Astakhova, N. V.
2018-01-01
Iron-manganese formations and igneous rocks of submarine elevations in the Sea of Japan contain overlapping mineral phases (grains) with quite identical morphology, localization, and chemical composition. Most of the grains conform to oxides, intermetallic compounds, native elements, sulfides, and sulfates in terms of the set of nonferrous, noble, and certain other metals (Cu, Zn, Sn, Pb, Ni, Mo, Ag, Pd, and Pt). The main conclusion that postvolcanic hydrothermal fluids are the key sources of metals is based upon a comparison of the data of electron microprobe analysis of iron-manganese formations and igneous rocks dredged at the same submarine elevations in the Sea of Japan.
NASA Astrophysics Data System (ADS)
Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim
2018-03-01
Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis
).
Submarine Landslides: A Multidisciplinary Crossroad
NASA Astrophysics Data System (ADS)
Moscardelli, L. G.
2014-12-01
The study of submarine landslides has advanced considerably in the last decade. A multitude of geoscience disciplines, including marine, petroleum and planetary geology, as well as geohazard assessments, are concerned with the study of these units. Oftentimes, researchers working in these fields disseminate their findings within their own communities and a multidisciplinary approach seems to lack. This presentation showcases several case studies in which a broader approach has increased our understanding of submarine landslides in a variety of geologic settings. Three-dimensional seismic data from several continental margins (Trinidad, Brazil, Morocco, Canada, GOM), as well as data from outcrop localities are shown to explore geomorphological complexities associated with submarine landslides. Discussion associated with the characterization and classification of submarine landslides is also part of this work. Topics that will be cover include: 1) how data from conventional oil and gas exploration activities can be used to increase our understanding of the dynamic behavior of submarine landslides, 2) analogies between terrestrial submarine landslides and potential Martian counterparts, 3) impact of submarine landslides in margin construction, as well as their economic significance and 4) the importance of quantifying the morphology of submarine landslides in a systematic fashion.
The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes
NASA Astrophysics Data System (ADS)
Bennett, Sarah A.; Achterberg, Eric P.; Connelly, Douglas P.; Statham, Peter J.; Fones, Gary R.; German, Christopher R.
2008-06-01
We have conducted a study of hydrothermal plumes overlying the Mid-Atlantic Ridge near 5° S to investigate whether there is a significant export flux of dissolved Fe from hydrothermal venting to the oceans. Our study combined measurements of plume-height Fe concentrations from a series of 6 CTD stations together with studies of dissolved Fe speciation in a subset of those samples. At 2.5 km down plume from the nearest known vent site dissolved Fe concentrations were ˜ 20 nM. This is much higher than would be predicted from a combination of plume dilution and dissolved Fe(II) oxidation rates, but consistent with stabilisation due to the presence of organic Fe complexes and Fe colloids. Using Competitive Ligand Exchange-Cathodic Stripping Voltammetry (CLE-CSV), stabilised dissolved Fe complexes were detected within the dissolved Fe fraction on the edges of one non-buoyant hydrothermal plume with observed ligand concentrations high enough to account for stabilisation of ˜ 4% of the total Fe emitted from the 5° S vent sites. If these results were representative of all hydrothermal systems, submarine venting could provide 12-22% of the global deep-ocean dissolved Fe budget.
Study of GaN nanorods converted from β-Ga2O3
NASA Astrophysics Data System (ADS)
Li, Yuewen; Xiong, Zening; Zhang, Dongdong; Xiu, Xiangqian; Liu, Duo; Wang, Shuang; Hua, Xuemei; Xie, Zili; Tao, Tao; Liu, Bin; Chen, Peng; Zhang, Rong; Zheng, Youdou
2018-05-01
We report here high-quality β-Ga2O3 nanorods (NRs) grown on sapphire substrates by hydrothermal method. Ammoniating the β-Ga2O3 NRs results in strain-free wurtzite gallium nitride (GaN) NRs. It was shown by XRD and Raman spectroscopy that β-Ga2O3 was partially converted to GaN/β-Ga2O3 at 1000 °C and then completely converted to GaN NRs at 1050 °C, as confirmed by high-resolution transmission electron microscopy (HRTEM). There is no band-edge emission of β-Ga2O3 in the cathodoluminescence spectrum, and only a deep-level broad emission observed at 3.68-3.73 eV. The band edge emission (3.39 eV) of GaN NRs converted from β-Ga2O3 can also be observed.
NASA Astrophysics Data System (ADS)
McIntosh, I. M.; Tani, K.; Nichols, A. R.
2014-12-01
Oomurodashi volcano is an active shallow submarine silicic volcano in the northern Izu-Bonin Arc, located ~20 km south of the inhabited active volcanic island of Izu-Oshima. Oomurodashi has a large (~20km diameter) flat-topped summit located at 100 - 150 metres below sea level (mbsl), with a small central crater, Oomuro Hole, located at ~200 mbsl. Surveys conducted during cruise NT12-19 of R/V Natsushima in 2012 using the remotely-operated vehicle (ROV) Hyper-Dolphin revealed that Oomuro Hole contains numerous active hydrothermal vents and that the summit of Oomurodashi is covered by extensive fresh rhyolitic lava and pumice clasts with little biogenetic or manganese cover, suggesting recent eruption(s) from Oomuro Hole. Given the shallow depth of the volcano summit, such eruptions are likely to have generated subaerial eruption columns. A ~10ka pumiceous subaerial tephra layer on the neighbouring island of Izu-Oshima has a similar chemical composition to the submarine Oomurodashi rocks collected during the NT12-19 cruise and is thought to have originated from Oomurodashi. Here we present FTIR measurements of the H2O contents of rhyolitic pumice from both the submarine deposits sampled during ROV dives and the subaerial tephra deposit on Izu-Oshima, in order to assess magma degassing and eruption processes occurring during shallow submarine eruptions.
NASA Astrophysics Data System (ADS)
Aihara, Y.; Kiyokawa, S.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Horie, K.; Sakamoto, R.; Miki, T.
2013-12-01
Stratigraphic transition of black chert to iron-rich sedimentary rocks above volcanic sequences with hydrothermal systems is common and characteristic feature of Archean greenstone belts. The 3.2 Ga Dixon Island Formation, exposed along the northern coast of Dixon Island located in the coastal Pilbara terrane, Western Australia, is one of such units and the focus of our study. We introduce field occurrence and lithology of the Dixon Island Formation that preserves features of paleohydrohermal environment in the Mesoarchean ocean. The Dixon Island Formation is composed of the following three members (in ascending order): Komatiite-Rhyolite Tuff, Black Chert, and Varicolored Chert members (Kiyokawa and Taira, 1998). Here we focus on the Komatiite-Rholite Tuff member. It preserves two cycles of highly altered komatiite lavas and well-stratified rhyolite tuff. Komatiite lavas include dendritic crystals of chrome spinel and ghosts of spinifex, euhedral and sheet-like olivines and pyroxenes. These rocks are now composed of granular microcrystalline quartz with chromian muscovite, chrome spinel and chrorite that formed by intense silicification. Its upper part contains hydrothermal veining and alteration (i.e., many vein swarms composed of veins of quartz and organic carbon-rich black chert). Most black chert veins intrude vertically into overlying layers, and contain barite, pyrite, monazite and clay minerals which were least affected by silicificatio. Based on the cross-cutting relationship seen in the outcrops, we recognized two generations of black chert veins (type 1 and type 2 veins; Kiyokawa et al., 2006). Type 1 veins are mainly composed of carbonaceous peloids in a microcrystalline quartz matrix. Euhedral and xenocrystic tourmaline are found only in Type1 veins. Type 2 veins are organic carbon-poor and contain fragments of black chert and siliceous volcanic breccia (Kiyokawa et al., 2006). Intense silicification of komatiitic volcaniclastics and lava, enriched in
Zhao, Baoxiu; Li, Xiang; Yang, Long; Wang, Fen; Li, Jincheng; Xia, Wenxiang; Li, Weijiang; Zhou, Li; Zhao, Colin
2015-01-01
ß-Ga2O3 nanorod was first directly prepared by the microwave irradiation hydrothermal way without any subsequent heat treatments, and its characterizations were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), UV-Vis diffuse reflection spectroscopy techniques, and also its photocatalytic degradation for perfluorooctanoic acid (PFOA) was investigated. XRD patterns revealed that ß-Ga2O3 crystallization increased with the enhancement of microwave power and the adding of active carbon (AC). PFOA, as an environmental and persistent pollutant, is hard decomposed by hydroxyl radicals (HO·); however, it is facilely destroyed by ß-Ga2O3 photocatalytic reaction in an anaerobic atmosphere. The important factors such as pH, ß-Ga2O3 dosage and bubbling atmosphere were researched, and the degradation and defluorination was 98.8% and 56.2%, respectively. Reductive atmosphere reveals that photoinduced electron may be the major reactant for PFOA. Furthermore, the degradation kinetics for PFOA was simulated and constant and half-life was calculated, respectively. © 2014 The American Society of Photobiology.
Holm, Nils G; Andersson, Eva
2005-08-01
The potential of life's origin in submarine hydrothermal systems has been evaluated by a number of investigators by conducting high temperature-high pressure experiments involving organic compounds. In the majority of these experiments little attention has been paid to the importance of constraining important parameters, such as the pH and the redox state of the system. This is particularly revealed in the apparent difficulties in interpreting experimental data from hydrothermal organic synthesis and stability studies. However, in those cases where common mineral assemblages have been used in an attempt to buffer the pH and redox conditions to geologically and geochemically realistic values, theoretical and experimental data seem to converge. The use of mineral buffer assemblages provides a convenient way by which to constrain the experimental conditions. Studies at high temperatures and pressure in the laboratory have revealed a number of reactions that proceed rapidly in hydrothermal fluids, including the Strecker synthesis of amino acids. In other cases, the verification of postulated abiotic reaction mechanisms has not been possible, at least for large molecules such as large fatty acids and hydrocarbons. This includes the Fischer-Tropsch synthesis reaction. High temperature-high pressure experimental methods have been developed and used successfully for a long time in, for example, mineral solubility studies under hydrothermal conditions. By taking advantage of this experimental experience new and, at times, unexpected directions can be taken in bioorganic geochemistry, one being, for instance, primitive two-dimensional information coding. This article critically reviews some of the organic synthesis and stability experiments that have been conducted under simulated submarine hydrothermal conditions. We also discuss some of the theoretical and practical considerations that apply to hydrothermal laboratory studies of organic molecules related to the origin of
NASA Technical Reports Server (NTRS)
Mautner, M. N.; Leonard, R. L.; Deamer, D. W.
1995-01-01
Up to 50% of the organics in the Murchison meteorite, possibly including some of the polymer, is released in high temperature and pressure aqueous environments, to 350 degrees C and 250 bar, that simulate submarine volcanic, hydrothermal or impact-induced conditions. Meteorite organics of prebiotic significance, such as nonanoic acid, glycine, and pyrene survive the hydrothermal conditions. The released material is surface active with surface pressures up to 19.8 x 10(-3) N m-1, and exhibits an extended surface tension isotherm which suggests a mixture of amphiphilic components. One component, nonanoic acid, is shown to form vesicles. The materials extracted under mild conditions, at 120 degrees C, are nutrients for the humic acid bacterium Pseudomonas maltophilia and efficient nutrients for the oligotroph Flavobacterium oryzihabitans, demonstrating the capability of microorganisms to metabolize extraterrestrial organics.
NASA Technical Reports Server (NTRS)
Burggraf, S.; Fricke, H.; Neuner, A.; Kristjansson, J.; Rouvier, P.; Mandelco, L.; Woese, C. R.; Stetter, K. O.
1990-01-01
A novel hyperthermophilic strictly chemolithoautotrophic member of the genus Methanococcus was isolated from a shallow (depth: 106 m) submarine vent system at the Kolbeinsey ridge, Iceland. The isolate grew between 45 and 91 degrees C with an optimum around 88 degrees C (doubling time: 25 min). It differs from Methanococcus jannaschii in its 16S rRNA sequence, its non-hybridizing DNA, and its selenium-independent growth. Therefore, the isolate represents a new species which we name Methanococcus igneus. Type strain is isolate "Kol 5" (DSM 5666).
Edmonds, H N; Michael, P J; Baker, E T; Connelly, D P; Snow, J E; Langmuir, C H; Dick, H J B; Mühe, R; German, C R; Graham, D W
2003-01-16
Submarine hydrothermal venting along mid-ocean ridges is an important contributor to ridge thermal structure, and the global distribution of such vents has implications for heat and mass fluxes from the Earth's crust and mantle and for the biogeography of vent-endemic organisms. Previous studies have predicted that the incidence of hydrothermal venting would be extremely low on ultraslow-spreading ridges (ridges with full spreading rates <2 cm x yr(-1)-which make up 25 per cent of the global ridge length), and that such vent systems would be hosted in ultramafic in addition to volcanic rocks. Here we present evidence for active hydrothermal venting on the Gakkel ridge, which is the slowest spreading (0.6-1.3 cm x yr(-1)) and least explored mid-ocean ridge. On the basis of water column profiles of light scattering, temperature and manganese concentration along 1,100 km of the rift valley, we identify hydrothermal plumes dispersing from at least nine to twelve discrete vent sites. Our discovery of such abundant venting, and its apparent localization near volcanic centres, requires a reassessment of the geologic conditions that control hydrothermal circulation on ultraslow-spreading ridges.
NASA Astrophysics Data System (ADS)
Kitada, K.; Kasaya, T.; Iwamoto, H.; Nogi, Y.
2017-12-01
The Okinawa Trough is an active back-arc basin formed by the rifting associated with extension of the continental margin behind the Ryukyu trench. New hydrothermal sites were recently discovered off Kumejima Island in the Mid-Okinawa Trough and the hydrothermal mineral deposits were identified by seafloor surveys and rock samplings by ROV (e.g., JOGMEC, 2015). In order to characterize the sub-seafloor structures and the spatial distribution of the magmatic activity around the sites, we conducted the dense magnetic, gravity and bathymetric surveys with a line spacing of 0.5 nmi aboard the R/Vs Yokosuka and Kairei, operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in 2016. The geophysical data collected during the previous cruises in the area by JAMSTEC were additionally used for this study. Magnetic anomaly was calculated by subtracting the IGRF model and the magnetization intensity was estimated by the method of Parker and Huestis (1974). Free-air gravity anomaly was calculated with subtracting the normal gravity field and with corrections of the drift and of the Eötvös effect. Bouguer gravity anomaly was calculated based on the method of Parker (1972). The magnetization intensity and the Bouguer gravity anomaly reveal three characteristics of the hydrothermal area off Kumejima Island: 1) The distribution of magnetization around the hydrothermal sites shows two different types of sub-seafloor magnetic features. One is corresponded to the submarine knolls with a relatively high magnetization of 4 A/M. The other is an ENE-WSW trending magnetization distribution with relatively high and low intensities, which is consistent with the trend of the bathymetric lineament. These features are considered to be formed by magmatism associated with submarine volcanoes and back-arc rifting. 2) The reduced magnetization zone corresponding to the hydrothermal area probably attributes to hydrothermal alteration of the host rock. 3) The hydrothermal
Current submarine atmosphere control technology.
Mazurek, W
1998-01-01
Air purification in submarines was introduced towards the end of World War II and was limited to the use of soda lime for the removal of carbon dioxide and oxygen candles for the regeneration of oxygen. The next major advances came with the advent of nuclear-powered submarines. These included the development of regenerative and, sometimes, energy-intensive processes for comprehensive atmosphere revitalization. With the present development of conventional submarines using air-independent propulsion there is a requirement for air purification similar to that of the nuclear-powered submarines but it is constrained by limited power and space. Some progress has been made in the development of new technology and the adoption of air purification equipment used in the nuclear-powered submarines for this application.
NASA Astrophysics Data System (ADS)
O'Sullivan, Edel M.; Goodhue, Robbie; Ames, Doreen E.; Kamber, Balz S.
2016-06-01
The 1.85 Ga Sudbury structure provides a unique opportunity to study the sequence of events that occurred within a hydrothermally active subaqueous impact crater during the late stages of an impact and in its aftermath. Here we provide the first comprehensive chemostratigraphic study for the lower crater fill, represented by the ca. 1.4 km thick Onaping Formation. Carefully hand-picked ash-sized matrix of 81 samples was analysed for major elements, full trace elements and C isotopes. In most general terms, the composition of the clast-free matrix resembles that of the underlying melt sheet. However, many elements show interesting chemostratigraphies. The high field strength element evolution clearly indicates that the crater rim remained intact during the deposition of the entire Onaping Formation, collapsing only at the transition to the overlying Onwatin Formation. An interesting feature is that several volatile metals (e.g., Pb, Sb) are depleted by >90% in the lower Onaping Formation, suggesting that the impact resulted in a net loss of at least some volatile species, supporting the idea of ;impact erosion,; whereby volatile elements were vaporised and lost to space during impact. Reduced C contents in the lower Onaping Formation are low (<0.1 wt%) but increase to 0.5-1 wt% up stratigraphy, where δ13C becomes constant at -31‰, indicating a biogenic origin. Elevated Y/Ho and U/Th require that the ash interacted with saline water, most likely seawater. Redox-sensitive trace metal chemostratigraphies (e.g., V and Mo) suggest that the basin was anoxic and possibly euxinic and became inhabited by plankton, whose rain-down led to a reservoir effect in certain elements (e.g., Mo). This lasted until the crater rim was breached, the influx of fresh seawater promoting renewed productivity. If the Sudbury basin is used as an analogue for the Hadean and Eoarchaean Earth, our findings suggest that hydrothermal systems, capable of producing volcanogenic massive sulphides
NASA Astrophysics Data System (ADS)
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.
2007-12-01
Seafloor hydrothermal systems 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 hydrothermal 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 hydrothermal 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
ERIC Educational Resources Information Center
Young, Jocelyn; Hardy, Kevin
2007-01-01
In this article, the authors discuss a unique and challenging laboratory exercise called, the paint-stir-stick submarine, that keeps the students enthralled. The paint-stir-stick submarine fits beautifully with the National Science Education Standards Physical Science Content Standard B, and with the California state science standards for physical…
NASA Astrophysics Data System (ADS)
Moreto, Carolina P. N.; Monteiro, Lena V. S.; Xavier, Roberto P.; Creaser, Robert A.; DuFrane, S. Andrew; Melo, Gustavo H. C.; Delinardo da Silva, Marco A.; Tassinari, Colombo C. G.; Sato, Kei
2015-06-01
The Southern Copper Belt, Carajás Province, Brazil, hosts several iron oxide-copper-gold (IOCG) deposits, including Sossego, Cristalino, Alvo 118, Bacuri, Bacaba, Castanha, and Visconde. Mapping and U-Pb sensitive high-resolution ion microprobe (SHRIMP) IIe zircon geochronology allowed the characterization of the host rocks, situated within regional WNW-ESE shear zones. They encompass Mesoarchean (3.08-2.85 Ga) TTG orthogneiss, granites, and remains of greenstone belts, Neoarchean (ca. 2.74 Ga) granite, shallow-emplaced porphyries, and granophyric granite coeval with gabbro, and Paleoproterozoic (1.88 Ga) porphyry dykes. Extensive hydrothermal zones include albite-scapolite, biotite-scapolite-tourmaline-magnetite alteration, and proximal potassium feldspar, chlorite-epidote and chalcopyrite formation. U-Pb laser ablation multicollector inductively coupled mass spectrometry (LA-MC-ICP-MS) analysis of ore-related monazite and Re-Os NTIMS analysis of molybdenite suggest multiple Neoarchean (2.76 and 2.72-2.68 Ga) and Paleoproterozoic (2.06 Ga) hydrothermal events at the Bacaba and Bacuri deposits. These results, combined with available geochronological data from the literature, indicate recurrence of hydrothermal systems in the Southern Copper Belt, including 1.90-1.88-Ga ore formation in the Sossego-Curral ore bodies and the Alvo 118 deposit. Although early hydrothermal evolution at 2.76 Ga points to fluid migration coeval with the Carajás Basin formation, the main episode of IOCG genesis (2.72-2.68 Ga) is related to basin inversion coupled with Neoarchean (ca. 2.7 Ga) felsic magmatism. The data suggest that the IOCG deposits in the Southern Copper Belt and those in the Northern Copper Belt (2.57-Ga Salobo and Igarapé Bahia-Alemão deposits) do not share a common metallogenic evolution. Therefore, the association of all IOCG deposits of the Carajás Province with a single extensive hydrothermal system is precluded.
Normark, W.R.
1986-01-01
The submersible Alvin was used to investigate 3 active hydrothermal discharge sites along the S Juan de Fuca Ridge in September 1984. The hydrothermal zones occur within a 10-30m-deep, 30-50m-wide cleft marking the center of the axial valley. This cleft is the eruptive locus for the axial valley. The hydrothermal vents coincide with the main eruptive vents along the cleft. Each hydrothermal zone has multiple discharge sites extending as much as 500m along the cleft. Sulfide deposits occur as clusters (15-100m2 area) of small chimneys (= or <2m high) and as individual and clustered fields of large, branched chimneys (= or <10m high). Recovered sulfide samples are predominantly the tops of chimneys and spires and typically contain more than 80% sphalerite and wurtzite with minor pyrrhotite, pyrite, marcasite, isocubanite, chalcopyrite, anhydrite, anhydrite, and amorphous silica. The associated hydrothermal fluids have the highest chlorinity of any reported to date.-Authors
Berndt, M.E.; Seal, R.R.; Shanks, Wayne C.; Seyfried, W.E.
1996-01-01
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 system. The effect of phase separation on hydrogen isotope distribution in subseafloor hydrothermal systems depends on a number of factors, including whether phase separation is induced by heating at depth or by decompression of hydrothermal fluids ascending to the seafloor. Phase separation in most subseafloor systems 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 system. Resulting vent fluids exhibit large ranges in Cl concentration with no measurable effect on ??D. Possible exceptions to this include hydrothermal 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 hydrothermal activity.
Yang, Liyang; Zhuang, Wan-E; Chen, Chen-Tung Arthur; Wang, Bing-Jye; Kuo, Fu-Wen
2017-03-15
The submarine hydrothermal systems are extreme environments where active cycling of dissolved organic matter (DOM) may occur. However, little is known about the optical properties and bioavailability of hydrothermal DOM, which could provide valuable insights into its transformation processes and biogeochemical reactivity. The quantity, quality, and bioavailability of DOM were investigated for four very different hydrothermal vents east of Taiwan, using dissolved organic carbon (DOC), absorption spectroscopy, and fluorescence excitation-emission matrices-parallel factor analysis (EEM-PARAFAC). The DOC and absorption coefficient a 280 were both lower in the two hydrothermal vents off the Orchid Island and on the Green Island than in the surrounding seawater and the two vents off the Kueishantao Island, indicating effective removals of DOM in the former two hydrothermal systems owing to possible adsorption/co-precipitation and thermal degradation respectively. The four hydrothermal DOM showed notable differences in the absorption spectral slope S 275-295 , humification index HIX, biological index BIX, EEM spectra, and the relative distributions of seven PARAFAC components. The results demonstrated a high diversity of chemical composition and transformation history of DOM under contrasting hydrothermal conditions. The little change in the hydrothermal DOC after 28-day microbial incubations indicated a low bioavailability of the bulk DOM, and different PARAFAC components showed contrasting bioavailability. The results have profound implications for understanding the biogeochemical cycling and environmental effects of hydrothermal DOM in the marine environments. Copyright © 2017 Elsevier Ltd. All rights reserved.
Hydrothermal synthesis of a photovoltaic material based on CuIn0.5Ga0.5Se2
NASA Astrophysics Data System (ADS)
Castellanos Báez, Y. T.; Fuquen Peña, D. A.; Gómez-Cuaspud, J. A.; Vera-López, E.; Pineda-Triana, Y.
2017-12-01
The present work report, the synthesis and characterization of the CuIn0.5Ga0.5Se2 system (abbreviated CIGS), by the implementation of a hydrothermal route, in order to obtain a solid with appropriate properties in terms of surface, morphological and texture properties for potential applications in the design of photovoltaic cells. The synthesis was carried out using the corresponding stoichiometric quantities (Cu:In:Ga:Se 1:0.5:0.5:2), which were mixed in a Teflon vessel under stirring conditions. The homogeneous solution was treated in a steel autoclave at 300°C for 72 hours at the end of which the resulting material was characterized by X-Ray Diffraction (XRD) and Rietveld refinement. The results of the structural characterization allowed to confirm the obtaining of a chalcopyrite type structure, with a I-42 d (122) structure and cell parameters a=0.570, b=0.570, c=1.140nm, α=90, β=90, γ=90° oriented along (1 0 4) facet, detecting the presence of a secondary phases, related with CuInSe and CuIn metallic selenides, derived from synthesis process. The structural refinement allowing to validate the obtaining of a nanometric crystalline material (10-20nm) for potential applications in field of photovoltaic technology.
Rytuba, James J.; John, David A.; Foster, Andrea; Ludington, Steven D.; Kotlyar, Boris
2003-01-01
Gallium is produced as a byproduct from bauxite and zinc sulfide ores and rarely from primary Ga ores. High Ga contents (>60 ppm) can occur in zones of advanced argillic alteration consisting of alunite+kaolinite+quartz associated with quartz-alunite (high sulfidation Au-Ag) deposits. In a magmatic-hydrothermal environment, the zones of advanced argillic alteration associated with quartz-alunite (high sulfidation) Au-Ag deposits have the highest Ga contents (max 120 ppm). In these Au deposits, Ga is enriched in the zone of alunite+kaolinite alteration and depleted in the zone of quartz-rich alteration within acid-leached rocks. Peripheral zones of argillic alteration have Ga contents and Al/Ga ratios similar to those in unaltered volcanic rocks. The zones of advanced argillic alteration that formed in a steam-heated environment in association with hot-spring-type Hg-Au deposits are not Ga enriched, and residual silicified zones have very low Ga contents. The McDermitt Hg and Paradise Peak Au-Hg deposits, Nev., have zones of advanced argillic alteration that are Ga enriched. At the Paradise Peak Au-Hg deposits, Ga is enriched in the zone of alunite+jarosite alteration that formed in a magmatic-hydrothermal environment. Ga is depleted in the zone of opal+alunite alteration formed in a steam-heated environment, in residual silicified zones formed in a magmatic-hydrothermal environment, and in zones of supergene jarosite alteration. At the McDermitt Hg deposit, Ga is enriched in the zone of alunite+kaolinite alteration below the zone of adularia-quartz alteration that coincides with the Hg ore body. The spatial relation of Ga enrichment to alunite-kaolinite alteration suggests that formation in a magmatic-hydrothermal environment. X-ray-absorption spectra of Ga-enriched samples from the McDermitt Hg deposit are similar to that of gallium sulfate and support the association of Ga enrichment with alunite alteration.
47 CFR 32.2424 - Submarine & deep sea cable.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 47 Telecommunication 2 2011-10-01 2011-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic submarine...
47 CFR 32.2424 - Submarine & deep sea cable.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 47 Telecommunication 2 2014-10-01 2014-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic submarine...
47 CFR 32.2424 - Submarine & deep sea cable.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 47 Telecommunication 2 2010-10-01 2010-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic submarine...
47 CFR 32.2424 - Submarine & deep sea cable.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 47 Telecommunication 2 2013-10-01 2013-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic submarine...
47 CFR 32.2424 - Submarine & deep sea cable.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 47 Telecommunication 2 2012-10-01 2012-10-01 false Submarine & deep sea cable. 32.2424 Section 32... Submarine & deep sea cable. (a) This account shall include the original cost of submarine cable and deep sea... defined below, are to be maintained for nonmetallic submarine and deep sea cable and metallic submarine...
Active submarine eruption of boninite in the northeastern Lau Basin
NASA Astrophysics Data System (ADS)
Resing, Joseph A.; Rubin, Kenneth H.; Embley, Robert W.; Lupton, John E.; Baker, Edward T.; Dziak, Robert P.; Baumberger, Tamara; Lilley, Marvin D.; Huber, Julie A.; Shank, Timothy M.; Butterfield, David A.; Clague, David A.; Keller, Nicole S.; Merle, Susan G.; Buck, Nathaniel J.; Michael, Peter J.; Soule, Adam; Caress, David W.; Walker, Sharon L.; Davis, Richard; Cowen, James P.; Reysenbach, Anna-Louise; Thomas, Hans
2011-11-01
Subduction of oceanic crust and the formation of volcanic arcs above the subduction zone are important components in Earth's geological and geochemical cycles. Subduction consumes and recycles material from the oceanic plates, releasing fluids and gases that enhance magmatic activity, feed hydrothermal systems, generate ore deposits and nurture chemosynthetic biological communities. Among the first lavas to erupt at the surface from a nascent subduction zone are a type classified as boninites. These lavas contain information about the early stages of subduction, yet because most subduction systems on Earth are old and well-established, boninite lavas have previously only been observed in the ancient geological record. Here we observe and sample an active boninite eruption occurring at 1,200m depth at the West Mata submarine volcano in the northeast Lau Basin, southwest Pacific Ocean. We find that large volumes of H2O, CO2 and sulphur are emitted, which we suggest are derived from the subducting slab. These volatiles drive explosive eruptions that fragment rocks and generate abundant incandescent magma-skinned bubbles and pillow lavas. The eruption has been ongoing for at least 2.5 years and we conclude that this boninite eruption is a multi-year, low-mass-transfer-rate eruption. Thus the Lau Basin may provide an important site for the long-term study of submarine volcanic eruptions related to the early stages of subduction.
NASA Astrophysics Data System (ADS)
Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.
2017-08-01
Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.
Analysis of SSN 688 Class Submarine Maintenance Delays
2017-06-01
Simplified Notional Submarine FRP (Independent Deployer) ..................11 Figure 8. Evolution of Los Angeles Class Submarine Notional...Number TFP Technical Foundation Paper URO Unrestricted Operations xv ACKNOWLEDGMENTS I would like to thank my lead advisor, Professor Nick Dew...only on Los Angeles (SSN 688)-class submarines. Being the higher quantity and older generation submarine hull type, the Los Angeles class submarine
Christakis, Christos A; Polymenakou, Paraskevi N; Mandalakis, Manolis; Nomikou, Paraskevi; Kristoffersen, Jon Bent; Lampridou, Danai; Kotoulas, Georgios; Magoulas, Antonios
2018-01-01
Over the last decades, there has been growing interest about the ecological role of hydrothermal sulfide chimneys, their microbial diversity and associated biotechnological potential. Here, we performed dual-index Illumina sequencing of bacterial and archaeal communities on active and inactive sulfide chimneys collected from the Kolumbo hydrothermal field, situated on a geodynamic convergent setting. A total of 15,701 OTUs (operational taxonomic units) were assigned to 56 bacterial and 3 archaeal phyla, 133 bacterial and 16 archaeal classes. Active chimney communities were dominated by OTUs related to thermophilic members of Epsilonproteobacteria, Aquificae and Deltaproteobacteria. Inactive chimney communities were dominated by an OTU closely related to the archaeon Nitrosopumilus sp., and by members of Gammaproteobacteria, Deltaproteobacteria, Planctomycetes and Bacteroidetes. These lineages are closely related to phylotypes typically involved in iron, sulfur, nitrogen, hydrogen and methane cycling. Overall, the inactive sulfide chimneys presented highly diverse and uniform microbial communities, in contrast to the active chimney communities, which were dominated by chemolithoautotrophic and thermophilic lineages. This study represents one of the most comprehensive investigations of microbial diversity in submarine chimneys and elucidates how the dissipation of hydrothermal activity affects the structure of microbial consortia in these extreme ecological niches.
Composition and Structure of Mauna Loa's Submarine West Flank, Hawaii
NASA Astrophysics Data System (ADS)
Borchers, D.; Morgan, J. K.; Clague, D. A.; Moore, G. F.
2003-12-01
James Moore's pioneering work on submarine landslides in the Hawaiian Islands contributed significantly to early models for the structure and evolution of Mauna Loa's submarine western flank. The west flank experienced catastrophic failure in the past, generating massive blocks and debris fields offshore. Moore recognized that the midslope bench near the base of the submarine flank must have postdated the debris avalanche, but little data existed to determine if it formed in response to further landsliding or to deeper volcanic processes. As the processes that shaped Mauna Loa are thought to be analogous to those currently active at Kilauea, an improved understanding of Mauna Loa's history can provide valuable insight into the future of the younger Hawaiian volcanoes. Several recent marine surveys in the area, including submersible surveys conducted by MBARI and JAMSTEC, and a multi-channel seismic (MCS) survey carried out by the University of Hawaii, provide important new data about the composition and structure of Mauna Loa's submarine west flank. We carried out detailed geochemical, petrographic and structural analyses of rock samples and dive videos collected from the exposed northern wall of the midslope bench, documenting a repeated sequences of volcaniclastic sandstones and breccias. This stratigraphy contrasts with the predominantly subaerially erupted basalts composing the upper flank. Several thick ponded flows or sill-like diabase units are also interspersed in the section. The volcaniclastic units are highly cemented, and many contain hydrothermal alteration products, including chlorite, zeolites, and actinolite. The most altered rocks occur near the base of the bench and the degree of alteration decreases upward in the section. Samples collected from the outer scarp of the bench show evidence for intense shearing and cataclasis at all scales. The new MCS line crosses Mauna Loa's southern submarine flank and central bench. More than 500 m of finely
A Serpentinite-Hosted Ecosystem: The Lost City Hydrothermal Field
NASA Astrophysics Data System (ADS)
Kelley, Deborah S.; Karson, Jeffrey A.; Früh-Green, Gretchen L.; Yoerger, Dana R.; Shank, Timothy M.; Butterfield, David A.; Hayes, John M.; Schrenk, Matthew O.; Olson, Eric J.; Proskurowski, Giora; Jakuba, Mike; Bradley, Al; Larson, Ben; Ludwig, Kristin; Glickson, Deborah; Buckman, Kate; Bradley, Alexander S.; Brazelton, William J.; Roe, Kevin; Elend, Mitch J.; Delacour, Adélie; Bernasconi, Stefano M.; Lilley, Marvin D.; Baross, John A.; Summons, Roger E.; Sylva, Sean P.
2005-03-01
The serpentinite-hosted Lost City hydrothermal field is a remarkable submarine ecosystem in which geological, chemical, and biological processes are intimately interlinked. Reactions between seawater and upper mantle peridotite produce methane- and hydrogen-rich fluids, with temperatures ranging from <40° to 90°C at pH 9 to 11, and carbonate chimneys 30 to 60 meters tall. A low diversity of microorganisms related to methane-cycling Archaea thrive in the warm porous interiors of the edifices. Macrofaunal communities show a degree of species diversity at least as high as that of black smoker vent sites along the Mid-Atlantic Ridge, but they lack the high biomasses of chemosynthetic organisms that are typical of volcanically driven systems.
Gas-rich submarine exhalations during the 1989 eruption of Macdonald Seamount
NASA Astrophysics Data System (ADS)
C´e, J.-L.; Stoffers, P.; McMurtry, G.; Richnow, H.; Puteanus, D.; Sedwick, P.
1991-11-01
In January 1989 we observed submarine eruptions on the summit of Macdonald volcano during a French-German diving programme with the IFREMER submersible Cyana. Gas-streaming of large amounts of CH 4, CO 2 and SO 2 from summit vents, inferred from water column anomalies and observed by submersible, was accompanied on the sea surface by steam bursts, turbulence, red-glowing gases, and black bubbles comprising volcanic ash, sulphur and sulphides. Chloride depletion of water sampled on the floor of an actively degassing summit crater suggests either boiling and phase separation or additions of magmatic water vapour. Submersible observations, in-situ sampling and shipboard geophysical and hydrographic measurements show that the hydrothermal system of this hotspot volcano is distinguished by the influence of magmatic gases released from its shallow summit.
Hydrovolcanic and Hydrothermal Biomediated Mineral Growth in Basaltic Tuff, Surtsey Volcano, Iceland
NASA Astrophysics Data System (ADS)
Jackson, M. D.; Couper, S.; Ivarsson, M.; Stan, C. V.; Tamura, N.; Miyagi, L. M.; Moore, J. G.
2017-12-01
Fine-scale analyses of hydroclasts in 1979 Surtsey basaltic tuff drill core provide new methods for examining hydrovolcanic and hydrothermal magma-rock influences on biomediated alteration in palagonitized submarine tephra. Synchrotron source X-ray microdiffraction and microfluorescence studies from Advanced Light Source beamline 12.3.2, epifluorescent UVA illumination microscopy, S/TEM EDX compositional analyses, and Raman spectroscopy define diverse nanocrystalline clay mineral structures at 137.9 m depth (93.8 °C (1980)) and 102.6 m depth (141.3 °C (1980)). At 137.9 m, olivine contains endolithic microborings; vermicular microstructures in altered glass contain nontronite exhibiting crystallographic preferred orientation; and 75-150 µm sub-circular microstructures in altered glass contain Al-tobermorite, a calcium-silicate-hydrate with 11.3 Å interlayer spacing, zeolite, and epifluorescent, thread-like structures. At 102.6 m depth, concentrically-layered microstructures occur in altered glass and altered olivine. These have nontronite crystallographic preferred orientations that rotate around a longitudinal axis commonly occupied by a 10-80 µm long, epifluorescent thread-like structure. Pronounced carbon concentrations detected by S/TEM EDX trace layer boundaries. First-order Raman bands at 1370 cm-1 (disorder-related) and at 1580 cm-1 (order-related), and second-order bands at 2500-3300 cm-1 (overtone scattering) detect degraded organic carbonaceous matter, a strong indication of biological origin. Sub-circular nanostructures in altered glass at 137.9 m depth show similar spectra. Borehole fluid temperatures at 102.6 m, 141.3 °C in 1980, exceeded 130 °C, the assumed limit for growth of microorganisms, however. Previous analyses suggest an early low temperature episode in submarine deposits, prior to development of a hydrothermal system driven by 1964-1967 magmatic intrusions. The abundant traces of biomediated nanocrystalline clay mineral growth validate
Submarine geothermal resources
Williams, D.L.
1976-01-01
Approximately 20% of the earth's heat loss (or 2 ?? 1012 cal/s) is released through 1% of the earth's surface area and takes the form of hydrothermal discharge from young (Pleistocene or younger) rocks adjacent to active seafloor-spreading centers and submarine volcanic areas. This amount is roughly equivalent to man's present gross energy consumption rate. A sub-seafloor geothermal reservoir, to be exploitable under future economic conditions, will have to be hot, porous, permeable, large, shallow, and near an energy-deficient, populated land mass. Furthermore, the energy must be recoverable using technology achievable at a competitive cost and numerous environmental, legal and institutional problems will have to be overcome. The highest-temperature reservoirs should be found adjacent to the zones of the seafloor extension or volcanism that are subject to high sedimentation rates. The relatively impermeable sediments reduce hydrothermal-discharge flow rates, forcing the heat to be either conducted away or released by high-temperature fluids, both of which lead to reservoir temperatures that can exceed 300??C. There is evidence that the oceanic crust is quite permeable and porous and that it was amenable to deep (3-5 km) penetration by seawater at least some time in the early stages of its evolution. Most of the heat escapes far from land, but there are notable exceptions. For example, in parts of the Gulf of California, thermal gradients in the bottom sediments exceed 1??C/m. In the coastal areas of the Gulf of California, where electricity and fresh water are at a premium, this potential resource lies in shallow water (< 200 m) and within sight of land. Other interesting areas include the Sea of Japan, the Sea of Okhotsk and the Andaman Sea along the margins of the western Pacific, the Tyrrhenian Sea west of Italy, and the southern California borderland and west flank of the Juan de Fuca Ridge off the west coast of the United States. Many questions remain to be
SnO2-gated AlGaN/GaN high electron mobility transistors based oxygen sensors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hung, S.T.; Chung, Chi-Jung; Chen, Chin Ching
2012-01-01
Hydrothermally grown SnO2 was integrated with AlGaN/GaN high electron mobility transistor (HEMT) sensor as the gate electrode for oxygen detection. The crystalline of the SnO2 was improved after annealing at 400 C. The grain growth kinetics of the SnO2 nanomaterials, together with the O2 gas sensing properties and sensing mechanism of the SnO2 gated HEMT sensors were investigated. Detection of 1% oxygen in nitrogen at 100 C was possible. A low operation temperature and low power consumption oxygen sensor can be achieved by combining the SnO2 films with the AlGaN/GaN HEMT structure
NASA Astrophysics Data System (ADS)
Ehya, Farhad; Mazraei, Shaghayegh Moalaye
2017-10-01
Barite mineralization occurs at Chenarvardeh deposit as layers and lenses in Upper Eocene volcanic and pyroclastic rocks. The host rocks are intensely saussuritized in most places. Barite is accompanied by calcite, Mn-oxides, galena and malachite as subordinate minerals. The amount of Sr in barites is low and varies between 0.11 and 0.30 wt%. The concentration of Rb, Zr, Y, Ta and Hf is also low (<5 ppm) in barite samples. The amount of total REEs (∑REE) is low in barites, ranging from 7.51 to 30.50 ppm. Chondrite-normalized REE patterns reveal LREE enrichment with respect to HREE, and positive Ce anomalies. Fluid inclusions are common in barite samples, being dominantly from liquid-rich two phase (L + V) type. Salinity values in fluid inclusions range from 9.41 to 18.69 wt% NaCl equivalent with most frequent salinities falling in the range of 10-15 wt% NaCl equivalent. Homogenization temperatures (Th) range between 160 and 220 °C, being the 180-200 °C range as the most common Th interval. A combination of factors, including geologic setting, host rock, mineral assemblages, REE geochemistry and fluid inclusion data are consistent with a submarine volcanic hydrothermal model for barite formation at the Chenarvardeh deposit. Mineral-forming fluids originated from solutions related to submarine hydrothermal activities deposited barite on seafloor as they encountered sulfate-bearing seawater.
Yokose, H.; Lipman, P.W.; Kanamatsu, T.
2005-01-01
To evaluate physical and chemical diversity in submarine basaltic rocks, approximately 280 deep submarine samples recovered by submersibles from the underwater flanks of the Hawaiian Islands were analyzed and compared. Based on observations from the submersibles and hand specimens, these samples were classified into three main occurrence types (lavas, coarse-grained volcaniclastic rocks, and fine-grained sediments), each with several subtypes. The whole-rock sulfur content and porosity in submarine basaltic rocks, recovered from depths greater than 2000 m, range from < 10 ppm and 2 vol.% to 2200 ppm and 47 vol.%, respectively. These wide variations cannot be due just to different ambient pressures at the collection depths, as inferred previously for submarine erupted lavas. The physical and chemical properties of the recovered samples, especially a combination of three whole-rock parameters (Fe-oxidation state, Sulfur content, and Porosity), are closely related to the occurrence type. The FSP triangular diagram is a valuable indicator of the source location of basaltic fragments deposited in deep submarine areas. This diagram can be applied to basaltic rocks such as clasts in debris-flow deposits, submarine-emplaced lava flows that may have crossed the shoreline, and slightly altered geological samples. ?? 2005 Elsevier B.V. All rights reserved.
Liquid and Emulsified Sulfur in Submarine Solfatara Fields of two Northern Mariana Arc Volcanoes.
NASA Astrophysics Data System (ADS)
Nakamura, K.; Embley, R. W.; Chadwick, W. W.; Butterfield, D. A.; Takano, B.; Resing, J. A.; de Ronde, C. E.; Lilley, M. D.; Lupton, J. E.; Merle, S. G.; Inagaki, F.
2006-12-01
Because elemental sulfur melting point is ca 100 deg C (depend on allotropes and heating rate, S8 triple point temperature: 115 deg C), the evidence of liquid sulfur has been known for many subaerial crater lakes and small ponds in geothermal regions throughout the world. But the milky nature of water (sulfur-in- water emulsion in limited water mass) prohibited the direct observation of on-going processes at the bottom of these subaerial lakes. In the passive degassing environment at the summit craters of Daikoku and Nikko Seamounts of the northern Mariana Arc, the continuous flushing of sulfur emulsion by seawater allowed us to observe on- going submarine solfatara processes and associated chemistry through dives with ROVs during the NT05-18 cruise (JAMSTEC R/V Natsushima and ROV hyper-Dolphin) and the Submarine Ring of Fire 2006 cruise (R/V Melville and ROV JASON II). A higher viscosity for liquid elemental sulfur relative to that of seawater, as well as a limited stability of sulfur emulsion (aqueous sulfur sol) at high temperatures in electrolyte solution (seawater), ensures limited mobility of liquid sulfur in the conduits of hydrothermal vents. The subseafloor boiling depth of hydrothermal fluid limits the locus of any liquid sulfur reservoir. It was observed in an exposed liquid sulfur pond that the penetration of gas bubbles (mostly CO2) created sulfur emulsion while collapsing liquid sulfur film between seawater and gas bubbles. Liquid sulfur pits, encrusted sulfur, liquid sulfur fountain structure, sulfur stalactites and stalagmites, mini-pillow lava-like sulfur flows, accretionary sulfur lapilli and sulfur deltas were also observed at the summits of two volcanoes. Note: Solfatara: Italian. A type of fumarole, the gases of which are characteristically sulfurous. In 'Glossary of geology.'
NASA Astrophysics Data System (ADS)
Hammond, S. R.; Baker, E. T.; Embley, R. W.
2015-12-01
Inspiration for the Vents program arose from two serendipitous events: the discovery of seafloor spreading-center hydrothermal venting on the Galápagos Rift in 1977, and NOAA's deployment of the first US civilian research multibeam bathymetric sonar on the NOAA Ship Surveyor in 1979. Multibeam mapping in the NE Pacific revealed an unprecedented and revolutionary perspective of the Gorda and Juan de Fuca spreading centers, thus stimulating a successful exploration for volcanic and hydrothermal activity at numerous locations along both. After the 1986 discovery of the first "megaplume,", quickly recognized as the water column manifestation of a deep submarine volcanic eruption, the Vents program embarked on a multi-decadal effort to discover and understand local-, regional-, and, ultimately, global-scale physical, chemical, and biological ocean environmental impacts of submarine volcanism and hydrothermal venting. The Vents program made scores of scientific discoveries, many of which owed their success to the program's equally innovative and productive technological prowess. These discoveries were documented in hundreds of peer-reviewed papers by Vents researchers and their colleagues around the world. An emblematic success was the internationally recognized, first-ever detection, location, and study of an active deep volcanic eruption in 1993. To continue the Vents mission and further enhance its effectiveness in marine science and technology innovation, the program was reorganized in 2014 into two distinct, but closely linked, programs: Earth-Oceans Interactions and Acoustics. Both are currently engaged in expeditions and projects that maintain the Vents tradition of pioneering ocean exploration and research.
2012-12-10
nuclear powered submarines, which are powered by energy sources such as diesel engines. A submarine’s use of nuclear or non-nuclear power as its energy ...WA, in Puget Sound; the other six are homeported at Kings Bay, GA, close to the Florida border. Unlike most Navy ships, which are operated by...countries on nuclear-related issues that is carried out under the 1958 Agreement for Cooperation on the Uses of Atomic Energy for Mutual Defense
Reference PMHS Sled Tests to Assess Submarining.
Uriot, Jérôme; Potier, Pascal; Baudrit, Pascal; Trosseille, Xavier; Petit, Philippe; Richard, Olivier; Compigne, Sabine; Masuda, Mitsutoshi; Douard, Richard
2015-11-01
Sled tests focused on pelvis behavior and submarining can be found in the literature. However, they were performed either with rigid seats or with commercial seats. The objective of this study was to get reference tests to assess the submarining ability of dummies in more realistic conditions than on rigid seat, but still in a repeatable and reproducible setup. For this purpose, a semi-rigid seat was developed, which mimics the behavior of real seats, although it is made of rigid plates and springs that are easy to reproduce and simulate with an FE model. In total, eight PMHS sled tests were performed on this semirigid seat to get data in two different configurations: first in a front seat configuration that was designed to prevent submarining, then in a rear seat configuration with adjusted spring stiffness to generate submarining. All subjects sustained extensive rib fractures from the shoulder belt loading. No pelvis fractures and no submarining were observed in the front seat configuration, but two subjects sustained lumbar vertebrae fractures. In the rear seat configuration, all subjects sustained pelvic fractures and demonstrated submarining. Corridors were constructed for the external forces and the PMHS kinematics. They are provided in this paper as new reference tests to assess the biofidelity of human surrogates in different configurations that either result in submarining or do not. In future, it is intended to analyze further seat and restraint system configurations to be able to define a submarining predictor.
Park, Geun Chul; Hwang, Soo Min; Lee, Seung Muk; Choi, Jun Hyuk; Song, Keun Man; Kim, Hyun You; Kim, Hyun-Suk; Eum, Sung-Jin; Jung, Seung-Boo; Lim, Jun Hyung; Joo, Jinho
2015-01-01
The incorporation of doping elements in ZnO nanostructures plays an important role in adjusting the optical and electrical properties in optoelectronic devices. In the present study, we fabricated 1-D ZnO nanorods (NRs) doped with different In contents (0% ~ 5%) on p-GaN films using a facile hydrothermal method, and investigated the effect of the In doping on the morphology and electronic structure of the NRs and the electrical and optical performances of the n-ZnO NRs/p-GaN heterojunction light emitting diodes (LEDs). As the In content increased, the size (diameter and length) of the NRs increased, and the electrical performance of the LEDs improved. From the electroluminescence (EL) spectra, it was found that the broad green-yellow-orange emission band significantly increased with increasing In content due to the increased defect states (oxygen vacancies) in the ZnO NRs, and consequently, the superposition of the emission bands centered at 415 nm and 570 nm led to the generation of white-light. These results suggest that In doping is an effective way to tailor the morphology and the optical, electronic, and electrical properties of ZnO NRs, as well as the EL emission property of heterojunction LEDs. PMID:25988846
Park, Geun Chul; Hwang, Soo Min; Lee, Seung Muk; Choi, Jun Hyuk; Song, Keun Man; Kim, Hyun You; Kim, Hyun-Suk; Eum, Sung-Jin; Jung, Seung-Boo; Lim, Jun Hyung; Joo, Jinho
2015-05-19
The incorporation of doping elements in ZnO nanostructures plays an important role in adjusting the optical and electrical properties in optoelectronic devices. In the present study, we fabricated 1-D ZnO nanorods (NRs) doped with different In contents (0% ~ 5%) on p-GaN films using a facile hydrothermal method, and investigated the effect of the In doping on the morphology and electronic structure of the NRs and the electrical and optical performances of the n-ZnO NRs/p-GaN heterojunction light emitting diodes (LEDs). As the In content increased, the size (diameter and length) of the NRs increased, and the electrical performance of the LEDs improved. From the electroluminescence (EL) spectra, it was found that the broad green-yellow-orange emission band significantly increased with increasing In content due to the increased defect states (oxygen vacancies) in the ZnO NRs, and consequently, the superposition of the emission bands centered at 415 nm and 570 nm led to the generation of white-light. These results suggest that In doping is an effective way to tailor the morphology and the optical, electronic, and electrical properties of ZnO NRs, as well as the EL emission property of heterojunction LEDs.
ESR dating of barite in sea-floor hydrothermal sulfide deposits at Okinawa Trough
NASA Astrophysics Data System (ADS)
Fujiwara, T.; Toyoda, S.; Uchida, A.; Ishibashi, J.; Nakai, S.; Takamasa, A.
2013-12-01
The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). With this aspect, Okumura et al. (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite to obtain preliminary ages, while Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. ESR is a method to observe radicals having unpaired electrons. As natural radiation creates unpaired electrons in minerals, the age is deduced by dividing the natural radiation dose (obtained from the amount of unpaired electrons) by the dose rate which is estimated by the amount of environmental radioactive elements. The samples were taken by the research cruises, NT12-10 and NT11-20 and NT12-06 operated by JAMSTEC from Hatoma, Yoron, Izena, North Iheya, and Yonaguni IV Knolls of Okinawa Trough. The blocks of sulfide deposits were cut into pieces, and about 2.0g was crushed. The samples were soaked in 12M hydrochloric acid, left for approximately 24 hours. Then, 13M nitric acid was added. Finally, after rinsing in distilled water, the sample was filtered and dried. Impurities were removed by handpicking. A X-ray diffraction study was made to confirm that the grains are pure barite. After γ-ray irradiation at Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, they were measured at room temperature with an ESR spectrometer (JES-PX2300) with a microwave power of 1mW, and the magnetic field modulation amplitude of 0.1mT. The equivalent natural radiation doses were obtained from the increase of ESR signal intensity of SO3- by irradiation. The bulk Ra concentration was measured by the low background pure Ge gamma ray spectrometer. Assuming that Ra is populated only in barite
Gas Chemistry of Submarine Hydrothermal Venting at Maug Caldera, Mariana Arc
NASA Astrophysics Data System (ADS)
Embley, R. W.; Lupton, J. E.; Butterfield, D. A.; Lilley, M. D.; Evans, L. J.; Olson, E. J.; Resing, J. A.; Buck, N.; Larson, B. I.; Young, C.
2014-12-01
Maug volcano consists of 3 islands that define the perimeter of a submerged caldera that was formed by an explosive eruption. The caldera reaches a depth of ~225 meters, and has a prominent central cone or pinnacle that ascends within 20 meters of the sea surface. Our exploration of Maug began in 2003, when a single hydrocast in the caldera detected a strong suspended particle and helium plume reaching a maximum of δ3He = 250% at ~180 meters depth, clearly indicating hydrothermal activity within the caldera. In 2004 we returned armed with the ROPOS ROV, and two ROPOS dives discovered and sampled low temperature (~4 °C) diffuse venting associated with bacterial mats on the NE flank of the central pinnacle at 145 m depth. Samples collected with titanium gas tight bottles were badly diluted with ambient seawater but allowed an estimate of end-member 3He/4He of 7.3 Ra. Four vertical casts lowered into the caldera in 2004 all had a strong 3He signal (δ3He = 190%) at 150-190 meters depth. A recent expedition in 2014 focused on the shallow (~10 m) gas venting along the caldera interior. Scuba divers were able to collect samples of the gas bubbles using evacuated SS bottles fitted with plastic funnels. The gas samples had a consistent ~170 ppm He, 8 ppmNe, 60% CO2, 40%N2, and 0.8% Ar, and an end-member 3He/4He ratio of 6.9 Ra. This 3He/4He ratio falls within the range for typical arc volcanoes. The rather high atmospheric component (N2, Ar, Ne) in these samples is not contamination but appears to be derived from subsurface exchange between the ascending CO2 bubbles and air saturated seawater. A single vertical cast in 2014 had a maximum δ3He = 55% at 140 m depth, much lower than in 2003 and 2004. This decrease is possibly due to recent flushing of the caldera by a storm event, or may reflect a decrease in the deep hydrothermal activity. This area of shallow CO2 venting in Maug caldera is of particular interest as a natural laboratory for studying the effects of ocean
REE geochemistry of 3.2 Ga BIF from the Mapepe Formation, Barberton Greenstone Belt, South Africa
NASA Astrophysics Data System (ADS)
Yahagi, T. R.; Yamaguchi, K. E.; Haraguchi, S.; Sano, R.; Teraji, S.; Kiyokawa, S.; Ikehara, M.; Ito, T.
2012-12-01
Banded iron formations (BIFs) are chemical sediments interbedded with Fe- and Si-rich layers, characteristically present in the early history of the Earth. A popular hypothesis for the formation of BIFs postulates that dissolved oxygen produced by photosynthesizers such as cyanobacteria oxidized dissolved ferrous Fe supplied by submarine hydrothermal activities. During precipitation of Fe-oxide minerals, phosphorus and rare earth elements (REEs) were most likely adsorbed on their surface. Therefore, chemical compositions of REEs that adsorbed onto Fe-oxide have useful information on the seawater chemistry at the time of deposition. Especially, information on the redox state of seawater and the extent of the contribution of hydrothermal activity during BIF deposition are expected to have been recorded. Occurrence of BIF has been traditionally tied to the chemical evolution of the atmosphere. Rise of atmospheric oxygen, or as known as GOE (Great Oxidation Event: e.g., Holland, 1994), has been widely believed to have occurred at around 2.4 Ga ago. Contrary, however, some studies have suggested that such oxygenation could have occurred much earlier (e.g., Hoashi et al., 2009). In this study, we used 3.2 Ga old BIF from the Mapepe Formation at the bottom of the Fig Tree Group of the Swaziland Supergroup in the northeastern part of the Barberton Greenstone Belt, South Africa. We aimed to constrain the marine environment, and by inference atmospheric environment, at the time of BIF deposition from REE geochemistry. Major elements and REE compositions of 37 samples were measured using XRF and ICP-MS, respectively. Samples with less than 1.0 wt% Al2O3 are considered to be "pure" BIFs with minimal amount of continental contamination, and are expected to have inherited marine REE signatures. Abundance of REE normalized by C1 chondrite for the analyzed samples commonly exhibits positive Eu anomaly and LREE
30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. ...
30. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONNECTICUT. 2 JUNE 1930. SUBMARINE TRAINING TANK - STEELWORK 98% COMPLETE; BRICKWORK 95% COMPLETE, PIPING 10% IN PLACE. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Liquid Carbon Dioxide Venting at the Champagne Hydrothermal Site, NW Eifuku Volcano, Mariana Arc
NASA Astrophysics Data System (ADS)
Lupton, J.; Lilley, M.; Butterfield, D.; Evans, L.; Embley, R.; Olson, E.; Proskurowski, G.; Resing, J.; Roe, K.; Greene, R.; Lebon, G.
2004-12-01
In March/April 2004, submersible dives with the remotely-operated vehicle ROPOS discovered an unusual CO2-rich hydrothermal system near the summit of NW Eifuku, a submarine volcano located at 21.49° N, 144.04° E in the northern Mariana Arc. Although several sites of hydrothermal discharge were located on NW Eifuku, the most intense venting was found at 1600-m depth at the Champagne site, slightly west of the volcano summit. The Champagne site was found to be discharging two distinct fluids into the ocean: a) several small white chimneys were emitting milky 103° C gas-rich hydrothermal fluid with at least millimolar levels of H2S and b) cold (< 4° C) droplets coated with a milky skin were rising slowly from the sediment. These droplets were later determined to consist mainly of liquid CO2, with H2S as a probable secondary component. The droplets were sticky, and did not tend to coalesce into larger droplets, even though they adhered to the ROV like clumps of grapes. The film coating the droplets was assumed to be CO2 hydrate (or clathrate) which is known to form whenever liquid CO2 contacts water under these P,T conditions. Samples of the 103° C hydrothermal fluids were collected in special gas-tight titanium sampling bottles that were able to withstand the high internal pressures created by the dissolved gases. The Champagne hydrothermal fluids contained a surprising 2.3 moles/kg of CO2, an order of magnitude higher than any CO2 values previously reported for submarine hydrothermal fluids. The overall gas composition was 87% CO2, < 0.1% CH4, < 2 ppm H2, 0.012 mM/kg 4He, with the remaining 13% (322 mM/kg) assumed to be sulfur gases (H2S, SO2, etc.). (Additional analyses planned will confirm the speciation of this sulfur gas component). The helium had R/RA = 7.3, typical of subduction zone systems (R = 3He/4He and RA = Rair). Isotopic analysis of the CO2 yielded δ 13C = -1.75 ‰ , much heavier than the -6.0 ‰ typical for carbon in MOR vent fluids. The C/3He
Arctic Submarine Slope Stability
NASA Astrophysics Data System (ADS)
Winkelmann, D.; Geissler, W.
2010-12-01
Submarine landsliding represents aside submarine earthquakes major natural hazard to coastal and sea-floor infrastructure as well as to coastal communities due to their ability to generate large-scale tsunamis with their socio-economic consequences. The investigation of submarine landslides, their conditions and trigger mechanisms, recurrence rates and potential impact remains an important task for the evaluation of risks in coastal management and offshore industrial activities. In the light of a changing globe with warming oceans and rising sea-level accompanied by increasing human population along coasts and enhanced near- and offshore activities, slope stability issues gain more importance than ever before. The Arctic exhibits the most rapid and drastic changes and is predicted to change even faster. Aside rising air temperatures, enhanced inflow of less cooled Atlantic water into the Arctic Ocean reduces sea-ice cover and warms the surroundings. Slope stability is challenged considering large areas of permafrost and hydrates. The Hinlopen/Yermak Megaslide (HYM) north of Svalbard is the first and so far only reported large-scale submarine landslide in the Arctic Ocean. The HYM exhibits the highest headwalls that have been found on siliciclastic margins. With more than 10.000 square kilometer areal extent and app. 2.400 cubic kilometer of involved sedimentary material, it is one of the largest exposed submarine slides worldwide. Geometry and age put this slide in a special position in discussing submarine slope stability on glaciated continental margins. The HYM occurred 30 ka ago, when the global sea-level dropped by app. 50 m within less than one millennium due to rapid onset of global glaciation. It probably caused a tsunami with circum-Arctic impact and wave heights exceeding 130 meters. The HYM affected the slope stability field in its neighbourhood by removal of support. Post-megaslide slope instability as expressed in creeping and smaller-scaled slides are
NASA Astrophysics Data System (ADS)
German, C. R.; von Damm, K. L.
2003-12-01
What is Hydrothermal Circulation?Hydrothermal circulation occurs when seawater percolates downward through fractured ocean crust along the volcanic mid-ocean ridge (MOR) system. 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 hydrothermal circulation plays a significant role in the cycling of energy and mass between the solid earth and the oceans; the first identification of submarine hydrothermal 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 hydrothermal 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
NASA Astrophysics Data System (ADS)
Oleson, S. R.; Lorenz, R. D.; Paul, M. V.; Hartwig, J. W.; Walsh, J. M.
2017-02-01
A NIAC Phase II submarine concept, dubbed 'Titan Turtle' for Saturn's moon Titan's northern sea, Ligea Mare. A design concept including science and operations is described for this -180°C liquid methane sea.
Nuclear Submarines and Aircraft Carriers | Radiation ...
2017-08-07
Nuclear submarines and aircraft carriers are powered by onboard nuclear reactors. Heat from the nuclear reaction makes the steam needed to power the submarine. When a nuclear vessel is taken out of service, its radioactive parts are disposed of and monitored.
NASA Astrophysics Data System (ADS)
Havig, J. R.; Hamilton, T. L.
2017-12-01
Mounting geochemical evidence suggests microorganisms capable of oxygenic photosynthesis (e.g., Cyanobacteria) colonized Archean continental surfaces, driving oxidative weathering of detrital pyrites prior to the 2.5 Ga great oxidation event. Modern terrestrial environments dominated by single-celled phototrophs include hydrothermal systems (e.g., Yellowstone National Park) and hypolithic communities found in arid to hyper-arid deserts (e.g., McMurdo Dry Valleys of Antarctica, Atacama Desert of Chile). Recent work indicates terrestrial hydrothermal systems date back at least as far as 3.5 Ga. Here, we explore phototrophic communities in both hypolithic (sub-sinter) and hydrothermal (subaqueous and subaerial) environments in Yellowstone National Park as potential analogs to Archean continental surfaces. Hydrothermal sub-sinter environments provide ideal conditions for phototrophic microbial communities, including blocking of harmful UV radiation, trapping and retention of moisture, and protection from erosion by rain and surface runoff. Hypolithic communities in geothermal settings were similar in both composition and carbon uptake rates to nearby hot spring communities. We hypothesize that hydrothermal area hypolithic communities represent modern analogs of phototrophic microbial communities that colonized Archean continental surfaces, producing oxygen locally and facilitating microbially-mediated pyrite oxidation prior to the presence of free oxygen in the global atmosphere. These results have implications for oxidation of the early Earth surface, the search for biosignatures in the rock record, as well as for potential harbors of past life on Mars and the search for life on Exoplanets.
NASA Astrophysics Data System (ADS)
Rhodes, M.; Bryce, J. G.; Jercinovic, M. J.; Fahnestock, M. F.; Jackson, M. D.
2017-12-01
The archetypal volcano Surtsey erupted spectacularly out of the North Atlantic Ocean from November 1963 to June 1967, on the southern submarine extension of the E. Icelandic Rift Zone. Twelve years later, in 1979, the eastern cone (Surtur I) was drilled to a depth of 181 m to document the growth of the volcano and the interaction of basaltic tephra with seawater [1]. The present study is a pilot project for the International Continental Drilling Project on Surtsey, SUSTAIN, starting in August, 2017. The overall intent is to document the nature, extent and rates of hydrothermal and seawater reaction with tephra over the past 50 years. This work builds on the 1979 drilling studies through new electron microprobe and laser ablation (LA- ICPMS) analyses to document varying degrees of palagonitic alteration of volcanic glass and primary phases to form authigenic minerals (smectite, zeolites, Al-tobermorite, anhydrite) in the intervening 12 years since the eruption. Combined with modal data and inferred phase densities, the data documents the mass balance of major and trace elements among the phases and the relationship of these changes to core depth, temperature and porosity. Although hydrothermal alteration is extensive, especially in the hotter submarine intervals from 60 to 120 m, detailed whole-rock major, trace and isotopic data (Sr, Nd, Pb), show that, apart from hydration and oxidation, there is only modest exchange of elements between tephra and seawater, or hydrothermal fluids, in the upper 140 m of the core prior to 1979. Below 140 m, in a cooler zone of coarse, more porous tephra, extensive exchange of elements, involving hydrothermal introduction of sulfur and growth of anhydrite, is associated with the loss of Ca, K, Rb, Sr and addition of MgO and Na and seawater isotopic signatures. It is surely no coincidence that this zone of elemental and isotopic exchange supports active microbial colonies [2]. Our results serve as an important baseline for the 2017
29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT ...
29. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION AT POINT JUST ABOVE THE SUBMARINE SECTION AT THE 110-FOOT LEVEL 1929-1930 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Geomorphic process fingerprints in submarine canyons
Brothers, Daniel S.; ten Brink, Uri S.; Andrews, Brian D.; Chaytor, Jason D.; Twichell, David C.
2013-01-01
Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics.
Anaerobic methanotrophic communities thrive in deep submarine permafrost.
Winkel, Matthias; Mitzscherling, Julia; Overduin, Pier P; Horn, Fabian; Winterfeld, Maria; Rijkers, Ruud; Grigoriev, Mikhail N; Knoblauch, Christian; Mangelsdorf, Kai; Wagner, Dirk; Liebner, Susanne
2018-01-22
Thawing submarine permafrost is a source of methane to the subsurface biosphere. Methane oxidation in submarine permafrost sediments has been proposed, but the responsible microorganisms remain uncharacterized. We analyzed archaeal communities and identified distinct anaerobic methanotrophic assemblages of marine and terrestrial origin (ANME-2a/b, ANME-2d) both in frozen and completely thawed submarine permafrost sediments. Besides archaea potentially involved in anaerobic oxidation of methane (AOM) we found a large diversity of archaea mainly belonging to Bathyarchaeota, Thaumarchaeota, and Euryarchaeota. Methane concentrations and δ 13 C-methane signatures distinguish horizons of potential AOM coupled either to sulfate reduction in a sulfate-methane transition zone (SMTZ) or to the reduction of other electron acceptors, such as iron, manganese or nitrate. Analysis of functional marker genes (mcrA) and fluorescence in situ hybridization (FISH) corroborate potential activity of AOM communities in submarine permafrost sediments at low temperatures. Modeled potential AOM consumes 72-100% of submarine permafrost methane and up to 1.2 Tg of carbon per year for the total expected area of submarine permafrost. This is comparable with AOM habitats such as cold seeps. We thus propose that AOM is active where submarine permafrost thaws, which should be included in global methane budgets.
A Hydrothermal-Sedimentary Context for the Origin of Life
Hickman-Lewis, K.; Hinman, N.; Gautret, P.; Campbell, K.A.; Bréhéret, J.G.; Foucher, F.; Hubert, A.; Sorieul, S.; Dass, A.V.; Kee, T.P.; Georgelin, T.; Brack, A.
2018-01-01
Abstract Critical to the origin of life are the ingredients of life, of course, but also the physical and chemical conditions in which prebiotic chemical reactions can take place. These factors place constraints on the types of Hadean environment in which life could have emerged. Many locations, ranging from hydrothermal vents and pumice rafts, through volcanic-hosted splash pools to continental springs and rivers, have been proposed for the emergence of life on Earth, each with respective advantages and certain disadvantages. However, there is another, hitherto unrecognized environment that, on the Hadean Earth (4.5–4.0 Ga), would have been more important than any other in terms of spatial and temporal scale: the sedimentary layer between oceanic crust and seawater. Using as an example sediments from the 3.5–3.33 Ga Barberton Greenstone Belt, South Africa, analogous at least on a local scale to those of the Hadean eon, we document constant permeation of the porous, carbonaceous, and reactive sedimentary layer by hydrothermal fluids emanating from the crust. This partially UV-protected, subaqueous sedimentary environment, characterized by physical and chemical gradients, represented a widespread system of miniature chemical reactors in which the production and complexification of prebiotic molecules could have led to the origin of life. Key Words: Origin of life—Hadean environment—Mineral surface reactions—Hydrothermal fluids—Archean volcanic sediments. Astrobiology 18, 259–293. PMID:29489386
32 CFR 707.7 - Submarine identification light.
Code of Federal Regulations, 2010 CFR
2010-07-01
... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light. Submarines may display, as a distinctive means of identification, an intermittent flashing amber beacon with...
Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds
NASA Astrophysics Data System (ADS)
Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik
2016-10-01
Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems 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 hydrothermal vents (Russell et al., 2014). Hydrothermal 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 systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal 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
32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. ...
32. VIEW OF PHOTO CAPTIONED 'SUBMARINE BASE, NEW LONDON, CONN. OCTOBER 3, 1932. COMPLETION OF ERECTION OF STEELWORK FOR ELEVATOR. LOOKING NORTH. CONTRACT NO. Y-1539-ELEVATOR, SUBMARINE ESCAPE TANK.' - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
32 CFR 700.1058 - Command of a submarine.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 32 National Defense 5 2011-07-01 2011-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in the Navy, eligible for command at sea and qualified for command of...
32 CFR 700.1058 - Command of a submarine.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 32 National Defense 5 2010-07-01 2010-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in the Navy, eligible for command at sea and qualified for command of...
32 CFR 700.1058 - Command of a submarine.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 32 National Defense 5 2012-07-01 2012-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in the Navy, eligible for command at sea and qualified for command of...
32 CFR 700.1058 - Command of a submarine.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 32 National Defense 5 2014-07-01 2014-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in the Navy, eligible for command at sea and qualified for command of...
32 CFR 700.1058 - Command of a submarine.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 32 National Defense 5 2013-07-01 2013-07-01 false Command of a submarine. 700.1058 Section 700... Command Detail to Duty § 700.1058 Command of a submarine. The officer detailed to command a submarine shall be an officer of the line in the Navy, eligible for command at sea and qualified for command of...
NASA Astrophysics Data System (ADS)
Weis, Philipp; Driesner, Thomas; Scott, Samuel; Lecumberri-Sanchez, Pilar
2016-04-01
Heat and mass transport in hydrothermal systems associated with upper crustal magmatic intrusions can result in resources with large economic potential (Kesler, 1994). Active hydrothermal systems can form high-enthalpy geothermal reservoirs with the possibility for renewable energy production. Fossil continental or submarine hydrothermal systems 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 hydrothermal 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 systems, as well as knowledge of fluid and rock properties and their interactions in natural systems. 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-hydrothermal 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-hydrothermal systems 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
Addressing submarine geohazards through scientific drilling
NASA Astrophysics Data System (ADS)
Camerlenghi, A.
2009-04-01
Natural submarine geohazards (earthquakes, volcanic eruptions, landslides, volcanic island flank collapses) are geological phenomena originating at or below the seafloor leading to a situation of risk for off-shore and on-shore structures and the coastal population. Addressing submarine geohazards means understanding their spatial and temporal variability, the pre-conditioning factors, their triggers, and the physical processes that control their evolution. Such scientific endeavour is nowadays considered by a large sector of the international scientific community as an obligation in order to contribute to the mitigation of the potentially destructive societal effects of submarine geohazards. The study of submarine geohazards requires a multi-disciplinary scientific approach: geohazards must be studied through their geological record; active processes must be monitored; geohazard evolution must be modelled. Ultimately, the information must be used for the assessment of vulnerability, risk analysis, and development of mitigation strategies. In contrast with the terrestrial environment, the oceanic environment is rather hostile to widespread and fast application of high-resolution remote sensing techniques, accessibility for visual inspection, sampling and installation of monitoring stations. Scientific Drilling through the IODP (including the related pre site-survey investigations, sampling, logging and in situ measurements capability, and as a platform for deployment of long term observatories at the surface and down-hole) can be viewed as the centre of gravity of an international, coordinated, multi-disciplinary scientific approach to address submarine geohazards. The IODP Initial Science Plan expiring in 2013 does not address openly geohazards among the program scientific objectives. Hazards are referred to mainly in relation to earthquakes and initiatives towards the understanding of seismogenesis. Notably, the only drilling initiative presently under way is the
Reducing Unsteady Loads on a Piggyback Miniature Submarine
NASA Technical Reports Server (NTRS)
Lin, John
2009-01-01
A small, simple fixture has been found to be highly effective in reducing destructive unsteady hydrodynamic loads on a miniature submarine that is attached in piggyback fashion to the top of a larger, nuclear-powered, host submarine. The fixture, denoted compact ramp, can be installed with minimal structural modification, and the use of it does not entail any change in submarine operations.
NASA Astrophysics Data System (ADS)
Clare, Michael; Pope, Edward; Talling, Peter; Hunt, James; Carter, Lionel
2016-04-01
The global economy relies on uninterrupted usage of a network of telecommunication cables on the seafloor. These submarine cables carry ~99% of all trans-oceanic digital data and voice communications traffic worldwide, as they have far greater bandwidth than satellites. Over 9 million SWIFT banks transfers alone were made using these cables in 2004, totalling 7.4 trillion of transactions per day between 208 countries, which grew to 15 million SWIFT bank transactions last year. We outline the challenge of why, how often, and where seafloor cables are broken by natural causes; primarily subsea landslides and sediment flows (turbidity currents and also debris flows and hyperpycnal flows). These slides and flows can be very destructive. As an example, a sediment flow in 1929 travelled up to 19 m/s and broke 11 cables in the NE Atlantic, running out for ~800 km to the abyssal ocean. The 2006 Pingtung earthquake triggered a sediment flow that broke 22 cables offshore Taiwan over a distance of 450 km. Here, we present initial results from the first statistical analysis of a global database of cable breaks and causes. We first investigate the controls on frequency of submarine cable breaks in different environmental and geological settings worldwide. We assess which types of earthquake pose a significant threat to submarine cable networks. Meteorological events, such as hurricanes and typhoons, pose a significant threat to submarine cable networks, so we also discuss the potential impacts of future climate change on the frequency of such hazards. We then go on to ask what are the physical impacts of submarine sediment flows on submerged cables? A striking observation from past cable breaks is sometimes cables remain unbroken, whilst adjacent cables are severed (and record powerful flows travelling at up to 6 m/s). Why are some cables broken, but neighbouring cables remain intact? We provide some explanations for this question, and outline the need for future in
Effect of Submarine Groundwater Discharge on Relict Arctic Submarine Permafrost and Gas Hydrate
NASA Astrophysics Data System (ADS)
Frederick, J. M.; Buffett, B. A.
2014-12-01
Permafrost-associated gas hydrate deposits exist at shallow depths within the sediments of the circum-Arctic continental shelves. Degradation of this shallow water reservoir has the potential to release large quantities of methane gas directly to the atmosphere. Gas hydrate stability and the permeability of the shelf sediments to gas migration is closely linked with submarine permafrost. Submarine permafrost extent depends on several factors, such as the lithology, sea level variations, mean annual air temperature, ocean bottom water temperature, geothermal heat flux, and the salinity of the pore water. The salinity of the pore water is especially relevant because it partially controls the freezing point for both ice and gas hydrate. Measurements of deep pore water salinity are few and far between, but show that deep off-shore sediments are fresh. Deep freshening has been attributed to large-scale topographically-driven submarine groundwater discharge, which introduces fresh terrestrial groundwater into deep marine sediments. We investigate the role of submarine ground water discharge on the salinity field and its effects on the seaward extent of relict submarine permafrost and gas hydrate stability on the Arctic shelf with a 2D shelf-scale model based on the finite volume method. The model tracks the evolution of the temperature, salinity, and pressure fields given imposed boundary conditions, with latent heat of water ice and hydrate formation included. The permeability structure of the sediments is coupled to changes in permafrost. Results show that pore fluid is strongly influenced by the permeability variations imposed by the overlying permafrost layer. Groundwater discharge tends to travel horizontally off-shore beneath the permafrost layer and the freshwater-saltwater interface location displays long timescale transient behavior that is dependent on the groundwater discharge strength. The seaward permafrost extent is in turn strongly influenced by the
Hydrothermal Vents of Juan de Fuca Ridge
NASA Astrophysics Data System (ADS)
Stark, Joyce
As a member of REVEL (Research and Education: Volcanoes, Exploration and Life), I had an opportunity to participant in a scientific research cruise focused on the active volcanoes along the Juan de Fuca Ridge, the submarine spreading center off the Washington- Oregon-Canada coast. REVEL was sponsored by the National Science Foundation, University of Washington, Pennsylvania State University and the American Museum of Natural History. We studied the geological, chemical and biological processes associated with active hydrothermal systems and my research focused on the biological communities of the sulfide structures. We worked on board the Woods Hole Oceanographic Institution Vessel, R/V Atlantis and the submersible ALVIN was used to sample the "Black Smokers". As a member of the scientific party, I participated in collection and sorting of biological specimens from the vent communities, attended lectures by scientists, contributed to the cruise log website, maintained a journal and developed my own research project. It was my responsibility to bring this cutting-edge research back to the classroom.
Influence of Anchoring on Burial Depth of Submarine Pipelines
Zhuang, Yuan; Li, Yang; Su, Wei
2016-01-01
Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952
34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION ...
34. VIEW OF SUBMARINE ESCAPE TRAINING TANK PRIOR TO ADDITION OF BLISTERS IN 1959, LOOKING SOUTHEAST - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
ORP and pH measurements to detect redox and acid-base anomalies from hydrothermal activity
NASA Astrophysics Data System (ADS)
Santana-Casiano, J. M.; González-Dávila, M.; Fraile-Nuez, E.
2017-12-01
The Tagoro submarine volcano is located 1.8 km south of the Island of El Hierro at 350 m depth and rises up to 88 m below sea level. It was erupting melting material for five months, from October 2011 to March 2012, changing drastically the physical-chemical properties of the water column in the area. After this eruption, the system evolved to a hydrothermal system. The character of both reduced and acid of the hydrothermal emissions in the Tagoro submarine volcano allowed us to detect anomalies related with changes in the chemical potential and the proton concentration using ORP and pH sensors, respectively. Tow-yos using a CTD-rosette with these two sensors provided the locations of the emissions plotting δ(ORP)/δt and ΔpH versus the latitude or longitude. The ORP sensor responds very quickly to the presence of reduced chemicals in the water column. Changes in potential are proportional to the amount of reduced chemical species present in the water. The magnitude of these changes are examined by the time derivative of ORP, δ(ORP)/δt. To detect changes in the pH, the mean pH for each depth at a reference station in an area not affected by the vent emission is subtracted from each point measured near the volcanic edifice, defining in this way ΔpH. Detailed surveys of the volcanic edifice were carried out between 2014 and 2016 using several CTD-pH-ORP tow-yo studies, localizing the ORP and pH changes, which were used to obtain surface maps of anomalies. Moreover, meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d-1 which increases the acidity above the volcano by 20%. Sites like the Tagoro submarine volcano, in its degasification stage, provide an excellent opportunity to study the carbonate system in a high CO2 world, the volcanic contribution to the global
Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.
2009-01-01
Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments from source craters that range from a few meters up to more than 2 km in diameter; associated breccia can be emplaced as much as 3 to 4 km from the largest craters. Hydrothermal explosions occur where shallow interconnected reservoirs of steam- and liquid-saturated fluids with temperatures at or near the boiling curve underlie thermal fields. Sudden reduction in confi ning pressure causes fluids to fl ash to steam, resulting in signifi cant expansion, rock fragmentation, and debris ejection. In Yellowstone, hydrothermal explosions are a potentially signifi cant hazard for visitors and facilities and can damage or even destroy thermal features. The breccia deposits and associated craters formed from hydrothermal explosions are mapped as mostly Holocene (the Mary Bay deposit is older) units throughout Yellowstone National Park (YNP) and are spatially related to within the 0.64-Ma Yellowstone caldera and along the active Norris-Mammoth tectonic corridor. In Yellowstone, at least 20 large (>100 m in diameter) hydrothermal explosion craters have been identifi ed; the scale of the individual associated events dwarfs similar features in geothermal areas elsewhere in the world. Large hydrothermal explosions in Yellowstone have occurred over the past 16 ka averaging ??1 every 700 yr; similar events are likely in the future. Our studies of large hydrothermal explosion events indicate: (1) none are directly associated with eruptive volcanic or shallow intrusive events; (2) several historical explosions have been triggered by seismic events; (3) lithic clasts and comingled matrix material that form hydrothermal explosion deposits are extensively altered, indicating that explosions occur in areas subjected to intense hydrothermal processes; (4) many lithic clasts contained in explosion breccia deposits preserve evidence of repeated fracturing
Hydrothermal activity lowers trophic diversity in Antarctic hydrothermal sediments
NASA Astrophysics Data System (ADS)
Bell, James B.; Reid, William D. K.; Pearce, David A.; Glover, Adrian G.; Sweeting, Christopher J.; Newton, Jason; Woulds, Clare
2017-12-01
Hydrothermal sediments are those in which hydrothermal fluid is discharged through sediments and are one of the least studied deep-sea ecosystems. We present a combination of microbial and biochemical data to assess trophodynamics between and within hydrothermal and background areas of the Bransfield Strait (1050-1647 m of depth). Microbial composition, biomass, and fatty acid signatures varied widely between and within hydrothermally active and background sites, providing evidence of diverse metabolic activity. Several species had different feeding strategies and trophic positions between hydrothermally active and inactive areas, and the stable isotope values of consumers were not consistent with feeding morphology. Niche area and the diversity of microbial fatty acids was lowest at the most hydrothermally active site, reflecting trends in species diversity. Faunal uptake of chemosynthetically produced organics was relatively limited but was detected at both hydrothermal and non-hydrothermal sites, potentially suggesting that hydrothermal activity can affect trophodynamics over a much wider area than previously thought.
Bourbouli, Maria; Katsifas, Efstathios A; Papathanassiou, Evangelos; Karagouni, Amalia D
2015-05-01
Microbes in hydrothermal vents with their unique secondary metabolism may represent an untapped potential source of new natural products. In this study, samples were collected from the hydrothermal field of Kolumbo submarine volcano in the Aegean Sea, in order to isolate bacteria with antimicrobial activity. Eight hundred and thirty-two aerobic heterotrophic bacteria were isolated and then differentiated through BOX-PCR analysis at the strain level into 230 genomic fingerprints, which were screened against 13 different type strains (pathogenic and nonpathogenic) of Gram-positive, Gram-negative bacteria and fungi. Forty-two out of 176 bioactive-producing genotypes (76 %) exhibited antimicrobial activity against at least four different type strains and were selected for 16S rDNA sequencing and screening for nonribosomal peptide (NRPS) and polyketide (PKS) synthases genes. The isolates were assigned to genus Bacillus and Proteobacteria, and 20 strains harbored either NRPS, PKS type I or both genes. This is the first report on the diversity of culturable mesophilic bacteria associated with antimicrobial activity from Kolumbo area; the extremely high proportion of antimicrobial-producing strains suggested that this unique environment may represent a potential reservoir of novel bioactive compounds.
35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, ...
35. INTERIOR VIEW OF EQUIPMENT HOUSE, SUBMARINE ESCAPE TRAINING TANK, PRIOR TO ENLARGEMENT OF ROOM AND INSTALLATION OF TRIPLE-LOCK RECOMPRESSION CHAMBER IN 1957 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF ...
31. VIEW OF SUBMARINE ESCAPE TRAINING TANK DURING CONSTRUCTION OF THE ELEVATOR AND PASSAGEWAYS TO THE 18- AND 50-FOOT LOCKS AND CUPOLA 1932 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Process sedimentology of submarine fan deposits - new perspectives
NASA Astrophysics Data System (ADS)
Postma, George
2017-04-01
To link submarine fan process sedimentology with sand distribution, sand body architecture, texture and fabric, the field geologist studies sedimentary facies, facies associations (fan elements) and stratigraphy. Facies analysis resides on factual knowledge of modern fan morphodynamics and physical modelling of en-masse sediment transport. Where do we stand after 55 years of submarine research, i.e. the date when the first submarine fan model was launched by Arnold Bouma in 1962? Since that date students of submarine fans have worked on a number of important, recurring questions concerned with facies analysis of submarine successions in outcrop and core: 1. What type of sediment transport produced the beds? 2. What facies can be related to initial flow conditions? 3. What is the significance of grain size jumps and bounding surface hierarchy in beds consisting of crude and spaced stratification (traction carpets)? Do these point to multi flow events or to flow pulsations by one and the same event? 4. What facies associations relate to the basic elements of submarine fans? 5. What are the autogenic and allogenic signatures in submarine fans? Particularly in the last decade, the enormous technical advancement helped to obtain high-quality data from observations of density flows in modern canyons, deep basins and deep-water delta slopes (refs 1,2,3). In combination with both physical (refs 4,5) and numerical modelling (ref 6) these studies broke new ground into our understanding of density flow processes in various submarine environments and have led to new concepts of submarine fan building by super- and subcritical high-density flow (ref 7). Do these new concepts provide better answers to our recurrent questions related to the morphodynamics of submarine fans and prediction of sand body architecture? In discussing this open question, I shall 1. apply the new concepts to a modern and ancient example of a channel-lobe-transition-zone (ref 8); 2. raise the problem of
Improved Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway
2010-01-15
information. 2.0 DESCRIPTION Naval Submarine Medical Research Laboratory (NSMRL) is seeking information from the eyewear industry that will provide...Improved Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway by Alison America, MA Wayne G. Horn, MD...Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway 50818 Alison America, MA Wayne G. Horn, MD Naval Submarine Medical Research
32 CFR 707.7 - Submarine identification light.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 32 National Defense 5 2013-07-01 2013-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all around...
32 CFR 707.7 - Submarine identification light.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 32 National Defense 5 2011-07-01 2011-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all around...
32 CFR 707.7 - Submarine identification light.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 32 National Defense 5 2014-07-01 2014-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all around...
32 CFR 707.7 - Submarine identification light.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 32 National Defense 5 2012-07-01 2012-07-01 false Submarine identification light. 707.7 Section... RULES WITH RESPECT TO ADDITIONAL STATION AND SIGNAL LIGHTS § 707.7 Submarine identification light... off-period. The light will be located where it can best be seen, as near as practicable, all around...
VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan
2014-06-01
1472G. VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan and Preliminary Results © Her Majesty the Queen in Right of...19 th International Command and Control Research and Technology Symposium Title: VICTORIA Class Submarine Human-in-the-Loop...TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan 5a. CONTRACT
Wang, Jian; Li, Qi; Qiu, Xiaohui; He, Yujian; Liu, Wei
2010-07-01
Micrometer-scale hollow spheres self-assembled by GaOOH nanorods were synthesized under hydrothermal conditions using gallium nitrate and sodium hydroxide as starting materials. The structures and morphologies of the products were studied by X-ray diffraction and scanning electron microscopy. Time-dependent experiments revealed three stages involved in the process of reaction including the initial stage of formation of surfactant vesicles which can be considered as soft templates, followed by the nucleation of GaOOH nanoclusters, and the assembling and growth of nanorods under the modulation of the spherical vesicles. The growth kinetics of the GaOOH nanorods was systematically investigated. Based on the experimental observation, a template-mediated assembling mechanism was proposed. We further demonstrated that the GaOOH nanorods could be converted to gallium oxide (beta-Ga2O3) nanorods by calcination without changing the spherical morphology of the assemblies.
NASA Astrophysics Data System (ADS)
Shibuya, Takazo; Komiya, Tsuyoshi; Takai, Ken; Maruyama, Shigenori; Russell, Michael J.
2017-12-01
It was previously revealed that the total CO2 concentration in seawater decreased during the Late Archean. In this paper, to assess the secular change of total CO2 concentration in seawater, we focused on the Paleoproterozoic era when the Earth experienced its first recorded global glaciation. The 2.4 Ga Ongeluk Formation outcrops in the Kaapvaal Craton, South Africa. The formation consists mainly of submarine volcanic rocks that have erupted during the global glaciation. The undeformed lavas are mostly carbonate-free but contain rare disseminated calcites. The carbon isotope ratio of the disseminated calcite (δ13Ccc vs. VPDB) ranges from - 31.9 to - 13.2 ‰. The relatively low δ13Ccc values clearly indicate that the carbonation was partially contributed by 13C-depleted CO2 derived from decomposition of organic matter beneath the seafloor. The absence of δ13Ccc higher than - 13.2‰ is consistent with the exceptionally 13C-depleted CO2 in the Ongeluk seawater during glaciation. The results suggest that carbonation occurred during subseafloor hydrothermal circulation just after the eruption of the lavas. Previously, it was reported that the carbonate content in the uppermost subseafloor crust decreased from 3.2 to 2.6 Ga, indicating a decrease in total CO2 concentration in seawater during that time. However, the average CO2 (as carbonate) content in the Ongeluk lavas (< 0.001 wt%) is much lower than those of 2.6 Ga representatives and even of modern equivalents. This finding suggests that the total CO2 concentration in seawater further decreased during the period between 2.6 and 2.4 Ga. Thus, the very low content of carbonate in the Ongeluk lavas is probable evidence for the extremely low CO2 concentration in seawater during the global glaciation. Considering that the carbonate content of the subseafloor crusts also shows a good correlation with independently estimated atmospheric pCO2 levels through the Earth history, it seem highly likely that the low
A descriptive analysis of asthma in the U.S. Navy Submarine Force.
Sims, J R; Tibbles, P M; Jackman, R P
1999-12-01
The U.S. Navy Submarine Force offers a unique opportunity to study asthma because of the relative socioeconomic and physical homogeneity of the population and the closed environment occupational exposure. Currently, asthma is disqualifying from submarine service, which results in a significant loss of experienced personnel. We performed a retrospective analysis of 119 U.S. Navy submariner disqualification packages for asthma between 1989-1993. We found a 0.16% annual period prevalence of asthma in the active duty enlisted Atlantic Fleet Submarine Force. Two groups of asthma disqualifications were identified with a significant increase above their proportional representation in the fleet: enlisted personnel (p < 0.01) and submarine recruits (p < 0.0001). The proportion of African-American personnel also had a tendency toward increased asthma disqualification (p < 0.08). There were no differences in prevalence of asthma between crews of ballistic missile submarines or fast attack submarines. Asthma risk factors reported in the civilian literature (childhood history of asthma, family history of asthma and non-drug allergies) were highly represented in our study (41%, 46% and 68% of submariners, respectively). Most disqualified submariners had "mild" asthma based on the diagnostic work-up. The methacholine challenge test appeared to carry a disproportionate diagnostic weight despite its low specificity. Although the period prevalence of asthma is low in the U.S. Navy Submarine Force, submariners disqualified for asthma have similar historical and ethnic risk factors as the civilian population.
33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Bangor Naval Submarine Base... Bangor Naval Submarine Base, Bangor, WA. (a) Location. The following is a security zone: The waters of... States Naval vessels. (ii) Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...
33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Bangor Naval Submarine Base... Bangor Naval Submarine Base, Bangor, WA. (a) Location. The following is a security zone: The waters of... States Naval vessels. (ii) Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...
33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Bangor Naval Submarine Base... Bangor Naval Submarine Base, Bangor, WA. (a) Location. The following is a security zone: The waters of... States Naval vessels. (ii) Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...
33 CFR 165.1302 - Bangor Naval Submarine Base, Bangor, WA.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Bangor Naval Submarine Base... Bangor Naval Submarine Base, Bangor, WA. (a) Location. The following is a security zone: The waters of... States Naval vessels. (ii) Vessels that are performing work at Naval Submarine Base Bangor pursuant to a...
Submarine radial vents on Mauna Loa Volcano, Hawai'i
Wanless, V. Dorsey; Garcia, M.O.; Trusdell, F.A.; Rhodes, J.M.; Norman, M.D.; Weis, Dominique; Fornari, D.J.; Kurz, M.D.; Guillou, Herve
2006-01-01
A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created “irregular” cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ∼2×109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.
NASA Astrophysics Data System (ADS)
Breier, J. A.; Toner, B. M.; Fakra, S. C.; Marcus, M. A.; White, S. N.; Thurnherr, A. M.; German, C. R.
2012-07-01
Deep-sea hydrothermal plume particles are known to sequester seawater trace elements and influence ocean-scale biogeochemical budgets. The relative importance of biotic versus abiotic oxidation-reduction and other particle-forming reaction, however, and the mechanisms of seawater trace element sequestration remain unknown. Suspended particulate material was collected from a non-buoyant hydrothermal plume by in situ filtration at 9°50‧N East Pacific Rise during a 3-day, 24 sample, time-series. Twenty-three samples were digested for total elemental analysis. One representative sample was selected for particle-by-particle geochemical analyses including elemental composition by X-ray fluorescence, speciation of Fe, S, and C by 1s X-ray absorption near edge structure spectroscopy, and X-ray diffraction. Consistent with past studies, positive linear correlations were observed for P, V, As, and Cr with Fe in the bulk chemistry. Arsenic was associated with both Fe oxyhydroxides and sulfides but not uniformly distributed among either mineral type. Particle aggregation was common. Aggregates were composed of minerals embedded in an organic matrix; the minerals ranged from <20 nm to >10 μm in diameter. The speciation of major mineral forming elements (Fe, Mn, S) was complex. Over 20 different minerals were observed, nine of which were either unpredicted by thermodynamic modeling or had no close match in the thermodynamic database. Sulfur-bearing phases consisted of polysulfides (S6, S8), and metal sulfides (Fe, Cu, Zn, Mn). Four dominant species, Fe oxyhydroxide, Fe monosulfide, pyrrhotite, and pyrite, accounted for >80% of the Fe present. Particulate Mn was prevalent in both oxidized and reduced minerals. The organic matrix was: (1) always associated with minerals, (2) composed of biomolecules, and (3) rich in S. Possible sources of this S-rich organic matter include entrained near vent biomass and in situ production by S-oxidizing microorganisms. These results indicate
47 CFR 32.6424 - Submarine and deep sea cable expense.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 47 Telecommunication 2 2011-10-01 2011-10-01 false Submarine and deep sea cable expense. 32.6424... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine and deep sea cable. (b) Subsidiary record categories shall be maintained as provided in § 32.2424. [67 FR...
47 CFR 32.6424 - Submarine and deep sea cable expense.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 47 Telecommunication 2 2013-10-01 2013-10-01 false Submarine and deep sea cable expense. 32.6424... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine and deep sea cable. (b) Subsidiary record categories shall be maintained as provided in § 32.2424. [67 FR...
47 CFR 32.6424 - Submarine and deep sea cable expense.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 47 Telecommunication 2 2012-10-01 2012-10-01 false Submarine and deep sea cable expense. 32.6424... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine and deep sea cable. (b) Subsidiary record categories shall be maintained as provided in § 32.2424. [67 FR...
47 CFR 32.6424 - Submarine and deep sea cable expense.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 47 Telecommunication 2 2014-10-01 2014-10-01 false Submarine and deep sea cable expense. 32.6424... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine and deep sea cable. (b) Subsidiary record categories shall be maintained as provided in § 32.2424. [67 FR...
47 CFR 32.6424 - Submarine and deep sea cable expense.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 47 Telecommunication 2 2010-10-01 2010-10-01 false Submarine and deep sea cable expense. 32.6424... Submarine and deep sea cable expense. (a) This account shall include expenses associated with submarine and deep sea cable. (b) Subsidiary record categories shall be maintained as provided in § 32.2424. [67 FR...
36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING ...
36. VIEW OF CUPOLA, SUBMARINE ESCAPE TRAINING TANK, SHOWING ROVING RESCUE BELL SUSPENDED ABOVE TANK, WITH TWO-LOCK RECOMPRESSION CHAMBER AT REAR, LOOKING WEST. Photo taken after installation of recompression chamber in 1956. - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
NASA Astrophysics Data System (ADS)
Jackson, M. D.; Gudmundsson, M. T.; Bach, W.; Cappelletti, P.; Coleman, N. J.; Ivarsson, M.; Jónasson, K.; Jørgensen, S. L.; Marteinsson, V.; McPhie, J.; Moore, J. G.; Nielson, D.; Rhodes, J. M.; Rispoli, C.; Schiffman, P.; Stefánsson, A.; Türke, A.; Vanorio, T.; Weisenberger, T. B.; White, J. D. L.; Zierenberg, R.; Zimanowski, B.
2015-12-01
A new International Continental Drilling Program (ICDP) project will drill through the 50-year-old edifice of Surtsey Volcano, the youngest of the Vestmannaeyjar Islands along the south coast of Iceland, to perform interdisciplinary time-lapse investigations of hydrothermal and microbial interactions with basaltic tephra. The volcano, created in 1963-1967 by submarine and subaerial basaltic eruptions, was first drilled in 1979. In October 2014, a workshop funded by the ICDP convened 24 scientists from 10 countries for 3 and a half days on Heimaey Island to develop scientific objectives, site the drill holes, and organize logistical support. Representatives of the Surtsey Research Society and Environment Agency of Iceland also participated. Scientific themes focus on further determinations of the structure and eruptive processes of the type locality of Surtseyan volcanism, descriptions of changes in fluid geochemistry and microbial colonization of the subterrestrial deposits since drilling 35 years ago, and monitoring the evolution of hydrothermal and biological processes within the tephra deposits far into the future through the installation of a Surtsey subsurface observatory. The tephra deposits provide a geologic analog for developing specialty concretes with pyroclastic rock and evaluating their long-term performance under diverse hydrothermal conditions. Abstracts of research projects are posted at http://surtsey.icdp-online.org.
ERIC Educational Resources Information Center
Cornacchia, Deborah J.
2002-01-01
Describes Archimedes principle and why a ship sinks when it gets a hole in it. Suggests an activity for teaching the concept of density and water displacement through the construction of a simple submarine. Includes materials and procedures for this activity. (KHR)
The Medical Implications of Women On Submarines
2001-11-26
as well as in health problems that have traditionally been problematic for submarines including cardiac disease , anemia, asthma, headaches, peptic...ulcer disease , orthopedic problems, and psychiatric disease . Gynecological and pregnancy related issues constitute the final area of review. 15. SUBJECT...traditionally been problematic for submarines including cardiac disease , anemia, asthma, headaches, peptic ulcer disease , orthopedic problems, and
Physiological Stresses Related to Hypercapnia during Patrols on Submarines
1975-12-01
Acid- base balance, CO., storage, and calcium homeostasis | I am trying to show that this delayed renal response in low level chronic hypercapnia is 1...C02 Co, P BONE 4 1 BLOOD Fig. 11. Cycles in acid- base balance, bone buffering, and renal regulation during prolonged exposure to 0.7...patrols on submarines K. E. SCHAEFER Naval Submarine Medical Research Laboratory, Naval Submarine Base . Groton. CT 06340 Schaefer, K. E. 1979
16. INTERIOR VIEW OF SUBMARINE SECTION AT 110FOOT LEVEL, ESCAPE ...
16. INTERIOR VIEW OF SUBMARINE SECTION AT 110-FOOT LEVEL, ESCAPE TRAINING TANK, SHOWING LADDER TO ESCAPE TANK, LOOKING SOUTH - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Phase 1 Final Report: Titan Submarine
NASA Technical Reports Server (NTRS)
Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.
2015-01-01
The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase 1 for 2014. The proposal stated the desire to investigate what science a submarine for Titan's liquid hydrocarbon seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (100 kg), it was found that a submersible platform can accomplish extensive science both above and below the surface of the Kraken Mare. Submerged science includes mapping using side-looking sonar, imaging and spectroscopy of the lake, as well as sampling of the lake's bottom and shallow shoreline. While surfaced, the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 km inland. This imaging requirement pushed the landing date to Titan's next summer period (2047) to allow for lighted conditions, as well as direct-to-Earth communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid, sediment, and chemical interactions. An estimated 25 Mb of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system.The baseline 90-day mission would be to sail submerged and surfaced around and through Kraken Mare investigating the shoreline and inlets to evaluate the sedimentary interaction both on the surface and then below. Depths of Kraken have yet to be sensed (Ligeia to the north is thought to be 200 m (656 ft) deep), but a maximum depth of 1,000 m (3,281 ft) for Kraken Mare was assumed for the design). The sub would spend 20 d at the interface between Kraken Mare and Ligeia Mare for clues to the drainage of
Aquilina, Alfred; Connelly, Douglas P.; Copley, Jon T.; Green, Darryl R. H.; Hawkes, Jeffrey A.; Hepburn, Laura E.; Huvenne, Veerle A. I.; Marsh, Leigh; Mills, Rachel A.; Tyler, Paul A.
2013-01-01
In the austral summer of 2011 we undertook an investigation of three volcanic highs in the Central Bransfield Basin, Antarctica, in search of hydrothermal activity and associated fauna to assess changes since previous surveys and to evaluate the extent of hydrothermalism in this basin. At Hook Ridge, a submarine volcanic edifice at the eastern end of the basin, anomalies in water column redox potential (Eh) were detected close to the seafloor, unaccompanied by temperature or turbidity anomalies, indicating low-temperature hydrothermal discharge. Seepage was manifested as shimmering water emanating from the sediment and from mineralised structures on the seafloor; recognisable vent endemic fauna were not observed. Pore fluids extracted from Hook Ridge sediment were depleted in chloride, sulfate and magnesium by up to 8% relative to seawater, enriched in lithium, boron and calcium, and had a distinct strontium isotope composition (87Sr/86Sr = 0.708776 at core base) compared with modern seawater (87Sr/86Sr ≈0.70918), indicating advection of hydrothermal fluid through sediment at this site. Biogeochemical zonation of redox active species implies significant moderation of the hydrothermal fluid with in situ diagenetic processes. At Middle Sister, the central ridge of the Three Sisters complex located about 100 km southwest of Hook Ridge, small water column Eh anomalies were detected but visual observations of the seafloor and pore fluid profiles provided no evidence of active hydrothermal circulation. At The Axe, located about 50 km southwest of Three Sisters, no water column anomalies in Eh, temperature or turbidity were detected. These observations demonstrate that the temperature anomalies observed in previous surveys are episodic features, and suggest that hydrothermal circulation in the Bransfield Strait is ephemeral in nature and therefore may not support vent biota. PMID:23359806
Hydrothermal oxidation in the Biwabik Iron Formation, MN, USA
NASA Astrophysics Data System (ADS)
Losh, Steven; Rague, Ryan
2018-02-01
mineralization is hypogene. The association of oxidation with epithermal conditions constrains the oxidation and subsequent mineralization to have taken place during the Precambrian, the only time when these rocks would have experienced the necessary temperatures. The mineralization at Fayal Reserve shows little supergene overprint: pyrite is largely unoxidized. Hydrothermal oxidation in both mines was likely produced by basinal fluids that were expelled during the 1.83-1.87 Ga Penokean Orogeny, and mixing with meteoric fluids along faults, although a 1.1 Ga rift-related fluid flow event is also possible. Later supergene overprinting of the iron formation was minor.
Modeling Submarine Lava Flow with ASPECT
NASA Astrophysics Data System (ADS)
Storvick, E. R.; Lu, H.; Choi, E.
2017-12-01
Submarine lava flow is not easily observed and experimented on due to limited accessibility and challenges posed by the fast solidification of lava and the associated drastic changes in rheology. However, recent advances in numerical modeling techniques might address some of these challenges and provide unprecedented insight into the mechanics of submarine lava flow and conditions determining its wide-ranging morphologies. In this study, we explore the applicability ASPECT, Advanced Solver for Problems in Earth's ConvecTion, to submarine lava flow. ASPECT is a parallel finite element code that solves problems of thermal convection in the Earth's mantle. We will assess ASPECT's capability to model submarine lava flow by observing models of lava flow morphology simulated with GALE, a long-term tectonics finite element analysis code, with models created using comparable settings and parameters in ASPECT. From these observations we will contrast the differing models in order to identify the benefits of each code. While doing so, we anticipate we will learn about the conditions required for end-members of lava flow morphology, for example, pillows and sheet flows. With ASPECT specifically we focus on 1) whether the lava rheology can be implemented; 2) how effective the AMR is in resolving morphologies of the solidified crust; 3) whether and under what conditions the end-members of the lava flow morphologies, pillows and sheets, can be reproduced.
Acute stress reactions after submarine accidents.
Eid, Jarle; Johnsen, Bjørn Helge
2002-05-01
The aim of the present study was to explore contextual and individual factors associated with acute stress reactions in three Norwegian submarine crews exposed to different significant peacetime maneuver accidents. Approximately 2 to 3 weeks after the accidents, crew members completed the Coping Style Questionnaire, the General Health Questionnaire, the Impact of Event Scale, and the Post-Traumatic Symptom Scale. Although exposed subjects (N = 47) revealed more posttraumatic stress symptoms than nonexposed crew members on shore leave (N = 7), they showed less acute stress reactions than survivors from a surface ship accident in the Norwegian Navy. Inspection of individual cases revealed that 4% of the exposed submariners showed high loads of acute stress symptoms. Unit cohesion and habitual coping styles emerged as resilience factors, whereas previous exposure to critical incidents and personal experience of not coping in the accident situation emerged as vulnerability factors, explaining 32% of the acute stress reactions reported by submarine crew members.
NASA Astrophysics Data System (ADS)
Costa, I. A.; Barriga, F. J.; Fouquet, Y.
2014-12-01
Siliceous hydrothermal breccias were sampled in two Mid-Atlantic Ridge active sites: Lucky Strike and Menez Gwen. These hydrothermal fields are located in the border of the Azorean plateau, southwest of the Azores islands where the alteration processes affecting basaltic rocks are prominent (Costa et al., 2003). The hydrothermal breccias are genetically related with the circulation of low temperature hydrothermal fluids in diffuse vents. The groundmass of these breccias precipitates from the fluid and consolidates the clastic fragments mostly composed of basalt. The main sources are the surrounding volcanic hills. Breccias are found near hydrothermal vents and may play an important role in the protection of subseafloor hydrothermal deposits forming an impermeable cap due to the high content in siliceous material. The amorphous silica tends to precipitate when the fluid is conductively cooled as proposed by Fouquet et al. (1998) after Fournier (1983). The process evolves gradually from an initial stage where we have just the fragments and circulating seawater. The ascending hydrothermal fluid mixes with seawater, which favours the precipitation of the sulphide components. Sealing of the initially loose fragments begins, the temperature rises below this crust, and the processes of mixing fluid circulation and conductive cooling are simultaneous. At this stage the fluid becomes oversaturated with respect to amorphous silica. This form of silica can precipitate in the open spaces of the porous sulphides and seal the system. Normally this can happen at low temperatures. At this stage the hydrothermal breccia is formed creating a progressively less permeable, eventually impermeable cap rock at the surface. Once the fluid is trapped under this impermeable layer, conductive cooling is enhanced and mixing with seawater is restricted, making the precipitation of amorphous silica more efficient. Since the first discovery and description of recent mineralized submarine
Submarine volcanic features west of Kealakekua Bay, Hawaii
Fornari, D.J.; Lockwood, J.P.; Lipman, P.W.; Rawson, M.; Malahoff, A.
1980-01-01
Visual observations of submarine volcanic vents were made from the submersible vehicle DSV "Sea Cliff" in water depths between 1310 and 690 m, west of Kealakekua Bay, Hawaii. Glass-rich, shelly submarine lavas surround circular 1- to 3-m-diameter volcanic vents between 1050 and 690 m depth in an area west-northwest of the southernpoint (Keei Pt.) of Kealakekua Bay. Eye-witness accounts indicate that this area was the site of a submarine eruption on February 24, 1877. Chemical analyses of lavas from these possible seafloor vent areas indicate that the eruptive products are very similar in composition to volcanic rocks produced by historic eruptions of Mauna Loa volcano. ?? 1980.
50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' ...
50. PIPING FOR SUBMARINE SECTION, Y&D No. 107728 Scale 3/8' = 1'; August 26, 1929 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Drieberg, Susan L.; Hagemann, Steffen G.; Huston, David L.; Landis, Gary; Ryan, Chris G.; Van Achterbergh, Esmé; Vennemann, Torsten
2013-01-01
The ~3240 Ma Panorama volcanic-hosted massive sulfide (VHMS) district is unusual for its high degree of exposure and low degree of postdepositional modification. In addition to typical seafloor VHMS deposits, this district contains greisen- and vein-hosted Mo-Cu-Zn-Sn mineral occurrences that are contemporaneous with VHMS orebodies and are hosted by the Strelley granite complex, which also drove VHMS circulation. Hence the Panorama district is a natural laboratory to investigate the role of magmatic-hydrothermal fluids in VHMS hydrothermal systems. Regional and proximal high-temperature alteration zones in volcanic rocks underlying the VHMS deposits are dominated by chlorite-quartz ± albite assemblages, with lesser low-temperature sericite-quartz ± K-feldspar assemblages. These assemblages are typical of VHMS hydrothermal systems. In contrast, the alteration assemblages associated with granite-hosted greisens and veins include quartz-topaz-muscovite-fluorite and quartz-muscovite (sericite)-chlorite-ankerite. These vein systems generally do not extend into the overlying volcanic pile. Fluid inclusion and stable isotope studies suggest that the greisens were produced by high-temperature (~590°C), high-salinity (38–56 wt % NaCl equiv) fluids with high densities (>1.3 g/cm3) and high δ18O (9.3 ± 0.6‰). These fluids are compatible with the measured characteristics of magmatic fluids evolved from the Strelley granite complex. In contrast, fluids in the volcanic pile (including the VHMS ore-forming fluids) were of lower temperature (90°–270°C), lower salinity (5.0–11.2 wt % NaCl equiv), with lower densities (0.88–1.01 g/cm3) and lower δ18O (−0.8 ± 2.6‰). These fluids are compatible with evolved Paleoarchean seawater. Fluids that formed the quartz-chalcopyrite-sphalerite-cassiterite veins, which are present within the granite complex near the contact with the volcanic pile, were intermediate in temperature and isotopic composition between the greisen
Submarine radial vents on Mauna Loa Volcano, Hawaìi
NASA Astrophysics Data System (ADS)
Wanless, V. Dorsey; Garcia, M. O.; Trusdell, F. A.; Rhodes, J. M.; Norman, M. D.; Weis, Dominique; Fornari, D. J.; Kurz, M. D.; Guillou, Hervé
2006-05-01
A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created "irregular" cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ˜2 × 109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.
49. DETAILS OF SUBMARINE SECTION, Y&D No. 107727 Scale 3/8' ...
49. DETAILS OF SUBMARINE SECTION, Y&D No. 107727 Scale 3/8' and 1-1/2' = 1'; July 2, 1929 - U.S. Naval Submarine Base, New London Submarine Escape Training Tank, Albacore & Darter Roads, Groton, New London County, CT
Submarine Volcanic Morphology of Santorini Caldera, Greece
NASA Astrophysics Data System (ADS)
Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.
2012-04-01
Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at
Di Bella, Letizia; Ingrassia, Michela; Frezza, Virgilio; Chiocci, Francesco L; Pecci, Raffaella; Bedini, Rossella; Martorelli, Eleonora
2018-05-01
The new record of a shallow-water submarine hydrothermal field (<150 m w.d.) in the western Mediterranean Sea (Tyrrhenian Sea, Italy) allows us to study CO 2 fluid impact on benthic foraminifers. Benthic foraminifers calcification process is sensitive to ocean acidification and to local chemical and physical parameters of seawater and pore water. Thus, foraminifers can record specific environmental conditions related to hydrothermal fluids, but at present their response to such activity is poorly defined. The major outcome of this study is the finding of a very uncommon taxon for the Mediterranean Sea, i.e., the Spiculosiphon oceana, a giant foraminifer agglutinating spicules of sponges. This evidence, along with the strong decrease of calcareous tests in the foraminiferal assemblages associated to hydrothermal activity, provides new insights on the meiofauna living in natural stressed environment. In particular, observations obtained from this study allow us to consider S. oceana a potential tolerant species of high CO 2 concentrations (about 2-4 times higher than the normal marine values) and a proxy of acidic environments as well as of recent ocean acidification processes. Copyright © 2018 Elsevier Ltd. All rights reserved.
Attitude changes during and after long submarine missions.
Weybrew, B B; Molish, H B
1979-01-01
To assess the kind and degree of attitude changes occurring during a 2-month submerged mission, two enlisted crews of one fleet ballistic missile submarine (FBM) (n = 101 each) were administered the Submarine Attitude Questionnaire before and after two 55-day submerged missions interspersed with a rehabilitation period of the same duration. Results showed that time-in-service and pay grade bore a U-shaped relationship to positive attitudes toward the service. During submergence, most attitudes became negative and then reversed polarity during rehabilitation. However, there were no cumulative effects upon attitudes during successive missions. Attitudes pertaining to the realities of the mission (for example, boredom, hazardous aspects) became more negative but recovered faster. On the other hand, attitude changes related to long-range expectancies in terms of goal achievement of the crew members were less likely to recover. Several possible explanations for these attitude changes are discussed in the context of the mission of the FBM submarine. Suggestions for preventing or alleviating untoward attitude changes during long submarine missions are also presented.
Dating of barite and anhydrite in sea-floor hydrothermal deposits in the Okinawa Trough
NASA Astrophysics Data System (ADS)
Taisei, F.; Toyoda, S.; Uchida, A.; Ishibashi, J. I.; Totsuka, S.; Shimada, K.; Nakai, S.
2016-12-01
Dating of submarine hydrothermal activities has been an important issue in the aspect of the ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). For this purpose, dating methods using radioactive disequilibrium such as U-Th method (e.g. You and Bickle, 1998) for sulfide, 226Ra-210Pb and 228Ra-228Th (e.g. Noguchi et al., 2011), Ra/Ba, and ESR (Electron Spin Resonance) methods for barite (Okumura et al., 2010) have been employed. In this study, firstly, we will report the first successful dating results on anhydrite using 226Ra-210Pb and 228Ra-228Th methods. The anhydrite samples were taken from the Daiyon-Yonaguni knoll field and the Hatoma knoll field and the Iheya North Knoll field of the Okinawa Trough by research cruises operated by JAMSTEC. The anhydrite crystals were physically scratched out of the samples. 226Ra, 228Ra and daughter nuclei were measured in the same samples for the ESR method by the low background gamma ray spectrometry. From the activity ratios, disequilibrium ages were obtained to be about 7.3 years by 226Ra-210Pb method, and to be 0.6-2.5 years by 228Ra-228Th method. Secondly, the ESR ages of barite taken from hydrothermal areas in the Okinawa trough range from 4.1 to 16000 years, filling the age gap of the maximum age, 150 years, of 226Ra-210Pb method and the minimum age, several thousand years of U-Th method, being the most appropriate age range to discuss the evolution of the hydrothermal systems. Interestingly, the 226Ra-210Pb and 228Ra-228Th ages for the same samples are the same or younger than the ESR ages. As for the latter samples, the reason has already been discussed (Uchida et al., 2015) as the deposits had been formed by two or more hydrothermal events. In the present paper, the disequilibrium and ESR ages will be simulated with these multiple hydrothermal events so that the differences in the ages are explained.
NASA Astrophysics Data System (ADS)
Jáger, Viktor; Molnár, Ferenc; Buchs, David; Koděra, Peter
2012-09-01
In the Early Cretaceous, the continental rift basin of the Mecsek Mts. (Hungary), was situated on the southern edge of the European plate. The opening of the North Atlantic Ocean created a dilatational regime that expanded to the southern edge of the European plate, where several extensional basins and submarine volcanoes were formed during the Early Cretaceous epoch. Permanent seaquake activity caused high swell events during which a large amount of terrestrial wood fragments entered into submarine canyons from rivers or suspended woods which had sunk into the deep seafloor. These fragments created extended wood-fall deposits which contributed large-scale flourishing of numerous burrowing thalassinid crustaceans. Twelve different thalassinid coprolite ichnospecies can be found in the Berriasian-Hauterivian volcano-sedimentary formations. According to the seladonitic crustacean burrows which associated with framboidal pyrite containing Zoophycos and Chondrites ichnofossils (i.e. a "fodinichnia" trace fossil association), the bottom water was aerobic and the pore water was anaerobic; in the latter sulfate reduction occurred. The preservation of wood fragments around thalassinid burrows can be explained by rapid sedimentation related to turbidity currents. Due to the low temperature hydrothermal circulations of seawater, large amounts of iron were released from intrusive, pillowed basaltic sills; these sills intruded into soft, water-saturated sediments containing large amounts of thalassinid excrement. In the coprolites can be found idiomorphic mineral particles originating from the basalts, and coprolites can often be found in peperitic interpillow sediments. This indicates that the life-activity of the decapoda crustaceans in many Lower Cretaceous occurrences initially preceded the first magmatic eruptions. The paroxysm of the rift volcanism took place during the Valanginian age, when some submarine volcanoes emerged above sea level, reaching a maximum height of
The development of permafrost bacterial communities under submarine conditions
NASA Astrophysics Data System (ADS)
Mitzscherling, Julia; Winkel, Matthias; Winterfeld, Maria; Horn, Fabian; Yang, Sizhong; Grigoriev, Mikhail N.; Wagner, Dirk; Overduin, Pier P.; Liebner, Susanne
2017-07-01
Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming, but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by seawater, bacteria stratify into communities in permafrost, marine-affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity, and abundance in submarine permafrost appears site specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice-bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.
Peter, J.M.; Shanks, Wayne C.
1992-01-01
Sulfur, carbon, and oxygen isotope values were measured in sulfide, sulfate, and carbonate from hydrothermal chimney, spire, and mound samples in the southern trough of Guaymas Basin, Gulf of California, USA. ??34S values of sulfides range from -3.7 to 4.5%. and indicate that sulfur originated from several sources: 1. (1) dissolution of 0??? sulfide contained within basaltic rocks, 2. (2) thermal reduction of seawater sulfate during sediment alteration reactions in feeder zones to give sulfide with positive ??34S, and 3. (3) entrainment or leaching of isotopically light (negative-??34S) bacteriogenic sulfide from sediments underlying the deposits. ??34S of barite and anhydrite indicate sulfur derivation mainly from unfractionated seawater sulfate, although some samples show evidence of sulfate reduction and sulfide oxidation reactions during mixing within chimneys. Oxygen isotope temperatures calculated for chimney calcites are in reasonable agreement with measured vent fluid temperatures and fluid inclusion trapping temperatures. Hydrothermal fluids that formed calcite-rich chimneys in the southern trough of Guaymas Basin were enriched in 18O with respect to seawater by about 2.4??? due to isotopic exchange with sedimentary and/or basaltic rocks. Carbon isotope values of calcite range from -9.6 to -14.0??? ??34CpDB, indicating that carbon was derived in approximately equal quantities from the dissolution of marine carbonate minerals and the oxidation of organic matter during migration of hydrothermal fluid through the underlying sediment column. Statistically significant positive, linear correlations of ??34S, ??34C, and ??18O of sulfides and calcites with geographic location within the southern trough of Guaymas Basin are best explained by variations in water/rock ( w r) ratios or sediment reactivity within subsurface alteration zones. Low w r ratios and the leaching of detrital carbonates and bacteriogenic sulfides at the southern vent sites result in relatively
NASA Astrophysics Data System (ADS)
Kang, B. S.; Wang, H. T.; Ren, F.; Pearton, S. J.; Morey, T. E.; Dennis, D. M.; Johnson, J. W.; Rajagopal, P.; Roberts, J. C.; Piner, E. L.; Linthicum, K. J.
2007-12-01
ZnO nanorod-gated AlGaN /GaN high electron mobility transistors (HEMTs) are demonstrated for the detection of glucose. A ZnO nanorod array was selectively grown on the gate area using low temperature hydrothermal decomposition to immobilize glucose oxidase (GOx). The one-dimensional ZnO nanorods provide a large effective surface area with high surface-to-volume ratio and provide a favorable environment for the immobilization of GOx. The AlGaN /GaN HEMT drain-source current showed a rapid response of less than 5s when target glucose in a buffer with a pH value of 7.4 was added to the GOx immobilized on the ZnO nanorod surface. We could detect a wide range of concentrations from 0.5nMto125μM. The sensor exhibited a linear range from 0.5nMto14.5μM and an experiment limit of detection of 0.5nM. This demonstrates the possibility of using AlGaN /GaN HEMTs for noninvasive exhaled breath condensate based glucose detection of diabetic application.
Improved Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway
2008-11-21
Research Laboratory (NSMRL) is seeking information from the eyewear industry that will provide prescription eyewear frames for use when wearing an EAB...Improved Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway by Alison America, MA Wayne G. Horn, MD...Submariner Eyewear for Routine Wear and Emergency Equipment Use Underway Authors: Alison America, MA Wayne G. Horn, MD Naval Submarine Medical Research
Tang, Kai; Zhang, Yao; Lin, Dan; Han, Yu; Chen, Chen-Tung A; Wang, Deli; Lin, Yu-Shih; Sun, Jia; Zheng, Qiang; Jiao, Nianzhi
2018-01-01
Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence in situ hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus Rhodovulum within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile
Tang, Kai; Zhang, Yao; Lin, Dan; Han, Yu; Chen, Chen-Tung A.; Wang, Deli; Lin, Yu-Shih; Sun, Jia; Zheng, Qiang; Jiao, Nianzhi
2018-01-01
Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limited studies on heterotrophic bacteria. Here, fluorescence in situ hybridization, high throughput 16S rRNA gene amplicon sequencing, and functional metagenomes were used to assess microbial communities from the shallow-sea hydrothermal system off Kueishantao Island, Taiwan. The results showed that the shallow-sea hydrothermal system harbored not only autotrophic bacteria but abundant heterotrophic bacteria. The potential for marker genes sulfur oxidation and carbon fixation were detected in the metagenome datasets, suggesting a role for sulfur and carbon cycling in the shallow-sea hydrothermal system. Furthermore, the presence of diverse genes that encode transporters, glycoside hydrolases, and peptidase indicates the genetic potential for heterotrophic utilization of organic substrates. A total of 408 cultivable heterotrophic bacteria were isolated, in which the taxonomic families typically associated with oligotrophy, copiotrophy, and phototrophy were frequently found. The cultivation-independent and -dependent analyses performed herein show that Alphaproteobacteria and Gammaproteobacteria represent the dominant heterotrophs in the investigated shallow-sea hydrothermal system. Genomic and physiological characterization of a novel strain P5 obtained in this study, belonging to the genus Rhodovulum within Alphaproteobacteria, provides an example of heterotrophic bacteria with major functional capacity presented in the metagenome datasets. Collectively, in addition to autotrophic bacteria, the shallow-sea hydrothermal system also harbors many heterotrophic bacteria with versatile
Breathing modes of Kolumbo submarine volcano (Santorini, Greece).
Bakalis, Evangelos; Mertzimekis, Theo J; Nomikou, Paraskevi; Zerbetto, Francesco
2017-04-13
Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo's hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.
Breathing modes of Kolumbo submarine volcano (Santorini, Greece)
NASA Astrophysics Data System (ADS)
Bakalis, Evangelos; Mertzimekis, Theo J.; Nomikou, Paraskevi; Zerbetto, Francesco
2017-04-01
Submarine volcanoes, such as Kolumbo (Santorini, Greece) are natural laboratories for fostering multidisciplinary studies. Their investigation requires the most innovative marine technology together with advanced data analysis. Conductivity and temperature of seawater were recorded directly above Kolumbo’s hydrothermal vent system. The respective time series have been analyzed in terms of non-equilibrium techniques. The energy dissipation of the volcanic activity is monitored by the temperature variations of seawater. The venting dynamics of chemical products is monitored by water conductivity. The analysis of the time series in terms of stochastic processes delivers scaling exponents with turning points between consecutive regimes for both conductivity and temperature. Changes of conductivity are shown to behave as a universal multifractal and their variance is subdiffusive as the scaling exponents indicate. Temperature is constant over volcanic rest periods and a universal multifractal behavior describes its changes in line with a subdiffusive character otherwise. The universal multifractal description illustrates the presence of non-conservative conductivity and temperature fields showing that the system never retains a real equilibrium state. The existence of a repeated pattern of the combined effect of both seawater and volcanic activity is predicted. The findings can shed light on the dynamics of chemical products emitted from the vents and point to the presence of underlying mechanisms that govern potentially hazardous, underwater volcanic environments.
Durable terrestrial bedrock predicts submarine canyon formation
Smith, Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.
2017-01-01
Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.
Insight from Genomics on Biogeochemical Cycles in a Shallow-Sea Hydrothermal System
NASA Astrophysics Data System (ADS)
Lu, G. S.; Amend, J.
2015-12-01
Shallow-sea hydrothermal ecosystems are dynamic, high-energy systems 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 hydrothermal system offshore Paleochori Bay, Milos, Greece, which is characterized by a central vent covered by white microbial mats with hydrothermally 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 hydrothermal 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
Submarine landslides on the north continental slope of the South China Sea
NASA Astrophysics Data System (ADS)
Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping
2018-02-01
Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.
Kikuchi, Sakiko; Mitsunobu, Satoshi; Takaki, Yoshihiro; Yamanaka, Toshiro; Toki, Tomohiro; Noguchi, Takuroh; Nakamura, Kentaro; Abe, Mariko; Hirai, Miho; Yamamoto, Masahiro; Uematsu, Katsuyuki; Miyazaki, Junichi; Nunoura, Takuro; Takahashi, Yoshio; Takai, Ken
2016-01-01
ABSTRACT It has been suggested that iron is one of the most important energy sources for photosynthesis-independent microbial ecosystems in the ocean crust. Iron-metabolizing chemolithoautotrophs play a key role as primary producers, but little is known about their distribution and diversity and their ecological role as submarine iron-metabolizing chemolithotrophs, particularly the iron oxidizers. In this study, we investigated the microbial communities in several iron-dominated flocculent mats found in deep-sea hydrothermal fields in the Mariana Volcanic Arc and Trough and the Okinawa Trough by culture-independent molecular techniques and X-ray mineralogical analyses. The abundance and composition of the 16S rRNA gene phylotypes demonstrated the ubiquity of zetaproteobacterial phylotypes in iron-dominated mat communities affected by hydrothermal fluid input. Electron microscopy with energy-dispersive X-ray microanalysis and X-ray absorption fine structure (XAFS) analysis revealed the chemical and mineralogical signatures of biogenic Fe-(oxy)hydroxide species and the potential contribution of Zetaproteobacteria to the in situ generation. These results suggest that putative iron-oxidizing chemolithoautotrophs play a significant ecological role in producing iron-dominated flocculent mats and that they are important for iron and carbon cycles in deep-sea low-temperature hydrothermal environments. IMPORTANCE We report novel aspects of microbiology from iron-dominated flocculent mats in various deep-sea environments. In this study, we examined the relationship between Zetaproteobacteria and iron oxides across several hydrothermally influenced sites in the deep sea. We analyzed iron-dominated mats using culture-independent molecular techniques and X-ray mineralogical analyses. The scanning electron microscopy–energy-dispersive X-ray spectroscopy SEM-EDS analysis and X-ray absorption fine structure (XAFS) analysis revealed chemical and mineralogical signatures of
Makita, Hiroko; Kikuchi, Sakiko; Mitsunobu, Satoshi; Takaki, Yoshihiro; Yamanaka, Toshiro; Toki, Tomohiro; Noguchi, Takuroh; Nakamura, Kentaro; Abe, Mariko; Hirai, Miho; Yamamoto, Masahiro; Uematsu, Katsuyuki; Miyazaki, Junichi; Nunoura, Takuro; Takahashi, Yoshio; Takai, Ken
2016-10-01
It has been suggested that iron is one of the most important energy sources for photosynthesis-independent microbial ecosystems in the ocean crust. Iron-metabolizing chemolithoautotrophs play a key role as primary producers, but little is known about their distribution and diversity and their ecological role as submarine iron-metabolizing chemolithotrophs, particularly the iron oxidizers. In this study, we investigated the microbial communities in several iron-dominated flocculent mats found in deep-sea hydrothermal fields in the Mariana Volcanic Arc and Trough and the Okinawa Trough by culture-independent molecular techniques and X-ray mineralogical analyses. The abundance and composition of the 16S rRNA gene phylotypes demonstrated the ubiquity of zetaproteobacterial phylotypes in iron-dominated mat communities affected by hydrothermal fluid input. Electron microscopy with energy-dispersive X-ray microanalysis and X-ray absorption fine structure (XAFS) analysis revealed the chemical and mineralogical signatures of biogenic Fe-(oxy)hydroxide species and the potential contribution of Zetaproteobacteria to the in situ generation. These results suggest that putative iron-oxidizing chemolithoautotrophs play a significant ecological role in producing iron-dominated flocculent mats and that they are important for iron and carbon cycles in deep-sea low-temperature hydrothermal environments. We report novel aspects of microbiology from iron-dominated flocculent mats in various deep-sea environments. In this study, we examined the relationship between Zetaproteobacteria and iron oxides across several hydrothermally influenced sites in the deep sea. We analyzed iron-dominated mats using culture-independent molecular techniques and X-ray mineralogical analyses. The scanning electron microscopy-energy-dispersive X-ray spectroscopy SEM-EDS analysis and X-ray absorption fine structure (XAFS) analysis revealed chemical and mineralogical signatures of biogenic Fe
Reed, Daniel C; Breier, John A; Jiang, Houshuo; Anantharaman, Karthik; Klausmeier, Christopher A; Toner, Brandy M; Hancock, Cathrine; Speer, Kevin; Thurnherr, Andreas M; Dick, Gregory J
2015-08-01
Submarine hydrothermal vents perturb the deep-ocean microbiome by injecting reduced chemical species into the water column that act as an energy source for chemosynthetic organisms. These systems thus provide excellent natural laboratories for studying the response of microbial communities to shifts in marine geochemistry. The present study explores the processes that regulate coupled microbial-geochemical dynamics in hydrothermal plumes by means of a novel mathematical model, which combines thermodynamics, growth and reaction kinetics, and transport processes derived from a fluid dynamics model. Simulations of a plume located in the ABE vent field of the Lau basin were able to reproduce metagenomic observations well and demonstrated that the magnitude of primary production and rate of autotrophic growth are largely regulated by the energetics of metabolisms and the availability of electron donors, as opposed to kinetic parameters. Ambient seawater was the dominant source of microbes to the plume and sulphur oxidisers constituted almost 90% of the modelled community in the neutrally-buoyant plume. Data from drifters deployed in the region allowed the different time scales of metabolisms to be cast in a spatial context, which demonstrated spatial succession in the microbial community. While growth was shown to occur over distances of tens of kilometers, microbes persisted over hundreds of kilometers. Given that high-temperature hydrothermal systems are found less than 100 km apart on average, plumes may act as important vectors between different vent fields and other environments that are hospitable to similar organisms, such as oil spills and oxygen minimum zones.
Reed, Daniel C; Breier, John A; Jiang, Houshuo; Anantharaman, Karthik; Klausmeier, Christopher A; Toner, Brandy M; Hancock, Cathrine; Speer, Kevin; Thurnherr, Andreas M; Dick, Gregory J
2015-01-01
Submarine hydrothermal vents perturb the deep-ocean microbiome by injecting reduced chemical species into the water column that act as an energy source for chemosynthetic organisms. These systems thus provide excellent natural laboratories for studying the response of microbial communities to shifts in marine geochemistry. The present study explores the processes that regulate coupled microbial-geochemical dynamics in hydrothermal plumes by means of a novel mathematical model, which combines thermodynamics, growth and reaction kinetics, and transport processes derived from a fluid dynamics model. Simulations of a plume located in the ABE vent field of the Lau basin were able to reproduce metagenomic observations well and demonstrated that the magnitude of primary production and rate of autotrophic growth are largely regulated by the energetics of metabolisms and the availability of electron donors, as opposed to kinetic parameters. Ambient seawater was the dominant source of microbes to the plume and sulphur oxidisers constituted almost 90% of the modelled community in the neutrally-buoyant plume. Data from drifters deployed in the region allowed the different time scales of metabolisms to be cast in a spatial context, which demonstrated spatial succession in the microbial community. While growth was shown to occur over distances of tens of kilometers, microbes persisted over hundreds of kilometers. Given that high-temperature hydrothermal systems are found less than 100 km apart on average, plumes may act as important vectors between different vent fields and other environments that are hospitable to similar organisms, such as oil spills and oxygen minimum zones. PMID:25658053
Mei, Nan; Postec, Anne; Monnin, Christophe; Pelletier, Bernard; Payri, Claude E; Ménez, Bénédicte; Frouin, Eléonore; Ollivier, Bernard; Erauso, Gaël; Quéméneur, Marianne
2016-01-01
High amounts of hydrogen are emitted in the serpentinite-hosted hydrothermal field of the Prony Bay (PHF, New Caledonia), where high-pH (~11), low-temperature (< 40°C), and low-salinity fluids are discharged in both intertidal and shallow submarine environments. In this study, we investigated the diversity and distribution of potentially hydrogen-producing bacteria in Prony hyperalkaline springs by using metagenomic analyses and different PCR-amplified DNA sequencing methods. The retrieved sequences of hydA genes, encoding the catalytic subunit of [FeFe]-hydrogenases and, used as a molecular marker of hydrogen-producing bacteria, were mainly related to those of Firmicutes and clustered into two distinct groups depending on sampling locations. Intertidal samples were dominated by new hydA sequences related to uncultured Firmicutes retrieved from paddy soils, while submarine samples were dominated by diverse hydA sequences affiliated with anaerobic and/or thermophilic submarine Firmicutes pertaining to the orders Thermoanaerobacterales or Clostridiales. The novelty and diversity of these [FeFe]-hydrogenases may reflect the unique environmental conditions prevailing in the PHF (i.e., high-pH, low-salt, mesothermic fluids). In addition, novel alkaliphilic hydrogen-producing Firmicutes (Clostridiales and Bacillales) were successfully isolated from both intertidal and submarine PHF chimney samples. Both molecular and cultivation-based data demonstrated the ability of Firmicutes originating from serpentinite-hosted environments to produce hydrogen by fermentation, potentially contributing to the molecular hydrogen balance in situ.
Cardiometabolic Health in Submariners Returning from a 3-Month Patrol
Gasier, Heath G.; Young, Colin R.; Gaffney-Stomberg, Erin; McAdams, Douglas C.; Lutz, Laura J.; McClung, James P.
2016-01-01
Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years) were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF%) ≥ 25% (obesity), and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR), leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5%) and fat-mass (11%) occurred in the obese group as a result of reduced energy intake (~2000 kJ) during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population. PMID:26867201
Did a "lucky shot" sink the submarine H.L. Hunley?
Lance, Rachel M; Warder, Henry; Bass, Cameron R Dale
2017-01-01
The H.L. Hunley was the first submarine to be successful in combat, sinking the Union vessel Housatonic outside Charleston Harbor in 1864 during the Civil War. However, despite marking a milestone in military history, little is known about this vessel or why it sank. One popular theory is the "lucky shot" theory: the hypothesis that small arms fire from the crew of the Housatonic may have sufficiently damaged the submarine to sink it. However, ballistic experiments with cast iron samples, analysis of historical experiments firing Civil War-era projectiles at cast iron samples, and calculation of the tidal currents and sinking trajectory of the submarine indicate that this theory is not likely. Based on our results, the "lucky shot" theory does not explain the sinking of the world's first successful combat submarine. Published by Elsevier B.V.
A Submarine Perspective on Hawaiian Volcanoes
NASA Astrophysics Data System (ADS)
Clague, D. A.; Moore, J. G.
2011-12-01
Postwar improvements in navigation, sonar-based mapping, and submarine photography enabled the development of bathymetric maps, which revealed submarine morphologic features that could be dredged or explored and sampled with a new generation of manned and unmanned submersibles. The maps revealed debris fields from giant landslides, the great extent of rift zones radiating from volcanic centers, and two previously unknown submarine volcanoes named Mahukona and Loihi, the youngest Hawaiian volcano. About 70 major landslides cover half the flanks of the Hawaiian Ridge out to Midway Island. Some of the landslides attain lengths of 200 km and have volumes exceeding 5,000 km3. More recent higher resolution bathymetry and sidescan data reveal that many submarine eruptions construct circular, flat-topped, monogenetic cones; that large fields of young strongly alkalic lava flows, such as the North Arch and South Arch lava fields, erupt on the seafloor within several hundred km of the islands; and that alkalic lavas erupt during the shield stage on Kilauea and Mauna Loa. The North Arch flow field covers about 24,000 km2, has an estimated volume between about 1000 and 1250 km3, has flows as long as 108 km, and erupted from over 100 vents. The source and melting mechanisms for their production is still debated. The maps also displayed stair-step terraces, mostly constructed of drowned coral reefs, which form during early rapid subsidence of the volcanoes during periods of oscillating sea level. The combination of scuba and underwater photography facilitated the first motion pictures of the mechanism of formation of pillow lava in shallow water offshore Kilauea. The age progression known from the main islands was extended westward along the Hawaiian Ridge past Midway Island, around a bend in the chain and northward along the Emperor Seamounts. Radiometric dating of dredged samples from these submarine volcanoes show that the magma source that built the chain has been active for
Displaying Uncertainty: A Comparison Between Submarine Subject Matter Experts
2007-03-01
known as the “submarine capital of the world” and is the home for many of the schools relating to the submarine service. The administering officer for...and Woods, D. D. (1988). Aiding Human Performance: I. Cognitive Analysis, Le Travail Humain 51(1), 39-64. Roth, E. M., Patterson, E. S., and Mumaw
NASA Astrophysics Data System (ADS)
Sarma, Nittala S.; Kiran, Rayaprolu; Rama Reddy, M.; Iyer, Sridhar D.; Peketi, A.; Borole, D. V.; Krishna, M. S.
2018-01-01
Anomalously high concentrations of humic-rich dissolved organic matter (DOM) in extant submarine hydrothermal vent plumes traveled far from source are increasingly being reported. This DOM, able to mobilize trace metals (e.g., Fe2+) has been hypothesized as originating from organic matter produced by thermogenic bacteria. To eliminate a possible abiogenic origin of this DOM, study is required of well-preserved organic compounds that can be attributed to thermogenic bacteria. The Central Indian Ocean Basin (CIOB) is part of a diffuse plate boundary and an intraplate deformation zone. Coarse fraction (>63 µ) characteristics, mineralogy, magnetic susceptibility, and geochemistry were examined in sediments of a core raised close to a north-south fracture zone near the Equator. Two horizons of distinctly brown-colored sediments were shown as hydrothermally altered from their charred fragments and geochemistry (CaCO3, Corg, Ti/Al, Al/(Al + Fe + Mn), Sr/Ba, Mg/Li, Mn micronodules, Fe/Mn). We examined whether humic substances were preserved in these sediments, and if so whether their carbon isotope distribution would support their hydrothermal origin. Alkali extraction of sediments afforded humic acids (HA) in yields up to 1.2% in the brown sediments. The remaining portions of the core had nil or low concentrations of HA. The carbon of hydrothermal HA is isotopically heavier (average δ13C, ˜ -16.3‰) compared to nonhydrothermal HA (-18.1‰), suggesting that they were probably formed from organic matter that remained after elimination of lighter carbon enriched functional groups during diagenesis. The results provide compelling evidence of HA formation from lipids originating from thermogenic bacteria.
Seasonal influence over serum and urine metabolic markers in submariners during prolonged patrols
Holy, Xavier; Bégot, Laurent; Renault, Sylvie; Butigieg, Xavier; André, Catherine; Bonneau, Dominique; Savourey, Gustave; Collombet, Jean-Marc
2015-01-01
Within the framework of earlier publications, we have consistently dedicated our investigations to eliciting the effects of both seasonal vitamin D deficiency and submarine-induced hypercapnia on serum parameters for acid–base balance and bone metabolism in submariners over a 2-month winter (WP) or summer (SP) patrols. The latest findings reported herein, contribute further evidence with regard to overall physiological regulations in the same submariner populations that underwent past scrutiny. Hence, urine and blood samples were collected in WP and SP submariners at control prepatrol time as well as on submarine patrol days 20, 41, and 58. Several urine and serum metabolic markers were quantified, namely, deoxypyridinoline (DPD), lactate, albumin, creatinine, nonesterified fatty acids (NEFA), and ionized sodium (Na+) or potassium (K+), with a view to assessing bone, muscle, liver, or kidney metabolisms. We evidenced bone metabolism alteration (urine DPD, calcium, and phosphorus) previously recorded in submarine crewmembers under prolonged patrols. We also highlighted transitory modifications in liver metabolism (serum albumin) occurring within the first 20 days of submersion. We further evidenced changes in submariners’ renal physiology (serum creatinine) throughout the entire patrol time span. Measurements of ionic homeostasis (serum Na+ and K+) displayed potential seasonal impact over active ionic pumps in submariners. Finally, there is some evidence that submersion provides beneficial conditions prone to fend off seasonal lactic acidosis (serum lactate) detected in WP submariners. PMID:26265754
NASA Astrophysics Data System (ADS)
Zakharov, D. O.; Bindeman, I. N.
2015-12-01
The early Paleoproterozoic was an eventful period in the Earth's history. The first portions of free oxygen emerged in the atmosphere, Snowball Earth glaciations happened several times and the first supercontinent broke up due to extensive rifting. These events should have affected the stable isotopic composition of the hydrosphere. In this study, we use rocks that were altered in underwater hydrothermal systems to investigate the stable isotopic composition of the hydrosphere 2.39-2.45 billion years ago (hereinafter, Ga). Extremely low-δ18O (down to -27.5‰ SMOW) rocks from 2.39 Ga metamorphosed subglacial hydrothermal systems of the Belomorian belt, Baltic Shield formed at near-equatorial latitudes suggesting a Snowball (or Slushball) Earth glaciation. These results motivated us to look at temporally and geographically close hydrothermal systems from the unmetamorhposed 2.45 Ga Vetreny Belt rift. The length of the rift is 250 km and it is composed of high-Mg basalts, mafic-ultramafic intrusions and sedimentary successions. We examined several localities of high-Mg basalt flows that include astonishingly fresh pillow lavas, often with preserved volcanic glass, eruptive breccias, and hydrothermal alteration zones. Collected samples serve a great textural evidence of water-rock interaction that occurred in situ while basalts were cooling. The preliminary results from coexisting quartz and epidote (T, D18O=311°C), and from coexisting calcite and quartz (T, D18O=190°C) yield values of δ18O of involved water between -1.6 and -0.9 ‰. The values of δ13C in calcites vary between -4.0 and -2.3 ‰. It is likely that hydrothermal fluids operated in the Vetreny Belt rift were derived from seawater that is no different from modern oceanic water in terms of δ18O. Apparently, the rift was a Paleoproterozoic analog of the modern Red Sea, filled with oceanic water. The result is important because the Vetreny Belt rift predates the onset of Snowball Earth glaciation at 2
Situation awareness measures for simulated submarine track management.
Loft, Shayne; Bowden, Vanessa; Braithwaite, Janelle; Morrell, Daniel B; Huf, Samuel; Durso, Francis T
2015-03-01
The aim of this study was to examine whether the Situation Present Assessment Method (SPAM) and the Situation Awareness Global Assessment Technique (SAGAT) predict incremental variance in performance on a simulated submarine track management task and to measure the potential disruptive effect of these situation awareness (SA) measures. Submarine track managers use various displays to localize and track contacts detected by own-ship sensors. The measurement of SA is crucial for designing effective submarine display interfaces and training programs. Participants monitored a tactical display and sonar bearing-history display to track the cumulative behaviors of contacts in relationship to own-ship position and landmarks. SPAM (or SAGAT) and the Air Traffic Workload Input Technique (ATWIT) were administered during each scenario, and the NASA Task Load Index (NASA-TLX) and Situation Awareness Rating Technique were administered postscenario. SPAM and SAGAT predicted variance in performance after controlling for subjective measures of SA and workload, and SA for past information was a stronger predictor than SA for current/future information. The NASA-TLX predicted performance on some tasks. Only SAGAT predicted variance in performance on all three tasks but marginally increased subjective workload. SPAM, SAGAT, and the NASA-TLX can predict unique variance in submarine track management performance. SAGAT marginally increased subjective workload, but this increase did not lead to any performance decrement. Defense researchers have identified SPAM as an alternative to SAGAT because it would not require field exercises involving submarines to be paused. SPAM was not disruptive, but it is potentially problematic that SPAM did not predict variance in all three performance tasks. © 2014, Human Factors and Ergonomics Society.
Titan Submarine: Exploring The Depths of Kraken Mare
NASA Technical Reports Server (NTRS)
Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.
2015-01-01
The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase I for 2014. The effort investigated what science a submarine for Titan's liquid hydrocarbon approximately 93 Kelvin (-180 degrees Centigrade) seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (approximately100 kilograms) it was found that a submersible platform can accomplish extensive and exciting science both above and below the surface of the Kraken Mare The submerged science includes mapping using side looking sonar, imaging and spectroscopy of the sea at all depths, as well as sampling of the sea's bottom and shallow shoreline. While surfaced the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 kilometers inland. This imaging requirement pushed the landing date to Titan's next summer period (approximately 2047) to allow for continuous lighted conditions, as well as direct-to-Earth (DTE) communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid/sediment/chemical interactions. An estimated 25 megabits of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system. This paper discusses the results of Phase I as well as the plans for Phase II.
Giant submarine canyons: Is size any clue to their importance in the rock record?
Normark, William R.; Carlson, Paul R.
2003-01-01
Submarine canyons are the most important conduits for funneling sediment from continents to oceans. Submarine canyons, however, are zones of sediment bypassing, and little sediment accumulates in the canyon until it ceases to be an active conduit. To understand the potential importance in the rock record of any given submarine canyon, it is necessary to understand sediment-transport processes in, as well as knowledge of, deep-sea turbidite and related deposits that moved through the canyons. There is no straightforward correlation between the final volume of the sedimentary deposits and size of the associated submarine canyons. Comparison of selected modern submarine canyons together with their deposits emphasizes the wide range of scale differences between canyons and their impact on the rock record.Three of the largest submarine canyons in the world are incised into the Beringian (North American) margin of the Bering Sea. Zhemchug Canyon has the largest cross-section at the shelf break and greatest volume of incision of slope and shelf. The Bering Canyon, which is farther south in the Bering Sea, is first in length and total area. In contrast, the largest submarine fans-e.g., Bengal, Indus, and Amazon-have substantially smaller, delta-front submarine canyons that feed them; their submarine drainage areas are one-third to less than one-tenth the area of Bering Canyon. some very large deep-sea channels and tubidite deposits are not even associated with a significant submarine canyon; examples include Horizon Channel in the northeast Pacific and Laurentian Fan Valley in the North Atlantic. Available data suggest that the size of turbidity currents (as determined by volume of sediment transported to the basins) is also not a reliable indicator of submarine canyon size.
Risk factors for dermatitis in submariners during a submerged patrol: an observational cohort study.
Flaxman, Amy; Allen, Elizabeth; Lindemann, Claudia; Yamaguchi, Yuko; O'Shea, Matthew K; Fallowfield, Joanne L; Lindsay, Michael; Gunner, Frances; Knox, Kyle; Wyllie, David H
2016-06-02
The aim of this pilot study was to determine risk factors, including Staphylococcus aureus nasal carriage, for dermatitis in submariners during a submarine patrol. 36 submariners undertaking a submerged 6-week patrol participated in the study. Severity of dermatitis and its impact was assessed using visual analogue scales and questionnaires at baseline and weekly throughout the patrol. S. aureus carriage levels in submariners were determined by nasal swabbing at baseline and shortly before disembarking the submarine. Occurrence of any skin or soft tissue infections (SSTI) were reported to the medical officer and swabs of the area were taken for subsequent analysis. S. aureus carriers were significantly more likely than non-carriers to have previously received treatment for a cutaneous abscess (39% vs 5%, OR=13 (95% CI 1.3 to 130)) with a trend to being submariners longer (p=0.051). Skin scores at baseline and on patrol were not significantly associated with carriage status. Higher dermatitis scores were observed in those who had been submariners longer (p=0.045). Smoking and allergies were not found to be linked to carriage status or skin health score in this cohort. This small pilot study investigates S. aureus carriage status and skin health in submariners. Length of submarine service but not S. aureus carriage was identified as a risk factor for worsening skin health in this small cohort during a 6-week patrol. This does not support S. aureus decolonisation to improve skin health in this population. Further investigation into causes of dermatitis in submariners is required. This data supports a better understanding of the potential impact of exposure to environmental factors that could affect skin health in submariners. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Submarine melting from repeat UAV surveys of icebergs
NASA Astrophysics Data System (ADS)
Hubbard, A., II; Ryan, J.; Smith, L. C.; Hamilton, G. S.
2017-12-01
Greenland's tidewater glaciers are a primary contributor to global sea-level rise, yet their future trajectory remains uncertain due to their non-linear response to oceanic forcing: particularly with respect to rapid submarine melting and under-cutting of their calving fronts. To improve understanding of ice-ocean interactions, we conducted repeat unmanned aerial vehicle (UAV) surveys across the terminus of Store Glacier and its adjacent fjord between May and June 2014. The derived imagery provides insight into frontal plume dynamics and the changing freeboard volume of icebergs in the fjord as they ablate. Following the methodology of Enderlin and Hamilton (2014), by differencing iceberg freeboard volume, we constrain submarine melt rates adjacent to the calving front. We find that plume and submarine melt rates are critical to mass loss variability across the calving front. Although the frontal ablation of Store Glacier is dominated by large mechanical calving events, the undercutting induced by the meltwater plume increases the frequency of calving and initiates frontal retreat. We conclude that even small increases in submarine melting due to changes in the meltwater plume duration and/or circulation patterns can have important consequences for frontal mass loss from large outlet glaciers draining the Greenland ice sheet.
Zhao, Weirong; Yang, Yong; Hao, Rui; Liu, Feifei; Wang, Yan; Tan, Min; Tang, Jing; Ren, Daqing; Zhao, Dongye
2011-09-15
Mesoporous wide bandgap semiconductors offer high photocatalytic oxidation and mineralization activities. In this study, mesoporous β-Ga(2)O(3) diamond nanorods with 200-300 nm in diameter and 1.0-1.2 μm in length were synthesized via a urea-based hydrothermal method using polyethylene glycol (PEG) as template agent. The UV photocatalytic oxidation activity of β-Ga(2)O(3) for gaseous toluene was evaluated, and 7 kinds of intermediates were monitored online by a proton transfer reaction mass spectrometry. Photoluminescence spectra manifested that the dosage and molecular weight of PEG are crucial for formation of vacancies and photocatalytic oxidation activities. A PEG-assisted hydrothermal formation mechanism of mesoporous β-Ga(2)O(3) diamond nanorods was proposed. Based on the health risk influence index (η) of the intermediates, the calculated health risks revealed that the β-Ga(2)O(3) nanorods with a η value of 9.6 are much safer than TiO(2) (η = 17.6). Copyright © 2011 Elsevier B.V. All rights reserved.
33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Thames River, Naval Submarine....75 Thames River, Naval Submarine Base New London, restricted area. (a) The area: The open waters of... restricted area provided their vessels display registration numbers issued by the Naval Submarine Base, New...
33 CFR 334.75 - Thames River, Naval Submarine Base New London, restricted area.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Thames River, Naval Submarine....75 Thames River, Naval Submarine Base New London, restricted area. (a) The area: The open waters of... restricted area provided their vessels display registration numbers issued by the Naval Submarine Base, New...
Submarines, spacecraft and exhaled breath.
Pleil, Joachim D; Hansel, Armin
2012-03-01
Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another
Tanaka, Hayato; Yasuhara, Moriaki
2016-10-01
Deep-sea hydrothermal vent fields are among the most extreme habitats on Earth. Major research interests in these ecosystems have focused on the anomalous macrofauna, which are nourished by chemoautotrophic bacterial endosymbionts. In contrast, the meiofauna is largely overlooked in this chemosynthetic environment. The present study describes a new species, Thomontocypris shimanagai sp. nov. (Crustacea: Ostracoda), which was collected from the surface of colonies of neoverrucid barnacles and paralvinellid worms on the chimneys at the Myojin-sho submarine caldera. This is the first discovery of an ostracode from deep-sea hydrothermal vent environments in the western Pacific region. In addition to the species description, we discuss three aspects: 1) adaptation, 2) endemism, and 3) dispersal strategy of the hydrothermal vent ostracodes. Regarding these aspects, we conclude the following: 1) the new species may feed on sloughed-off tissues, mucus secretions, or fecal pellets of sessile organisms, rather than depend on chemoautotrophic bacteria as symbionts for energy; 2) as has been pointed out by other studies, Thomontocypris does not likely represent a vent-specific genus; however, this new species is considered to be endemic at the species level, as it has not been found outside of the type locality; and 3) this new species may have migrated from adjacent deep-sea chemosynthesis-based habitats, such as hydrothermal vents, with wood falls potentially having acted as stepping stones.
NASA Astrophysics Data System (ADS)
Foutrakis, Panagiotis M.; Anastasakis, George
2018-05-01
Methana peninsula shows the longest recorded volcanic history at the western end of the South Aegean Active Volcanic Arc, including volcanic products from the Upper Pliocene to recent times. The volcanic rocks comprise widespread dacite domes and andesite lava flows from several small volcanic centers and are only imprecisely dated. In this paper, the integrated analysis of swath bathymetry, side scan sonar data, and high resolution seismic reflection profiles correlated with core samples, has allowed detailed mapping, characterization and precise chronological identification of the Pausanias submarine volcanic field activity offshore northern Methana. Six volcanic cones or domes are recognized, typically 1-3 km in diameter, some elongated NE-SW and some with a small central crater. On their flanks, the acoustically reflective volcanic rocks pass laterally into incoherent transparent seismic facies interpreted as volcaniclastic deposits, possibly including hyaloclastites, that interfinger with the regional basin sediments. A sea-bottom hummocky field, is interpreted as volcanic avalanche and appears to be the submarine continuation of the volcaniclastic apron of northern Methana peninsula. A robust chronostratigraphic framework has been established, based on the recognition of shoreline progradational units and their connection with Quaternary eustatic sea level cycles. Relative dating of the different phases of submarine volcanic activity during the Upper Quaternary has been achieved by correlating the imaged volcaniclastic flows, interlayered within the chronostratigraphically dated sediments. Dating by stratigraphic position, relative to 2D imaged eustatic sea level clinoform wedges appears to be more precise than radiometric methods on land. Three main submarine Volcanic Events (VE) are recognized: VE3 at 450 ka, a less precisely dated interval at 200-130 ka (VE2), and VE1 at 14 ka. Based on chronostratigraphic constraints, subsidence rates of 0.16 (±0.008) m
Howard, Dougal P; Marchand, Peter; McCafferty, Liam; Carmalt, Claire J; Parkin, Ivan P; Darr, Jawwad A
2017-04-10
High-throughput continuous hydrothermal flow synthesis was used to generate a library of aluminum and gallium-codoped zinc oxide nanoparticles of specific atomic ratios. Resistivities of the materials were determined by Hall Effect measurements on heat-treated pressed discs and the results collated into a conductivity-composition map. Optimal resistivities of ∼9 × 10 -3 Ω cm were reproducibly achieved for several samples, for example, codoped ZnO with 2 at% Ga and 1 at% Al. The optimum sample on balance of performance and cost was deemed to be ZnO codoped with 3 at% Al and 1 at% Ga.
The Stratigraphic Incompleteness of Submarine Channels
NASA Astrophysics Data System (ADS)
Vendettuoli, D.; Clare, M. A.; Hughes Clarke, J. E.; Cartigny, M.; Vellinga, A. J.; Talling, P.; Hizzett, J. L.; Hage, S.; Waltham, D.; Hubbard, S. M.
2017-12-01
Turbidity currents transport prodigious quantities of sediment across the world's oceans through submarine channels. These flows damage strategically important seafloor infrastructure and their deposits host major oil and gas reservoirs. We therefore need to understand these flows, but their very powerful nature makes direct monitoring challenging. Most studies to date focus on the deposits that turbidity currents leave behind in the sedimentological record. However, deposits of individual flows are likely to be reworked by successive flows, but it is unclear as to what extent. How complete is the stratigraphy of these deposits? What percentage of flow deposits are preserved in the rock record? Are some events better preserved than others, and if so, why? We address these questions by re-analysing the most detailed time-lapse mapping yet of a turbidity current system. This field dataset comes from the fjord-head Squamish Delta in British Columbia, Canada where Hughes Clarke (2016) collected 93 near-daily repeat surveys in 2011. These surveys revealed the seafloor response to more than 100 turbidity currents. Here we use temporal changes in seabed elevation to understand patterns of deposition and erosion. We calculate the total thickness of sediment deposited at each location, and document the percentage of sediment that is preserved (i.e. stratigraphic completeness) at multiple time-steps over the surveyed period. The average stratigraphic completeness across the delta near submarine channels is <1%, but this is highly spatially variable. Some levees record up to 40% completeness. The low value is largely due to upstream migrating bedforms that constantly rework previously emplaced sediments. Surprisingly, even at the terminal lobes, stratigraphic completeness is typically <5%. These results provide new insights into the evolution of submarine channels and why their deposits produce a highly incomplete record of submarine flows.
Hampton, M.A.; Lee, H.J.; Locat, J.
1996-01-01
Landslides are common on inclined areas of the seafloor, particularly in environments where weak geologic materials such as rapidly deposited, finegrained sediment or fractured rock are subjected to strong environmental stresses such as earthquakes, large storm waves, and high internal pore pressures. Submarine landslides can involve huge amounts of material and can move great distances: slide volumes as large as 20,000 km3 and runout distances in excess of 140 km have been reported. They occur at locations where the downslope component of stress exceeds the resisting stress, causing movement along one or several concave to planar rupture surfaces. Some recent slides that originated nearshore and retrogressed back across the shoreline were conspicuous by their direct impact on human life and activities. Most known slides, however, occurred far from land in prehistoric time and were discovered by noting distinct to subtle characteristics, such as headwall scarps and displaced sediment or rock masses, on acoustic-reflection profiles and side-scan sonar images. Submarine landslides can be analyzed using the same mechanics principles as are used for occurrences on land. However, some loading mechanisms are unique, for example, storm waves, and some, such as earthquakes, can have greater impact. The potential for limited-deformation landslides to transform into sediment flows that can travel exceedingly long distances is related to the density of the slope-forming material and the amount of shear strength that is lost when the slope fails.
NASA Astrophysics Data System (ADS)
Fujii, M.; Okino, K.; Honsho, C.; Mochizuki, N.; Szitkar, F.; Dyment, J.
2013-12-01
Near-bottom magnetic profiling using submersible, deep-tow, Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) make possible to conduct high-resolution surveys and depict detailed magnetic features reflecting, for instance, the presence of fresh lavas or hydrothermal alteration, or geomagnetic paleo-intensity variations. We conducted near-bottom three component magnetic measurements onboard submersible Shinkai 6500 in the Southern Mariana Trough, where five active hydrothermal vent fields (Snail, Yamanaka, Archean, Pica, and Urashima sites) have been found in both on- and off-axis areas of the active back-arc spreading center, to detect signals from hydrothermally altered rock and to distinguish old and new submarine lava flows. Fourteen dives were carried out at an altitude of 1-40 m during the R/V Yokosuka YK10-10 and YK10-11 cruises in 2010. We carefully corrected the effect of the induced and permanent magnetizations of the submersible by applying the correction method for the shipboard three-component magnetometer measurement modified for deep-sea measurement, and subtracted the IGRF values from the corrected data to obtain geomagnetic vector anomalies along the dive tracks. We then calculated the synthetic magnetic vector field produced by seafloor, assumed to be uniformly magnetized, using three dimensional forward modeling. Finally, values of the absolute magnetizations were estimated by using a linear transfer function in the Fourier domain from the observed and synthetic magnetic anomalies. The distribution of estimated absolute magnetization generally shows low values around the five hydrothermal vent sites. This result is consistent with the equivalent magnetization distribution obtained from previous AUV survey data. The areas of low magnetization are also consistent with hydrothermal deposits identified in video records. These results suggest that low magnetic signals are due to hydrothermal alteration zones where host rocks are
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sahoo, Trilochan; Ju, Jin-Woo; Kannan, V.
2008-03-04
Single crystalline ZnO thin film on p-GaN/sapphire (0 0 0 1) substrate, using two different precursors by hydrothermal route at a temperature of 90 deg. C were successfully grown. The effect of starting precursor on crystalline nature, surface morphology and optical emission of the films were studied. ZnO thin films were grown in aqueous solution of zinc acetate and zinc nitrate. X-ray diffraction analysis revealed that all the thin films were single crystalline in nature and exhibited wurtzite symmetry and c-axis orientation. The thin films obtained with zinc nitrate had a more pitted rough surface morphology compared to the filmmore » grown in zinc acetate. However the thickness of the films remained unaffected by the nature of the starting precursor. Sharp luminescence peaks were observed from the thin films almost at identical energies but deep level emission was slightly prominent for the thin film grown in zinc nitrate.« less
The Human Powered Submarine Team of Virginia Tech Propulsion System Design Final Report
NASA Technical Reports Server (NTRS)
An, Eric; Bennett, Matt; Callis, Ron; Chen, Chester; Lee, John; Milan-Williams, Kristy
1999-01-01
The Human Powered Submarine Team has been in existence at Virginia Tech since its conception in 1993. Since then, it has served as a way for engineering students from many different disciplines to implement design conception and realization. The first submarine built was Phantom 1, a two-man submarine made of fiberglass. After construction was complete, Phantom 1 was ready for racing, but, unfortunately, suffered fatal problems come race time. The submarine team slowed down a bit after experiencing racing problems, but was revived in 1995 when design efforts for a new two-man submarine, the Phantom 2 commence. The propulsion system consisted of a chain and gear drive system using an ultra-light helicopter tail rotor for a propeller. Although the team learned valuable lessons as a result of Phantom 1's problems, Phantom 2 still experiences problems at races. After various parts of Phantom 2 are redesigned, it is once again ready for racing and proves that the redesign was well worth the time and effort. In 1997, Phantom 2 not only finishes its first race, held in San Diego, California, but comes in third. This success sparks yet another revival of the submarine team and design for the team's current project, the Phantom 3, a one-man submarine, is started. In 1998, the plug for Phantom 3 is built and the hull is constructed. With so many past problems from which to learn, Phantom 3 promises to be the fastest and best-designed submarine the team has developed thus far. The current speed world-record is 7 knots.
NASA Astrophysics Data System (ADS)
Crone, T. J.; Kinsey, J. C.; Mittelstaedt, E. L.
2017-12-01
Hydrothermal venting at mid-ocean ridges influences ocean chemistry, the thermal and chemical structure of the oceanic crust, and the evolution of unique and diverse autolithotrophically-supported ecosystems. Axially-hosted hydrothermal systems are responsible for 20-25% of the total heat flux out of Earth's interior, and likely play a large role in local as well as global biogeochemical cycles. Despite the importance of these systems, only a few studies have attempted to constrain the volume and heat flux of an entire hydrothermal vent field. In July of 2014 we used the Sentry autonomous underwater vehicle (AUV) to survey the water column over the ASHES hydrothermal vent field which is located within the caldera of Axial Seamount, an active submarine volcano located on the Juan de Fuca Ridge. To estimate the total heat and mass flux from this vent field, we equipped Sentry with a Nortek acoustic Doppler velocimeter (ADV), an inertial measurement unit (IMU), two acoustic Doppler current profilers (ADCPs), and two SBE3 temperature probes, allowing us to obtain precise measurements of fluid temperature and water velocity. The survey was designed using a control volume approach in which Sentry was pre-programmed to survey a 150-m-square centered over the vent field flying a grid pattern with 5-m track line spacing followed by a survey of the perimeter. This pattern was repeated multiple times during several 10-h dives at different altitudes, including 10, 20, 40, and 60 m above the seafloor, and during one 40-h survey at an altitude of 10 m. During the 40-h survey, the pattern was repeated nine times allowing us to obtain observations over several tidal cycles. Water velocity data obtained with Sentry were corrected for platform motion and then combined with the temperature measurements to estimate heat flux. The analysis of these data will likely provide the most accurate and highest resolution heat and mass flux estimates at a seafloor hydrothermal field to date.
Detail of conning tower atop the submarine. Note the wire ...
Detail of conning tower atop the submarine. Note the wire rope wrapped around the base of the tower, which may have been used in an attempt to pull the submarine offshore. - Sub Marine Explorer, Located along the beach of Isla San Telmo, Pearl Islands, Isla San Telmo, Former Panama Canal Zone, CZ
Submarine landslides: advances and challenges
Locat, Jacques; Lee, Homa J.
2002-01-01
Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarinemass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors. Key words : submarine slides, hazards, risk assessment, morphology, mobility, tsunami. Le dveloppement rcent de techniques de levs hydrograhiques pour les fonds marins nous a permis d'atteindre une qualit ingale dans la cartographie et la description des glissements sous marins. l'exception des courants de turbidit, on retrouve dans le domaine aquatique les mmes types de mouvements de terrain que sur terre. Par contre, les glissements sous-marins peuvent atteindre des distances excdant 100 km de telle sorte que leur impact sur les activits offshore doit tre pris en compte sur degrandes tendues. La grande mobilit des glissements sous-marins n'est pas encore bien comprise, comme pour le cas des coules dedbris cartographies sur le cne du Mississippi ainsi que pour les grandes avalanches rocheuses sous-marines retrouves au pourtour des les volcaniques. Un dfi majeur
Infrared and infrared emission spectroscopy of gallium oxide alpha-GaO(OH) nanostructures.
Yang, Jing Jeanne; Zhao, Yanyan; Frost, Ray L
2009-10-01
Infrared spectroscopy has been used to study nano- to micro-sized gallium oxyhydroxide alpha-GaO(OH), prepared using a low temperature hydrothermal route. Rod-like alpha-GaO(OH) crystals with average length of approximately 2.5 microm and width of 1.5 microm were prepared when the initial molar ratio of Ga to OH was 1:3. beta-Ga(2)O(3) nano and micro-rods were prepared through the calcination of alpha-GaO(OH). The initial morphology of alpha-GaO(OH) is retained in the beta-Ga(2)O(3) nanorods. The combination of infrared and infrared emission spectroscopy complimented with dynamic thermal analysis were used to characterise the alpha-GaO(OH) nanotubes and the formation of beta-Ga(2)O(3) nanorods. Bands at around 2903 and 2836 cm(-1) are assigned to the -OH stretching vibration of alpha-GaO(OH) nanorods. Infrared bands at around 952 and 1026 cm(-1) are assigned to the Ga-OH deformation modes of alpha-GaO(OH). A significant number of bands are observed in the 620-725 cm(-1) region and are assigned to GaO stretching vibrations.
Submarine Construction (Unterseebootsbau)
1972-08-01
PIPE FOR THE SNORKEL EXHAUST MAST 11 AIR EXIT (GENERALLY TO MAIN AIR INDUCTION LINE) 12 EXHAUST GAS INLET FROM EXHAUST GAS LINE SIDE VIEW (MAST...Electric Engine 76 Diesel Engines 79 Air Intake and Gas Exhaust Systems for the Diesel Engines 79 Diesel Fuel and Pressurized Water System 82...Lines of a Submarine ■. 31 Figure 6 - Lines of a Submersible 31 Figure 7 - Twin- Screw Stern Configurations 34 Figure 8 - Single- Screw Stern
Underwater drag-reducing effect of superhydrophobic submarine model.
Zhang, Songsong; Ouyang, Xiao; Li, Jie; Gao, Shan; Han, Shihui; Liu, Lianhe; Wei, Hao
2015-01-01
To address the debates on whether superhydrophobic coatings can reduce fluid drag for underwater motions, we have achieved an underwater drag-reducing effect of large superhydrophobic submarine models with a feature size of 3.5 cm × 3.7 cm × 33.0 cm through sailing experiments of submarine models, modified with and without superhydrophobic surface under similar power supply and experimental conditions. The drag reduction rate reached as high as 15%. The fabrication of superhydrophobic coatings on a large area of submarine model surfaces was realized by immobilizing hydrophobic copper particles onto a precross-linked polydimethylsiloxane (PDMS) surface. The pre-cross-linking time was optimized at 20 min to obtain good superhydrophobicity for the underwater drag reduction effect by investigating the effect of pre-cross-linking on surface wettability and water adhesive property. We do believe that superhydrophobic coatings may provide a promising application in the field of drag-reducing of vehicle motions on or under the water surface.
Scattering effect of submarine hull on propeller non-cavitation noise
NASA Astrophysics Data System (ADS)
Wei, Yingsan; Shen, Yang; Jin, Shuanbao; Hu, Pengfei; Lan, Rensheng; Zhuang, Shuangjiang; Liu, Dezhi
2016-05-01
This paper investigates the non-cavitation noise caused by propeller running in the wake of submarine with the consideration of scattering effect caused by submarine's hull. The computation fluid dynamics (CFD) and acoustic analogy method are adopted to predict fluctuating pressure of propeller's blade and its underwater noise radiation in time domain, respectively. An effective iteration method which is derived in the time domain from the Helmholtz integral equation is used to solve multi-frequency waves scattering due to obstacles. Moreover, to minimize time interpolation caused numerical errors, the pressure and its derivative at the sound emission time is obtained by summation of Fourier series. It is noted that the time averaging algorithm is used to achieve a convergent result if the solution oscillated in the iteration process. Meanwhile, the developed iteration method is verified and applied to predict propeller noise scattered from submarine's hull. In accordance with analysis results, it is summarized that (1) the scattering effect of hull on pressure distribution pattern especially at the frequency higher than blade passing frequency (BPF) is proved according to the contour maps of sound pressure distribution of submarine's hull and typical detecting planes. (2) The scattering effect of the hull on the total pressure is observable in noise frequency spectrum of field points, where the maximum increment is up to 3 dB at BPF, 12.5 dB at 2BPF and 20.2 dB at 3BPF. (3) The pressure scattered from hull is negligible in near-field of propeller, since the scattering effect surrounding analyzed location of propeller on submarine's stern is significantly different from the surface ship. This work shows the importance of submarine's scattering effect in evaluating the propeller non-cavitation noise.
Slack, J.F.; Grenne, Tor; Bekker, A.; Rouxel, O.J.; Lindberg, P.A.
2007-01-01
A current model for the evolution of Proterozoic deep seawater composition involves a change from anoxic sulfide-free to sulfidic conditions 1.8??Ga. In an earlier model the deep ocean became oxic at that time. Both models are based on the secular distribution of banded iron formation (BIF) in shallow marine sequences. We here present a new model based on rare earth elements, especially redox-sensitive Ce, in hydrothermal silica-iron oxide sediments from deeper-water, open-marine settings related to volcanogenic massive sulfide (VMS) deposits. In contrast to Archean, Paleozoic, and modern hydrothermal iron oxide sediments, 1.74 to 1.71??Ga hematitic chert (jasper) and iron formation in central Arizona, USA, show moderate positive to small negative Ce anomalies, suggesting that the redox state of the deep ocean then was at a transitional, suboxic state with low concentrations of dissolved O2 but no H2S. The presence of jasper and/or iron formation related to VMS deposits in other volcanosedimentary sequences ca. 1.79-1.69??Ga, 1.40??Ga, and 1.24??Ga also reflects oxygenated and not sulfidic deep ocean waters during these time periods. Suboxic conditions in the deep ocean are consistent with the lack of shallow-marine BIF ??? 1.8 to 0.8??Ga, and likely limited nutrient concentrations in seawater and, consequently, may have constrained biological evolution. ?? 2006 Elsevier B.V. All rights reserved.
U-Th isotopic systematics and ages of carbonate chimneys at the Lost City Hydrothermal Field
NASA Astrophysics Data System (ADS)
Ludwig, K. A.; Shen, C.; Kelley, D. S.; Cheng, H.; Edwards, R.
2009-12-01
The Lost City Hydrothermal Field (LCHF) is a serpentinite-hosted vent field located 15 km west of the spreading axis of the Mid-Atlantic Ridge. In this study, uranium-thorium (U-Th) geochronological techniques have been used to examine the U-Th isotopic systematics of hydrothermal fluids and the 230Th ages of hydrothermally-precipitated carbonate chimneys at the LCHF. Fluid sample analyses indicate that endmember fluids likely contain only 0.0073 ng/g U or less compared to 3.28 ± 0.03 ng/g of U in ambient seawater. For fluid samples with <15 mmol/kg Mg, 232Th concentration is 0.11 to 0.13 pg/g and surrounding seawater concentration average is 0.133 ± 0.016 pg/g. The 230Th/232Th atomic ratios of the vent fluids range from 1 ± 10 to 26 ± 4 ×10-6 and are less than those of seawater. Chimney U is seawater-derived and 238U concentrations range from 1-10 μg/g and the mean chimney corrected initial δ234U is 146.9 ± 0.5, which is not significantly different from the ambient seawater value of 146.5 ± 0.6. Carbonate thorium concentrations range broadly from 0.035-125 ng/g and 230Th/232Th atomic ratios vary from near seawater values of 43 ± 8 × 10-6 up to 530 ± 25 × 10-3. Chimney ages range from 18 ± 6 yrs to 122 ± 12 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all <4 kyrs old, indicating that mass wasting in this region is relatively recent. Comparison of results to prior age-dating investigations of submarine hydrothermal systems shows that the LCHF is the most long-lived hydrothermal system known to date. It is likely that seismic activity and active faulting within the Atlantis Massif and the Atlantis Fracture Zone, coupled with volumetric expansion of the underlying serpentinized host rocks play major roles in sustaining
NASA Astrophysics Data System (ADS)
Miki, T.; Kiyokawa, S.; Takahata, N.; Ishida, A.; Ito, T.; Ikehara, M.; Sano, Y.
2015-12-01
Sulfur isotopic (δ34S) analysis is used as one of the methods of Precambrian environmental reconstruction. It has been pointed out that δ34S fluctuations of sulfate and sulfide have close relationship with rise of oxygen level and increase in biological activity of sulfate reducing bacteria. For example, the difference of δ34S between sulfate and sulfide is small in Archean while it gets larger after evolution of oxygen level and biological activity (e.g. Canfield and Farquhar, 2009). However, evidence of δ34S difference between sulfate and sulfide in Archean is scarce. In this study, we focused on barite and pyrite occurred at the layer in the 3.2 Ga Dixon Island Formation in coastal Pilbara terrane, Western Australia. We found pyrites in from the bottom of the Black Chert Member to the Varicolored Chert Member of the Dixon Island Formation. Particularly, we can see pyrite layers of a few millimeters thick which make an alternate layers with black chert layers in the Varicolored Chert Member. The bulk δ34S values of these layers are -10.1~+26.8‰ (Sakamoto, 2010MS) and micro-meter scale heterogeneity of δ34S can be seen in minute spherical shell pyrite which was formed at early stage of diagenesis (Miki, 2015MS). On the other hand, barite layers are remained in the lower part of the Black Chert Member in the Dixon Island Formation. In these layers, columnar quartz crystals were representative which are considered to be a pseudomorph of barite. Such equigranular occurrences of barite are typical character in submarine hydrothermal system (Kiyokawa et al., 2006). There exist small crystals of barite (less than 200 um in diameter) which are expected to be remnants of original barite. We performed microscale sulfur isotope analyses using a NanoSIMS. As a preliminary result, we obtained δ34S value of +3.4~+9.1‰ (n=11). These values are similar to the reported values of barite which are considered to be a hydrothermal origin in 3.47 Ga North Pole
Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii
Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.
2016-01-01
Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.
A model for the submarine depthkeeping team
NASA Technical Reports Server (NTRS)
Ware, J. R.; Best, J. F.; Bozzi, P. J.; Kleinman, D. W.
1981-01-01
The most difficult task the depthkeeping team must face occurs during periscope-depth operations during which they may be required to maintain a submarine several hundred feet long within a foot of ordered depth and within one-half degree of ordered pitch. The difficulty is compounded by the facts that wave generated forces are extremely high, depth and pitch signals are very noisy and submarine speed is such that overall dynamics are slow. A mathematical simulation of the depthkeeping team based on the optimal control models is described. A solution of the optimal team control problem with an output control restriction (limited display to each controller) is presented.
Does calving matter? Evidence for significant submarine melt
Bartholomaus, Timothy C.; Larsen, Christopher F.; O’Neel, Shad
2013-01-01
During the summer in the northeast Pacific Ocean, the Alaska Coastal Current sweeps water with temperatures in excess of 12 °C past the mouths of glacierized fjords and bays. The extent to which these warm waters affect the mass balance of Alaskan tidewater glaciers is uncertain. Here we report hydrographic measurements made within Icy Bay, Alaska, and calculate rates of submarine melt at Yahtse Glacier, a tidewater glacier terminating in Icy Bay. We find strongly stratified water properties consistent with estuarine circulation and evidence that warm Gulf of Alaska water reaches the head of 40 km-long Icy Bay, largely unaltered. A 10–20 m layer of cold, fresh, glacially-modified water overlies warm, saline water. The saline water is observed to reach up to 10.4 °C within 1.5 km of the terminus of Yahtse Glacier. By quantifying the heat and salt deficit within the glacially-modified water, we place bounds on the rate of submarine melt. The submarine melt rate is estimated at >9 m d−1, at least half the rate at which ice flows into the terminus region, and can plausibly account for all of the submarine terminus mass loss. Our measurements suggest that summer and fall subaerial calving is a direct response to thermal undercutting of the terminus, further demonstrating the critical role of the ocean in modulating tidewater glacier dynamics.
NASA Astrophysics Data System (ADS)
Brengman, Latisha A.; Fedo, Christopher M.
2018-04-01
We investigated a group of silicified volcanic rocks from the ∼2.72 Ga Hunter Mine Group (HMG), Abitibi Greenstone Belt, Canada, in order to document progressive compositional change associated with alteration in a subaqueous caldera system. Rocks of the HMG divide into three groups based on mineralogy and texture for petrographic and geochemical analyses. Volcanic features (phenocrysts, pseudomorphs after primary glass shards, lapilli, volcanic clasts) are preserved in all groups, despite changing mineralogy from primarily quartz, feldspar, chlorite (Groups 1 and 2), to quartz, hematite and carbonate (Groups 2 and 3). Compositionally, Group 1 rocks resemble volcanic rocks in the region, while Group 2 and 3 rocks show a change in mineralogy to iron, silica, and carbonate minerals, which is associated with depletion of many major and trace elements associated with volcanic rocks (Al2O3, Na2O, K2O, Zr). In addition, rare earth elements display a clear progression from volcanic signatures in Group 1 (PrSN/YbSN = 1.7-2.96, EuSN/EuSN∗ = 0.84-1.72, Y/Ho = 25.20-27.41, LaSN/LaSN∗ = 0.97-1.29, and Zr/Hf = 38.38-42.09) to transitional mixed volcanic, hydrothermal, and seawater signatures in Group 2 (PrSN/YbSN 1.33-2.89, EuSN/EuSN∗ 1.33-2.5, Y/Ho = 23.94-30, LaSN/LaSN∗ 0.93-1.34, and Zr/Hf = 40-70), to mixed hydrothermal and seawater signatures in Group 3 (PrSN/YbSN 0.62-2.88, EuSN/EuSN∗ 1.30-7.15, LaSN/LaSN∗ 1.02-1.86, Y/Ho = 25.56-55, and Zr/Hf = 35-50). We interpret that silicification of volcanic rocks (Group 1) produced transitional altered volcanic rocks (Group 2), and siliceous and jaspilitic rocks (Group 3), based on preservation of delicate volcanic features. Building on this explanation, we interpret that major, trace- and rare-earth element mobility occurred during the process of silicification, during which siliceous and jaspilitic rocks (Group 3) acquired aspects of the rare-earth element geochemical signatures of marine chemical precipitates. We
Research on Submarine Pipeline Steel with High Performance
NASA Astrophysics Data System (ADS)
Ren, Yi; Liu, Wenyue; Zhang, Shuai; Wang, Shuang; Gao, Hong
Submarine pipeline steel has largely uniform elongation, low yield ratio and good balance between high strength and high plasticity because of the microstructure with dual phase. In this work, the microstructure and properties of the submarine pipeline steel are studied. The results show that the matrix structure is consisted of ferrite, bainite and martensite -austenite islands. The structure has a tight relationship with the thermal-mechanical controlled process. Fine dual phase shows good plasticity and low yield ratio, which can support the good balance between high strength and high plasticity.
Submarine fans: Characteristics, models, classification, and reservoir potential
NASA Astrophysics Data System (ADS)
Shanmugam, G.; Moiola, R. J.
1988-02-01
Submarine-fan sequences are important hydrocarbon reservoirs throughout the world. Submarine-fan sequences may be interpreted from bed-thickness trends, turbidite facies associations, log motifs, and seismic-reflection profiles. Turbidites occurring predominantly in channels and lobes (or sheet sands) constitute the major portion of submarine-fan sequences. Thinning- and thickening-upward trends are suggestive of channel and lobe deposition, respectively. Mounded seismic reflections are commonly indicative of lower-fan depositional lobes. Fan models are discussed in terms of modern and ancient fans, attached and detached lobes, highly efficient and poorly efficient systems, and transverse and longitudinal fans. In general, depositional lobes are considered to be attached to feeder channels. Submarine fans can be classified into four types based on their tectonic settings: (1) immature passive-margin fans (North Sea type); (2) mature passive-margin fans (Atlantic type); (3) active-margin fans (Pacific type); and (4) mixed-setting fans. Immature passive-margin fans (e.g., Balder, North Sea), and active-margin fans (e.g., Navy, Pacific Ocean) are usually small, sand-rich, and possess well developed lobes. Mature passive-margin fans (e.g., Amazon, Atlantic Ocean) are large, mud-rich, and do not develop typical lobes. However, sheet sands are common in the lower-fan regions of mature passive-margin fans. Mixed-setting fans display characteristics of either Atlantic type (e.g., Bengal, Bay of Bengal), or Pacific type (Orinoco, Caribbean), or both. Conventional channel-lobe models may not be applicable to fans associated with mature passive margins. Submarine fans develop primarily during periods of low sea level on both active- and passive-margin settings. Consequently, hydrocarbon-bearing fan sequences are associated generally with global lowstands of sea level. Channel-fill sandstones in most tectonic settings are potential reservoirs. Lobes exhibit the most favorable
A submarine perspective of the Honolulu Volcanics, Oahu
NASA Astrophysics Data System (ADS)
Clague, David A.; Paduan, Jennifer B.; McIntosh, William C.; Cousens, Brian L.; Davis, Alicé S.; Reynolds, Jennifer R.
2006-03-01
Lavas and volcaniclastic deposits were observed and collected from 4 submarine cones that are part of the Honolulu Volcanics on Oahu, Hawaii. The locations of these and a few additional, but unsampled, vents demonstrate that nearly all the vents are located on or very close to the shoreline of Oahu, with the most distal vent just 12 km offshore. The clastic samples and outcrops range from coarse breccias to cross-bedded ash deposits and show that explosive volcanism at depths between about 350 and 590 m depth played a part in forming these volcanic cones. The eruptive styles appear to be dominantly effusive to strombolian at greater depths, but apparently include violent phreatomagmatic explosive activity at the shallower sites along the submarine southwest extension of the Koko Rift. The compositions of the recovered samples are broadly similar to the strongly alkalic subaerial Honolulu Volcanics lavas, but the submarine lavas, erupted further from the Koolau caldera, have slightly more radiogenic Sr isotopic ratios, and trace element patterns that are distinct from either the subaerial Honolulu Volcanics or the submarine North Arch lavas. These patterns are characterized by moderate to strong positive Sr and P anomalies, and moderate to strong negative Cs, Rb, U, Th, Zr, and Hf anomalies. Most samples have strong negative K and moderate negative Ti anomalies, as do all subaerial Honolulu Volcanics and North Arch samples, but one group of samples from the Koko Rift lack this chemical signature. The data are consistent with more garnet in the source region for the off-shore samples than for either the on-shore Honolulu Volcanics lavas. New Ar-Ar ages show that eruptions at the submarine vents and Diamond Head occurred between about 0.5 Ma and 0.1 Ma, with the youngest ages from the Koko Rift. These ages are in general agreement with most published ages for the formation and suggest that some much younger ages reported previously from the Koko Rift are probably
NASA Astrophysics Data System (ADS)
Ruchala, T. L.; Chen, M.; Tominaga, M.; Carey, S.
2016-12-01
Kick'em Jenny (KEJ) is an active submarine volcano located in the Lesser Antilles subduction zone, 7.5 km north of the Caribbean island Grenada. KEJ, known as one of the most explosive volcanoes in Caribbean, erupted 12 times since 1939 with recent eruptions in 2001 and possibly in 2015. Multiple generations of submarine landslides and canyons have been observed in which some of them can be attributed to past eruptions. The structure of KEJ can be characterized as a 1300 m high conical profile with its summit crater located around 180 m in depth. Active hydrothermal venting and dominantly CO2 composition gas seepage take place inside this 250m diameter crater, with the most activity occurring primarily within a small ( 70 x 110 m) depression zone (inner crater). In order to characterize the subsurface structure and decipher the processes of this volcanic system, the Nautilus NA054 expedition in 2014 deployed the underwater Remotely Operated Vehicle (ROV) Hercules to conduct near-bottom geological observations and magnetometry surveys transecting KEJ's caldera. Raw magnetic data was corrected for vehicle induced magnetic noise, then merged with ROV to ship navigation at 1 HZ. To extract crustal magnetic signatures, the reduced magnetic data was further corrected for external variations such as the International Geomagnetic Reference Field and diurnal variations using data from the nearby San Juan Observatory. We produced a preliminary magnetic anomaly map of KEJ's caldera for subsequent inversion and forward modeling to delineate in situ magnetic source distribution in understanding volcanic processes. We integrated the magnetic characterization of the KEJ craters with shipboard multibeam, ROV visual descriptions, and photomosaics. Initial observations show the distribution of short wavelength scale highly magnetized source centered at the north western part of the inner crater. Although locations of gas seeps are ubiquitous over the inner crater area along ROV
Navy Operational Planner: Anti-Submarine Warfare with Time-Dependent Performance
2017-09-01
PLANNER: ANTI-SUBMARINE WARFARE WITH TIME -DEPENDENT PERFORMANCE by Anthony M. Baldessari September 2017 Thesis Advisor: W. Matthew...reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instruction, searching...REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE NAVY OPERATIONAL PLANNER: ANTI-SUBMARINE WARFARE WITH TIME -DEPENDENT
Fan, Rui; Li, Nan; Xu, Honggao; Xiang, Jun; Wang, Lei; Gao, Yanxiang
2016-01-01
To improve the bioactivity and sweetness properties of glycyrrhizic acid (GL), the hydrothermal hydrolysis of GL into glycyrrhetinic acid (GA) and glycyrrhetinic acid 3-O-mono-β-D-glucuronide (GAMG) in subcritical water was investigated. The effects of temperature, time and their interaction on the conversion ratios were analyzed and the reactions were elaborated with kinetics and thermodynamics. The results showed that GL hydrothermal hydrolysis was significantly (P < 0.05) affected by reaction time and temperature, as well as their interaction, and could be fitted into first-order kinetics. The thermodynamic analysis indicated that the hydrolysis of GL was endergonic and non-spontaneous. The hydrolytic pathways were composed of complex consecutive and parallel reactions. It was concluded that subcritical water may be a potential medium for producing GAMG and GA. Copyright © 2015 Elsevier Ltd. All rights reserved.
Detecting frontal ablation processes from direct observations of submarine terminus morphology
NASA Astrophysics Data System (ADS)
Fried, M.; Carroll, D.; Catania, G. A.; Sutherland, D. A.; Stearns, L. A.; Bartholomaus, T. C.; Shroyer, E.; Nash, J. D.
2017-12-01
Tidewater glacier termini couple glacier and ocean systems. Subglacial discharge emerging from the terminus produces buoyant plumes that modulate submarine melting, calving, fjord circulation and, in turn, changes in ice dynamics from back-stress perturbations. However, the absence of critical observational data at the ice-ocean interface limits plume and, by extension, melt models from incorporating realistic submarine terminus face morphologies and assessing their impact on terminus behavior at tidewater glaciers. Here we present a comprehensive inventory and characterization of submarine terminus face shapes from a side-looking, multibeam echo sounding campaign across Kangerdlugssuaq Sermerssua glacier, central-west Greenland. We combine these observations with in-situ measurements of ocean stratification and remotely sensed subglacial discharge, terminus positions, ice velocity, and ice surface datasets to infer the spectrum of processes sculpting the submarine terminus face. Subglacial discharge outlet locations are confirmed through observations of sediment plumes, localized melt-driven undercutting of the terminus face, and bathymetry of the adjacent seafloor. From our analysis, we differentiate terminus morphologies resulting from submarine melt and calving and assess the contribution of each process to the net frontal ablation budget. Finally, we constrain a plume model using direct observations of the submarine terminus face and conduit geometry. Plume model simulations demonstrate that the majority of discharge outlets are fed by small discharge fluxes, suggestive of a distributed subglacial hydrologic system. Outlets with the largest, concentrated discharge fluxes are morphologically unique and strongly control seasonal terminus position. At these locations, we show that the spatiotemporal pattern of terminus retreat is well correlated with time periods when local melt rate exceeds ice velocity.
A submarine volcanic eruption leads to a novel microbial habitat.
Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia
2017-04-24
Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.
Low sulfur content in submarine lavas: an unreliable indicator of subaerial eruption
Davis, A.S.; Clague, D.A.; Schulz, M.S.; Hein, J.R.
1991-01-01
Low S content (<250 ppm) has been used to identify subaerially erupted Hawaiian and Icelandic lavas. Large differences in S content of submarine-erupted lavas from different tectonic settings indicate that the behavior of S is complex. Variations in S abundance in undegassed, submarine-erupted lavas can result from different source compositions, different percentages of partial melting, and crystal fractionation. Low S concentrations in highly vesicular submarine lavas suggest that partial degassing can occur despite great hydrostatic pressure. These processes need to be evaluated before using S content as an indicator of eruption depth. -Authors
Honda, M.; McDougall, I.; Patterson, D.B.; Doulgeris, A.; Clague, D.A.
1993-01-01
Noble gas elemental and isotopic abundances have been analysed in twenty-two samples of basaltic glass dredged from the submarine flanks of two currently active Hawaiian volcanoes, Loihi Seamount and Kilauea. Neon isotopic ratios are enriched in 20Ne and 21Ne by as much as 16% with respect to atmospheric ratios. All the Hawaiian basalt glass samples show relatively high 3He 4He ratios. The high 20Ne 22Ne values in some of the Hawaiian samples, together with correlations between neon and helium systematics, suggest the presence of a solar component in the source regions of the Hawaiian mantle plume. The solar hypothesis for the Earth's primordial noble gas composition can account for helium and neon isotopic ratios observed in basaltic glasses from both plume and spreading systems, in fluids in continental hydrothermal systems, in CO2 well gases, and in ancient diamonds. These results provide new insights into the origin and evolution of the Earth's atmosphere. ?? 1993.
Fortunato, Caroline S; Huber, Julie A
2016-08-01
The chemolithoautotrophic microbial community of the rocky subseafloor potentially provides a large amount of organic carbon to the deep ocean, yet our understanding of the activity and metabolic complexity of subseafloor organisms remains poorly described. A combination of metagenomic, metatranscriptomic, and RNA stable isotope probing (RNA-SIP) analyses were used to identify the metabolic potential, expression patterns, and active autotrophic bacteria and archaea and their pathways present in low-temperature hydrothermal fluids from Axial Seamount, an active submarine volcano. Metagenomic and metatranscriptomic results showed the presence of genes and transcripts for sulfur, hydrogen, and ammonium oxidation, oxygen respiration, denitrification, and methanogenesis, as well as multiple carbon fixation pathways. In RNA-SIP experiments across a range of temperatures under reducing conditions, the enriched (13)C fractions showed differences in taxonomic and functional diversity. At 30 °C and 55 °C, Epsilonproteobacteria were dominant, oxidizing hydrogen and primarily reducing nitrate. Methanogenic archaea were also present at 55 °C, and were the only autotrophs present at 80 °C. Correspondingly, the predominant CO2 fixation pathways changed from the reductive tricarboxylic acid (rTCA) cycle to the reductive acetyl-CoA pathway with increasing temperature. By coupling RNA-SIP with meta-omics, this study demonstrates the presence and activity of distinct chemolithoautotrophic communities across a thermal gradient of a deep-sea hydrothermal vent.
Morphodynamic Model of Submarine Canyon Incision by Sandblasting
NASA Astrophysics Data System (ADS)
Zhang, L.; Parker, G.; Izumi, N.; Cartigny, M.; Li, T.; Wang, G.
2017-12-01
Submarine canyons are carved by turbidity currents under the deep sea. As opposed to subaerial canyons, the relevant processes are not easy to observe directly. Turbidity currents are bottom-hugging sediment gravity flows of that can incise or deposit on the seafloor to create submarine canyons or fans. The triggers of turbidity currents can be storms, edge waves, internal waves, canyon wall sapping, delta failure, breaching and hyperpycnal flows. The formation and evolution mechanisms of submarine canyons are similar to those of subaerial canyons, but have substantial differences. For example, sandblasting, rather than wear due to colliding gravel clasts is more likely to be the mechanism of bedrock incision. Submarine canyons incise downward, and often develop meander bends and levees within the canyon, so defining "fairways". Here we propose a simple model for canyon incision. The starting point of our model is the Macro Roughness Saltation Abrasion Alluviation model of Zhang et al. [2015], designed for bedrock incision by gravel clasts in mixed bedrock-alluvial rivers. We adapt this formulation to consider sandblasting as a means of wear. We use a layer-averaged model for turbidity current dynamics. The current contains a mixture of mud, which helps drive the flow but which does not cause incision, and sand, which is the agent of incision. We show that the model can successfully model channel downcutting, and indeed illustrate the early formation of net incisional cyclic steps, i.e. upstream-migrating undulations on the bed associated with transcritical (in the Froude sense) flow. These steps can be expected to abet the process of incision.
NASA Astrophysics Data System (ADS)
Jellinek, M.; Carazzo, G.
2011-12-01
Observations of the temporal variability of hydrothermal activity over the Juan de Fuca Ridge provide valuable clues for understanding the dynamics of hydrothermal plumes in the deep ocean. Analyses of hydrothermal temperature and light attenuation anomalies show that the structure of these plumes varies on an interannual rather than weekly or monthly time scale. This surprising stability is in complete disagreement with calculations of the residence time for the suspended particles, which suggest a complete particle sedimentation within a few days or weeks. In order to understand this difference, we performed analog experiments simulating particle-laden hydrothermal plumes. These experiments consist in injecting upwards at a fixed rate a hot mixture of fresh water and solid particles in a tank containing stratified salt water. Measurements of light attenuation, temperature and salinity anomalies are conducted during the experiments in order to decipher the causal links between real-time observations and venting conditions. Our results show that depending on the source conditions and the strength of density stratification in the tank, large-scale instabilities may develop due to the differential diffusion of heat and fine particles. Diffusive particle convection enhances the dispersion of fine particles and increases the longevity of the plume. We show that this process is a common phenomenon in natural submarine plumes, which not only increases the longevity of the plumes up to at least 5 years, but also permits dissolution processes to occur providing large amounts of dissolved chemical species far from the point of emission. A new model for particle sedimentation from hydrothermal plumes is presented and tested against natural data collected over the Cleft segment of the Juan de Fuca Ridge between 1987 and 1991. This model is found to be in good agreement with measurements of the rate of change of light attenuation within the chronic plume overlying the north
NASA Astrophysics Data System (ADS)
Del Moro, S.; Di Roberto, A.; Meletlidis, S.; Pompilio, M.; Bertagnini, A.; Agostini, S.; Ridolfi, F.; Renzulli, A.
2015-06-01
On 15 October 2011, a submarine eruption offshore of El Hierro Island gave rise to floating volcanic products, known as xenopumices, i.e., pumiceous xenoliths partly mingled and coated with the juvenile basanitic magma. Over the last few years, no consensus in the scientific community in explaining the origin of these products has been reached. In order to better understand the formation of xenopumice, we present a textural, mineralogical, and geochemical study of the possible magmatic, hydrothermal, and pyrometamorphic processes, which usually operate in the plumbing systems of active volcanoes. We carried out a comprehensive SEM investigation and Sr-Nd-Pb isotope analyses on some samples representative of three different xenopumice facies. All the data were compared with previous studies, new data for El Hierro extrusives and a literature dataset of Canary Islands igneous and sedimentary rocks. In the investigated xenopumices, we emphasize the presence of restitic magmatic phases as well as crystallization of minerals (mainly olivine + pyroxene + magnetite aggregates) as pseudomorphs after pre-existing mafic phenocrysts, providing evidence of pyrometamorphism induced by the high-T juvenile basanitic magma. In addition, we identify veins consisting of zircon + REE-oxides + mullite associated with Si-rich glass and hydrothermal quartz, which indicate the fundamental role played by hydrothermal fluid circulation in the xenopumice protolith. The petrological data agree with a pre-syneruptive formation of the xenopumice, when El Hierro basanite magma intruded hydrothermally altered trachyandesite to trachyte rocks and triggered local partial melting. Therefore, the El Hierro xenopumice represents a snapshot of the transient processes at the magma-wall rock interface, which normally occurs in the feeding system of active volcanoes.
NASA Astrophysics Data System (ADS)
Medialdea, T.; Somoza, L.; González, F. J.; Vázquez, J. T.; de Ignacio, C.; Sumino, H.; Sánchez-Guillamón, O.; Orihashi, Y.; León, R.; Palomino, D.
2017-08-01
New seismic profiles, bathymetric data, and sediment-rock sampling document for the first time the discovery of hydrothermal vent complexes and volcanic cones at 4800-5200 m depth related to recent volcanic and intrusive activity in an unexplored area of the Canary Basin (Eastern Atlantic Ocean, 500 km west of the Canary Islands). A complex of sill intrusions is imaged on seismic profiles showing saucer-shaped, parallel, or inclined geometries. Three main types of structures are related to these intrusions. Type I consists of cone-shaped depressions developed above inclined sills interpreted as hydrothermal vents. Type II is the most abundant and is represented by isolated or clustered hydrothermal domes bounded by faults rooted at the tips of saucer-shaped sills. Domes are interpreted as seabed expressions of reservoirs of CH4 and CO2-rich fluids formed by degassing and contact metamorphism of organic-rich sediments around sill intrusions. Type III are hydrothermal-volcanic complexes originated above stratified or branched inclined sills connected by a chimney to the seabed volcanic edifice. Parallel sills sourced from the magmatic chimney formed also domes surrounding the volcanic cones. Core and dredges revealed that these volcanoes, which must be among the deepest in the world, are constituted by OIB-type, basanites with an outer ring of blue-green hydrothermal Al-rich smectite muds. Magmatic activity is dated, based on lava samples, at 0.78 ± 0.05 and 1.61 ± 0.09 Ma (K/Ar methods) and on tephra layers within cores at 25-237 ky. The Subvent hydrothermal-volcanic complex constitutes the first modern system reported in deep water oceanic basins related to intraplate hotspot activity.
Effect of Topography on Subglacial Discharge and Submarine Melting During Tidewater Glacier Retreat
NASA Astrophysics Data System (ADS)
Amundson, J. M.; Carroll, D.
2018-01-01
To first order, subglacial discharge depends on climate, which determines precipitation fluxes and glacier mass balance, and the rate of glacier volume change. For tidewater glaciers, large and rapid changes in glacier volume can occur independent of climate change due to strong glacier dynamic feedbacks. Using an idealized tidewater glacier model, we show that these feedbacks produce secular variations in subglacial discharge that are influenced by subglacial topography. Retreat along retrograde bed slopes (into deep water) results in rapid surface lowering and coincident increases in subglacial discharge. Consequently, submarine melting of glacier termini, which depends on subglacial discharge and ocean thermal forcing, also increases during retreat into deep water. Both subglacial discharge and submarine melting subsequently decrease as glacier termini retreat out of deep water and approach new steady state equilibria. In our simulations, subglacial discharge reached peaks that were 6-17% higher than preretreat values, with the highest values occurring during retreat from narrow sills, and submarine melting increased by 14% for unstratified fjords and 51% for highly stratified fjords. Our results therefore indicate that submarine melting acts in concert with iceberg calving to cause tidewater glacier termini to be unstable on retrograde beds. The full impact of submarine melting on tidewater glacier stability remains uncertain, however, due to poor understanding of the coupling between submarine melting and iceberg calving.
Land Ahoy! Understanding Submarine Command and Control During the Completion of Inshore Operations.
Roberts, Aaron P J; Stanton, Neville A; Fay, Daniel
2017-12-01
The aim of this study was to use multiple command teams to provide empirical evidence for understanding communication flow, information pertinence, and tasks undertaken in a submarine control room when completing higher- and lower-demand inshore operation (INSO) scenarios. The focus of submarine operations has changed, and submarines are increasingly required to operate in costal littoral zones. However, submarine command team performance during INSO is not well understood, particularly from a sociotechnical systems perspective. A submarine control-room simulator was built. The creation of networked workstations allowed a team of nine operators to perform tasks completed by submarine command teams during INSO. The Event Analysis of Systematic Teamwork method was used to model the social, task, and information networks and to describe command team performance. Ten teams were recruited for the study, affording statistical comparisons of how command-team roles and level of demand affected performance. Results indicated that the submarine command-team members are required to rapidly integrate sonar and visual data as the periscope is used, periodically, in a "duck-and-run" fashion, to maintain covertness. The fusion of such information is primarily completed by the operations officer (OPSO), with this operator experiencing significantly greater demand than any other operator. The OPSO was a bottleneck in the command team when completing INSO, experiencing similar load in both scenarios, suggesting that the command team may benefit from data synthesis tasks being more evenly distributed within the command team. The work can inform future control-room design and command-team ways of working by identifying bottlenecks in terms of information and task flow between operators.
Measuring currents in submarine canyons: technological and scientific progress in the past 30 years
Xu, J. P.
2011-01-01
The development and application of acoustic and optical technologies and of accurate positioning systems in the past 30 years have opened new frontiers in the submarine canyon research communities. This paper reviews several key advancements in both technology and science in the field of currents in submarine canyons since the1979 publication of Currents in Submarine Canyons and Other Sea Valleys by Francis Shepard and colleagues. Precise placements of high-resolution, high-frequency instruments have not only allowed researchers to collect new data that are essential for advancing and generalizing theories governing the canyon currents, but have also revealed new natural phenomena that challenge the understandings of the theorists and experimenters in their predictions of submarine canyon flow fields. Baroclinic motions at tidal frequencies, found to be intensified both up canyon and toward the canyon floor, dominate the flow field and control the sediment transport processes in submarine canyons. Turbidity currents are found to frequently occur in active submarine canyons such as Monterey Canyon. These turbidity currents have maximum speeds of nearly 200 cm/s, much smaller than the speeds of turbidity currents in geological time, but still very destructive. In addition to traditional Eulerian measurements, Lagrangian flow data are essential in quantifying water and sediment transport in submarine canyons. A concerted experiment with multiple monitoring stations along the canyon axis and on nearby shelves is required to characterize the storm-trigger mechanism for turbidity currents.
Temperature dependence of single-crystal elastic constants of flux-grown alpha-GaPO(4).
Armand, P; Beaurain, M; Rufflé, B; Menaert, B; Papet, P
2009-06-01
The lattice parameter change with respect to temperature (T) has been measured using high-temperature powder X-ray diffraction techniques for high-temperature flux-grown GaPO(4) single crystals with the alpha-quartz structure. The lattice and the volume linear thermal expansion coefficients in the temperature range 303-1173 K were computed from the X-ray data. The percentage linear thermal expansions along the a and c axes at 1173 K are 1.5 and 0.51, respectively. The temperature dependence of the mass density rho of flux-grown GaPO(4) single crystals was evaluated using the volume thermal expansion coefficient alpha(V)(T) = 3.291 x 10(-5) - 2.786 x 10(-8) [T] + 4.598 x 10(-11)[T](2). Single-crystal high-resolution Brillouin spectroscopy measurements have been carried out at ambient pressure from 303 to 1123 K to determine the elastic constants C(IJ) of high-temperature flux-grown GaPO(4) material. The single-crystal elastic moduli were calculated using the sound velocities via the measured Brillouin frequency shifts Deltanu(B). These are, to our knowledge, the highest temperatures at which single-crystal elastic constants of alpha-GaPO(4) have been measured. Most of the room-temperature elastic constant values measured on flux-grown GaPO(4) material are higher than the ones found for hydrothermally grown GaPO(4) single crystals. The fourth-order temperature coefficients of both the Brillouin frequency shifts T(nuB)((n)) and the single-crystal elastic moduli T(C(IJ))((n)) were obtained. The first-order temperature coefficients of the C(IJ) are in excellent agreement with previous reports on low-temperature hydrothermally grown alpha-GaPO(4) single crystals, while small discrepancies in the higher-order temperature coefficients are observed. This is explained in terms of the OH content in the GaPO(4) network, which is an important parameter in the crystal thermal behavior.
A sodium gallophosphate with an original tunnel structure: NaGa 2(OH)(PO 4) 2
NASA Astrophysics Data System (ADS)
Guesdon, A.; Monnin, Y.; Raveau, B.
2003-05-01
A new sodium gallophosphate, NaGa 2(OH)(PO 4) 2, has been obtained by hydrothermal synthesis under autogeneous pressure at 473 K. It crystallizes in the P2 1/ n space group with the cell parameters a=8.9675(8) Å, b=8.9732(5) Å, c=9.2855(7) Å, β=114.812(6)°, V=678.2 Å 3 ( Z=4). In its original three-dimensional framework, monophosphate groups share their apices with [Ga 4O 16(OH) 2] tetrameric units, which are built from two GaO 5(OH) octahedra and two GaO 4(OH) trigonal bipyramids. The sodium cations are located in tunnels running along a, whereas the tunnels running along b are empty.
Conjecture of plume components in hydrothermal sea area
NASA Astrophysics Data System (ADS)
Noda, K., IV; Aoyama, C.
2017-12-01
Investigation at Southern Okinawa Trough, western Kume Island, and Tokara Islands was performed from June 26 to July 12, 2016, as a part of Japan's cross ministerial Strategic Innovation Promotion Program (SIP) for a complete understanding of active hydrothermal vents. In this investigation, water column sonar data was obtained using multi-beam sonar (EM122) onboard YOKOSUKA (Japan Agency for Marine-Earth Science and Technology) and methane plumes were alsp monitored (YK16-07). Multi-beam sonar is an acoustic instrument used to measure submarine topography, and in this investigation, plumes were observed to successfully regenerate the data. It also became clear that volume backscattering strength (SV) of plumes varies, depending on the area where they are settled. On the other hand, components of plumes are still unknown. In this study, acoustic data obtained from YK16-07 will be reviewed using analytical software (echo view 7) to calculate volume backscattering strength (SV) of plumes. Likewise, multi-beam sonar (EM122) onboard DAIICHI KAIYOMARU (KAIYO ENGINEERING CO., LTD) was used to collect acoustic data. This already known data of methane plume from Sea of Japan will be analyzed using echo view 7. By comparing these data, plume components will be examined from plume size.
US Navy Submarine Sea Trial of the NASA Air Quality Monitor
NASA Technical Reports Server (NTRS)
Limero, Thomas; Wallace, William T.; Manney, Joshua A.; Mudgett, Paul D.
2017-01-01
For the past four years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Most importantly, the AQM operates at atmospheric pressure and uses air as the GC carrier gas, which translates into a small reliable instrument. Onboard ISS there are two AQMs, with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard ISS for each crew increment. The U.S. Navy is looking to update its submarine air monitoring suite of instruments, and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which was successfully flown on ISS as a technology demonstration to measure major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial results. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only one AQM will be deployed during the sea trial, but it is sufficient to detect the compounds of interest to the Navy for the purposes of this trial. A significant benefit of the AQM is that runs can be scripted for pre-determined intervals and no crew intervention is required. The data from the sea trial will be compared to archival samples collected prior to and during the trial period. This paper will give a brief overview of the AQM technology and protocols for the submarine trial. After a quick review of the AQM preparation, the main focus of the paper will be on the results of the submarine trial. Of particular interest will be the comparison of the contaminants found in the ISS and submarine atmospheres, as both represent
2004-01-01
destruction of many civilian lives in sunken passenger ships—notably the Cunard liner Lusitania , attacked in May 1915 with a loss of 1,200 lives, 128...former Ger- man passenger liners interned by their owners in American harbors in order to avoid capture by blockading British cruisers. Eventually there...submarines torpedoed merchant ships, including passenger liners , without warning. Then, because they had no way of rescuing those who had survived the
Wang, Liping; Li, Aimin; Chang, Yuzhi
2017-04-01
Hydrothermal treatment is an effective method to enhance the deep dewaterability of excess sludge with low energy consumption. In this study, an insight into the relationship between enhanced dewaterability and structural properties of the produced hydrothermal sludge was presented, aiming at better understanding the effect of hydrothermal process on excess sludge dewatering performance. The results indicated that hydrothermal effect induced the transformation of surface water to interstitial and free water by lowering the binding strength between adjacent water and solid particles and that free water became the main form for moisture existence in hydrothermal sludge as temperature was higher than 180 °C. Increase in temperature of hydrothermal treatment generated a significant size reduction of sludge flocs but treated sludge with a higher rigidity, which not only strengthened the network of hydrothermal sludge but also destroyed the binding of EPS with water. Hydrothermal process caused crevice and pore structures of excess sludge to disappear gradually, which was a main driving force of water removal as temperature was below 150 °C. With the temperature of hydrothermal treatment exceeding 180 °C, the morphology of hydrothermal sludge became rough which linked closely to the solid precipitation of condensation polymerization, and further became smooth at higher temperature (210 °C) due to the coal-like structures with higher aromaticities, indicating that hydrothermal reaction pathways began to play a main role in enhanced dewaterability. Hydrothermal treatment led to more alkyl and aromatic carbon, but lower O-alkyl, carboxyl and carbonyl carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.
Submarine harbor navigation using image data
NASA Astrophysics Data System (ADS)
Stubberud, Stephen C.; Kramer, Kathleen A.
2017-01-01
The process of ingress and egress of a United States Navy submarine is a human-intensive process that takes numerous individuals to monitor locations and for hazards. Sailors pass vocal information to bridge where it is processed manually. There is interest in using video imaging of the periscope view to more automatically provide navigation within harbors and other points of ingress and egress. In this paper, video-based navigation is examined as a target-tracking problem. While some image-processing methods claim to provide range information, the moving platform problem and weather concerns, such as fog, reduce the effectiveness of these range estimates. The video-navigation problem then becomes an angle-only tracking problem. Angle-only tracking is known to be fraught with difficulties, due to the fact that the unobservable space is not the null space. When using a Kalman filter estimator to perform the tracking, significant errors arise which could endanger the submarine. This work analyzes the performance of the Kalman filter when angle-only measurements are used to provide the target tracks. This paper addresses estimation unobservability and the minimal set of requirements that are needed to address it in this complex but real-world problem. Three major issues are addressed: the knowledge of navigation beacons/landmarks' locations, the minimal number of these beacons needed to maintain the course, and update rates of the angles of the landmarks as the periscope rotates and landmarks become obscured due to blockage and weather. The goal is to address the problem of navigation to and from the docks, while maintaining the traversing of the harbor channel based on maritime rules relying solely on the image-based data. The minimal number of beacons will be considered. For this effort, the image correlation from frame to frame is assumed to be achieved perfectly. Variation in the update rates and the dropping of data due to rotation and obscuration is considered
Submarine laser communications
NASA Astrophysics Data System (ADS)
McConathy, D. R.
The Department of the Navy and the Defense Advanced Research Projects Agency (DARPA) are sponsoring a joint study to investigate the use of blue-green laser technology to comunicate with submarines at operating depths. Two approaches are under investigation - one in which the laser itself is space-based, and the other in which the laser is ground-based with its beam redirected to the earth's surface by an orbiting mirror. This paper discusses these two approaches, and presents a brief history of activities which led to the current studies.
EAARL submarine topography: Florida Keys National Marine Sanctuary
Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Woolard, Jason; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.
2007-01-01
This Web site contains 46 Lidar-derived submarine topography maps and GIS files for the Florida Keys National Marine Sanctuary. These Lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Oceanic and Atmospheric Administration (NOAA), Remote Sensing Division, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography within cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to coastal resource managers.
Cold-water coral banks and submarine landslides: a review
NASA Astrophysics Data System (ADS)
de Mol, Ben; Huvenne, Veerle; Canals, Miquel
2009-06-01
This paper aims to review the relation between cold-water coral bank development and submarine landslides. Both are common features on continental margins, but so far it has not been reviewed which effect—if at all—they may have upon each other. Indirect and direct relations between coral banks and landslides are evaluated here, based on four case studies: the Magellan Mound Province in the Porcupine Seabight, where fossil coral banks appear partly on top of a buried slide deposit; the Sula Ridge Reef Complex and the Storegga landslide both off mid-Norway; and the Mauritania coral bank province, associated with the Mauritanian Slide Complex. For each of these locations, positive and negative relationships between both features are discussed, based on available datasets. Locally submarine landslides might directly favour coral bank development by creating substratum where corals can settle on, enhancing turbulence due to abrupt seabed morphological variations and, in some cases, causing fluid seepage. In turn, some of these processes may contribute to increased food availability and lower sedimentation rates. Landslides can also affect coral bank development by direct erosion of the coral banks, and by the instantaneous increase of turbidity, which may smother the corals. On the other hand, coral banks might have a stabilising function and delay or stop the headwall retrogradation of submarine landslides. Although local relationships can be deduced from these case studies, no general and direct relationship exists between submarine landslides and cold-water coral banks.
Submarine paleoseismology based on turbidite records.
Goldfinger, Chris
2011-01-01
Many of the largest earthquakes are generated at subduction zones or other plate boundary fault systems near enough to the coast that marine environments may record evidence of them. During and shortly after large earthquakes in the coastal and marine environments, a spectrum of evidence may be left behind, mirroring onshore paleoseismic evidence. Shaking or displacement of the seafloor can trigger processes such as turbidity currents, submarine landslides, tsunami (which may be recorded both onshore and offshore), and soft-sediment deformation. Marine sites may also share evidence of fault scarps, colluvial wedges, offset features, and liquefaction or fluid expulsion with their onshore counterparts. This article reviews the use of submarine turbidite deposits for paleoseismology, focuses on the dating and correlation techniques used to establish stratigraphic continuity of marine deposits, and outlines criteria for distinguishing earthquake deposits and the strategies used to acquire suitable samples and data for marine paleoseismology.
Photoluminescence and photocatalytic properties of rhombohedral CuGaO2 nanoplates
Shi, Linlin; Wang, Fei; Wang, Yunpeng; Wang, Dengkui; Zhao, Bin; Zhang, Ligong; Zhao, Dongxu; Shen, Dezhen
2016-01-01
Rhombohedral phase CuGaO2 nanoplates with a diameter of about 10 μm were synthesized via low temperature hydrothermal method. Room temperature and low temperature photoluminescence of the obtained CuGaO2 nanoplates were characterized. CuGaO2 nanoplates exhibited blue emission at room temperature and free exciton emission were appeared at low temperature. The blue emission is originated from defects such as Cu vacancies, which is the possible origin of p-type conductivity. The appearance of free exciton emission can demonstrate the direct bandgap transition behavior of CuGaO2 nanoplates. The as-prepared p-type CuGaO2 nanoplates were further decorated by n-type ZnO nanoparticles via calcination method to fabricate p-n junction nanocomposites. The nanocomposites exhibited enhanced photocatalytic activity which can be ascribed to the effective separation of photogenerated carriers by the internal electrostatic field in the p-n junction region, and the enhanced light absorption properties resulted from sub-bandgap absorption effect of p-n junction. This work has offered a new insight into the design of p-n junction devices using p-type CuGaO2 nanoplates. PMID:26887923
Submarine optical fiber cable: development and laying results.
Kojima, N; Yabuta, T; Negishi, Y; Iwabuchi, K; Kawata, O; Yamashita, K; Miyajima, Y; Yoshizawa, N
1982-03-01
This paper describes the structural design, trial production, and laying results for submarine optical fiber cables that can be deployed in shallow seas between islands and/or channel crossings without repeaters. Structural design methods for the submarine optical fiber cable are proposed, which take into consideration suppressing cable elongation under tension and excess loss under hydraulic pressure. This paper describes good laying results for the cable using this structural design method. The average loss for single-mode fibers was 0.72 dB/km, and the average loss for multimode fibers was 0.81 dB/km for a 10.2-km long cable operated at 1.3-microm wavelength.
Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making.
Rodeheffer, Christopher D; Chabal, Sarah; Clarke, John M; Fothergill, David M
2018-06-01
Submarines routinely operate with higher levels of ambient carbon dioxide (CO2) (i.e., 2000 - 5000 ppm) than what is typically considered normal (i.e., 400 - 600 ppm). Although significant cognitive impairments are rarely reported at these elevated CO2 levels, recent studies using the Strategic Management Simulation (SMS) test have found impairments in decision-making performance during acute CO2 exposure at levels as low as 1000 ppm. This is a potential concern for submarine operations, as personnel regularly make mission-critical decisions that affect the safety and efficiency of the vessel and its crew while exposed to similar levels of CO2. The objective of this study was to determine if submariner decision-making performance is impacted by acute exposure to levels of CO2 routinely present in the submarine atmosphere during sea patrols. Using a subject-blinded balanced design, 36 submarine-qualified sailors were randomly assigned to receive 1 of 3 CO2 exposure conditions (600, 2500, or 15,000 ppm). After a 45-min atmospheric acclimation period, participants completed an 80-min computer-administered SMS test as a measure of decision making. There were no significant differences for any of the nine SMS measures of decision making between the CO2 exposure conditions. In contrast to recent research demonstrating cognitive deficits on the SMS test in students and professional-grade office workers, we were unable to replicate this effect in a submariner population-even with acute CO2 exposures more than an order of magnitude greater than those used in previous studies that demonstrated such effects.Rodeheffer CD, Chabal S, Clarke JM, Fothergill DM. Acute exposure to low-to-moderate carbon dioxide levels and submariner decision making. Aerosp Med Hum Perform. 2018; 89(6):520-525.
Analysis of Health Data from Ten Years of Polaris Submarine Patrols
1979-01-01
Niemoeller 1979b). Those illnesses under the systemic heading (including infectious mononucleosis ) were much more common in submariners; the reason for...and a lower rate in genitourinary, systemic (including mononucleosis ), cranial, and neuropsychiatric illness compared to submarine personnel...and nearly five times the rate of days lost from duty in this category (P < 0.01). Systemic This category included mononucleosis , viremia
Simulating a Submarine Hydrothermal Vent
2013-01-16
A team of scientists at NASA Jet Propulsion Laboratory is testing whether organic molecules can be brewed in a simulated ocean vent. Pictured here is Lauren White, a member of the NASA Astrobiology Icy Worlds team.
Topology Model of the Flow around a Submarine Hull Form
2015-12-01
UNCLASSIFIED Topology Model of the Flow around a Submarine Hull Form S.-K. Lee Maritime Division Defence Science and Technology Group DST-Group–TR...3177 ABSTRACT A topology model constructed from surface-streamer visualisation describes the flow around a generic conventional submarine hull form at...pure yaw angles of 0 ◦, 10 ◦ and 18 ◦. The model is used to develop equations for sway-force and yaw-moment coefficients which relate to the hull - form
Air Purity in Diving from Submarines. 1. Review and Preliminary Analyses
1987-12-01
Nathaniel Howard for technical assistance, and Susan Cecire for editorial assistance. iv INTRODUCTION The need for divers to use compressed air from...pneumatic control systems) and emergency submarine functions, and submarine interior air is frequently compressed back into the bank which will cycle...breathe the interior air for long periods, so why the concern for divers? First, the processes of compression (by multi-stage oil lubricated
Satellite/Submarine Arctic Sea Ice Remote Sensing in 2004 and 2007
NASA Astrophysics Data System (ADS)
Hughes, N. E.; Wadhams, P.; Rodrigues, J.
2007-12-01
After an interlude of 8 years the U.K. Royal Navy returned to the Arctic Ocean with an under-ice mission by the submarine shape HMS Tireless in April 2004. A full environmental monitoring programme in which U.K. civilian scientists were allowed to participate was integrated into the mission. This was subsequently followed by a second expedition, in March 2007, which allowed further measurements to be acquired. These have so far been the only opportunities for civilian scientists to utilise navy submarines in the Arctic since the demise of the U.S. SCICEX programme in 2000. This paper presents some of the data collected on these new missions and uses it for validation of sea ice information derived from coincident acquisitions by modern satellite sensors such as the ESA Envisat ASAR and NASA MODIS. In both the 2004 and 2007 expeditions shape Tireless took a track north of Greenland along the latitude 85° N. This was similar to the route used for an earlier submarine-aircraft combined survey in April 1987 with which our results shall be compared. In all three missions the submarine was equipped with a standard upward-looking echosounder and sidescan for ice observations and a full range of satellite-borne, or airborne in the case of the earlier mission, microwave and optical sensors were available for validation. In this study we concentrate on the submarine track north of Greenland from the Marginal Ice Zone (MIZ) in Fram Strait through to the Lincoln Sea around 65° W. This transect encompasses a wide range of differing sea ice conditions, from the highly mobile mixture of first year and multi year ice being transported on the trans-polar drift through to the highly deformed ice north of Greenland and Ellesmere Island. The combination of submarine measurements of ice thickness and satellite/aircraft top-side measurements gives an accurate indication of how changes in the ice regime are taking place and allows the potential development of multi-sensor data fusion
NASA Astrophysics Data System (ADS)
Knuth, F.; Crone, T. J.; Marburg, A.
2017-12-01
The Ocean Observatories Initiative's (OOI) Cabled Array is delivering real-time high-definition video data from an HD video camera (CAMHD), installed at the Mushroom hydrothermal vent in the ASHES hydrothermal vent field within the caldera of Axial Seamount, an active submarine volcano located approximately 450 kilometers off the coast of Washington at a depth of 1,542 m. Every three hours the camera pans, zooms and focuses in on nine distinct scenes of scientific interest across the vent, producing 14-minute-long videos during each run. This standardized video sampling routine enables scientists to programmatically analyze the content of the video using automated image analysis techniques. Each scene-specific time series dataset can service a wide range of scientific investigations, including the estimation of bacterial flux into the system by quantifying chemosynthetic bacterial clusters (floc) present in the water column, relating periodicity in hydrothermal vent fluid flow to earth tides, measuring vent chimney growth in response to changing hydrothermal fluid flow rates, or mapping the patterns of fauna colonization, distribution and composition across the vent over time. We are currently investigating the seventh scene in the sampling routine, focused on the bacterial mat covering the seafloor at the base of the vent. We quantify the change in bacterial mat coverage over time using image analysis techniques, and examine the relationship between mat coverage, fluid flow processes, episodic chimney collapse events, and other processes observed by Cabled Array instrumentation. This analysis is being conducted using cloud-enabled computer vision processing techniques, programmatic image analysis, and time-lapse video data collected over the course of the first CAMHD deployment, from November 2015 to July 2016.
NASA Astrophysics Data System (ADS)
Rubin, Ken
1997-09-01
Recently, it has been reported that the element polonium degasses from mid-ocean ridge and seamount volcanoes during eruptions. Published and new observations on other volatile metal and metalloid elements can also be interpreted as indicating significant degassing of magmatic vapors during submarine eruptions. This process potentially plays an important role in the net transfer of chemical elements from erupting volcanoes to seawater in addition to that arising from sea floor hydrothermal systems. In this paper, a framework is constructed for predicting and assessing semiquantitatively the potential magnitude and chemical fingerprints in the water column of metal and metalloid degassing using (1) predictions from a summary of element volatilities during mafic subaerial volcanism worldwide and (2) limited data from submarine volcanic effusives. The latter include analyses of polonium and trace metals in near-volcano water masses sampled following a submarine eruption at Loihi seamount, Hawaii (1000 m bsl) in 1996. The element volatility predictions and observations show good agreement, considering the limited dataset. Some of the highest volatility main group and transition element enrichments in seawater over Loihi are predicted by the degassing mass transfer model I present. When expanded to cover all submarine volcanic activity, it is predicted that exit fluxes of these elements are up to 10 2-10 3 greater by degassing than by normal MOR hydrothermalism. In contrast, MOR exit fluxes of low volatility alkali and alkaline earth elements are likely 10 2-10 6 greater from hydrothermal inputs. Degassing inputs to the ocean are probably highly episodic, occurring almost entirely during eruptions; these are times of enhanced and abnormal hydrothermalism as well. Although major hydrothermal and degassing events may not be chemically recognizable in real water masses as wholly distinct entities, it is nevertheless possible to predict to what extent each process flavors
Navy Virginia (SSN 774) Class Attack Submarine Procurement: Background and Issues for Congress
2016-04-14
programs before the Seapower subcommittee of the Senate Armed Services Committee, the following exchange occurred: SENATOR KELLY AYOTTE (continuing... Bryan Bender, “Navy Eyes Cutting Submarine Force,” Boston Globe, May 12, 2004, p. 1; Lolita C. Baldor, “Study Recommends Cutting Submarine Fleet
Mineralogy, chemical composition and structure of the MIR Mound, TAG Hydrothermal Field
NASA Astrophysics Data System (ADS)
Stepanova, T. V.; Krasnov, S. G.; Cherkashev, G. A.
The study of samples collected from the surface of the MIR mound (TAG Hydrothermal Field) by video-controlled hydraulic grab allowed identification of a number of mineralogical types. These include pyrite-chalcopyrite (Py-Cp), bornite-chalcopyrite-opaline (Bn-Cp-Op) and sphalerite-opaline (Sp-Op) sulfide chimneys, massive sulfides composed of pyrite (Py), chalcopyrite-pyrite (Cp-Py), marcasite-pyrite-opaline (Mc-Py-Op), sphalerite-pyrite-opaline (Sp-Py-Op) and sphalerite-chalcopyrite-pyrite-opaline (Sp-Cp-Py-Op), as well as siliceous and Fe-Mn oxide hydrothermal deposits. Most of the minor elements (Ag, Au, Cd, Ga, Hg, Sb and Pb) are associated with Zn-rich massive sulfides, Co Bi, Pb, and As with Ferich ones, while Cu-rich sulfides are depleted of trace metals. Cu-enriched assemblages are concentrated in the northern part, Zn-enriched in the center, and siliceous rocks in the south of the MIR mound. According to paragenetic relations, the development of the mound started with the formation of quartz (originally opaline) rocks and dendritic assemblages of melnikovite-pyrite, followed by deposition of chalcopyrite and recrystallization of primary pyrite, subsequent generation of sphalerite-rich assemblages and final deposition of opaline rocks. The late renewal of hydrothermal activity led to local formation of Cu-rich chimneys enriched in Au, Ag, Hg and Pb probably due to their remobilization from inner parts of the deposit.
2011-06-10
Subamrine, Medium) LCDR Lieutenant Commander LT Lieutenant NM Nautical Mile RADM Rear Admiral ST Sen- Taka (Submarine, High Speed) STo Sen-Toku...Special Submarine) STS Sen- Taka -Sho (Submarine, High Speed(Victory)) USS United States Ship VADM Vice Admiral 1 CHAPTER 1 INTRODUCTION On...Kirai-Sen meaning Mine-Layer, KT for Kai-Toku-Chu meaning Medium, Special Submarine, ST for Sen- Taka meaning Submarine, High speed, STo for Sen Toku
Submarine Volcanic Eruptions and Potential Analogs for Venus
NASA Technical Reports Server (NTRS)
Wilson, L.; Mouginismark, P. J.; Fryer, P.; Gaddis, L. R.
1985-01-01
As part of an analysis program to better understand the diversity of volcanic processes on the terrestrial planets, an investigation of the volcanic landforms which exist on the Earth's ocean floor was initiated. In part, this analysis is focused toward gaining a better understanding of submarine volcanic landforms in their own right, but also it is hoped that these features may show similarities to volcanic landforms on Venus, due to the high ambient water (Earth) and atmospheric (Venus) pressures. A series of numerical modelling experiments was performed to investigate the relative importance of such attributes as water pressure and temperature on the eruption process, and to determine the rate of cooling and emplacement of lava flows in the submarine environment. Investigations to date show that the confining water pressure and the buoyancy effects of the surrounding water significantly affect the styles of volcanism on the ocean floor. In the case of Venusian volcanism, confining pressures will not be as great as that found at the ocean's abyssal plains, but nevertheless the general trend toward reducing magma vesiculation will hold true for Venus as well as the ocean floor. Furthermore, other analogs may also be found between submarine volcanism and Venusian activity.
1985-11-01
also the combat system design for the proposed new attack submarine class, SSN 21. In December 1983, the Navy awarded the International Business Machines...VI: Comments From International Business 35 Machines Corporation Abbreviations DNSARC Department of the Navy Systems Acquisition Review Council DSARC...Defense Systems Acquisition Review Council GAO General Accounting Office IBM International Business Machines Corporation NAVsEA Naval Sea Systems
Solution of Supplee's submarine paradox through special and general relativity
NASA Astrophysics Data System (ADS)
Vieira, R. S.
2016-12-01
In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink to observers at rest within the ocean, but it rather seems to float in the submarine proper frame. In this letter, we show that the paradox arises from a misuse of the Archimedes principle in the relativistic case. Considering first the special relativity, we show that any relativistic force field can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. These gravitomagnetic effects provide a relativistic formulation of Archimedes principle, from which the paradox is explained. Besides, if the curved spacetime on the vicinity of the Earth is taken into account, we show that the gravitational force exerted by the Earth on a moving body must increase with the speed of the body. The submarine paradox is then analyzed again with this speed-dependent gravitational force.
U-Th systematics and 230Th ages of carbonate chimneys at the Lost City Hydrothermal Field
NASA Astrophysics Data System (ADS)
Ludwig, Kristin A.; Shen, Chuan-Chou; Kelley, Deborah S.; Cheng, Hai; Edwards, R. Lawrence
2011-04-01
The Lost City Hydrothermal Field (LCHF) is a serpentinite-hosted vent field located 15 km west of the spreading axis of the Mid-Atlantic Ridge. In this study, uranium-thorium (U-Th) geochronological techniques have been used to examine the U-Th systematics of hydrothermal fluids and the 230Th ages of hydrothermally-precipitated carbonate chimneys at the LCHF. Fluid sample analyses indicate that endmember fluids likely contain only 0.0073 ng/g U or less compared to 3.28 ± 0.03 ng/g of U in ambient seawater. For fluid samples containing only 2-21% ambient seawater (1.1-11 mmol/kg Mg), Th concentration is 0.11-0.13 pg/g and surrounding seawater concentrations average 0.133 ± 0.016 pg/g. The 230Th/ 232Th atomic ratios of the vent fluids range from 1 (±10) × 10 -6 to 11 (±5) × 10 -6, are less than those of seawater, and indicate that the vent fluids may contribute a minor amount of non-radiogenic 230Th to the LCHF carbonate chimney deposits. Chimney 238U concentrations range from 1 to 10 μg/g and the average chimney corrected initial δ 234U is 147.2 ± 0.8, which is not significantly different from the ambient seawater value of 146.5 ± 0.6. Carbonate 232Th concentrations range broadly from 0.0038 ± 0.0003 to 125 ± 16 ng/g and 230Th/ 232Th atomic ratios vary from near seawater values of 43 (±8) × 10 -6 up to 530 (±25) × 10 -3. Chimney ages, corrected for initial 230Th, range from 17 ± 6 yrs to 120 ± 13 kyrs. The youngest chimneys are at the intersection of two active, steeply-dipping normal faults that cut the Atlantis Massif; the oldest chimneys are located in the southwest portion of the field. Vent deposits on a steep, fault-bounded wall on the east side of the field are all <4 kyrs old, indicating that mass wasting in this region is relatively recent. Comparison of results to prior age-dating investigations of submarine hydrothermal systems shows that the LCHF is the most long-lived hydrothermal system known to date. It is likely that seismic
Gasier, H G; Hughes, L M; Young, C R; Richardson, A M; Richardson, A R
2014-09-01
The submarine environment is unique in that there is limited space and no sunlight, which may negatively affect skeletal health and lead to accelerated bone loss, osteoporosis, and fractures. The primary purpose of this study was to determine whether there was an association with submarine service, specifically time spent at sea, and bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine and dual proximal femur (total hip and femoral neck) measured by DXA. This is a cross-sectional study of 462 submariners 20-91 years old. Variables included in the analysis were age, height, race, alcohol intake, tobacco use, fracture history, conditions, and medications known to cause bone loss and osteoporosis and submarine service. Of the submarine service predictors, only serving onboard a diesel submarine was determined to be independently associated with a reduction in BMD of the total hip and femur neck, while no submarine service predictor increased the odds of having low BMD. In submariners 50+ years old, the age-adjusted prevalence of osteopenia was 15.7 % (lumbar spine) and 40.4 % (femur neck), while the prevalence of osteoporosis was 4.8 % (lumbar spine) and 4.2 % (femur neck), rates that did not differ from NHANES 2005-2008. In submariners <50 years old, 3.1 % was below the expected range for age. The proportion of submariners 50+ years old that met the FRAX criteria for pharmacological treatment was 12 %. Intermittent periods of submergence that can range from a few days to 3+ months do not appear to compromise skeletal health differently than the general population.
Submarine Groundwater Discharge in the Coastal Zone
NASA Astrophysics Data System (ADS)
Bakti, Hendra
2018-02-01
Indonesia is one of the archipelagic countries that has the longest coastline in the world. Because it is located in the tropics, in general it has a very high rainfall. Each island has a different morphology which is composed of a variety of rocks with different hydrogeological properties. This natural condition allows for the presence of groundwater in different amount in each island. The difference in groundwater hydraulics gradients in aquifer continuous to the sea has triggered the discharge of groundwater to offshore known as submarine groundwater discharge (SGD). Its presence can be as seepage or submarine springs with components derived from land and sea and a mixture between them. The understanding of SGD phenomenon is very important because it can be useful as a source of clean water in coastal areas, affecting marine health, and improving marine environment.
Hypercortisolism as a potential concern for submariners.
Reini, Seth A
2010-12-01
Cortisol is a stress-response hormone that is important for survivability in fight or flight situations. Hypercortisolism is a state of chronically elevated cortisol levels due to a failure to return to, or maintain baseline levels. It is a condition that is often undiagnosed and can aid in the development of many physiological and psychological health problems. Some of the health ailments associated with hypercortisolism include metabolic syndrome, decreases in bone mineral density, and depression. Chronic stress and sleep deprivation are two common causes of hypercortisolism, both areas of concern within the submarine community. This review discusses the etiology of hypercortisolism and the likelihood of submariner vulnerability to the condition along with health problems associated with it. Lastly, strategies to prevent chronic elevation of cortisol and mitigate the potential health risks associated with the condition are covered.
2011-12-15
for Retrofit Design of Submarine Actuation Systems 5b. GRANT NUMBER Energy Storage for Electric Actuators NOOO 14-08-1-0424 5c. PROGRAM ELEMENT...are used to derive power and energy storage requirements for control surface actuation during extreme submarine maneuvers, such as emergency...and for initially sizing system components. 15. SUBJECT TERMS Submarines, electromagnetic actuators, energy storage, simulation-based design
2018-03-01
HISTORICAL CONTRIBUTIONS, CIVIL-MILITARY CHALLENGES, AND ANTI-SUBMARINE WARFARE CAPABILITIES ON COAST GUARD CUTTERS by Brian A. Smicklas...CONTRIBUTIONS, CIVIL- MILITARY CHALLENGES, AND ANTI-SUBMARINE WARFARE CAPABILITIES ON COAST GUARD CUTTERS 5. FUNDING NUMBERS 6. AUTHOR(S) Brian A...MILITARY CHALLENGES, AND ANTI-SUBMARINE WARFARE CAPABILITIES ON COAST GUARD CUTTERS Brian A. Smicklas Commander, U.S. Coast Guard B.S., Coast
1986-01-15
children and osteomalacia in adults. It is highly unlikely that the young, healthy population of submariners is at any significant risk for... osteomalacia ; there have been no reported cases of the disease in submariners. Yet, if 25(OH)vitamin D levels decrease over one patrol to a point where
NASA Astrophysics Data System (ADS)
Tao, W.; Tao, C.; Li, H.; Zhaocai, W.; Jinhui, Z.; Qinzhu, C.; Shili, L.
2014-12-01
Mid-ocean ridges, largely present far from the continental plates, are characterized by complex geological structures and numerous hydrothermal systems with complex controlling factors. Exploring seafloor sulfide resources for industrial and scientific applications is a challenge. With the advent of geophysical surveys for seabed investigation, near-bottom magnetic prospecting, which yields shallow geological structure, is an efficient method for investigating active and inactive hydrothermal fields and for researching the structure of hydrothermal systems (Tivey et al., 1993, 1996;German et al., 2008). We collected near-bottom magnetic data in the Longqi hydrothermal area, located in the southwest Indian ridge (49.6° E; Zhu et al., 2010; Tao et al., 2014), using the autonomous benthic explorer, an autonomous underwater vehicle, during the second leg of the Chinese cruise DY115-19 on board R/V DaYangYiHao. Based on the results of the intensity of the spatial differential vector method (Seaman et al., 1993), we outline the hydrothermal alternation zone. By building models, we subsequently infer a fault along the discovered hydrothermal vents; this fault line may be connected to a detachment fault (Zhao et al., 2013). In addition, we discuss the channels of the hydrothermal circulation system (Figure 1), and presume that heat was conducted to the sea subsurface by the detachment fault; the aqueous fluid that infiltrated the fault is heated and conveyed to the seafloor, promoting the circulation of the hydrothermal system.
Stability of submarine slopes in the northern South China Sea: a numerical approach
NASA Astrophysics Data System (ADS)
Zhang, Liang; Luan, Xiwu
2013-01-01
Submarine landslides occur frequently on most continental margins. They are effective mechanisms of sediment transfer but also a geological hazard to seafloor installations. In this paper, submarine slope stability is evaluated using a 2D limit equilibrium method. Considerations of slope, sediment, and triggering force on the factor of safety (FOS) were calculated in drained and undrained ( Φ=0) cases. Results show that submarine slopes are stable when the slope is <16° under static conditions and without a weak interlayer. With a weak interlayer, slopes are stable at <18° in the drained case and at <9° in the undrained case. Earthquake loading can drastically reduce the shear strength of sediment with increased pore water pressure. The slope became unstable at >13° with earthquake peak ground acceleration (PGA) of 0.5 g; whereas with a weak layer, a PGA of 0.2 g could trigger instability at slopes >10°, and >3° for PGA of 0.5 g. The northern slope of the South China Sea is geomorphologically stable under static conditions. However, because of the possibility of high PGA at the eastern margin of the South China Sea, submarine slides are likely on the Taiwan Bank slope and eastern part of the Dongsha slope. Therefore, submarine slides recognized in seismic profiles on the Taiwan Bank slope would be triggered by an earthquake, the most important factor for triggering submarine slides on the northern slope of the South China Sea. Considering the distribution of PGA, we consider the northern slope of the South China Sea to be stable, excluding the Taiwan Bank slope, which is tectonically active.
China’s Future Nuclear Submarine Force. Insights from Chinese Writings
2007-01-01
ts056058.pdf. 115. , , [Lu Jiaben, Wang Shen- glong, Liu Wen, et al.], “‘ ’ ” [Evaluation of Health Protective Effects of “Silver Ginseng ...Based on his instructions, in the course of developing nuclear-powered submarines, we formed a seamless and effective nuclear safety mechanism by...the manner in which France strives to maximize the effectiveness of its second-tier nuclear submarine force.32 The September 2005 issue of (Naval
High-Performance Ga2O3 Anode for Lithium-Ion Batteries.
Tang, Xun; Huang, Xin; Huang, Yongmin; Gou, Yong; Pastore, James; Yang, Yao; Xiong, Yin; Qian, Jiangfeng; Brock, Joel D; Lu, Juntao; Xiao, Li; Abruña, Héctor D; Zhuang, Lin
2018-02-14
There is a great deal of interest in developing battery systems that can exhibit self-healing behavior, thus enhancing cyclability and stability. Given that gallium (Ga) is a metal that melts near room temperature, we wanted to test if it could be employed as a self-healing anode material for lithium-ion batteries (LIBs). However, Ga nanoparticles (NPs), when directly applied, tended to aggregate upon charge/discharge cycling. To address this issue, we employed carbon-coated Ga 2 O 3 NPs as an alternative. By controlling the pH of the precursor solution, highly dispersed and ultrafine Ga 2 O 3 NPs, embedded in carbon shells, could be synthesized through a hydrothermal carbonization method. The particle size of the Ga 2 O 3 NPs was 2.6 nm, with an extremely narrow size distribution, as determined by high-resolution transmission electron microscopy and Brunauer-Emmett-Teller measurements. A lithium-ion battery anode based on this material exhibited stable charging and discharging, with a capacity of 721 mAh/g after 200 cycles. The high cyclability is due to not only the protective effects of the carbon shell but also the formation of Ga 0 during the lithiation process, as indicated by operando X-ray absorption near-edge spectroscopy.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Honda, M.; McDougall, I.; Patterson, D.B.
1993-02-01
Noble gas elemental and isotopic abundances have been analysed in twenty-two samples of basaltic glass dredged from the submarine flanks of two currently active Hawaiian volcanoes, Loihi Seamount and Kilauea. Neon isotopic ratios are enriched in [sup 20]Ne and [sup 21]Ne by as much as 16% with respect to atmospheric ratios. All the Hawaiian basalt glass samples show relatively high [sup 3]He/[sup 4]He ratios. The high [sup 20]Ne/[sup 22]Ne values in some of the Hawaiian samples, together with correlations between neon and helium systematics, suggest the presence of a solar component in the source regions of the Hawaiian mantle plume.more » The solar hypothesis for the Earth's primordial noble gas composition can account for helium and neon isotopic ratios observed in basaltic glasses from both plume and spreading systems, in fluids in continental hydrothermal systems, in CO[sub 2] well gases, and in ancient diamonds. These results provide new insights into the origin and evolution of the Earth's atmosphere.« less
Numerous Submarine Radial Vents Revealed on Mauna Loa Volcano
NASA Astrophysics Data System (ADS)
Wanless, D.; Garcia, M. O.; Rhodes, J. M.; Trusdell, F. A.; Schilling, S.; Weis, D.; Fornari, D.; Vollinger, M.
2003-12-01
Among Hawaiian shield volcanoes, Mauna Loa is distinct in having vents outside of its summit and rift zones. These radial vents are located on its northern and western flanks and account for approximately 10% of historic eruptions outside the summit region. Thirty-three subaerial and one submarine vent (active in 1877) were known prior to our work. During a recent Jason2 expedition to the volcano's western flank, nine new submarine radial vents were discovered. Eighty-five samples were collected from these and the 1877 radial vent. Bathymetry and side-scan imagery were acquired using an EM300 multibeam echo sounder. The high resolution data (vertical resolution of approximately 4 m and horizontal resolution of 25 m) allowed us to create the first detailed geologic map of Mauna Loa's western submarine flank. The map was compiled using video and still photography from the Jason2 ROV and geochemical analysis of the samples. The geochemistry includes microprobe glass and XRF whole rock major and trace element data. Eight of the submarine radial vents sampled erupted tholeiitic lavas that are geochemically similar to historical subaerial eruptions on Mauna Loa. However, in contrast to all previously collected Mauna Loa lavas, two of the young vents erupted alkalic basalts. These lavas may have been derived from Mauna Loa, as they have somewhat higher FeO and TiO2 values at a given MgO content than alkalic lavas from neighboring Hualalai volcano, whose vents are located only on rifts 16 km away. Alkalic lavas are indicative of the postshield stage of volcanism and may signal the impending demise of Mauna Loa volcano.
Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress
2011-04-21
Procurement Congressional Research Service 4 Figure 1. Virginia-Class Attack Submarine Source: U.S. Navy file photo accessed by CRS on January...May 12, 2004, p. 1; Lolita C. Baldor, “Study Recommends Cutting Submarine Fleet,” NavyTimes.com, May 13, 2004. 44 U.S. Department of the Navy, An
Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress
2011-04-12
Research Service 4 Figure 1. Virginia-Class Attack Submarine Source: U.S. Navy file photo accessed by CRS on January 11, 2011, at http...September 2001, p. 23. 42 Bryan Bender, “Navy Eyes Cutting Submarine Force,” Boston Globe, May 12, 2004, p. 1; Lolita C. Baldor, “Study Recommends
NASA Astrophysics Data System (ADS)
Sun, H.; Jiang, T.; Wang, Z.; Zhang, Y.
2014-12-01
Submarine channel is one of key conduits for coarse terrigenous clastic sediments to abyssal plain, which provides the possibility for deepwater hydrocarbon exploration. Recently, a new high-quality 3D seismic data is acquired in south Yinggehai basin (YGHB) and the detailed interpretations on those seismic profiles as well as RMS amplitude attributes and variance slices reveal a submarine channel system developed in late Miocene, which could be supplied from Hainan Island via turbidity currents so that it would be filled with sand-rich turbidites as good hydrocarbon reservoir. Based on the integration between regional seismic survey and some boreholes, the investigations on its infilling architectures and depositional processes are carried out. The results show that it composes two converged submarine channels with two channelized submarine fans to their west and the main submarine channel (MSC) is characterized by a downstream increasing width and is infilled by sediments with high amplitude seismic facies, which could be originated from channelized submarine fans. Furthermore, the complicated depositional processes around the confluence region of these two channels are pointed out and the interactions between the submarine channel system and nearby channelized submarine fans are discussed. The detailed illustration on the seismic features and depositional processes of the subsurface submarine system provides us better understanding deepwater sedimentary dynamics and would be more benefit for the hydrocarbon exploration in similar deepwater area around the world.
Collection of Arctic Ocean Data from US Navy Submarines on the New SCICEX Program
NASA Astrophysics Data System (ADS)
Smethie, W. M.; Sambrotto, R.; Boyd, T.; Richter-Menge, J.; Corbett, J.
2011-12-01
The SCICEX submarine Arctic science program originated in the 1990s when six dedicated science cruises were conducted in the Arctic Ocean aboard US Navy Sturgeon class submarines. After the cold war era Sturgeon class submarines were retired, several Science Accommodation cruises, for which a few days for scientific measurements were added to planned submarine transits through the Arctic Ocean, were carried out when opportunities arose. Renewed interest in conducting further Science Accommodation cruises on a regular basis to better document and understand how the Arctic Ocean responds to climate change resulted in publication of a scientific plan in 2010 (http://www.arctic.gov/publications/scicex_plan.pdf). In the spring of 2011 testing of data collection and water sampling methods aboard newer Virginia and Seawolf class submarines on transit from a Navy ice camp in the Beaufort Sea, was conducted in order to develop protocols and evaluate techniques. Ice draft measurements were also taken in the vicinity of the ice camp and near the North Pole to evaluate new data collection systems. This evaluation will include a comparison of the ice draft data with a comprehensive set of in situ ice thickness measurements taken near the ice camp. Under-ice submarine-launched eXpendable Condutivity Temperature Depth (XCTD) probes were deployed from the USS Connecticut (SSN-22), a Seawolf class submarine, and the resulting profiles compared to CTD casts from the APLIS ice station and historical profiles. Water samples were collected through the hull for measurements of tritium, helium isotopes, oxygen isotopes, chlorofluorocarbons, sulfur hexafluoride, nutrients, dissolved organic carbon, bacterioplankton, phytoplankton and particulates levels. These samples were returned to Lamont-Doherty Earth Observatory and were in the process of being measured at the time this abstract was written. Measurements completed at this time indicate good samples can be collected for CFC-12
Temporal changes in fluid chemistry and energy profiles in the vulcano island hydrothermal system.
Rogers, Karyn L; Amend, Jan P; Gurrieri, Sergio
2007-12-01
In June 2003, the geochemical composition of geothermal fluids was determined at 9 sites in the Vulcano hydrothermal system, 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 system 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 hydrothermal system 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 hydrothermal system have the potential to influence not only microbial diversity but also the metabolic strategies of the resident microbial communities.
Why is there a large submarine landslide in the Jan Mayen Ridge, north Norway?
NASA Astrophysics Data System (ADS)
Kawamura, Kiichiro; Sverre Laberg, Jan
2013-04-01
This paper deals with the formation process/mechanism of a large submarine landslide in the Jan Mayen Ridge. The Jan Mayen Ridge, being a continental sliver, is ~250 km long in N-S direction with a flat plateau of ~800 m in water depth standing on an abyssal plane of 2500-3000 m in water depth. There is only a large submarine landslide scar of ~50 km wide in the central east side. In the central east side, the internal geologic architecture is characterized by an Eocene-Oligocene sedimentary sequence, which tilts eastward. This sedimentary sequence is cut by large normal faults, that have formed by the spread of the Norwegina-Greenland Sea since 20 Ma. The wasted mass of the large submarine landslide could slip down along the bedding plane and/or the normal faults dipping to east. Thus, the slide form a big spoon-shaped basin. The slide scar was collapsed retrogressively to make a small spoon-shaped basin on the upper part of the big basin. There are long channels from the retrogressive slide scars to the lower basin. The retrogressive slides would continue to discharge progressively gravity flows to make the long channels on the basin after the large submarine landslide occurred. On contrary to the slide region, the sedimentary sequence has a large anticline in an east foot of the ridge in other regions. This anticline could be an obstruction to a large submarine landslide. Thus, the geologic architecture plays an important role in the formation mechanism of a large submarine landslides in the Jan Mayen Ridge.
Microbiology of ancient and modern hydrothermal systems.
Reysenbach, A L; Cady, S L
2001-02-01
Hydrothermal systems have prevailed throughout geological history on earth, and ancient ARCHAEAN hydrothermal deposits could provide clues to understanding earth's earliest biosphere. Modern hydrothermal systems support a plethora of microorganisms and macroorganisms, and provide good comparisons for paleontological interpretation of ancient hydrothermal systems. However, all of the microfossils associated with ancient hydrothermal deposits reported to date are filamentous, and limited STABLE ISOTOPE analysis suggests that these microfossils were probably autotrophs. Therefore, the morphology and mode of carbon metabolism are attributes of microorganisms from modern hydrothermal systems that provide valuable information for interpreting the geological record using morphological and isotopic signatures.
Hydrothermal Growth of Polyscale Crystals
NASA Astrophysics Data System (ADS)
Byrappa, Kullaiah
In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.
Decompression illness in goats following simulated submarine escape: 1993-2006.
Seddon, F M; Thacker, J C; Fisher, A S; Jurd, K M; White, M G; Loveman, G A M
2014-01-01
The United Kingdom Ministry of Defence commissioned work to define the relationship between the internal pressure of a distressed submarine (DISSUB), the depth from which escape is made and the risk of decompression illness (DCI). The program of work used an animal model (goat) to define these risks and this paper reports the incidence and type of DCI observed. A total of 748 pressure exposures comprising saturation only, escape only or saturation followed by escape were conducted in the submarine escape simulator between 1993 and 2006. The DCI following saturation exposures was predominantly limb pain, whereas following escape exposures the DCI predominantly involved the central nervous system and was fast in onset. There was no strong relationship between the risk of DCI and the range of escape depths investigated. The risk of DCI incurred from escape following saturation was greater than that obtained by combining the risks for the independent saturation only, and escape only, exposures. The output from this program of work has led to improved advice on the safety of submarine escape.
NASA Astrophysics Data System (ADS)
Rai, A.; Wang, H.; Singh, S. C.; Crawford, W. C.; Escartin, J.; Cannat, M.
2010-12-01
Hydrothermal circulation at ocean spreading centres plays fundamental role in crustal accretion process, heat extraction from the earth and helps to maintain very rich ecosystem in deep Ocean. Recently, it has been suggested that hydrothermal circulation is mainly along the ridge axis at fast spreading centres above along axis melt lens (AMC). Using a combination of micro-earthquake and seismic reflection data, we show that the hydrothermal circulation at the Lucky Strike segment of slow spreading Mid-Atlantic Ridge is also along axis in a narrow (~1 km) zone above a wide (2-3 km) AMC. We find that the seismicity mainly lies above the seismically imaged 3 km wide 7 km long melt lens at 3.2 km depth. We observe a vertical plume of seismicity above a weak AMC reflection just north of the hydrothermal vent fields that initiates just above the AMC and continues to the seafloor. This zone is collocated with active rifting of the seafloor in the neo-volcanic zone. Beneath the hydrothermal vents sites, where a strong melt lens is imaged, the seismicity initiates at 500 m above the AMC and continues to the seafloor. Just south of the hydrothermal field, where the AMC is widest and strongest, the seismicity band lies 500 m above the melt lens in a 800 m thick zone, which does not continue to the seafloor. The presence the weak melt lens reflection could be due to a cooled and crystallised AMC (mush) that permits the penetration of hydrothermal fluids down to the top of the AMC indicated by seismicity plume and might be the in-flow zone for hydrothermal circulation. The strong AMC reflection could be due to fresh supply of melt in the AMC (pure melt), which has pushed the cracking front 500 m above the AMC. Beneath the hydrothermal fields, the strong AMC reflection and seismicity 500 above the AMC to the seafloor could represent cracking along the up-flow zone. The 800 m thick zone of seismicity above the pure melt zone could be the zone of hydrothermal cracking zone. We do
Vitamin D Status of Submariners during Patrol
1989-01-31
osteomalacia in adults5. Davis and Morris6 have reported that the calcium metabolism of submariners is deficient, and they attribute this alteration to...question. In severe vitamin D deficiencies in adults osteomalacia results with attendant softening of the bones. Ulis softening increases the
NASA Astrophysics Data System (ADS)
Harigane, Y.; Ishizuka, O.; Shimoda, G.; Sato, T.
2014-12-01
The Ryukyu Arc occurs between the islands of Kyushu and Taiwan with approximately 1200 km in the full length. This volcanic arc is caused by subduction of the Philippine Sea plate beneath the Eurasia Plate along the Ryukyu trench, and is composed of forearc islands, chains of arc volcanoes, and a back-arc rift called Okinawa Trough. The Ryukyu Arc is commonly divided into three segments (northern, central and southern) that bounded by the Tokara Strait and the Kerama Gap, respectively (e.g., Konishi 1965; Kato et al., 1982). Sato et al. (2014) mentioned that there is no active subaerial volcano in the southwest of Iotori-shima in the Central Ryukyu Arc whereas the Northern Ryukyu Arc (i.e., the Tokara Islands) has active frontal arc volcanoes. Therefore, the existence of volcanoes and volcanotectonic history of active volcanic front in the southwestern part of the Central Ryukyu Arc are still ambiguous. Detailed geophysical and geological survey was mainly conducted using R/V Kaiyou-maru No.7 during GK12 cruise operated by the Geological Survey of Japan/National Institute of Advanced Industrial Science and Technology, Japan. As a result, we have found a new submarine volcanic caldera on the west of Kume-jima island, where located the southwestern part of Central Ryukyu Arc. Here, we present (1) the bathymetrical feature of this new submarine caldera for the first time and (2) the microstructural and petrological observations of volcanic rocks (20 volcanic samples in 13 dredge sites) sampled from the small volcanic cones of this caldera volcano. The dredged samples from the caldera consist of mainly rhyolite pumice with minor andesites, Mn oxides-crust and hydrothermally altered rocks. Andesite has plagioclase, olivine and pyroxene phenocrysts. Key words: volcanic rock, caldera, arc volcanism, active volcanic front, Kume-jima island, Ryukyu Arc
Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress
2013-09-27
Submarine Source: U.S. Navy file photo accessed by CRS on January 11, 2011, at http://www.navy.mil/search/display.asp? story_id=55715. Past and Projected...May 12, 2004, p. 1; Lolita C. Baldor, “Study Recommends Cutting Submarine Fleet,” NavyTimes.com, May 13, 2004. 51 U.S. Department of the Navy, An
Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival
2014-01-01
UNCLASSIFIED UNCLASSIFIED Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival Clare...operational impacts and biosecurity risks. Approved for public release RELEASE LIMITATION UNCLASSIFIED...UNCLASSIFIED UNCLASSIFIED Biosecurity Management of Submarine Niche Areas: the Effect of Water Pressure on Biofouling Survival Executive Summary
Banning Cigarette Smoking on US Navy Submarines: A Case Study
Lando, Harry A.; Michaud, Mark. E.; Poston, Walker S.C.; Jahnke, Sara A.; Williams, Larry; Haddock, Christopher K.
2014-01-01
Background The military has had a long pro-tobacco tradition. Despite official policy discouraging smoking, tobacco still is widely seen as part of military culture. While active smoking has presented a particular challenge for the military, in recent years there also has been increasing concern with secondhand smoke. This is especially true in closed environments and submarines may be deployed for months at a time. The current case study describes the successful implementation by the Navy of a comprehensive ban on smoking aboard submarines. Methods The authors searched documents on the Internet, popular media, military-based news outlets, and the scientific literature. We also conducted interviews with Navy officers who were instrumental in policy implementation. Findings Data demonstrating substantial exposure of nonsmokers to tobacco smoke aboard submarines had major impact on successful adoption of the policy. A systematic and extended roll out of the ban included establishing a working group, soliciting input and active engagement from submarine personnel, and offering cessation assistance. Support was enlisted from Chief Petty Officers who could have been strongly opposed but who became strong proponents. Fewer problems were encountered than had been expected. In contrast to a previous unsuccessful attempt by a Navy captain to ban smoking on his ship, the ban was adopted without apparent tobacco industry interference. Conclusions Lessons learned included the importance of strong empirical support, effective framing of the issue, setting a realistic timeline, soliciting support from key personnel, and providing appropriate resources. These lessons have implications for those considering further tobacco policy changes in the military and elsewhere. PMID:25163466
Saad, Amit; Kala, Carmel; Ohayon, Sharon; Feldman, Lior; Galili, Eran; Yanir, Yoav; Nemet, Dan; Netzer, Itamar
2015-07-01
Submariners are known to have decreased bone mass following periods of long submersion. We examined whether this produces a higher predilection to fractures. This is a retrospective cohort study. Data were collected from the computerized medical records of 457 consecutive submariners (serving 1091.42 man-years). The control group included 3,219 consecutive sailors, (serving 5845.04 man-years). Groups were stratified according to age at induction, body mass index, place of birth, and status of service (i.e., compulsory versus professional). Analysis of fracture incidence and comparison of proportions between the groups was conducted using χ(2) tests and Fisher's exact test. The hazard ratio for fractures was performed using a survival analysis regression model for each group (Cox Proportional Hazard Model). Nineteen submariners (4.2%) and 94 sailors (2.9%) were shown to have fractures during their service (RR = 1.42, p = 0.15). A Cox proportional hazard model was employed. No statistically significant difference was found between the 2 groups (HR = 1.037, p = 0.89). No correlation was found between length of service and risk of fracture. Most fractures suffered by submariners occurred outside their work environment. Submariners are repeatedly exposed to prolonged submersions that are deleterious to bone strength. However, no statistically significant difference in the incidence of fractures was found between submariners and surface sailors. This is an important finding for the bone and occupational health of submariners in general. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.
NASA Astrophysics Data System (ADS)
Toki, T.; Otake, T.; Ishibashi, J. I.; Matsui, Y.; Kawagucci, S.; Kato, H.; Fuchida, S.; Miyahara, R.; Tsutsumi, A.; Kawakita, R.; Uza, H.; Uehara, R.; Shinjo, R.; Nozaki, T.; Kumagai, H.; Maeda, L.
2017-12-01
From 16th November to 15th December 2016, D/V Chikyu drilled the sea bottom around hydrothermal fields at HAKUREI site in the Izena Hole, Okinawa Trough. Site C9025, C9026, C9027, C9028, and C9032 are located along the transect line from the top of the northern mound of HAKUREI site to the eastward, and Site C9030 for the control site is located about 500 m northwest of the mound. Mg concentrations have generally been used to estimate mixing ratios between hydrothermal end-member and seawater in samples from hydrothermal vents. Higher Mg concentrations, however, were detected in the interstitial water than that of seawater, which could be due to artificially dissolution of Mg-bearing minerals that had formed in in-situ environments, when the cored sediments had become cool after their recovery on ship. Similar features were observed with regard to sulfate concentrations, and it suggests that these chemical species are not suitable to estimate quantitatively the contribution of hydrothermally-derived components. In some layers, chloride concentrations were different from that of seawater, indicating that hydrothermal fluids that had been suffered from phase separation flowed into the layers. The deviation, however, was positive or negative relative to that of seawater for an influence of brine or vapor phase, respectively. Therefore chloride concentrations are also not suitable to evaluate a quantitative contribution of hydrothermal end-member. On the other hand, K and B showed only enrichments relative to the seawater, and their highest concentrations are consistent with the reported hydrothermal end-members of each species at HAKUREI site. Using the concentrations of K and B can be evaluated for an influence of hydrothermal components. Furthermore, the headspace gas data are useful in the layers of sulfide minerals and silicified rocks, even though the interstitial waters could not be obtained because of their hardness. Based on these indices, hydrothermal fluids
NASA Astrophysics Data System (ADS)
Sawyer, D.; Reece, R.; Gulick, S. P. S.; Lenz, B. L.
2017-12-01
The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure within the slope and Surveyor Fan. This conclusion is supported because shear strength follows an expected active margin profile outside of the fan, where background sedimentation rates occur. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking
Federal Register 2010, 2011, 2012, 2013, 2014
2013-12-02
...-AA87 Security Zones; Naval Base Point Loma; Naval Mine Anti Submarine Warfare Command; San Diego Bay... establishing a new security zone at the Naval Mine and Anti-Submarine Warfare Command to protect the relocated... Commander of Naval Base Point Loma, the Commander of the Naval Mine Anti Submarine Warfare Command, and the...
The Italian Submarine Force in the Battle of the Atlantic: Left in the Dark
2014-12-12
ADM Admiral ASW Anti-submarine warfare BDA Battle damage assessment C2 Command and Control CDR Commander HF/DF High frequency direction finder...damage assessment ( BDA ) if you will, the submarine captain decided if further action might be warranted, and made a decision as to how to engage
230Th/238U dating of hydrothermal sulfides from Duanqiao hydrothermal field, Southwest Indian Ridge
NASA Astrophysics Data System (ADS)
Yang, Weifang; Tao, Chunhui; Li, Huaiming; Liang, Jin; Liao, Shili; Long, Jiangping; Ma, Zhibang; Wang, Lisheng
2017-06-01
Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones at the central volcano, at 50°28'E in the ultraslow-spreading Southwest Indian Ridge (SWIR). Twenty-eight subsamples from a relict chimney and massive sulfides were dated using the 230Th/238U method. Four main episodes of hydrothermal activity were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. The periodic character of hydrothermal activity may be related to the heat source provided by the interaction of local magmatism and tectonism. The estimated mean growth rate of the sulfide chimney is <0.02 mm/yr. This study is the first to estimate the growth rate of chimneys in the SWIR. The maximum age of the relict chimney in Duanqiao hydrothermal filed is close to that of the chimneys from Mt. Jourdanne (70 kyrs). The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. The preliminarily estimated reserves of sulfide ores of Duanqiao are approximately 0.5-2.9 million tons.
Long-term eruptive activity at a submarine arc volcano.
Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko
2006-05-25
Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes.
Long-term eruptive activity at a submarine arc volcano
Embley, R.W.; Chadwick, W.W.; Baker, E.T.; Butterfield, D.A.; Resing, J.A.; de Ronde, Cornel E. J.; Tunnicliffe, V.; Lupton, J.E.; Juniper, S.K.; Rubin, K.H.; Stern, R.J.; Lebon, G.T.; Nakamura, K.-I.; Merle, S.G.; Hein, J.R.; Wiens, D.A.; Tamura, Y.
2006-01-01
Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.
Channel-parameter estimation for satellite-to-submarine continuous-variable quantum key distribution
NASA Astrophysics Data System (ADS)
Guo, Ying; Xie, Cailang; Huang, Peng; Li, Jiawei; Zhang, Ling; Huang, Duan; Zeng, Guihua
2018-05-01
This paper deals with a channel-parameter estimation for continuous-variable quantum key distribution (CV-QKD) over a satellite-to-submarine link. In particular, we focus on the channel transmittances and the excess noise which are affected by atmospheric turbulence, surface roughness, zenith angle of the satellite, wind speed, submarine depth, etc. The estimation method is based on proposed algorithms and is applied to low-Earth orbits using the Monte Carlo approach. For light at 550 nm with a repetition frequency of 1 MHz, the effects of the estimated parameters on the performance of the CV-QKD system are assessed by a simulation by comparing the secret key bit rate in the daytime and at night. Our results show the feasibility of satellite-to-submarine CV-QKD, providing an unconditionally secure approach to achieve global networks for underwater communications.
Code of Federal Regulations, 2014 CFR
2014-07-01
... Submarine Warfare Command; San Diego Bay, San Diego, CA. 165.1103 Section 165.1103 Navigation and Navigable... Eleventh Coast Guard District § 165.1103 Security Zone; Naval Mine Anti Submarine Warfare Command; San... the Naval Mine Anti Submarine Warfare Command, bound by the following coordinates: 32°43′40.9″ N, 117...
Federal Register 2010, 2011, 2012, 2013, 2014
2010-06-15
... information about the vessel or persons on board, whether they pose a threat to the submarine. The security...-AA87 Security Zone; Escorted U.S. Navy Submarines in Sector Honolulu Captain of the Port Zone AGENCY... establishing a moving security zone around all U.S. Navy submarines that are operating in the Sector Honolulu...
Structural evolution of deep-water submarine intraplate volcanoes / Azores
NASA Astrophysics Data System (ADS)
Stakemann, Josefine; Huebscher, Christian; Beier, Christoph; Hildenbrand, Anthony; Nomikou, Paraskevi; Terrinha, Pedro; Weiß, Benedikt
2017-04-01
We present multibeam and high-resolution reflection seismic data which elucidate the architecture of three submarine intraplate volcanoes located in the southern Azores Archipelago. Data have been collected during RV Meteor cruise M113 in 2015. Four GI-Guns served as the seismic source. The digital streamer comprised 144 channels distributed over a length of 600 m. The three cones are situated in a depth down to 2300 m with heights varying between 200 m and 243 m, an average diameter of 1360 m and an average slope angle of ca. 22°. All three circular cones are surrounded by a circular channel. These features, previously named "fried eggs" were previously interpreted as impact crater (Dias et al., 2009). A comparison with nearby submarine volcanoes close to São Miguel island (Weiß et al., 2015), however, strongly suggests a volcanic origin. The seismic data indicate that the volcanic cones formed on top of a ca. 100 m thick pelagic succession covering the igneous basement. Magma ascent deformed the volcanic basement, displaced the pelagic sediments and a first eruption phase formed a small, seismically transparent volcanic cone. Further eruptions created a volcanic cone with rather transparent reflections within the inferior region changing to strong reflection amplitudes with a chaotic pattern in the superior area. Compared to the igneous basement internal reflection amplitudes are mainly weak. The seismic transparency and slope angle exclude the presence of effusive rocks, since lavas usually create strong impedance contrasts. A comparison of the seismic characteristics with those from submarine Kolumbo volcano (Hübscher et al., 2015) suggests volcaniclastic lithologies from explosive eruptions. The circular channel around the volcanic cone shows the characteristics of a moat channel created by bottom currents. References: Dias, F.C., Lourenco, N., Lobo, A., Santos de Campos, A., Pinto de Abreu, M., 2009. "Fried Egg": An Oceanic Impact Crater in the Mid
The Lassen hydrothermal system
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.
Estimating the empirical probability of submarine landslide occurrence
Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger
2010-01-01
The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.
NASA Astrophysics Data System (ADS)
Moyer, Alexis N.; Nienow, Peter W.; Gourmelen, Noel; Sole, Andrew J.; Slater, Donald A.
2017-12-01
Oceanic forcing of the Greenland Ice Sheet is believed to promote widespread thinning at tidewater glaciers, with submarine melting proposed as a potential trigger of increased glacier calving, retreat, and subsequent acceleration. The precise mechanism(s) driving glacier instability, however, remain poorly understood, and while increasing evidence points to the importance of submarine melting, estimates of melt rates are uncertain. Here we estimate submarine melt rate by examining freeboard changes in the seasonal ice tongue of Kangiata Nunaata Sermia at the head of Kangersuneq Fjord, southwest Greenland. We calculate melt rates for March and May 2013 by differencing along-fjord surface elevation, derived from high-resolution TanDEM-X digital elevation models, in combination with ice velocities derived from offset tracking applied to TerraSAR-X imagery. Estimated steady state melt rates reach up to 1.4 ± 0.5 m d^-1 near the glacier grounding line, with mean values of up to 0.8 ± 0.3 and 0.7 ± 0.3 m d^1 for the eastern and western parts of the ice tongue, respectively. Melt rates decrease with distance from the ice front and vary across the fjord. This methodology reveals spatio-temporal variations in submarine melt rates at tidewater glaciers which develop floating termini, and can be used to improve our understanding of ice-ocean interactions and submarine melting in glacial fjords.
NASA Astrophysics Data System (ADS)
Phillips, B. T.; Albert, S.; Carey, S.; DeCiccio, A.; Dunbabin, M.; Flinders, A. F.; Grinham, A. R.; Henning, B.; Howell, C.; Kelley, K. A.; Scott, J. J.
2015-12-01
Kavachi is a highly active undersea volcano located in the Western Province of the Solomon Islands, known for its frequent phreatomagmatic eruptions and ephemeral island-forming activity. The remote location of Kavachi and its explosive behavior has restricted scientific exploration of the volcano, limiting observations to surface imagery and peripheral water-column data. An expedition to Kavachi in January 2015 was timed with a rare lull in volcanic activity, allowing for observation of the inside of Kavachi's caldera and its flanks. Here we present medium-resolution bathymetry of the main peak paired with benthic imagery, petrologic analysis of samples from the caldera rim, measurements of gas flux over the main peak, and hydrothermal plume structure data. A second peak was discovered to the Southwest of the main cone and displayed evidence of diffuse-flow venting. Populations of gelatinous animals, small fish, and sharks were observed inside the active crater, raising new questions about the ecology of active submarine volcanoes. Most equipment used in this study was lightweight, relatively low-cost, and deployed using small boats; these methods may offer developing nations an economic means to explore deep-sea environments within their own territorial waters.
Lava delta deformation as a proxy for submarine slope instability
NASA Astrophysics Data System (ADS)
Di Traglia, Federico; Nolesini, Teresa; Solari, Lorenzo; Ciampalini, Andrea; Frodella, William; Steri, Damiano; Allotta, Benedetto; Rindi, Andrea; Marini, Lorenzo; Monni, Niccolò; Galardi, Emanuele; Casagli, Nicola
2018-04-01
The instability of lava deltas is a recurrent phenomenon affecting volcanic islands, which can potentially cause secondary events such as littoral explosions (due to interactions between hot lava and seawater) and tsunamis. It has been shown that Interferometric Synthetic Aperture Radar (InSAR) is a powerful technique to forecast the collapse of newly emplaced lava deltas. This work goes further, demonstrating that the monitoring of lava deltas is a successful strategy by which to observe the long-term deformation of subaerial-submarine landslide systems on unstable volcanic flanks. In this paper, displacement measurements derived from Synthetic Aperture Radar (SAR) imagery were used to detect lava delta instability at Stromboli volcano (Italy). Recent flank eruptions (2002-2003, 2007 and 2014) affected the Sciara del Fuoco (SdF) depression, created a "stacked" lava delta, which overlies a pre-existing scar produced by a submarine-subaerial tsunamigenic landslide that occurred on 30 December 2002. Space-borne X-band COSMO-SkyMED (CSK) and C-band SENTINEL-1A (SNT) SAR data collected between February 2010 and October 2016 were processed using the SqueeSAR algorithm. The obtained ground displacement maps revealed the differential ground motion of the lava delta in both CSK and SNT datasets, identifying a stable area (characterized by less than 2 mm/y in both datasets) within the northern sector of the SdF and an unstable area (characterized by velocity fields on the order of 30 mm/y and 160 mm/y in the CSK and SNT datasets, respectively) in the central sector of the SdF. The slope stability of the offshore part of the SdF, as reconstructed based on a recently performed multibeam bathymetric survey, was evaluated using a 3D Limit Equilibrium Method (LEM). In all the simulations, Factor of Safety (F) values between 0.9 and 1.1 always characterized the submarine slope between the coastline and -250 m a.s.l. The critical surfaces for all the search volumes corresponded to
Size distributions and failure initiation of submarine and subaerial landslides
ten Brink, Uri S.; Barkan, R.; Andrews, B.D.; Chaytor, J.D.
2009-01-01
Landslides are often viewed together with other natural hazards, such as earthquakes and fires, as phenomena whose size distribution obeys an inverse power law. Inverse power law distributions are the result of additive avalanche processes, in which the final size cannot be predicted at the onset of the disturbance. Volume and area distributions of submarine landslides along the U.S. Atlantic continental slope follow a lognormal distribution and not an inverse power law. Using Monte Carlo simulations, we generated area distributions of submarine landslides that show a characteristic size and with few smaller and larger areas, which can be described well by a lognormal distribution. To generate these distributions we assumed that the area of slope failure depends on earthquake magnitude, i.e., that failure occurs simultaneously over the area affected by horizontal ground shaking, and does not cascade from nucleating points. Furthermore, the downslope movement of displaced sediments does not entrain significant amounts of additional material. Our simulations fit well the area distribution of landslide sources along the Atlantic continental margin, if we assume that the slope has been subjected to earthquakes of magnitude ??? 6.3. Regions of submarine landslides, whose area distributions obey inverse power laws, may be controlled by different generation mechanisms, such as the gradual development of fractures in the headwalls of cliffs. The observation of a large number of small subaerial landslides being triggered by a single earthquake is also compatible with the hypothesis that failure occurs simultaneously in many locations within the area affected by ground shaking. Unlike submarine landslides, which are found on large uniformly-dipping slopes, a single large landslide scarp cannot form on land because of the heterogeneous morphology and short slope distances of tectonically-active subaerial regions. However, for a given earthquake magnitude, the total area
Scientific Ocean Drilling to Assess Submarine Geohazards along European Margins
NASA Astrophysics Data System (ADS)
Ask, M. V.; Camerlenghi, A.; Kopf, A.; Morgan, J. K.; Ocean DrillingSeismic Hazard, P. E.
2008-12-01
Submarine geohazards are some of the most devastating natural events in terms of lives lost and economic impact. Earthquakes pose a big threat to society and infrastructure, but the understanding of their episodic generation is incomplete. Tsunamis are known for their potential of striking coastlines world-wide. Other geohazards originating below the sea surface are equally dangerous for undersea structures and the coastal population: submarine landslides and volcanic islands collapse with little warning and devastating consequences. The European scientific community has a strong focus on geohazards along European and nearby continental margins, especially given their high population densities, and long historic and prehistoric record of hazardous events. For example, the Mediterranean is surrounded by very densely-populated coastline and is the World's leading holiday destination, receiving up 30% of global tourism. In addition, its seafloor is criss-crossed by hydrocarbon pipelines and telecommunication cables. However, the governing processes and recurrence intervals of geohazards are still poorly understood. Examples include, but are not limited to, earthquakes and volcanic eruptions along the active tectonic margins of the Mediterranean and Sea of Marmara, landslides on both active and passive margins, and tsunamites and seismites in the sedimentary record that suggest a long history of similar events. The development of geophysical networks, drilling, sampling and long-term monitoring are crucial to the understanding of earthquake, landslide, and tsunami processes, and to mitigate the associated risks in densely populated and industrialized regions such as Europe. Scientific drilling, particularly in the submarine setting, offers a unique tool to obtain drill core samples, borehole measurements and long-term observations. Hence, it is a critical technology to investigate past, present, and possible future influences of hazardous processes in this area. The
Argon-40: Excess in submarine pillow basalts from Kilauea Volcano, Hawaii
Brent, Dalrymple G.; Moore, J.G.
1968-01-01
Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon-40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.
A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera
Iizasa; Fiske; Ishizuka; Yuasa; Hashimoto; Ishibashi; Naka; Horii; Fujiwara; Imai; Koyama
1999-02-12
Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.
Argon-40: excess in submarine pillow basalts from kilauea volcano, hawaii.
Dalrymple, G B; Moore, J G
1968-09-13
Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.
Shanks, Wayne C.
2001-01-01
The recognition of abundant and widespread hydrothermal 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 hydrothermal 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.
The Keelung Submarine volcanoes and gas plumes in the nearshore of northern Taiwan
NASA Astrophysics Data System (ADS)
Huang, J. C.; Tsia, C. H.; Hsu, S. K.; Lin, S. S.
2016-12-01
Taiwan is located in the collision zone between Philippine Sea Plate and Eurasian Plate. The Philippine Sea Plate subducts northward beneath the Ryukyu arc system while the Eurasian Plate subducts eastward beneath the Luzon arc system. The Taiwan mountain building started at 9 My ago and the most active collision has migrated to middle Taiwan. In consequence, the northern Taiwan has changed its stress pattern from forms a series of thrust faults to normal faults. The stress pattern change has probably induced the post-collisional extension and volcanism in and off northern Taiwan. Under such a tectonic environment, the volcanism and gas plumes are widespread in northern Taiwan and its offshore area. Among the volcanoes of the northern Taiwan volcanic zone, the Tatun Volcano Group is the most obvious one. In this study, we use sub-bottom profiler, EK500 echo sounder, and multibeam echo sounder to study the geophysical structure of a submarine volcano in the nearshore of northern Taiwan. We have analyzed the shallow structures and identified the locations of the gas plumes. The identification of the gas plumes can help us understand the nature of the submarine volcano. Our results show that the gas plumes appear near the Kanchiao Fault and Keelung islet. Some intrusive volcanoes can be observed in the subbottom profiler data. Finally, according to the observations, we found that the Keelung Submarine Volcano is still active. We need the monitor of the active Keelung Submarine Volcano to avoid the volcanic hazard. Additionally, we need to pay attention to the earthquakes related to the Keelung Submarine Volcano.
Submarine slope failures near Seward, Alaska, during the M9.2 1964 earthquake
Haeussler, Peter J.; Lee, H.J.; Ryan, H.F.; Labay, K.; Kayen, R.E.; Hampton, M.A.; Suleimani, E.
2007-01-01
Following the 1964 M9.2 megathrust earthquake in southern Alaska, Seward was the only town hit by tsunamis generated from both submarine landslides and tectonic sources. Within 45 seconds of the start of the earthquake, a 1.2-km-long section of waterfront began sliding seaward, and soon after, ~6-8-m high waves inundated the town. Studies soon after the earthquake concluded that submarine landslides along the Seward waterfront generated the tsunamis that occurred immediately after the earthquake. We analyze pre- and post-earthquake bathymetry data to assess the location and extent of submarine mass failures and sediment transport. New NOAA multibeam bathymetry shows the morphology of the entire fjord at 15 m resolution. We also assembled all older soundings from smooth sheets for comparison to the multibeam dataset. We gridded the sounding data, applied corrections for coseismic subsidence, post-seismic rebound, unrecovered co-seismic subsidence, sea-level rise (vertical datum shift), and measurement errors. The difference grids show changes resulting from the 1964 earthquake. We estimate the total volume of slide material to be about 211 million m3. Most of this material was transported to a deep, flat area, which we refer to as “the bathtub”, about 6 to 13 km south of Seward. Sub-bottom profiling of the bathtub shows an acoustically transparent unit, which we interpret as a sediment flow deposit resulting from the submarine landslides. The scale of the submarine landslides and the distance over which sediment was transported is much larger than previously appreciated.
Comparison of Envisat ASAR and Submarine Sea Ice Thickness Statistics
NASA Astrophysics Data System (ADS)
Hughes, Nicolas E.; Rodrigues, Joao; Wadhams, Peter
2010-12-01
In April 2004 and March 2007 the Royal Navy sent the submarine HMS Tireless on missions into the Arctic Ocean. On both occasions the submarine traversed the area of remaining multi-year sea ice at latitude 85°N north of Greenland acquiring ice draft measurements using upward-looking sonar. The area is outside of the "Gore Box" used for the release of U.S. Submarine data and was beyond the latitude range of the radar altimeter satellites available at that time. This paper compares ice draft statistics with contemporary data from Envisat ASAR to evaluate the level of correlation between SAR backscatter and sea ice thickness. The decline in sea ice volume over the past decade has predominantly been caused by the loss of old multi-year ice due to increased outflow through Fram Strait. Although Tireless found little decrease in the overall ice thickness between 2004 and 2007, the ice rheology was significantly changed with greatly increased quantities of first- and second-year ice in 2007 than had been encountered in 2004. These are evident in changes to the ice draft probability density functions (PDFs) and the ice appearance as seen by the SAR, and presented here.
Reservoir properties of submarine- fan facies: Great Valley sequence, California.
McLean, H.
1981-01-01
Submarine-fan sandstones of the Great Valley sequence west of the Sacramento Valley, California, have low porosities and permeabilities. However, petrography and scanning electron microscope studies indicate that most sands in almost all submarine-fan environments are originally porous and permeable. Thin turbidite sandstones deposited in areas dominated by shale in the outer-fan and basin-plain are cemented mainly by calcite; shale dewatering is inferred to contribute to rapid cementation early in the burial process. Sands deposited in inner- and middle-fan channels with only thin shale beds have small percentrages of intergranular cement. The original porosity is reduced mechanically at shallow depths and by pressure solution at deeperlevels. Permeability decreases with increasing age of the rocks, as a result of increasing burial depths. Computer-run stepwise regression analyses show that the porosity is inversely related to the percentage of calcite cement. The results reported here indicate original porosity and permeability can be high in deep-water submarine fans and that fan environments dominated by sand (with high sand/shale ratios) are more likely to retain higher porosity and permeability to greater depths than sand interbedded with thick shale sequences.-from Author
High-Resolution Mapping of Kick`em Jenny Submarine Volcano and Associated Landslides
NASA Astrophysics Data System (ADS)
Ruchala, T. L.; Carey, S.; Hart, L.; Chen, M.; Scott, C.; Tominaga, M.; Dondin, F. J. Y.; Fujii, M.
2016-02-01
To understand the physical and geological processes that drive the volcanism and control the morphology of Kick`em Jenny (KEJ) volcano, the only active submarine volcano in the in the Lesser Antilles volcanic arc, we conducted near-source, high-resolution mapping of KEJ and its subsurface using the Remotely Operated Vehicle (ROV) Hercules during cruise NA054 of the E/V Nautilus (Sept.-Oct. 2014). Shipboard bathymetric data (EM302 system) and slope analysis maps were used to decipher the detailed seafloor morphology surrounding KEJ. Multiple generations of submarine landslides and canyons were observed, suggesting the area has been hosting dynamic sediment transport systems at multiple scales over time. Some of them might have been associated by past eruptions. Clear contacts between partially lithified carbonate sediments and volcanic formations were identified from ROV videos at the middle of the landslide slope face. Detailed observations of facies on these exposures provide constraints on the time intervals between landslide events along the western slope of KEJ. ROV video imagery also identified outcrops of columnar basalts located in the middle of the landslide deposits. These are similar in appearance to those observed in the KEJ crater during previous ROV dives, indicating a possible travel distance of volcanic materials from the crater region along landslide path. High-resolution photo mosaics, bathymetry, and magnetic data acquired by ROV Hercules were used to investigate geological processes and the possible volcanic source of landslide material within the KEJ crater. Mapping in the northwestern part of the crater floor revealed distinctive regions, including (i) microbial mats, (ii) active hydrothermal vent sites; (iii) landforms curved by channelized bottom current where seafloor is outcropped; and (iv) coarse scree the distribution of which may correlate with the distance from the crater rim. Near-bottom magnetic profiles show coherent magnetic
Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands
NASA Astrophysics Data System (ADS)
Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.
2016-12-01
Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.
Crustal volumes of the continents and of oceanic and continental submarine plateaus
NASA Technical Reports Server (NTRS)
Schubert, G.; Sandwell, D.
1989-01-01
Using global topographic data and the assumption of Airy isostasy, it is estimated that the crustal volume of the continents is 7182 X 10 to the 6th cu km. The crustal volumes of the oceanic and continental submarine plateaus are calculated at 369 X 10 to the 6th cu km and 242 X 10 to the 6th cu km, respectively. The total continental crustal volume is found to be 7581 X 10 to the 6th cu km, 3.2 percent of which is comprised of continental submarine plateaus on the seafloor. An upper bound on the contintental crust addition rate by the accretion of oceanic plateaus is set at 3.7 cu km/yr. Subduction of continental submarine plateaus with the oceanic lithosphere on a 100 Myr time scale yields an upper bound to the continental crustal subtraction rate of 2.4 cu km/yr.
A submarine landslide source for the devastating 1964 Chenega tsunami, southern Alaska
Brothers, Daniel; Haeussler, Peter J.; Lee Liberty,; David Finlayson,; Geist, Eric L.; Labay, Keith A.; Michael Byerly,
2016-01-01
During the 1964 Great Alaska earthquake (Mw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m. Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (∼0.7 km3) of glacimarine sediment was destabilized and evacuated from the steep face of a submerged moraine and an adjacent ∼21 km2 perched sedimentary basin. Once mobilized, landslide debris poured over the steep, 130 m-high face of a deeper moraine and then blanketed the terminal basin (∼465 m water depth) in 11 ± 5 m of sediment. These results, combined with inverse tsunami travel-time modeling, suggest that earthquake- triggered submarine landslides generated the tsunami that struck the village of Chenega roughly 4 min after shaking began. Unlike other tsunamigenic landslides observed in and around Prince William Sound in 1964, the failures in Dangerous Passage are not linked to an active submarine delta. The requisite environmental conditions needed to generate large submarine landslides in glacimarine fjords around the world may be more common than previously thought.
Evolution and Submarine Landslide Potential of Monterey Canyon Head, Offshore Central California
NASA Astrophysics Data System (ADS)
Maier, K. L.; Johnson, S. Y.; Hart, P. E.; Hartwell, S. R.
2016-12-01
Monterey Canyon, offshore central California, incises the shelf from near the shoreline to 30 km seaward where axial water depths approach 2,000 m. It is one of the world's most studied submarine canyons, yet debate continues concerning its age, formation, and associated geologic hazards. To address these issues, the USGS, with partial support from the California Seafloor Mapping Program, collected hundreds of kilometers of high-resolution, mini-sparker, single-channel (2009 and 2011 surveys) and multichannel (2015 survey) seismic-reflection profiles near the canyon head. The seismic data were combined with multibeam bathymetry to generate a geologic map of the proximal canyon, which delineates numerous faults and compound submarine landslide headwall scarps (covering up to 4 km2) along canyon walls. Seismic-reflection data reveal a massive ( 100 km2 lateral extent) paleochannel cut-and-fill complex underlying the proximal canyon. These subsurface cut-and-fill deposits span both sides of the relatively narrow modern canyon head, crop out in canyon walls, and incise into Purisima Formation (late Miocene and Pliocene) bedrock to depths of up to 0.3 s two-way travel time ( 240 m) below the modern shelf. We propose that the paleochannel complex represents previous locations of a migrating canyon head, and attribute its origin to multiple alternating cycles of fluvial and submarine canyon erosion and deposition linked to fluctuating sea levels. Thus, the canyon head imaged in modern bathymetry is a relatively young feature, perhaps forming in the last 20,000 years of sea-level rise. The paleocanyon deposits are significantly less consolidated than bedrock in deeper canyon walls, and therefore, are probably more prone to submarine landsliding. Nearby mapped faults occur within the active, distributed, San Andreas fault system, and earthquake-generated strong ground motions are likely triggers for past and future submarine landslides and potential associated tsunamis.
Deep-Sea Submarine 'Ben Franklin'
NASA Technical Reports Server (NTRS)
1969-01-01
The deep-sea submarine 'Ben Franklin' is being docked in the harbor. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life. It also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effect of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.
NASA Astrophysics Data System (ADS)
Chrismianto, Deddy; Zakki, Ahmad Fauzan; Arswendo, Berlian; Kim, Dong Joon
2015-12-01
Optimization analysis and computational fluid dynamics (CFDs) have been applied simultaneously, in which a parametric model plays an important role in finding the optimal solution. However, it is difficult to create a parametric model for a complex shape with irregular curves, such as a submarine hull form. In this study, the cubic Bezier curve and curve-plane intersection method are used to generate a solid model of a parametric submarine hull form taking three input parameters into account: nose radius, tail radius, and length-height hull ratio ( L/ H). Application program interface (API) scripting is also used to write code in the ANSYS design modeler. The results show that the submarine shape can be generated with some variation of the input parameters. An example is given that shows how the proposed method can be applied successfully to a hull resistance optimization case. The parametric design of the middle submarine type was chosen to be modified. First, the original submarine model was analyzed, in advance, using CFD. Then, using the response surface graph, some candidate optimal designs with a minimum hull resistance coefficient were obtained. Further, the optimization method in goal-driven optimization (GDO) was implemented to find the submarine hull form with the minimum hull resistance coefficient ( C t ). The minimum C t was obtained. The calculated difference in C t values between the initial submarine and the optimum submarine is around 0.26%, with the C t of the initial submarine and the optimum submarine being 0.001 508 26 and 0.001 504 29, respectively. The results show that the optimum submarine hull form shows a higher nose radius ( r n ) and higher L/ H than those of the initial submarine shape, while the radius of the tail ( r t ) is smaller than that of the initial shape.
Submarine cable OBS using a retired submarine telecommunication cable: GeO-TOC program
NASA Astrophysics Data System (ADS)
Kasahara, Junzo; Utada, Hisashi; Sato, Toshinori; Kinoshita, Hajimu
1998-06-01
In order to study the Earth's structure and subduction zone tectonics, seismic data from the oceanic region are extremely important. The present seismograph distribution in the oceanic region, however, provides a very poor coverage. To improve this poor seismic coverage, a cable OBS system using a retired submarine telecommunication cable is proposed. The GeO-TOC cable runs from Ninomiya, Japan, to Guam through the Izu-Bonin forearc and the Marina Trough. The total length of the cable is 2659 km. An OBS, IZU, using the GeO-TOC cable, was successfully installed at the landward slope of the Izu-Bonin Trench in January 1997. The IZU OBS is located approximately 400 km south of Tokyo. The installation method is similar to repair work on submarine cables. The IZU OBS is equipped with three accelerometers, a hydrophone, a quartz pressure gauge, and a quartz precision thermometer with a few temperature sensors to monitor overheating of the internal electronics. After installation, the voltage increase is 90 V when the current is maintained at a constant 370 mA. Data from accelerometers are digitized by 24-bit A/D converters and sent to Ninomiya at 9600 bps for each component. Hydrophone data are sent to Ninomiya as analog signals using the AM (Amplitude Modulation) method for safety reasons. Hydrophone data are digitized at the shore station. Other slow-rate data are multiplexed and sent to the shore at 9600 bps. The instrument can be controlled by a shore computer. All data will be transmitted from Ninomiya to Tokyo and combined with other existing seismic data.
Duplessis, C A; Miller, J C; Crepeau, L J; Osborn, C M; Dyche, J
2007-01-01
With a desire to increase health, cognitive performance effectiveness, and quality of life for submarine watch-standers underway, we performed an evaluation comparing an alternative, compressed-work (ALT) schedule, designed to enhance circadian rhythm entrainment and sleep hygiene, to the contemporary submarine (SUB) forward rotating schedule, aboard the ballistic-missile submarine, USS Henry M. Jackson (SSBN-730 Gold). We assessed a compressed close-6 watch-schedule ("ALT") relative to the existing backward rotating 6-hr on, 12-hr off 18-hr watch schedule ("SUB") employed underway aboard submarines. We monitored 40 subjects' sleep, and temperature and salivary cortisol from 10 of the 40 for approximately two weeks on each respective schedule underway. The cortisol cosinor mesors (midline estimating statistic of rhythm), and amplitudes did not differ significantly between conditions. The temperature cosinor mesors, and the cosinor amplitude were not significantly different, while the cosine curve fit accounted for significantly more variance in the ALT condition than in the SUB condition. The SUB schedule garnered significantly more sleep (7.1 +/- 0.2 hours) than that of the ALTMID schedule (6.3 +/- 0.3 hours). Surveys revealed that 52% of respondents preferred the SUB schedule, 15% preferred the ALT, and 33% were either indifferent or submitted uninterpretable surveys. The ALT schedule was not superior to the existing SUB schedule by physiological or subjective measures and was incompatible to accommodating operational constraints.
Intertidal and submarine groundwater discharge on the west coast of Ireland
NASA Astrophysics Data System (ADS)
R., R.; | T., Cave; Henry
2011-05-01
Submarine Groundwater Discharge is now a phenomenon of global interest, as studies show that it represents both a significant proportion of the fresh water input to the ocean, and a significant contribution to the loads of many substances. At present, little monitoring of groundwater in Ireland is carried out at its point of entry to seawater, and consequently the volumes of fresh water, and the loads of nutrients and contaminants being carried into Irish coastal waters by submarine and intertidal groundwater discharge (SiGD), are unknown. SiGD is the principal source of fresh water entering Irish coastal waters between the major west coast estuaries of the Corrib and the Shannon. Calculations of the volume of submarine SiGD delivered to southern Galway bay in winter indicate it equals 10-25% of the discharge of the R. Corrib, and that its nutrient load may be of the same order of magnitude as that from the R. Corrib. This coastal karst area includes important commercial shellfish waters, which may be strongly impacted by SiGD.
NASA Astrophysics Data System (ADS)
Kendall, B.; Yang, S.; Lu, X.; Zhang, F.; Zheng, W.
2016-12-01
The U isotope system represents a relatively new paleoredox proxy that can help trace the evolution of global ocean redox chemistry, but has rarely been applied to the Mid-Proterozoic. We report U isotope data for marine black shales of the early Mesoproterozoic Velkerri Formation (Roper Group) and late Paleoproterozoic Wollogorang Formation (Tawallah Group) from the McArthur Basin, Northern Australia. An average authigenic δ238U of 0.13 ± 0.04‰ (1SD; relative to standard CRM145) was obtained for six euxinic shales from a 1 m interval that previously yielded a precise Re-Os depositional age of 1361 ± 21 Ma. After correcting for a U isotope fractionation of 0.60-0.85‰ between seawater and open-ocean euxinic sediments, we infer that coeval global seawater had a δ238U of -0.47‰ to -0.72‰, which is 0.1-0.3‰ lighter than modern seawater (-0.40 ± 0.03‰). A U isotope mass-balance model suggests that anoxic marine environments accounted for 25-50% of the global oceanic U sink at 1.36 Ga, which is 3-7 times greater than today. The model suggests that a significant proportion, potentially even a majority, of the seafloor was not covered by anoxic waters. Hence, we infer that a significant extent of the ocean floor was covered by O2-bearing waters at 1.36 Ga. The O2 concentrations of those waters were not necessarily high, and a large expanse of weakly to mildly oxygenated deep waters is consistent with the U isotope data. Uranium isotope data from a 1 m interval in the lower Velkerri Formation, deposited at 1417 ± 29 Ma based on Re-Os geochronology, yield a greater estimate for the extent of ocean anoxia. Hence, the upper Velkerri Formation may capture a transient episode of increased ocean oxygenation. Previous Re-Os isotope data from black shales of the ca. 1.73 Ga Paleoproterozoic Wollogorang Formation yielded an erroneously young date of 1359 ± 150 Ma because hydrothermal fluids percolated through the Tawallah Group rocks at ca. 1640 Ma. Higher δ238U
Submarine Pressure Hull Collapse Considering Corrosion and Penetrations
2010-11-01
Original signed by Liam Gannon Liam Gannon Defence Scientist Approved by Original signed by Neil Pegg Neil Pegg Head/Warship Performance Approved... Heath , D.C. (2001). Submarine Structural Analysis Suite, SubSAS Phase 1. (DREA TM 2001-025). Defence Research Establishment Atlantic. DRDC
NASA Astrophysics Data System (ADS)
Lilley, M. D.; Lupton, J. E.; Olson, E. J.
2002-12-01
Magmatic degassing is a common occurrence in subaerial volcanoes and has been reported in shallow submarine volcanoes. It has been speculated that mid-ocean ridge magma chambers may exhibit degassing behavior but to date there has been no direct documentation of its occurrence. Based on very high CO2 and He concentrations, we believe that we now have evidence for a degassing magma chamber at 9°N, East Pacific Rise. M Vent, in the immediate vicinity of the 1991 eruption, exhibited high and relatively stable CO2 concentrations in excess of 150 mmol/kg for at least eight years post-eruption. Such high values are many times the value that can be extracted from basalt by hydrothermal fluid and have previously been seen only at Axial and Loihi Seamounts. Two vents about one km south (Bio 9 and P Vents) had CO2 concentrations around 50 mmol/kg in 1991 which increased to maxima near 200 mmol/kg in 1993. We believe this represents a southward movement of the magma body in this area. He concentrations were also elevated at all the vents but showed different temporal trends from CO2 and reached maximum values in 1994. 3He/heat ratios are significantly different between M and Bio 9 and P Vents implying that separate magma bodies with differing degrees of degassing underlie the two areas. We have seen similarly high concentrations of CO2 and He at 31.8°S on the East Pacific Rise (Lupton et al., 1999) and suggest that magmatic degassing into the hydrothermal convection cell is occurring there as well. This work indicates that the concentrations of magmatic gases in hydrothermal fluids may provide fine scale data bearing on the locations and along-axis dimensions of magma chambers. Reference: Lupton, J., D. Butterfield, M. Lilley, J. Ishibashi, D. Hey and L. Evans, Gas chemistry of hydrothermal fluids along the East Pacific Rise, 5°S to 32°S, EOS, 80, F1099, 1999.
Quantifying dispersal from hydrothermal vent fields in the western Pacific Ocean
Mitarai, Satoshi; Watanabe, Hiromi; Nakajima, Yuichi; Shchepetkin, Alexander F.; McWilliams, James C.
2016-01-01
Hydrothermal vent fields in the western Pacific Ocean are mostly distributed along spreading centers in submarine basins behind convergent plate boundaries. Larval dispersal resulting from deep-ocean circulations is one of the major factors influencing gene flow, diversity, and distributions of vent animals. By combining a biophysical model and deep-profiling float experiments, we quantify potential larval dispersal of vent species via ocean circulation in the western Pacific Ocean. We demonstrate that vent fields within back-arc basins could be well connected without particular directionality, whereas basin-to-basin dispersal is expected to occur infrequently, once in tens to hundreds of thousands of years, with clear dispersal barriers and directionality associated with ocean currents. The southwest Pacific vent complex, spanning more than 4,000 km, may be connected by the South Equatorial Current for species with a longer-than-average larval development time. Depending on larval dispersal depth, a strong western boundary current, the Kuroshio Current, could bridge vent fields from the Okinawa Trough to the Izu-Bonin Arc, which are 1,200 km apart. Outcomes of this study should help marine ecologists estimate gene flow among vent populations and design optimal marine conservation plans to protect one of the most unusual ecosystems on Earth. PMID:26929376
Quantifying dispersal from hydrothermal vent fields in the western Pacific Ocean.
Mitarai, Satoshi; Watanabe, Hiromi; Nakajima, Yuichi; Shchepetkin, Alexander F; McWilliams, James C
2016-03-15
Hydrothermal vent fields in the western Pacific Ocean are mostly distributed along spreading centers in submarine basins behind convergent plate boundaries. Larval dispersal resulting from deep-ocean circulations is one of the major factors influencing gene flow, diversity, and distributions of vent animals. By combining a biophysical model and deep-profiling float experiments, we quantify potential larval dispersal of vent species via ocean circulation in the western Pacific Ocean. We demonstrate that vent fields within back-arc basins could be well connected without particular directionality, whereas basin-to-basin dispersal is expected to occur infrequently, once in tens to hundreds of thousands of years, with clear dispersal barriers and directionality associated with ocean currents. The southwest Pacific vent complex, spanning more than 4,000 km, may be connected by the South Equatorial Current for species with a longer-than-average larval development time. Depending on larval dispersal depth, a strong western boundary current, the Kuroshio Current, could bridge vent fields from the Okinawa Trough to the Izu-Bonin Arc, which are 1,200 km apart. Outcomes of this study should help marine ecologists estimate gene flow among vent populations and design optimal marine conservation plans to protect one of the most unusual ecosystems on Earth.
On the global distribution of hydrothermal vent fields: One decade later
NASA Astrophysics Data System (ADS)
Beaulieu, S. E.; Baker, E. T.; German, C. R.
2012-12-01
Since the last global compilation one decade ago, the known number of active submarine hydrothermal vent fields has almost doubled. At the end of 2009, a total of 518 active vent fields was catalogued, with about half (245) visually confirmed and others (273) inferred active at the seafloor. About half (52%) of these vent fields are at mid-ocean ridges (MORs), 25% at volcanic arcs, 21% at back-arc spreading centers (BASCs), and 2% at intra-plate volcanoes and other settings. One third are in high seas, and the nations with the most known active vent fields within EEZs are Tonga, USA, Japan, and New Zealand. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. Here, we have comprehensively documented the percentage of strike length at MORs and BASCs that has been systematically explored for hydrothermal activity. As of the end of 2009, almost 30% of the ~60,000 km of MORs had been surveyed at least with spaced vertical profiles to detect hydrothermal plumes. A majority of the vents discovered at MORs in the past decade occurred at segments with < 60 mm/yr full spreading rate. Discoveries at ultra-slow MORs in the past decade included the deepest known vent (Beebe at Mid-Cayman Rise) and high-temperature black smoker vents (e.g., Dragon at SWIR and Loki's Castle at Mohns Ridge), and the highest temperature vent was measured at the slow-spreading S MAR (Turtle Pits). Using a previously published equation for the linear relationship between the number of active vent fields per 100 km strike length (F_s) vs. weighted-average full spreading rate (u_s), we predicted 676 vent fields remaining to be discovered at MORs. Even accounting for the lower F_s at slower spreading rates, almost half of the vents that are predicted remaining to be discovered at MORs are at ultra-slow to slow spreading rates (< 40 mm/yr) and about 1/3 at intermediate rates (40-80 mm
NASA Astrophysics Data System (ADS)
Chen, S.; Tao, C.; Li, H.; Zhou, J.; Deng, X.; Tao, W.; Zhang, G.; Liu, W.; He, Y.
2014-12-01
The Precious Stone Mountain hydrothermal field (PSMHF) is located on the southern rim of the Galapagos Microplate. It was found at the 3rd leg of the 2009 Chinese DY115-21 expedition on board R/V Dayangyihao. It is efficient to learn the distribution of hydrothermal plumes and locate the hydrothermal vents by detecting the anomalies of turbidity and temperature. Detecting seawater turbidity by MAPR based on deep-tow technology is established and improved during our cruises. We collected data recorded by MAPR and information from geological sampling, yielding the following results: (1)Strong hydrothermal turbidity and temperature anomalies were recorded at 1.23°N, southeast and northwest of PSMHF. According to the CTD data on the mooring system, significant temperature anomalies were observed over PSMHF at the depth of 1,470 m, with anomalies range from 0.2℃ to 0.4℃, which gave another evidence of the existence of hydrothermal plume. (2)At 1.23°N (101.4802°W/1.2305°N), the nose-shaped particle plume was concentrated at a depth interval of 1,400-1,600 m, with 200 m thickness and an east-west diffusion range of 500 m. The maximum turbidity anomaly (0.045 △NTU) was recorded at the depth of 1,500 m, while the background anomaly was about 0.01△NTU. A distinct temperature anomaly was also detected at the seafloor near 1.23°N. Deep-tow camera showed the area was piled up by hydrothermal sulfide sediments. (3) In the southeast (101.49°W/1.21°N), the thickness of hydrothermal plume was 300 m and it was spreading laterally at a depth of 1,500-1,800 m, for a distance about 800 m. The maximum turbidity anomaly of nose-shaped plume is about 0.04 △NTU at the depth of 1,600 m. Distinct temperature anomaly was also detected in the northwest (101.515°W/1.235°N). (4) Terrain and bottom current were the main factors controlling the distribution of hydrothermal plume. Different from the distribution of hydrothermal plumes on the mid-ocean ridges, which was mostly
Onset of submarine debris flow deposition far from original giant landslide.
Talling, P J; Wynn, R B; Masson, D G; Frenz, M; Cronin, B T; Schiebel, R; Akhmetzhanov, A M; Dallmeier-Tiessen, S; Benetti, S; Weaver, P P E; Georgiopoulou, A; Zühlsdorff, C; Amy, L A
2007-11-22
Submarine landslides can generate sediment-laden flows whose scale is impressive. Individual flow deposits have been mapped that extend for 1,500 km offshore from northwest Africa. These are the longest run-out sediment density flow deposits yet documented on Earth. This contribution analyses one of these deposits, which contains ten times the mass of sediment transported annually by all of the world's rivers. Understanding how this type of submarine flow evolves is a significant problem, because they are extremely difficult to monitor directly. Previous work has shown how progressive disintegration of landslide blocks can generate debris flow, the deposit of which extends downslope from the original landslide. We provide evidence that submarine flows can produce giant debris flow deposits that start several hundred kilometres from the original landslide, encased within deposits of a more dilute flow type called turbidity current. Very little sediment was deposited across the intervening large expanse of sea floor, where the flow was locally very erosive. Sediment deposition was finally triggered by a remarkably small but abrupt decrease in sea-floor gradient from 0.05 degrees to 0.01 degrees. This debris flow was probably generated by flow transformation from the decelerating turbidity current. The alternative is that non-channelized debris flow left almost no trace of its passage across one hundred kilometres of flat (0.2 degrees to 0.05 degrees) sea floor. Our work shows that initially well-mixed and highly erosive submarine flows can produce extensive debris flow deposits beyond subtle slope breaks located far out in the deep ocean.
Air blast injuries killed the crew of the submarine H.L. Hunley.
Lance, Rachel M; Stalcup, Lucas; Wojtylak, Brad; Bass, Cameron R
2017-01-01
The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb) black powder torpedo at a distance less than 5 m (16 ft) off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull.
Air blast injuries killed the crew of the submarine H.L. Hunley
Stalcup, Lucas; Wojtylak, Brad; Bass, Cameron R.
2017-01-01
The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb) black powder torpedo at a distance less than 5 m (16 ft) off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull. PMID:28832592
Banning cigarette smoking on US Navy submarines: a case study.
Lando, Harry A; Michaud, Mark E; Poston, Walker S C; Jahnke, Sara A; Williams, Larry; Haddock, Christopher K
2015-10-01
The military has had a long pro-tobacco tradition. Despite official policy discouraging smoking, tobacco still is widely seen as part of military culture. While active smoking has presented a particular challenge for the military, in recent years there also has been increasing concern with secondhand smoke. This is especially true in closed environments and submarines may be deployed for months at a time. The current case study describes the successful implementation by the Navy of a comprehensive ban on smoking aboard submarines. The authors searched documents on the internet, popular media, military-based news outlets and the scientific literature. We also conducted interviews with Navy officers who were instrumental in policy implementation. Data demonstrating substantial exposure of non-smokers to tobacco smoke aboard submarines had major impact on successful adoption of the policy. A systematic and extended roll out of the ban included establishing a working group, soliciting input and active engagement from submarine personnel, and offering cessation assistance. Support was enlisted from Chief Petty Officers who could have been strongly opposed but who became strong proponents. Fewer problems were encountered than had been expected. In contrast to a previous unsuccessful attempt by a Navy captain to ban smoking on his ship, the ban was adopted without apparent tobacco industry interference. Lessons learned included the importance of strong empirical support, effective framing of the issue, setting a realistic timeline, soliciting support from key personnel and providing appropriate resources. These lessons have implications for those considering further tobacco policy changes in the military and elsewhere. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
Hodges, Tyler W; Olson, Julie B
2009-03-01
Iron oxide sheaths and filaments are commonly found in hydrothermal environments and have been shown to have a biogenic origin. These structures were seen in the flocculent material associated with two submarine volcanoes along the Kermadec Arc north of New Zealand. Molecular characterization of the bacterial communities associated with the flocculent samples indicated that no known Fe-oxidizing bacteria dominated the recovered clone libraries. However, clones related to the recently described Fe-oxidizing bacterium Mariprofundus ferrooxydans were obtained from both the iron-containing flocculent (Fe-floc) and sediment samples, and peaks corresponding to Mariprofundus ferrooxydans, as well as the related clones, were observed in several of our terminal restriction fragment length polymorphism profiles. A large group of epsilonproteobacterial sequences, for which there is no cultured representative, dominated clones from the Fe-floc libraries and were less prevalent in the sediment sample. Phylogenetic analyses indicated that several operational taxonomic units appeared to be site specific, and statistical analyses of the clone libraries found that all samples were significantly different from each other. Thus, the bacterial communities in the Fe-floc samples were not more closely related to each other than to the sediment communities.
NASA Astrophysics Data System (ADS)
Wang, Shujie; Li, Huaiming; Zhai, Shikui; Yu, Zenghui; Cai, Zongwei
2017-12-01
mainly attributed to precipitating directly from the hydrothermal fluid, while those collected from the extinct hydrothermal chimney might have already been altered by the seawater. Generally, ore-forming elements in the sulfides can be divided into three groups: Fe-based element group, Cu-based element group and Zn-based element group. The first group includes Fe, Mn, Cr, Mo, Sn, Rb and bio-enriching elements, such as P and Si, reflecting the similar characteristics to Fe in the study area. And the second group contains Cu, W, Co, Se, Te and Bi, suggesting the similar behavior with Cu. Moreover, the third group includes Zn, Hf, Hg, Cd, Ta, Ga, Pb, As, Ag, Ni and Sb, which indicates the geochemical characteristics of most dispersed trace elements controlled by Zn-bearing minerals to some extent.
Positron Spectroscopy of Hydrothermally Grown Actinide Oxides
2014-03-27
POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS Edward C. Schneider...United States Government. AFIT-ENP-14-M-33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES THESIS...33 POSITRON SPECTROSCOPY OF HYDROTHERMALLY GROWN ACTINIDE OXIDES Edward C. Schneider, BS Captain, USAF Approved
History of Military Psychology at the U. S. Naval Submarine Medical Research Laboratory
1979-10-23
g ,,- .. ................................. "~VV*4 SUMMARY PAGE THE PRO13LEM To present a descriptive chronicle of events associated with the...the first nuclear submarine, were gigantic increases in the environmental demands imposed upon the submarine crewmembers. Some of these changes had to...34sub" mission at that time (1956), tended to exonerate airborne toxins in the ambient atmosphere of the "sub" as a major etiological agent. 9o. S[9
Dynamics of the Yellowstone hydrothermal system
Hurwitz, Shaul; Lowenstern, Jacob B.
2014-01-01
The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a hydrothermal system that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and hydrothermal 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 hydrothermal system 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 hydrothermal system. Specific advances include more refined geophysical images of the magmatic system, 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 hydrothermal explosions and their relation to glacial cycles, defining possible links between hydrothermal activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive hydrothermal activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.
Synthesis, characterization and electrocatalytic properties of delafossite CuGaO2
NASA Astrophysics Data System (ADS)
Ahmed, Jahangeer; Mao, Yuanbing
2016-10-01
Delafossite CuGaO2 has been employed as photocatalysts for solar cells, but their electrocatalytic properties have not been extensively studied, especially no comparison among samples made by different synthesis routes. Herein, we first reported the successful synthesis of delafossite CuGaO2 particles with three different morphologies, i.e. nanocrystalline hexagons, sub-micron sized plates and micron-sized particles by a modified hydrothermal method at 190 °C for 60 h [1-3], a sono-chemical method followed by firing at 850 °C for 48 h, and a solid state route at 1150 °C, respectively. Morphology, composition and phase purity of the synthesized samples was confirmed by powder X-ray diffraction and Raman spectroscopic studies, and then their electrocatalytic performance as active and cost effective electrode materials to the oxygen and hydrogen evolution reactions in 0.5 M KOH electrolyte versus Ag/AgCl was investigated and compared under the same conditions for the first time. The nanocrystalline CuGaO2 hexagons show enhanced electrocatalytic activity than the counterpart sub-micron sized plates and micron-sized particles.
Submarine slope failures due to pipe structure formation.
Elger, Judith; Berndt, Christian; Rüpke, Lars; Krastel, Sebastian; Gross, Felix; Geissler, Wolfram H
2018-02-19
There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.
NASA Astrophysics Data System (ADS)
Idarraga Garcia, J.; Vargas-Jimenez, C. A.
2013-05-01
We analyzed ~17000 km2 of high-resolution-bathymetric data in the southwestern Caribbean Sea of Colombia between the La Aguja Submarine Canyon (LASC) and the Gulf of Urabá. The data allowed us to identify and describe submarine landslides and to calculate their ages based on scarp dating by using numerical solutions of the diffusion equation. The ages are presented in terms of the constant k of diffusivity due to the absence of well constrained values for submarine environments. In the northeastern sector of the study area we differentiated 31 submarine failures associated with the LASC flanks, between 1200 and 3285 m depth, with escarpments slopes ranging between 6.1° and 36.8°; estimated ages suggest ranges between ~407 and ~103.5 k (m2). Triggering mechanisms of these landslides are close related to the occurrence of earthquakes originated in the convergence zone of the Santa Marta and Oca fault systems, and to the flanks instabilities product of the mud diapirism phenomena that is present in the area. In the central sector of the study zone, the continental margin is dominated by the presence of the Magdalena Submarine Fan (MSF). Here, most of the submarine failures are disintegrative (i.e. with no obvious deposit near or at the base of the scar) and all are related to a system of canyons belonging to the Magdalena turbidite system and to an abrupt slope break at the border of the continental shelf. Scarp dating suggests a wide range of ages fluctuating between ~207.1 and ~146427.8 k (m2). Landslides at southernmost sector of the study zone are mainly associated to anticline-related ridges of the Sinú Accretionary Prism. These ridges are structural highs cut by channels and canyons, and are associated with slopes of 10°-25°. In many cases, the failures are disintegrative and it is probable that the associated landslide deposits are buried by subsequent sediments related to broad fans forming in the mouth of channels and canyons. Additionally, some
Simple models for the simulation of submarine melt for a Greenland glacial system model
NASA Astrophysics Data System (ADS)
Beckmann, Johanna; Perrette, Mahé; Ganopolski, Andrey
2018-01-01
Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid-1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with high-resolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating
Health Risks Among Submarine Personnel in the U.S. Navy, 1974-1979
1986-12-11
Storrie, M. C., R. L. Sphar, R. N. Sawyer, and A. S. Evans. 1976. Seroepidemiological studies of Polaris submarine crews. II. Infectious mononucleosis ...and the spread of infectious mononulcleosis (Storrie, Sphar, Sawyer, and Evans, 1976). Also, the confining nature of the submarine, with its constant... Mononucleosis 128 50.7 33.2 68.2 203 73.2 55.2 91.2 0.69 Venereal Diseases 52 19.8 8.2 31.4 119 44.0 30.4 57.7 0.45 NNOI’•iA 316 120.4 73.3 167.5 367 135.6
NASA Astrophysics Data System (ADS)
Spelz, R. M.; Lupton, J. E.; Evans, L. J.; Zierenberg, R. A.; Clague, D. A.; Neumann, F.; Paduan, J. B.
2015-12-01
Numerous submarine deep-sea hydrothermal vents related to volcanic activity of the East Pacific Rise (EPR) are situated along the Pacific margins of Mexico. Until recently, active hydrothermal venting was unknown between the Guaymas Basin and 21°N on the EPR. MBARI's recent oceanographic surveys have added 7 new active vent sites. In this study, we aimed to sample the high-temperature hydrothermal fluids emanating from two distinct vent sites, named Meyibo and Auka, located in the Alarcon Rise and Pescadero Basin, respectively. Mantle-derived He have long been identified in hydrothermal fluid releases. The presence of He in aqueous fluids with 3He/4He ratios greater than in-situ production values (~0.05 RA, where RA = air He or 1.4 x 10-6) indicates the presence of mantle-derived melts. Preliminary analyses of He-isotope ratios derived from the newly discovered Meyibo and Auka hydrothermal fields show high 3He/4He ratios (~8RA), typical of MORB's. Auka vent field, characterized by chimneys composed of light carbonate minerals and oil-like hydrocarbons, and temperatures between 250-290oC, show average values of ~7.87RA. In contrast, the black-smokers at the Meyibo field, composed of dark sulfide minerals and temperatures over 350oC, yielded a higher He ratio of ~8.24RA. Recently, it has become clear that regional maximum mantle He values correlate with the velocity structure in the mantle, therefore, He has the potential to map regions of the underlying mantle that are undergoing partial melting. Seismic records could then be compared with the geochemical He ratio signal and supply information regarding tectonics and other processes involved in the generation of these gases. The data presented here will be completing a totally new inventory of He results from hydrothermal vents in the EPR and fault-termination basins distributed along the P-NA plate boundary in the Gulf of California. The results will be further coupled with the analysis of other geochemical
NASA Astrophysics Data System (ADS)
Sawyer, Derek E.; Reece, Robert S.; Gulick, Sean P. S.; Lenz, Brandi L.
2017-08-01
The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure. This conclusion is supported by shear strength outside of the fan that follow an active margin trend. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking.
The three scales of submarine groundwater flow and discharge across passive continental margins
Bratton, John F.
2010-01-01
Increased study of submarine groundwater systems in recent years has provided a wealth of new data and techniques, but some ambiguity has been introduced by insufficient distinguishing of the relevant spatial scales of the phenomena studied. Submarine groundwater flow and discharge on passive continental margins can be most productively studied and discussed by distinct consideration of the following three spatial scales: (1) the nearshore scale, spanning approximately 0–10 m offshore and including the unconfined surficial aquifer; (2) the embayment scale, spanning approximately 10 m to as much as 10 km offshore and including the first confined submarine aquifer and its terminus; and (3) the shelf scale, spanning the width and thickness of the aquifers of the entire continental shelf, from the base of the first confined aquifer downward to the basement, and including influences of geothermal convection and glacio-eustatic change in sea level.
Go big or die out: Bifurcation and bimodality in submarine sediment flow behaviour
NASA Astrophysics Data System (ADS)
Talling, P.; Paull, C. K.; Lintern, G.; Gwiazda, R.; Cartigny, M.; Hughes Clarke, J. E.; Xu, J.; Clare, M. A.; Parsons, D. R.; Simmons, S.; Maier, K. L.; Gales, J. A.; Hage, S.; McGann, M.; Pope, E.; Rosenberger, K. J.; Stacey, C.; Barry, J.; Lundsten, E. M.; Anderson, K.; O'Reilly, T. C.; Chapplow, N.; Vendettuoli, D.
2017-12-01
Submarine flows of sediment (turbidity currents) flush globally significant volumes of sediment and organic carbon into deep-sea basins. These flows create the largest sediment accumulations on Earth, which hold valuable oil and gas reserves. These flows affect global carbon burial, how deep-sea ecosystems function, and pose a hazard to offshore infrastructure. Only river systems transport such large amounts of sediment across such long distances. However, there are remarkably few direct measurements from active submarine flows, which is a stark contrast to >1 million direct observations from rivers. Here we present unusually detailed information on frequency, power and runout distance of multiple submarine flows at two contrasting locations. The first data set comes from Monterey Canyon, offshore California, which is fed by littoral cells. The second site is a river-fed delta in Bute Inlet, British Columbia. In both cases, the timing and runout distance of submarine flows was documented using instruments on multiple moorings placed along the 50-km long flow pathway. A striking observation is that flow behaviour and runout is strongly bimodal in both locations. Flows tend to either dissipate rapidly, or runout through the entire mooring arrays. We thus test whether i) the character of short or long runout flows can be distinguished at the first mooring and ii) whether long and short runout flows have different triggers. It has been proposed that submarine flows have two modes of behaviour; either eroding and accelerating, or depositing and dissipating. These field data support such a view of bifurcation and bimodality in flow behaviour. However, some short runout flows resemble their longer runout cousins at the first mooring, and there is no clear relationship between flow trigger and runout. Thus, some flows reach a point where their character is no longer dependent on their initial trigger or initial structure, but on factors acting along the flow pathway.
Cau, Alessandro; Alvito, Andrea; Moccia, Davide; Canese, Simonepietro; Pusceddu, Antonio; Rita, Cannas; Angiolillo, Michela; Follesa, Maria C
2017-10-15
By means of ROV surveys, we assessed the quantity, composition and bathymetric distribution of marine litter in 17 sites along the Sardinian continental margin (Central Western Mediterranean) at depths ranging from 100 to 480m. None of the investigated sites was litter free, but the mean density of litter (0.0175±0.0022itemsm -2 ) was lower than that reported from other Tyrrhenian regions. The difference in the total litter density among sites was negligible, but the density of derelict fishing gear (DFG) items (most of which ascribable to small scale fishery) in submarine canyons was higher in submarine canyons than in other habitats. Our result suggest that submarine canyons (known to be highly vulnerable ecosystems) act as major repositories of DFGs, and, therefore, we anticipate the need of specific measures aimed at minimizing the loss and abandonment of DFGs in submarine canyons. Copyright © 2017 Elsevier Ltd. All rights reserved.
Hydrothermal Reactivity of Amines
NASA Astrophysics Data System (ADS)
Robinson, K.; Shock, E.; Hartnett, H. E.; Williams, L. B.; Gould, I.
2013-12-01
The reactivity of aqueous amines depends on temperature, pH, and redox state [1], all of which are highly variable in hydrothermal systems. Temperature and pH affect the ratio of protonated to unprotonated amines (R-NH2 + H+ = R-NH3+), which act as nucleophiles and electrophiles, respectively. We hypothesize that this dual nature can explain the pH dependence of reaction rates, and predict that rates will approach a maximum at pH = pKa where the ratio of protonated and unprotonated amines approaches one and the two compounds are poised to react with one another. Higher temperatures in hydrothermal systems allow for more rapid reaction rates, readily reversible reactions, and unique carbon-nitrogen chemistry in which water acts as a reagent in addition to being the solvent. In this study, aqueous benzylamine was used as a model compound to explore the reaction mechanisms, kinetics, and equilibria of amines under hydrothermal conditions. Experiments were carried out in anoxic silica glass tubes at 250°C (Psat) using phosphate-buffered solutions to observe changes in reaction rates and product distributions as a function of pH. The rate of decomposition of benzylamine was much faster at pH 4 than at pH 9, consistent with the prediction that benzylamine acts as both nucleophile and an electrophile, and our estimate that the pKa of benzylamine is ~5 at 250°C and Psat. Accordingly, dibenzylamine is the primary product of the reaction of two benzylamine molecules, and this reaction is readily reversible under hydrothermal conditions. Extremely acidic or basic pH can be used to suppress dibenzylamine production, which also suppresses the formation of all other major products, including toluene, benzyl alcohol, dibenzylimine, and tribenzylamine. This suggests that dibenzylamine is the lone primary product that then itself reacts as a precursor to produce the above compounds. Analog experiments performed with ring-substituted benzylamine derivatives and chiral
Anthropogenic impacts on deep submarine canyons of the western Mediterranean Sea
NASA Astrophysics Data System (ADS)
Sanchez-Vidal, A.; Tubau, X.; Llorca, M.; Woodall, L.; Canals, M.; Farré, M.; Barceló, D.; Thompson, R.
2016-02-01
Submarine canyons are seafloor geomorphic features connecting the shallow coastal ocean to the deep continental margin and basin. Often considered biodiversity hotspots, submarine canyons have been identified as preferential pathways for water, sediment, pollutant and litter transfers from the coastal to the deep ocean. Here we provide insights on the presence of some of the most insidious man-made debris and substances in submarine canyons of the western Mediterranean Sea, which are relevant to achieve a "Good Environmental Status" by 2020 as outlined in the European Union's ambitious Marine Strategy Framework Directive. Ranked by size on a decreasing basis, we review the origin, distribution and transport mechanisms of i) marine litter, including plastic, lost fishing gear and metallic objects; ii) microplastics in the form of fibers of rayon, polyester, polyamide and acetates; and iii) persistent organic pollutants including the toxic and persistent perfluoroalkyl substances. This integrated analysis allows us to understand the pivotal role of atmospheric driven oceanographic processes occurring in Mediterranean deep canyons (dense shelf water cascading, coastal storms) in spreading any type of man-made compound to the deep sea, where they sink and accumulate before getting buried.
Post-eruptive Submarine Terrace Development of Capelinhos, Azores
NASA Astrophysics Data System (ADS)
Zhongwei Zhao, Will; Mitchell, Neil; Quartau, Rui; Tempera, Fernando; Bricheno, Lucy
2017-04-01
Erosion of the coasts of volcanic islands by waves creates shallow banks, but how erosion proceeds with time to create them and how it relates to wave climate is unclear. In this study, historical and recent marine geophysical data collected around the Capelinhos promontory (western Faial Island, Azores) offer an unusual opportunity to characterize how a submarine terrace developed after the eruption. The promontory was formed in 1957/58 during a Surtseyan eruption that terminated with extensive lava forming new rocky coastal cliffs. Historical measurements of coastline position are supplemented here with coastlines measured from 2004 and 2014 Google Earth images in order to characterize coastline retreat rate and distance for lava- and tephra-dominated cliffs. Swath mapping sonars were used to characterize the submarine geometry of the resulting terrace (terrace edge position, gradient and morphology). Limited photographs are available from a SCUBA dive and drop-down camera deployments to ground truth the submarine geomorphology. The results reveal that coastal retreat rates have decreased rapidly with the time after the eruption, possibly explained by the evolving resistance to erosion of cliff base materials. Surprisingly, coastline retreat rate decreases with terrace width in a simple inverse power law with terrace width. We suspect this is only a fortuitous result as wave attenuation over the terrace will not obviously produce the variation, but nevertheless it shows how rapidly the retreat rate declines. Understanding the relationship between terrace widening shelf and coastal cliff retreat rate may be more widely interesting if they can be used to understand how islands evolve over time into abrasional banks and guyots.
Teske, Andreas; de Beer, Dirk; McKay, Luke J.; Tivey, Margaret K.; Biddle, Jennifer F.; Hoer, Daniel; Lloyd, Karen G.; Lever, Mark A.; Røy, Hans; Albert, Daniel B.; Mendlovitz, Howard P.; MacGregor, Barbara J.
2016-01-01
The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heat flow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for comprehensive surveys of the wider spreading region. PMID:26925032
Hydrothermal Signatures at Gale Crater, Mars, and Possible In-Situ Formation of Tridymite
NASA Astrophysics Data System (ADS)
Yen, A. S.; Morris, R. V.; Gellert, R.; Berger, J. A.; Sutter, B.; Downs, R. T.; Bristow, T.; Treiman, A. H.; Ming, D. W.; Achilles, C.; Blake, D. F.; Chipera, S.; Clark, B. C.; Craig, P.; Morrison, S. M.; Rampe, E. B.; Schmidt, M. E.; Schwenzer, S. P.; Thompson, L. M.; Vaniman, D.
2017-12-01
The occurrence of tridymite, a high temperature SiO2 polymorph definitively identified by the Curiosity rover in the Buckskin mudstone sample at Gale crater, Mars, has been attributed to detrital accumulation of rhyolitic material. This interpretation of a detrital origin is revisited in light of the observation that the tridymite-hosting sediments appear to have interacted with the same fluids that produced alteration halos in the overlying sandstone. The alteration halos in the Stimson sandstone are light-toned, elevated silica zones within 50 cm of a central fracture. They have likely experienced chemical leaching under acidic conditions resulting in depletion of metals (including Al), retention of Ti, formation of amorphous iron sulfates, 50% reduction of the pyroxene:plagioclase ratio, a factor of two increase in the Fe/Mn ratio, and passive enrichment of Si. This alteration is not constrained (nor precluded) to have occurred at elevated temperatures, but there are abundant indicators of hydrothermal activity within Gale crater. High concentrations of Ge, Zn, Ni, Pb, Cu, Se and Ga in a variety of samples analyzed by the Alpha Particle X-ray Spectrometer are indicative of mobility in hydrothermal solutions. Mineralogy of Gale crater samples determined by the CheMin X-ray diffraction instrument includes phases which may be associated with hydrothermal activity (smectites, anhydrite, hematite), but definitive detections of mineral assemblages that are necessarily hydrothermal in origin remain absent. The nearly identical patterns of enriched and depleted elements of the Stimson alteration halos (relative to parent rocks) and the tridymite-bearing unit (relative to typical mudstone samples) require the consideration of co-genetic origins. Cristobalite, a SiO2 polymorph stable above 1470°C found in the Buckskin sample, is known to form in hydrothermal solutions at temperatures well below its stability field (Henderson et al., 1971). Formation of well
Nonentrained circadian rhythms of melatonin in submariners scheduled to an 18-hour day.
Kelly, T L; Neri, D F; Grill, J T; Ryman, D; Hunt, P D; Dijk, D J; Shanahan, T L; Czeisler, C A
1999-06-01
The human circadian timing system has previously been shown to free run with a period slightly longer than 24 h in subjects living in the laboratory under conditions of forced desynchrony. In forced desynchrony, subjects are shielded from bright light and periodic time cues and are required to live on a day length outside the range of circadian entrainment. The work schedule used for most personnel aboard American submarines is 6 h on duty alternating with 12 h off duty. This imposed 18-h cycle is too short for human circadian synchronization, especially given that there is no bright-light exposure aboard submarines. However, crew members are exposed to 24-h stimuli that could mediate synchronization, such as clocks and social contacts with personnel who are living on a 24-h schedule. The authors investigated circadian rhythms of salivary melatonin in 20 crew members during a prolonged voyage on a Trident nuclear submarine. The authors found that in crew members living on the 18-h duty cycle, the endogenous rhythm of melatonin showed an average period of 24.35 h (n = 12, SD = 0.18 h). These data indicate that social contacts and knowledge of clock time are insufficient for entrainment to a 24-h period in personnel living by an 18-h rest-activity cycle aboard a submarine.
Federal Register 2010, 2011, 2012, 2013, 2014
2011-09-15
... National Marine Sanctuaries Final Policy and Permit Guidance for Submarine Cable Projects AGENCY: Office of National Marine Sanctuaries (ONMS), National Oceanic and Atmospheric Administration (NOAA), Department of... Marine Sanctuaries (ONMS) has developed final policy and permitting guidance for submarine cable projects...
NASA Astrophysics Data System (ADS)
Thompson, Patricia M. E.; Kempton, Pamela D.; Kerr, Andrew C.
2008-08-01
Nd and Hf isotope systematics of oceanic basaltic rocks are often assumed to be largely immune to the effects of hydrothermal alteration. We have tested this assumption by comparing Nd and Hf isotope data for acid-leached Cretaceous oceanic basalts from Gorgona and DSDP Leg 15 with unleached data on the same rocks. Hf isotope values and Lu/Hf ratios are relatively unaffected by leaching, but 143Nd/ 144Nd values of leached samples are significantly higher than those of unleached fractions of the same sample in most cases. Furthermore, the Sm/Nd ratios of the majority of leached samples are 10-40% greater than those of unleached samples. X-ray diffraction studies indicate that selective removal of secondary minerals, such as smectite, during the acid leaching process is responsible for the fractionation of Sm/Nd ratios. These results have implications for interpretation of the Hf-Nd isotope systematics of ancient submarine rocks (older than ~ 50 Ma), as (1) the age-corrected 143Nd/ 144Nd ratio may not be representative of the primary magmatic signature and (2) the uncertainty of the age-corrected ɛNd value may exceed the assumed analytical precision.
NASA Astrophysics Data System (ADS)
Duplessis, C. A.; Cullum, M. E.; Crepeau, L. J.
2005-05-01
Submarine watch-standers adhere to a 6 hour-on, 12 hour-off (6/12) watch-standing schedule, yoking them to an 18-hr day, engendering circadian desynchronization and chronic sleep deprivation. Moreover, the chronic social crowding, shift work, and confinement of submarine life provide additional stressors known to correlate with elevated secretory immunoglobulin A (sIgA) and cortisol levels, reduced performance, immunologic dysfunction, malignancies, infections, gastrointestinal illness, coronary disease, anxiety, and depression. We evaluated an alternative, compressed, fixed work schedule designed to enhance circadian rhythm entrainment, sleep hygiene, performance, and health on 10 underway submariners, who followed the alternative and 6/12 schedules for approximately 2 weeks each. We measured subjects" sleep, cognitive performance, and salivary biomarker levels. Pilot analysis of the salivary data on one subject utilizing ELISA suggests elevated biomarker levels of stress. Average PM cortisol levels were 0.2 μg/L (normal range: nondetectable - 0.15 μg/L), and mean sIgA levels were 562 μg/ml (normal range: 100-500 μg/ml). Future research exploiting real-time salivary bioassays, via fluorescent polarimetry technology, identified by the Office of Naval Research (ONR) as a future Naval requirement, allows researchers to address correlations between stress-induced elaboration of salivary biomarkers with physiological and performance decrements, thereby fostering insight into the underway submariner"s psychoimmunological status. This may help identify strategies that enhance resilience to stressors. Specifically, empirically-based modeling can identify optimal watch-standing schedules and stress-mitigating procedures -- within the operational constraints of the submarine milieu and the mission --that foster improved circadian entrainment and reduced stress reactivity, enhancing physiological health, operational performance, safety, and job satisfaction.
ERIC Educational Resources Information Center
Horikoshi, Ryo; Takeiri, Fumitaka; Kobayashi, Yoji; Kageyama, Hiroshi
2016-01-01
We describe an activity that is suitable for high school students and makes use of plastic bottles. This activity allows students to familiarize themselves with gas chemistry by introducing technologies that were applied in old submarine systems. Plastic bottles, which are representative of submarines, are used as reaction vessels. Three simple…
Submarine melt rates under Greenland's ice tongues
NASA Astrophysics Data System (ADS)
Wilson, Nat; Straneo, Fiametta; Heimbach, Patrick; Cenedese, Claudia
2017-04-01
The few remaining ice tongues (ice-shelf like extensions) of Greenland's glaciers are undergoing rapid changes with potential implications for the stability of the ice sheet. Submarine melting is recognized as a major contributor to mass loss, yet the magnitude and spatial distribution of melt are poorly known or understood. Here, we use high resolution satellite imagery to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues: Ryder Glacier, Petermann Glacier and Nioghalvfjerdsbræ (79 North Glacier). We find that submarine plus aerial melt approximately balance the ice flux from the grounded ice sheet for the first two while at Nioghalvfjerdsbræ the total melt flux exceeds the inflow of ice indicating thinning of the ice tongue. We also show that melt rates under the ice tongues vary considerably, exceeding 60 m yr-1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. Using derived melt rates, we test simplified melt parameterizations appropriate for ice sheet models and find the best agreement with those that incorporate ice tongue geometry in the form of depth and slope.
Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar transects
NASA Astrophysics Data System (ADS)
Wadhams, Peter; Hughes, Nick; Rodrigues, JoãO.
2011-08-01
A transect of the Arctic Ocean by the British submarine Tireless in March 2007 enabled the thickness characteristics of the ice cover to be measured during the winter immediately preceding the exceptional retreat of summer 2007. In this paper we report on mean and modal drafts, probability density functions of draft, and the frequency and depth distribution of pressure ridges, and we compare results with those from an earlier submarine cruise in winter 2004 which covered part of the same area. In the region from north of Fram Strait to Ellesmere Island (about 85°N, 0-70°W) we find no change in mean drafts between 2004 and 2007 though there is a change in ice composition, with more ridging in 2007 but a lesser modal draft. This agrees with the observations of younger ice being driven toward Fram Strait in 2007. The region north of Ellesmere Island continues to be a "redoubt" containing more thick deformed multiyear ice than any other part of the transect. In the west the submarine profiled extensively under the SEDNA ice camp at 73°N 145°W. This is in the same location as the 1976 AIDJEX ice camp and a sonar survey done by a U.S. submarine in April 1976. We found that a large decrease in mean draft had occurred (32%) over 31 years and that in 2007 the SEDNA region contained the thinnest ice of any part of the Arctic surveyed by the submarine; this was a region from which the ice completely retreated during the subsequent summer of 2007.
NASA Astrophysics Data System (ADS)
Hay, D. Robert; Brassard, Michel; Matthews, James R.; Garneau, Stephane; Morchat, Richard
1995-06-01
The convergence of a number of contemporary technologies with increasing demands for improvements in inspection capabilities in maritime applications has created new opportunities for ultrasonic inspection. An automated ultrasonic inspection and data collection system APHIUS (automated pressure hull intelligent ultrasonic system), incorporates hardware and software developments to meet specific requirements for the maritime vessels, in particular, submarines in the Canadian Navy. Housed within a hardened portable computer chassis, instrumentation for digital ultrasonic data acquisition and transducer position measurement provide new capabilities that meet more demanding requirements for inspection of the aging submarine fleet. Digital data acquisition enables a number of new important capabilites including archiving of the complete inspection session, interpretation assistance through imaging, and automated interpretation using artificial intelligence methods. With this new reliable inspection system, in conjunction with a complementary study of the significance of real defect type and location, comprehensive new criteria can be generated which will eliminate unnecessary defect removal. As a consequence, cost savings will be realized through shortened submarine refit schedules.
NASA Astrophysics Data System (ADS)
Dai, Shifeng; Nechaev, Victor P.; Chekryzhov, Igor Yu.; Zhao, Lixin; Vysotskiy, Sergei V.; Graham, Ian; Ward, Colin R.; Ignatiev, Alexander V.; Velivetskaya, Tatyana A.; Zhao, Lei; French, David; Hower, James C.
2018-03-01
Clay-altered volcanic ash with highly-elevated concentrations of Nb(Ta), Zr(Hf), rare earth elements (REE), and Ga, is a new type of critical metal deposit with high commercial prospects that has been discovered in Yunnan Province, southwest China. Previous studies showed that the volcanic ashes had been subjected to hydrothermal fluids, the nature of which, however, is not clear. Here we show that the volcanic ashes were originated from alkaline magmatism, followed by a continuous hydrothermal-weathering process. Heated meteoric waters, which were sourced from acidic rains and mixed with CO2 from degassing of the Emeishan plume, have caused partial, but widespread, acidic leaching of Nb, Ta, Zr, Hf, REE, and Ga into ground water and residual enrichment of these elements, along with Al and Ti, in the deeply altered rocks. Subsequent alteration occurring under cooler, neutral or alkaline conditions, caused by water-rock interaction, resulted in precipitation of the leached critical metals in the deposit. Polymetallic mineralization of similar origin may be found in other continental regions subjected to explosive alkaline volcanism associated with deep weathering in humid conditions.
Measurement of Arctic sea-ice thickness by submarine 5 years after SCICEX
NASA Astrophysics Data System (ADS)
Hughes, Nicholas E.; Wadhams, Peter
In April 2004 the Royal Navy submarine HMS Tireless became the first UK submarine to conduct environmental monitoring in the Arctic Ocean since 1996. As the last US SCICEX (Scientific Ice Expeditions) cruise was in 2000, this has been the only opportunity for a civilian scientist to carry out measurement of ice draft and oceanography over a wide area of the Arctic. This paper presents preliminary results and compares them with similar investigations in the 1970s-90s. The route of Tireless covered a large area of the European sector of the Arctic from 5° E to 62° W. Transects were carried out from the marginal ice zone in Fram Strait up to the North Pole and along the 85° N parallel north of Greenland. As part of work for the European Commission IRIS project, image intensity from the advanced synthetic aperture radar instrument on the European Space Agency's Envisat satellite has been compared with ice draft from the submarine. The raw data were found to be highly variable, so a moving average was applied, producing a correlation of 0.79. Tireless carried a full oceanographic sensor suite and expendable probes for investigation into changes in the Arctic Ocean. The results from these show further erosion of the Arctic cold halocline layer by advancing Atlantic Water compared to previous climatologies and fieldwork expeditions. Preliminary ice-draft data from 85° N show deeper ice keels than those encountered by a submarine on the same route in 1987.
Sugitani, K; Mimura, K; Takeuchi, M; Yamaguchi, T; Suzuki, K; Senda, R; Asahara, Y; Wallis, S; Van Kranendonk, M J
2015-11-01
The 3.4-Ga Strelley Pool Formation (SPF) at the informally named 'Waterfall Locality' in the Goldsworthy greenstone belt of the Pilbara Craton, Western Australia, provides deeper insights into ancient, shallow subaqueous to possibly subaerial ecosystems. Outcrops at this locality contain a thin (<3 m) unit of carbonaceous and non-carbonaceous cherts and silicified sandstones that were deposited in a shallow-water coastal environment, with hydrothermal activities, consistent with the previous studies. Carbonaceous, sulfide-rich massive black cherts with coniform structures up to 3 cm high are characterized by diverse rare earth elements (REE) signatures including enrichment of light [light rare earth elements (LREE)] or middle rare earth elements and by enrichment of heavy metals represented by Zn. The massive black cherts were likely deposited by mixing of hydrothermal and non-hydrothermal fluids. Coniform structures in the cherts are characterized by diffuse laminae composed of sulfide particles, suggesting that unlike stromatolites, they were formed dominantly through physico-chemical processes related to hydrothermal activity. The cherts yield microfossils identical to previously described carbonaceous films, small and large spheres, and lenticular microfossils. In addition, new morphological types such as clusters composed of large carbonaceous spheroids (20-40 μm across each) with fluffy or foam-like envelope are identified. Finely laminated carbonaceous cherts are devoid of heavy metals and characterized by the enrichment of LREE. This chert locally contains conical to domal structures characterized by truncation of laminae and trapping of detrital grains and is interpreted as siliceous stromatolite formed by very early or contemporaneous silicification of biomats with the contribution of silica-rich hydrothermal fluids. Biological affinities of described microfossils and microbes constructing siliceous stromatolites are under investigation. However, this
The solubility of gallium oxide in vapor and two-phase fluid filtration in hydrothermal systems
NASA Astrophysics Data System (ADS)
Bychkov, Andrew; Matveeva, Svetlana; Nekrasov, Stanislav
2010-05-01
The solubility of gallium and aluminum oxides in gas phase in the system Ga2O3 (Al2O3)-HCl-H2O was studied at 150-350°C and pressure up to saturated vapor. The concentration of gallium increases with the increasing of HCl pressure. The formulae of gallium gaseous specie was determined as GaOHCl2. The constant of gallium oxide solubility reaction was calculated at 150, 200, 250, 300 and 350°C. The concentration of aluminum in gas phase is insignificant in the same conditions. The possibility of gallium transportation in gas phase with small quantity of Al allow to divide this elements in hydrothermal processes with gas phase. The Ga/Al ratio in muscovite can be used as the indicator of gas phase separation and condensation. This indicator was not considered in the geochemical literature earlier. The separation of gas and liquid phases was determined in Akchatau (Kazahstan) and Spokoinoe (Russia) greisen W deposit by carbon isotope fractionation of carbon dioxide in fluid inclusion. The important feature of both ore mains is heterogenization and boiling of ore-forming fluids. Greisen ore bodies are formed as a result of strongly focused solution flow in the T-P gradient fields. It is possible to divide ore bodies of Akchatau in two types: muscovite and quartz. Muscovite type veins are thin and have small metasyntactic zone. Quartz type veins are localized in fault with large vertical extent (500 m) and content the large quantity of wolframite. These veins formed in condition of significant pressure decreasing from 2.5 to 0.5 kbar with fluid boiling. Gas and liquid phase separation specifies the vertical zonality of quartz type veins. The gas phase with the high gallium concentration is separated from a flow of liquid phase. Liquid phase react with the granites forming greisen metasomatites. Condensation of the gas phase in upper parts of massive produces the increasing of Ga/Al ratio in muscovite 3-5 times more, then in granites and bottom part of vein (from 2×10
2016-04-05
Navy Ohio Replacement (SSBN[ X ]) Ballistic Missile Submarine Program: Background and Issues for Congress Ronald O’Rourke Specialist in Naval...Affairs April 5, 2016 Congressional Research Service 7-5700 www.crs.gov R41129 Navy Ohio Replacement (SSBN[ X ]) Ballistic Missile Submarine...as the SSBN( X ) program, as the Navy’s top priority program. The Navy wants to procure the first Ohio replacement boat in FY2021, and the $773.1
Analysis of health data from 10 years of Polaris submarine patrols.
Tansey, W A; Wilson, J M; Schaefer, K E
1979-01-01
Medical reports from 885 Fleet Ballistic Missile (FBM) submarine patrols (7,650,000 man-days) were analyzed. The data were categorized and compared with data obtained by medical personnel from surface fleet personnel (1,215,918 man-days) during a continuous 7--8 months' deployment of surface vessels in 1973. Surface fleet personnel had a higher illness rate in the categories of respiratory, traumatic, gastrointestinal, dermal, infections, and miscellaneous illness, and a lower rate in genitourinary, systemic (including mononucleosis), cranial, and neuropsychiatric illness compared to submarine personnel. Because of improved atmosphere control, a sharp decline in the level of submarine contaminants occurred between 1965--67. Reports from the 1968--73 period showed a decrease in: 1) respiratory; 2) ear, nose, and throat; 3) gastrointestinal; 4) cardiovascular; 5) urologic; and 6) general medical illness categories; the number of general surgery, orthopedics, dental, and eye illness cases was not affected. Neurologic and psychiatric disease showed the only increases in incidence for this period. The overall decrease in illness can be attributed mainly to the fall in the incidence of respiratory disease, known to be affected by reduced air pollution, and the decline in gastrointestinal illness. This decline occurred in a period during which the incidence of both classes of illness went up in the general population, according to the Health Interview Survey published by DHEW. The improvement of atmosphere control in submarines caused a substantial reduction in contaminants (a decline in tobacco smoking also occurred in this period), which led to a decrease in incidence of illness, particularly respiratory disease. No direct causal relationship between reduction in air pollution and reduction in the incidence of disease could be proven within the framework of this study, however.
Hemispherical Field-of-View Above-Water Surface Imager for Submarines
NASA Technical Reports Server (NTRS)
Hemmati, Hamid; Kovalik, Joseph M.; Farr, William H.; Dannecker, John D.
2012-01-01
A document discusses solutions to the problem of submarines having to rise above water to detect airplanes in the general vicinity. Two solutions are provided, in which a sensor is located just under the water surface, and at a few to tens of meter depth under the water surface. The first option is a Fish Eye Lens (FEL) digital-camera combination, situated just under the water surface that will have near-full- hemisphere (360 azimuth and 90 elevation) field of view for detecting objects on the water surface. This sensor can provide a three-dimensional picture of the airspace both in the marine and in the land environment. The FEL is coupled to a camera and can continuously look at the entire sky above it. The camera can have an Active Pixel Sensor (APS) focal plane array that allows logic circuitry to be built directly in the sensor. The logic circuitry allows data processing to occur on the sensor head without the need for any other external electronics. In the second option, a single-photon sensitive (photon counting) detector-array is used at depth, without the need for any optics in front of it, since at this location, optical signals are scattered and arrive at a wide (tens of degrees) range of angles. Beam scattering through clouds and seawater effectively negates optical imaging at depths below a few meters under cloudy or turbulent conditions. Under those conditions, maximum collection efficiency can be achieved by using a non-imaging photon-counting detector behind narrowband filters. In either case, signals from these sensors may be fused and correlated or decorrelated with other sensor data to get an accurate picture of the object(s) above the submarine. These devices can complement traditional submarine periscopes that have a limited field of view in the elevation direction. Also, these techniques circumvent the need for exposing the entire submarine or its periscopes to the outside environment.
NASA Astrophysics Data System (ADS)
Fornari, D. J.; Kurz, M. D.; Geist, D. J.; Johnson, P. D.; Peckman, U. G.; Scheirer, D.
2001-12-01
The submarine flanks of oceanic volcanoes are dynamic environments that reflect the history of volcanic construction and mass-wasting. The submarine slopes of the Galápagos had only been investigated during two modern research cruises - the 1990 PLUME 2 cruise and during the 2000 AHA-Nemo cruise. These data provide the backdrop for a recent sonar mapping and dredging cruise, carried out in Aug-Sept., 2001 on board R/V Revelle, over the southwestern and western edge of the Galápagos platform. The survey included detailed MR1 side-scan sonar imagery (gridded at 8 m pixel resolution) and EM120 multibeam bathymetry (gridded at 100 m pixel resolution), which provided the basis for detailed dredging and towed camera investigations of the submarine flanks of Fernandina and Isabela. The principal geologic provinces delineated by the MR1 sonar imagery include submarine rift zones, major landslides between the rifts, and inferred young lava flows at 3000-3500 m depth located 10-20 km west of the islands. Prominent submarine terraces extend for tens of kilometers along the platform edge south of Isabela and west of Floreana, and in the bight between Fernandina and Cerro Azul volcanoes. The depth range for the terraces is variable between 2000-3300 m. Galápagos submarine rift zones are characterized by mottled backscatter reflectivity seen elsewhere on seamounts, Hawaiian submarine rifts, and the mid-ocean ridge, and are interpreted as constructional submarine volcanic terrain comprising pillow and lobate lava. Extensive spatial variability in acoustic contrast is visible in the MR1 sonar data and is interpreted as complex inter-fingering of submarine eruptive units. These areas of presumably young, high reflectivity flows are located away from the submarine rifts and appear to overlie sediment. These flows cover distances as great as ~10-15 km and are located 10-20 km from the nearest coastline. These large submarine flows may relate to large subaerial events such as the
NASA Astrophysics Data System (ADS)
Nugroho, W. H.; Purnomo, N. J. H.; Soedarto, T.
2016-11-01
This paper presents an experimental work to monitor the health of submarine hull structures using strain sensors and wireless communication technology. The monitored - submarine hull was built in a hydro elastic model scale 1: 30 with a steel bar backbone and tested on water tank of Indonesian Hydrodynamic Laboratory (IHL). Specifically, this health monitoring system for the submarine model was developed using wireless modems, data communication software and conventional strain sensors. This system was used to monitor the loads on a steel bar backbone of the running submarine model from the edge of the water tank. Commands were issued from a notebook to instruct the health monitoring system to acquire data from sensors mounted externally to the steel bar. Data from measurements made on the structure are then transmitted wirelessly back to a notebook computer for processing and analysis. The results of the tank test have been validated and showed no loss of communication signal over an area of the tank. This work also presents a potential use of involving complete automation of this system with an in-service structure coupled with an on-line warning/damage detection capability.
NASA Astrophysics Data System (ADS)
Lau, A. Y. Annie; Terry, James P.; Ziegler, Alan; Pratap, Arti; Harris, Daniel
2018-02-01
The characteristics of a reef-top boulder field created by a local submarine landslide tsunami are presented for the first time. Our examination of large reef-derived boulders deposited by the 1953 tsunami near Suva City, Fiji, revealed that shorter-than-normal-period tsunami waves generated by submarine landslides can create a boulder field resembling a storm boulder field due to relatively short boulder transport distances. The boulder-inferred 1953 tsunami flow velocity is estimated at over 9 m s- 1 at the reef edge. Subsequent events, for example Cyclone Kina (1993), appear to have remobilised some large boulders. While prior research has demonstrated headward retreat of Suva Canyon in response to the repeated occurrence of earthquakes over the past few millennia, our results highlight the lingering vulnerability of the Fijian coastlines to high-energy waves generated both in the presence (tsunami) and absence (storm) of submarine failures and/or earthquakes. To explain the age discrepancies of U-Th dated coral comprising the deposited boulders, we introduce a conceptual model showing the role of repeated episodes of tsunamigenic submarine landslides in removing reef front sections through collapse. Subsequent high-energy wave events transport boulders from exposed older sections of the reef front onto the reef where they are deposited as 'new' boulders, alongside freshly detached sections of the living reef. In similar situations where anachronistic deposits complicate the deposition signal, age-dating of the coral boulders should not be used as a proxy for determining the timing of the submarine landslides or the tsunamis that generated them.
Forrest, Matthew J.; Ledesma-Vazquez, Jorge; Ussler, William; Kulongoski, Justin T.; Hilton, David R.; Greene, H. Gary
2005-01-01
We investigated hydrothermal gas venting associated with a coastal fault zone along the western margin of Bahía Concepción, B.C.S., México. Copious discharge of geothermal liquid (≈ 90 °C) and gas is occurring in the intertidal and shallow subtidal zones (to a depth of 13 m) through soft sediments and fractures in rocks along a ∼750 m linear trend generally sub-parallel to an onshore fault near Punta Santa Barbara. Hydrothermal activity shows negative correlation with tidal height; temperatures in the area of hydrothermal activity were up to 11.3 °C higher at low tide than at high tide (measured tidal range ≈ 120 cm). Gas samples were collected using SCUBA and analyzed for chemical composition and stable isotope values. The main components of the gas are N2 (≈ 53%; 534 mmol/mol), CO2 (≈ 43%; 435 mmol/mol), and CH4 (≈ 2.2%; 22 mmol/mol). The δ13C values of the CH4 (mean = − 34.3‰), and the ratios of CH4 to C2H6(mean = 89), indicate that the gas is thermogenic in origin. The carbon stable isotopes and the δ15N of the N2 in the gas (mean = 1.7‰) suggest it may be partially derived from the thermal alteration of algal material in immature sedimentary organic matter. The He isotope ratios (3He / 4He = 1.32 RA) indicate a significant mantle component (16.3%) in the gas. Here, we suggest the name El Requesón fault zone for the faults that likely formed as a result of extension in the region during the late Miocene, and are currently serving as conduits for the observed hydrothermal activity.
They Have Not Yet Begun to Fight: Women in the United States Navy Submarine Fleet
2016-03-11
culture. Cost to modify submarines, fear of disciplinary issues, and potential health concerns and readiness due to pregnancy are historic...in the submarine fleet may be the immediate health concerns resulting from pregnancy . Current Navy policy states that female Sailors must notify...their chain of command within two weeks of receiving confirmation of pregnancy . Servicewomen are then allowed to remain on board while the ship is in
Biogeochemistry of hydrothermally and adjacent non-altered soils
USDA-ARS?s Scientific Manuscript database
As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized seven pedons, developed in hydrothermally and adjacent non-hydrothermally altered andesitic parent material near Reno, NV. Hydrothermally altered soils had considerably lo...
EAARL Submarine Topography - Northern Florida Keys Reef Tract
Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Travers, Laurinda J.; Wilson, Iris
2007-01-01
This Web site contains 32 Lidar-derived bare earth topography maps and GIS files for the Northern Florida Keys Reef Tract. These lidar-derived submarine topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, Florida, the National Park Service (NPS) South Florida/Caribbean Network Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs and barrier islands for the purposes of geomorphic change studies, habitat mapping, ecological monitoring, change detection, and event assessment. As part of this project, data from an innovative instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Airborne Advanced Research Lidar (EAARL) are being used. This sensor has the potential to make significant contributions in this realm for measuring subaerial and submarine topography wthin cross-environment surveys. High spectral resolution, water-column correction, and low costs were found to be key factors in providing accurate and affordable imagery to costal resource managers.
Characteristics of Hydrothermal Mineralization in Ultraslow Spreading Ridges
NASA Astrophysics Data System (ADS)
Zhou, H.; Yang, Q.; Ji, F.; Dick, H. J.
2014-12-01
Hydrothermal activity is a major component of the processes that shape the composition and structure of the ocean crust, providing a major pathway for the exchange of heat and elements between the Earth's crust and oceans, and a locus for intense biological activity on the seafloor and underlying crust. In other hand, the structure and composition of hydrothermal systems are the result of complex interactions between heat sources, fluids, wall rocks, tectonic controls and even biological processes. Ultraslow spreading ridges, including the Southwest Indian Ridge, the Gakkel Ridge, are most remarkable end member in plate-boundary structures (Dick et al., 2003), featured with extensive tectonic amagmatic spreading and frequent exposure of peridotite and gabbro. With intensive surveys in last decades, it is suggested that ultraslow ridges are several times more effective than faster-spreading ridges in sustaining hydrothermal activities. This increased efficiency could attributed to deep mining of heat and even exothermic serpentinisation (Baker et al., 2004). Distinct from in faster spreading ridges, one characteristics of hydrothermal mineralization on seafloor in ultraslow spreading ridges, including the active Dragon Flag hydrothermal field at 49.6 degree of the Southwest Indian Ridge, is abundant and pervasive distribution of lower temperature precipitated minerals ( such as Fe-silica or silica, Mn (Fe) oxides, sepiolite, pyrite, marcasite etc. ) in hydrothermal fields. Structures formed by lower temperature activities in active and dead hydrothermal fields are also obviously. High temperature precipitated minerals such as chalcopyrite etc. are rare or very limited in hydrothermal chimneys. Distribution of diverse low temperature hydrothermal activities is consistence with the deep heating mechanisms and hydrothermal circulations in the complex background of ultraslow spreading tectonics. Meanwhile, deeper and larger mineralization at certain locations along the
NASA Astrophysics Data System (ADS)
Manikyamba, C.; Said, Nuru; Santosh, M.; Saha, Abhishek; Ganguly, Sohini; Subramanyam, K. S. V.
2018-05-01
Phanerozoic boninites record enrichments of U over Th, giving Th/U: 0.5-1.6, relative to intraoceanic island arc tholeiites (IAT) where Th/U averages 2.6. Uranium enrichment is attributed to incorporation of shallow, oxidized fluids, U-rich but Th-poor, from the slab into the melt column of boninites which form in near-trench to forearc settings of suprasubduction zone ophiolites. Well preserved Archean komatiite-tholeiite, plume-derived, oceanic volcanic sequences have primary magmatic Th/U ratios of 4.4-3.6, and Archean convergent margin IAT volcanic sequences, having REE and HFSE compositions similar to Phanerozoic IAT equivalents, preserve primary Th/U of 4-3.6. The best preserved Archean boninites of the 3.0 Ga Olondo and 2.7 Ga Gadwal greenstone belts, hosted in convergent margin ophiolite sequences, also show relative enrichments of U over Th, with low average Th/U ∼3 relative to coeval IAT, and Phanerozoic counterparts which are devoid of crustal contamination and therefore erupted in an intraoceanic setting, with minimal contemporaneous submarine hydrothermal alteration. Later enrichment of U is unlikely as Th-U-Nb-LREE patterns are coherent in these boninites whereas secondary effects induce dispersion of Th/U ratios. The variation in Th/U ratios from Archean to Phanerozoic boninites of greenstone belts to ophiolitic sequences reflect on genesis of boninitic lavas at different tectono-thermal regimes. Consequently, if the explanation for U enrichment in Phanerozoic boninites also applies to Archean examples, the implication is that U was soluble in oxygenated Archean marine water up to 600 Ma before the proposed great oxygenation event (GOE) at ∼2.4 Ga. This interpretation is consistent with large Ce anomalies in some hydrothermally altered Archean volcanic sequences aged 3.0-2.7 Ga.
NASA Astrophysics Data System (ADS)
John, D. A.; Breit, G. N.; Sisson, T. W.; Vallance, J. W.; Rye, R. O.
2005-12-01
Mount Rainier is the result of episodic stages of edifice growth during periods of high eruptive activity and edifice destruction during periods of relative magmatic quiescence over the past 500 kyr. Edifice destruction occurred both by slow erosion and by catastrophic collapses, some of which were strongly influenced by hydrothermal alteration. Several large-volume Holocene debris-flow deposits contain abundant clasts of hydrothermally altered rocks, most notably the 4-km3 clay-rich Osceola Mudflow which formed by collapse of the northeast side and upper 1000+ m of the edifice about 5600 ya and flowed >120 km downstream into Puget Sound. Mineral assemblages and stable isotope data of hydrothermal alteration products in Holocene debris-flow deposits indicate formation in distinct hydrothermal environments, including magmatic-hydrothermal, steam-heated (including a large fumarolic component), magmatic steam (including a possible fumarolic component), and supergene. The Osceola Mudflow and phreatic components of coeval tephras contain the highest-temperature and inferred most deeply formed alteration minerals; assemblages include magmatic-hydrothermal quartz-alunite, quartz-topaz, quartz-pyrophyllite and quartz-illite (all +pyrite), in addition to steam-heated opal-alunite-kaolinite and abundant smectite-pyrite. In contrast, the Paradise lahar, which formed by a collapse of the surficial upper south side of the edifice, contains only steam-heated assemblages including those formed largely above the water table from condensation of fumarolic vapor (opal-alunite-jarosite). Younger debris-flow deposits on the west side of the volcano (Round Pass lahar and Electron Mudflow) contain only smectite-pyrite alteration, whereas an early 20th century rock avalanche on Tahoma Glacier also contains magmatic-hydrothermal alteration that is exposed in the avalanche headwall of Sunset Amphitheater. Mineralogy and isotopic composition of the alteration phases, geologic and
NASA Astrophysics Data System (ADS)
Lackschewitz, K. S.; Devey, C. W.; Stoffers, P.; Botz, R.; Eisenhauer, A.; Kummetz, M.; Schmidt, M.; Singer, A.
2004-11-01
During ODP Leg 193, 4 sites were drilled in the active PACMANUS hydrothermal field on the crest of the felsic Pual Ridge to examine the vertical and lateral variations in mineralization and alteration patterns. We present new data on clay mineral assemblages, clay and whole rock chemistry and clay mineral strontium and oxygen isotopic compositions of altered rocks from a site of diffuse low-temperature venting (Snowcap, Site 1188) and a site of high-temperature venting (Roman Ruins, Site 1189) in order to investigate the water-rock reactions and associated elemental exchanges. The volcanic succession at Snowcap has been hydrothermally altered, producing five alteration zones: (1) chlorite ± illite-cristobalite-plagioclase alteration apparently overprinted locally by pyrophyllite bleaching at temperatures of 260-310°C; (2) chlorite ± mixed-layer clay alteration at temperatures of 230°C; (3) chlorite and illite alteration; (4) illite and chlorite ± illite mixed-layer alteration at temperatures of 250-260°C; and (5) illite ± chlorite alteration at 290-300°C. Felsic rocks recovered from two holes (1189A and 1189B) at Roman Ruins, although very close together, show differing alteration features. Hole 1189A is characterized by a uniform chlorite-illite alteration formed at ˜250°C, overprinted by quartz veining at 350°C. In contrast, four alteration zones occur in Hole 1189B: (1) illite ± chlorite alteration formed at ˜300°C; (2) chlorite ± illite alteration at 235°C; (3) chlorite ± illite and mixed layer clay alteration; and (4) chlorite ± illite alteration at 220°C. Mass balance calculations indicate that the chloritization, illitization and bleaching (silica-pyrophyllite assemblages) alteration stages are accompanied by different chemical changes relative to a calculated pristine precursor lava. The element Cr appears to have a general enrichment in the altered samples from PACMANUS. The clay concentrate data show that Cr and Cu are predominantly
Bertocci, Gina; Souza, Aaron L; Szobota, Stephanie
2003-01-01
Many wheelchair users must travel in motor vehicles while seated in their wheelchairs. The safety features of seat assemblies are key to motor vehicle occupant crash protection. Seating system properties such as strength, stiffness, and energy absorbance have been shown to have significant influence on risk of submarining. This study investigated the effects of wheelchair seat stiffness and energy absorption properties on occupant risk of submarining during a frontal motor vehicle 20 g/30 mph impact using a validated computer crash simulation model. The results indicate that wheelchair-seating stiffness and energy absorption characteristics influence occupant kinematics associated with the risk of submarining. Softer seat surfaces and relatively high energy absorption/permanent deformation were found to produce pelvis excursion trajectories associated with increased submarining risk. Findings also suggest that the current American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America (ANSI/RESNA) WC-19 seating integrity may not adequately assess submarining risk.
NASA Astrophysics Data System (ADS)
Bindeman, I. N.; Serebryakov, N. S.
2011-06-01
This paper deals with strongly 18O-depleted (down to - 27.3‰ VSMOW) 1.9Ga Paleoproterozoic mid-grade metamorphic rocks found in the Belomorian Belt of Karelia (E. Baltic Shield). The protolith of these rocks is attributed to have been altered by glacial meltwaters during the world's first 2.4-2.3 Ga Paleoproterozoic "Slushball" glaciation, when Karelia was located near equatorial latitudes. We describe in detail three and report seven new localities with unusually depleted 18O signatures that now span 220 km across the Belomorian Belt. Hydrogen isotope ratios measured in amphibole, biotite and staurolite also display remarkably low values of - 212 to - 235‰. Isotope mapping in the three best exposed localities has allowed us to identify the world's most 18O depleted rock, located at Khitostrov with a δ 18O value - 27‰. In Khitostrov samples, zircons have normal δ 18O detrital cores and low-δ 18O metamorphic rims. Mapping demonstrates that zones of δ 18O depletion occur in a concentric pattern 100-400 m in dimension, and each locality displays significant δ 18O and δD heterogeneity on a meter to centimeter scale, characteristic of meteoric-hydrothermal systems worldwide. The zone of maximum δ 18O depletions usually has the highest concentration of metamorphic corundum, rutile, and zircon and also display doubled concentrations of insoluble trace elements (Zr, Ti, Cr, HREE). These results are explained by elemental enrichment upon mass loss during hydrothermal dissolution in pH-neutral meteoric fluid. Remarkably low-δ 18O and δD values suggest that alteration could have only happened by glacial meltwaters in a subglacial rift zone. Many localities with δ 18O depletions occur inside metamorphozed 2.4 Ga gabbro-noritic intrusions, or near their contact with Belomorian gneisses, implying that the intrusions were driving meteoric hydrothermal systems during the known 2.4 Ga episode of Belomorian rifting. Given that the isotopically-depleted localities now
NASA Astrophysics Data System (ADS)
Liang, Jing; Yu, Jian-xing; Yu, Yang; Lam, W.; Zhao, Yi-yu; Duan, Jing-hui
2016-06-01
Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.
NASA Astrophysics Data System (ADS)
Pazos, Antonio; Martín Davila, José; Buforn, Elisa; Jesús García Fernández, Maria; Bullón, Mercedes; Gárate, Jorge
2010-05-01
The Eurasian-African plate boundary crosses the called "Ibero-Maghrebian" region from San Vicente Cape (SW Portugal) to Tunisia including the South of Iberia, Alboran Sea, and northern of Morocco and Algeria. The low convergence rate at this plate boundary produces a continuous moderate seismic activity of low magnitude and shallow depth, where the occurrence of large earthquakes is separated by long time intervals. In this region, there are also intermediate and very deep earthquakes. Since more than hundred years ago San Fernando Naval Observatory (ROA), in collaboration with other Institutes, has deployed different geophysical and geodetic equipment in the Southern Spain - North-western Africa area in order to study this broad deformation. Currently a Broad Band seismic net (Western Mediterranean, WM net), a permanent geodetic GPS net and a Geomagnetic Observatory have been installed by ROA in this area. To complement the available data, since past October a permanent marine-on land geophysical observatory is being installed by ROA in Alboran Island and surrounding marine zones. Till now the following facilities has been installed: • Submarine: 2 km submarine fibre optics cable (power and data transmission); Broad Band Seismometer (CMG-3T, buried); Accelerometer (Guralp 3 channels), buried); Differential Pressure Gauge (DPG); Thermometer. • On land: Permanent geodetic GPS station; Automatic meteorological station; Data acquisition system for submarine equipment; Satellite Data Transmission system. Data are already being transmitted in real time to ROA headquarters via satellite Intranet. The marine part, currently installed in a 50 m depth platform, has been designed to be enlarged by extending the cable to greater depths and/or installing additional submarine equipment, such a way in short an ADCP profiler will be installed. In this work we aim to show the present status, scientific possibilities and the next future plans of this submarine-on land
Hydrothermal mineralization at seafloor spreading centers
NASA Astrophysics Data System (ADS)
Rona, Peter A.
1984-01-01
The recent recognition that metallic mineral deposits are concentrated by hydrothermal processes at seafloor spreading centers constitutes a scientific breakthrough that opens active sites at seafloor spreading centers as natural laboratories to investigate ore-forming processes of such economically useful deposits as massive sulfides in volcanogenic rocks on land, and that enhances the metallic mineral potential of oceanic crust covering two-thirds of the Earth both beneath ocean basins and exposed on land in ophiolite belts. This paper reviews our knowledge of processes of hydrothermal mineralization and the occurrence and distribution of hydrothermal mineral deposits at the global oceanic ridge-rift system. Sub-seafloor hydrothermal convection involving circulation of seawater through fractured rocks of oceanic crust driven by heat supplied by generation of new lithosphere is nearly ubiquitous at seafloor spreading centers. However, ore-forming hydrothermal systems are extremely localized where conditions of anomalously high thermal gradients and permeability increase hydrothermal activity from the ubiquitous low-intensity background level (⩽ 200°C) to high-intensity characterized by high temperatures ( > 200-c.400°C), and a rate and volume of flow sufficient to sustain chemical reactions that produce acid, reducing, metal-rich primary hydrothermal solutions. A series of mineral phases with sulfides and oxides as high- and low-temperature end members, respectively, are precipitated along the upwelling limb and in the discharge zone of single-phase systems as a function of increasing admixture of normal seawater. The occurrence of hydrothermal mineral deposits is considered in terms of spatial and temporal frames of reference. Spatial frames of reference comprise structural features along-axis (linear sections that are the loci of seafloor spreading alternating with transform faults) and perpendicular to axis (axial zone of volcanic extrusion and marginal
Sievert, Stefan M.; Kuever, Jan; Muyzer, Gerard
2000-01-01
In a recent publication (S. M. Sievert, T. Brinkhoff, G. Muyzer, W. Ziebis, and J. Kuever, Appl. Environ. Microbiol. 65:3834–3842, 1999) we described spatiotemporal changes in the bacterial community structure at a shallow-water hydrothermal vent in the Aegean Sea near the isle of Milos (Greece). Here we describe identification and phylogenetic analysis of the predominant bacterial populations at the vent site and their distribution at the vent site as determined by sequencing of DNA molecules (bands) excised from denaturing gradient gels. A total of 36 bands could be sequenced, and there were representatives of eight major lineages of the domain Bacteria. Cytophaga-Flavobacterium and Acidobacterium were the most frequently retrieved bacterial groups. Less than 33% of the sequences exhibited 90% or more identity with cultivated organisms. The predominance of putative heterotrophic populations in the sequences retrieved is explained by the input of allochthonous organic matter at the vent site. PMID:10877814
Anti-Submarine Warfare: Still an Essential Warfare Art
1993-02-19
34 U.S. Naval Institute ProceedinQs, June 1992, 52. 11. Ibid., 53. 21. Ibid., 53. "D. Holland, 33. 2. Robert 0. Crawshaw , "What Is a Maritime Action...June 1992, 52-54. 4. Byron, John L. "A New Target for the Submarine Force." U.S. Naval Institute Proceedings, January 1990, 38-39. 5. Crawshaw
Fungal colonization of an Ordovician impact-induced hydrothermal system
Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan
2013-01-01
Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal 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 hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life. PMID:24336641
Fungal colonization of an Ordovician impact-induced hydrothermal system
NASA Astrophysics Data System (ADS)
Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan
2013-12-01
Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal 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 hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life.
Fungal colonization of an Ordovician impact-induced hydrothermal system.
Ivarsson, Magnus; Broman, Curt; Sturkell, Erik; Ormö, Jens; Siljeström, Sandra; van Zuilen, Mark; Bengtson, Stefan
2013-12-16
Impacts are common geologic features on the terrestrial planets throughout the solar system, and on at least Earth and Mars impacts have induced hydrothermal convection. Impact-generated hydrothermal systems have been suggested to possess the same life supporting capability as hydrothermal systems associated with volcanic activity. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is scarce in the literature. Here we report of fossilized microorganisms in association with cavity-grown hydrothermal 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 hydrothermal activity and migration of hydrocarbons in the system. Our results from the Lockne impact structure show that hydrothermal systems associated with impact structures can support colonization by microbial life.
NASA Astrophysics Data System (ADS)
Barreyre, Thibaut; Escartin, Javier; Cannat, Mathilde; Garcia, Rafael; Science Party, Momar'08; Science Party, Bathyluck'09
2010-05-01
The Lucky Strike hydrothermal site, located South of the Azores along the Mid-Atlantic Ridge, is one of the largest and best-known active hydrothermal fields along the ridge system. This site within the MoMAR area is also the target for the installation in 2010 of a pilot deep-sea observatory with direct telemetry to land, to be part of the European Seafloor Observatory Network (ESONET). The Lucky Strike hydrothermal site has seen extensive high-resolution, near-bottom geophysical surveys in 1996 (Lustre'96), 2006 (Momareto06), 2008 (MOMAR08) and 2009 (Bathyluck09). Vertically acquired black-and-white electronic still camera images have been projected and georeferenced to obtain 3 image mosaics covering the zone of active venting, extending ~ 700x800 m2, and with full image resolution (~10 mm pixels). These data allow us to study how hydrothermal outflow is structured, including the relationships between the zones of active high-temperature venting, areas of diffuse outflow, and the geological structure (nature of the substrate, faults and fissures, sediments, etc.). Hydrothermal outflow is systematically associated with bacterial mats that are easily identified in the imagery, allowing us to study temporal variability at two different scales. Over the 13-year period we can potentially track changes in both the geometry and intensity of hydrothermal activity throughout the system; our preliminary study of the Eiffel Tower, White Castle and Mt Segur indicate that activity has been sustained in recent times, with small changes in the detailed geometry of the diffuse outflow and its intensity. At longer times scales (hundreds to 1000 years?) imagery also shows evidence of areas of venting that are no longer active, often associated with the active structures. In combination with the high-resolution bathymetry, the imagery data thus allow us to characterize the shallow structure of hydrothermal outflow at depth, the structural and volcanic control, and ultimately
Hydrothermal pretreatment of palm oil empty fruit bunch
NASA Astrophysics Data System (ADS)
Simanungkalit, Sabar Pangihutan; Mansur, Dieni; Nurhakim, Boby; Agustin, Astrid; Rinaldi, Nino; Muryanto, Fitriady, Muhammad Ariffudin
2017-01-01
Hydrothermal pretreatment methods in 2nd generation bioethanol production more profitable to be developed, since the conventional pretreatment, by using acids or alkalis, is associated with the serious economic and environmental constraints. The current studies investigate hydrothermal pretreatment of palm oil empty fruit bunch (EFB) in a batch tube reactor system with temperature and time range from 160 to 240 C and 15 to 30 min, respectively. The EFB were grinded and separated into 3 different particles sizes i.e. 10 mesh, 18 mesh and 40 mesh, prior to hydrothermal pretreatment. Solid yield and pH of the treated EFB slurries changed over treatment severities. The chemical composition of EFB was greatly affected by the hydrothermal pretreatment especially hemicellulose which decreased at higher severity factor as determined by HPLC. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused negatively affect for enzymatic hydrolysis. This studies provided important factors for maximizing hydrothermal pretreatment of EFB.
Hu, Jingwen; Klinich, Kathleen D; Reed, Matthew P; Kokkolaras, Michael; Rupp, Jonathan D
2012-06-01
In motor-vehicle crashes, young school-aged children restrained by vehicle seat belt systems often suffer from abdominal injuries due to submarining. However, the current anthropomorphic test device, so-called "crash dummy", is not adequate for proper simulation of submarining. In this study, a modified Hybrid-III six-year-old dummy model capable of simulating and predicting submarining was developed using MADYMO (TNO Automotive Safety Solutions). The model incorporated improved pelvis and abdomen geometry and properties previously tested in a modified physical dummy. The model was calibrated and validated against four sled tests under two test conditions with and without submarining using a multi-objective optimization method. A sensitivity analysis using this validated child dummy model showed that dummy knee excursion, torso rotation angle, and the difference between head and knee excursions were good predictors for submarining status. It was also shown that restraint system design variables, such as lap belt angle, D-ring height, and seat coefficient of friction (COF), may have opposite effects on head and abdomen injury risks; therefore child dummies and dummy models capable of simulating submarining are crucial for future restraint system design optimization for young school-aged children. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Glass, J. B.; Fornari, D. J.; Tivey, M. A.; Hall, H. F.; Cougan, A. A.; Berkenbosch, H. A.; Holmes, M. L.; White, S. M.; de La Torre, G.
2006-12-01
We combine high-resolution MR-1 sidescan sonar and EM-300 bathymetric data collected on four cruises (AHA-Nemo2 in 2000 (R/V Melville), DRIFT4 in 2001 (R/V Revelle), TN188 and TN189 in January 2006 (R/V Thompson) to study volcanic platform-building processes on the submarine flanks of Fernandina, Isabela, Roca Redonda and Santiago volcanoes, in the western Galapagos. Three primary volcanic provinces were identified including: rift zones (16, ranging from 5 to 20 km in length), small submarine volcanic cones (<3 km in diameter and several 100 m high) and deep (>3000 m), long (>10 km), large-area submarine lava flows. Lengths of the Galapagos rift zones are comparable to western Canary Island rift zones, but significantly shorter than Hawaiian submarine rift zones, possibly reflecting lower magma supply. A surface-towed magnetic survey was conducted over the NW Fernandina rift on TN189 and Fourier inversions were performed to correct for topographic effects. Calculated magnetization was highest (up to +32 A/m) over the shallow southwest flank of the rift, coinciding with cone fields and suggesting most recent volcanism has focused at this portion of the rift. Small submarine volcanic cones with various morphologies (e.g., pointed, cratered and occasionally breached) are common in the submarine western Galapagos both on rift zones and on the island flanks where no rifts are present, such as the northern flank of Santiago Island. Preliminary study of these cones suggests that their morphologies and depth of occurrence may reflect a combination of petrogenetic and eruption processes. Deep, long large-area lava flow fields in regions of low bathymetric relief have been previously identified as a common seafloor feature in the western Galapagos by Geist et al. [in press], and new EM300 data show that a number of the deep lava flows originate from small cones along the mid-lower portion of the NW submarine rift of Fernandina. Our high-resolution sonar data suggest that
Characteristics of vibrational wave propagation and attenuation in submarine fluid-filled pipelines
NASA Astrophysics Data System (ADS)
Yan, Jin; Zhang, Juan
2015-04-01
As an important part of lifeline engineering in the development and utilization of marine resources, the submarine fluid-filled pipeline is a complex coupling system which is subjected to both internal and external flow fields. By utilizing Kennard's shell equations and combining with Helmholtz equations of flow field, the coupling equations of submarine fluid-filled pipeline for n=0 axisymmetrical wave motion are set up. Analytical expressions of wave speed are obtained for both s=1 and s=2 waves, which correspond to a fluid-dominated wave and an axial shell wave, respectively. The numerical results for wave speed and wave attenuation are obtained and discussed subsequently. It shows that the frequency depends on phase velocity, and the attenuation of this mode depends strongly on material parameters of the pipe and the internal and the external fluid fields. The characteristics of PVC pipe are studied for a comparison. The effects of shell thickness/radius ratio and density of the contained fluid on the model are also discussed. The study provides a theoretical basis and helps to accurately predict the situation of submarine pipelines, which also has practical application prospect in the field of pipeline leakage detection.
Pirates of the Nuclear Age: The Role of U.S. Submarines in Modern Trade Warfare
2016-07-14
have sought to influence the outcome of the conflict by targeting enemy commerce . This influence historically called for the use of privateers...submarines took the position of privateers as the ideal force for conducting commerce warfare. Throughout World War Two (WWII) commerce warfare using... commerce ) remains. From the time of Greek city-states, to the privateers of the age of sail, to the submarines of WWI and WWII, targeting the
Zhang, Zi-Hui; Tan, Swee Tiam; Liu, Wei; Ju, Zhengang; Zheng, Ke; Kyaw, Zabu; Ji, Yun; Hasanov, Namig; Sun, Xiao Wei; Demir, Hilmi Volkan
2013-02-25
This work reports both experimental and theoretical studies on the InGaN/GaN light-emitting diodes (LEDs) with optical output power and external quantum efficiency (EQE) levels substantially enhanced by incorporating p-GaN/n-GaN/p-GaN/n-GaN/p-GaN (PNPNP-GaN) current spreading layers in p-GaN. Each thin n-GaN layer sandwiched in the PNPNP-GaN structure is completely depleted due to the built-in electric field in the PNPNP-GaN junctions, and the ionized donors in these n-GaN layers serve as the hole spreaders. As a result, the electrical performance of the proposed device is improved and the optical output power and EQE are enhanced.
Study on Safety Monitoring System for Submarine Power Cable on the Basis of AIS and Radar Technology
NASA Astrophysics Data System (ADS)
Jie, Wang; Yao-Tian, Fan
Through analyzing the risks of submarine power cable, the highest risk to damage the cable identified is from ship. Based on concept of Vessel Traffic Management Information Systems, the three core sub-systems of safety monitoring system for submarine power cable were studied and described, also some suggestions were given.
Yarnall, Nicholas J; Hughes, Linda M; Turnbull, Paul S; Michaud, Mark
2013-05-01
To evaluate the effectiveness of the US Navy and Marine Corps tobacco policy in protecting submariners from secondhand smoke (SHS) by determining if non-tobacco users experienced a significant increase in urinary cotinine levels at sea when compared with in port levels. From February to August 2009, 634 volunteers recruited from nine US Navy submarines completed a survey to collect demographic data, information on tobacco use and pre-deployment exposure to SHS. Non-tobacco users (n=239) were requested to provide two urine samples (pre-deployment and while at sea) to quantify exposure to SHS using urinary cotinine as a biomarker. Matched samples were analysed using liquid chromatography-tandem mass spectrometry. Overall, deployed cotinine levels were 2.1 times the in port levels in non-tobacco using submariners (95% CI 1.8 to 2.4, p<0.001, n=197). A significant increase in deployed urinary cotinine levels was found aboard six of nine submarines (p<0.05). A subgroup of submariners (n=91) who reported no SHS exposure within 10 days prior to in port cotinine sampling had deployed cotinine levels 2.7 times the in port levels (95% CI 2.2 to 3.3, p<0.001). Applying a 4.5:1 urine cotinine to serum cotinine correction factor, submariners' deployed geometric means are similar to recent US male population values at the 75th percentile. This study provides evidence that non-tobacco using submariners were exposed to SHS. Exposure was seen in all submarine classes and was not limited to personnel working in proximity to the smoking area. The existing policy was inadequate to protect non-smokers from exposure to SHS and required revision. As a result of a policy review, informed by this study, smoking below decks was banned aboard all US Navy submarines effective 31 December 2010.
Three-dimensional structure of the submarine flanks of La Réunion inferred from geophysical data
NASA Astrophysics Data System (ADS)
Gailler, Lydie-Sarah; LéNat, Jean-FrançOis
2010-12-01
La Réunion (Indian Ocean) constitutes a huge volcanic oceanic system of which most of the volume is submerged. We present a study of its submarine part based on the interpretation of magnetic and gravity data compiled from old and recent surveys. A model of the submarine internal structure is derived from 3-D and 2-D models using constraints from previous geological and geophysical studies. Two large-scale, previously unknown, buried volcanic construction zones are discovered in continuation of the island's construction. To the east, the Alizés submarine zone is interpreted as the remnants of Les Alizés volcano eastward flank whose center is marked by a large hypovolcanic intrusion complex. To the southwest, the Etang Salé submarine zone is interpreted as an extension of Piton des Neiges, probably fed by a volcanic rift zone over a large extent. They were predominantly built during the Matuyama period and thus probably belong to early volcanism. A correlation exists between their top and seismic horizons recognized in previous studies and interpreted as the base of the volcanic edifice. Their morphology suggested a lithospheric bulging beneath La Réunion, not required to explain our data, since the seismic interfaces match the top of our volcanic constructions. The coastal shelf coincides with a negative Bouguer anomaly belt, often associated with magnetic anomalies, suggesting a shelf built by hyaloclastites. A detailed analysis of the offshore continuation of La Montagne Massif to the north confirms this hypothesis. The gravity analysis confirms that the bathymetric bulges, forming the northern, eastern, southern, and western submarine flanks, are predominantly built by debris avalanche deposits at the surface.
Bortoluzzi, G; Romeo, T; La Cono, V; La Spada, G; Smedile, F; Esposito, V; Sabatino, G; Di Bella, M; Canese, S; Scotti, G; Bo, M; Giuliano, L; Jones, D; Golyshin, P N; Yakimov, M M; Andaloro, F
2017-09-01
Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe 3+ oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe 2+ and NH 4 + ) are important energy sources in supporting primary production in microbial mats, which form a habitat
Federal Register 2010, 2011, 2012, 2013, 2014
2013-08-28
...-AA87 Security Zones; Naval Base Point Loma; Naval Mine Anti-Submarine Warfare Command; San Diego Bay... Anti-Submarine Warfare Command to protect the relocated marine mammal program. These security zone... Warfare Command, the Commander of Naval Region Southwest, or a designated representative of those...
Wikberg, Hanne; Grönqvist, Stina; Niemi, Piritta; Mikkelson, Atte; Siika-Aho, Matti; Kanerva, Heimo; Käsper, Andres; Tamminen, Tarja
2017-07-01
The suitability of several abundant but underutilized agro and forest based biomass residues for hydrothermal treatment followed by enzymatic hydrolysis as well as for hydrothermal carbonization was studied. The selected approaches represent simple biotechnical and thermochemical treatment routes suitable for wet biomass. Based on the results, the hydrothermal pre-treatment followed by enzymatic hydrolysis seemed to be most suitable for processing of carbohydrate rich corn leaves, corn stover, wheat straw and willow. High content of thermally stable components (i.e. lignin) and low content of ash in the biomass were advantageous for hydrothermal carbonization of grape pomace, coffee cake, Scots pine bark and willow. Copyright © 2017 Elsevier Ltd. All rights reserved.
NASA Technical Reports Server (NTRS)
2002-01-01
The NASA/Navy Benchmarking Exchange (NNBE) was undertaken to identify practices and procedures and to share lessons learned in the Navy's submarine and NASA's human space flight programs. The NNBE focus is on safety and mission assurance policies, processes, accountability, and control measures. This report is an interim summary of activity conducted through October 2002, and it coincides with completion of the first phase of a two-phase fact-finding effort.In August 2002, a team was formed, co-chaired by senior representatives from the NASA Office of Safety and Mission Assurance and the NAVSEA 92Q Submarine Safety and Quality Assurance Division. The team closely examined the two elements of submarine safety (SUBSAFE) certification: (1) new design/construction (initial certification) and (2) maintenance and modernization (sustaining certification), with a focus on: (1) Management and Organization, (2) Safety Requirements (technical and administrative), (3) Implementation Processes, (4) Compliance Verification Processes, and (5) Certification Processes.
Sample Return from Ancient Hydrothermal Springs
NASA Technical Reports Server (NTRS)
Allen, Carlton C.; Oehler, Dorothy Z.
2008-01-01
Hydrothermal spring deposits on Mars would make excellent candidates for sample return. Molecular phylogeny suggests that that life on Earth may have arisen in hydrothermal settings [1-3], and on Mars, such settings not only would have supplied energy-rich waters in which martian life may have evolved [4-7] but also would have provided warm, liquid water to martian life forms as the climate became colder and drier [8]. Since silica, sulfates, and clays associated with hydrothermal settings are known to preserve geochemical and morphological remains of ancient terrestrial life [9-11], such settings on Mars might similarly preserve evidence of martian life. Finally, because formation of hydrothermal springs includes surface and subsurface processes, martian spring deposits would offer the potential to assess astrobiological potential and hydrological history in a variety of settings, including surface mineralized terraces, associated stream deposits, and subsurface environments where organic remains may have been well protected from oxidation. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data [12-14]. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel, and based on these new data, we have interpreted several features in Vernal Crater, Arabia Terra as ancient hydrothermal springs [15, 16].
First hydrothermal active vent discovered on the Galapagos Microplate
NASA Astrophysics Data System (ADS)
Tao, C.; Li, H.; Wu, G.; Su, X.; Zhang, G.; Chinese DY115-21 Leg 3 Scientific Party
2011-12-01
The Galapagos Microplate (GM) lies on the western Gaplapagos Spreading Center (GSC), representing one of the classic Ridge-Ridge-Ridge (R-R-R) plate boundaries of the Nazca, Cocos, and Pacific plates. The presence of the 'black smoke' and hydrothermal vent community were firstly confirmed on the GSC. Lots of hydrothermal fields were discovered on the center and eastern GSC, while the western GSC has not been well investigated. During 17th Oct. to 9th Nov. 2009, the 3rd leg of Chinese DY115-21 cruise with R/V Dayangyihao has been launched along 2°N-5°S near equatorial East Pacific Rise (EPR). Two new hydrothermal fields were confirmed. One is named 'Precious Stone Mountain', which is the first hydrothermal field on the GM. The other is found at 101.47°W, 0.84°S EPR. The 'Precious Stone Mountain' hydrothermal field (at 101.49°W, 1.22°N) is located at an off-axial seamount on the southern GM boundary, with a depth from 1,450 to 1,700m. Hydrothermal fluids emitting from the fissures and hydrothermal fauna were captured by deep-tow video. Few mineral clasts of pyrite and chalcopyrite were separated from one sediment sample, but no sulfide chimney was found yet. Hydrothermal fauna such as alive mussels, crabs, shrimps, tubeworms, giant clams, as well as rock samples were collected by TV-Grab. The study of the seafloor classification with Simrad EM120 multi-beam echosounder has been conducted on the 'Precious Stone Mountain' hydrothermal field. The result indicates that seafloor materials around the hydrothermal field can be characterized into three types, such as the fresh lava, hydrothermal sediment, and altered rock.
The down canyon evolution of submarine sediment density flows
NASA Astrophysics Data System (ADS)
Parsons, D. R.; Barry, J.; Clare, M. A.; Cartigny, M.; Chaffey, M. R.; Gales, J. A.; Gwiazda, R.; Maier, K. L.; McGann, M.; Paull, C. K.; O'Reilly, T. C.; Rosenberger, K. J.; Simmons, S.; Sumner, E. J.; Talling, P.; Xu, J.
2017-12-01
Submarine density flows, known as turbidity currents, transfer globally significant volumes of terrestrial and shelf sediments, organic carbon, nutrients and fresher-water into the deep ocean. Understanding such flows has wide implications for global organic carbon cycling, the functioning of deep-sea ecosystems, seabed infrastructure hazard assessments, and interpreting geological archives of Earth history. Only river systems transport comparable volumes of sediment over such large areas of the globe. Despite their clear importance, there are remarkably few direct measurements of these oceanic turbidity currents in action. Here we present results from the multi-institution Coordinated Canyon Experiment (CCE) which deployed multiple moorings along the axis of Monterey Canyon (offshore California). An array of six moorings, with downward looking acoustic Doppler current profilers (ADCP) were positioned along the canyon axis from 290 m to 1850 m water depth. The ADCPs reveal the internal flow structure of submarine density flows at each site. We use a novel inversion method to reconstruct the suspended sediment concentration and flow stratification field during each event. Together the six moorings provide the first ever views of the internal structural evolution of turbidity current events as they evolve down system. Across the total 18-month period of deployment at least 15 submarine sediment density flows were measured with velocities up to 8.1 m/sec, with three of these flows extending 50 kms down the canyon beyond the 1850 m water depth mooring. We use these novel data to highlight the controls on ignition, interval structure and collapse of individual events and discuss the implications for the functioning and deposits produced by these enigmatic flows.
NASA Astrophysics Data System (ADS)
Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen
2014-12-01
We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge
Comparative investigation of InGaP/GaAs/GaAsBi and InGaP/GaAs heterojunction bipolar transistors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wu, Yi-Chen; Tsai, Jung-Hui, E-mail: jhtsai@nknucc.nknu.edu.tw; Chiang, Te-Kuang
2015-10-15
In this article the characteristics of In{sub 0.49}Ga{sub 0.51}P/GaAs/GaAs{sub 0.975}Bi{sub 0.025} and In{sub 0.49}Ga{sub 0.51}P/GaAs heterojunction bipolar transistor (HBTs) are demonstrated and compared by two-dimensional simulated analysis. As compared to the traditional InGaP/GaAs HBT, the studied InGaP/GaAs/GaAsBi HBT exhibits a higher collector current, a lower base-emitter (B–E) turn-on voltage, and a relatively lower collector-emitter offset voltage of only 7 mV. Because the more electrons stored in the base is further increased in the InGaP/GaAs/GaAsBi HBT, it introduces the collector current to increase and the B–E turn-on voltage to decrease for low input power applications. However, the current gain is slightlymore » smaller than the traditional InGaP/GaAs HBT attributed to the increase of base current for the minority carriers stored in the GaAsBi base.« less
Deep-Sea Research Submarine 'Ben Franklin'
NASA Technical Reports Server (NTRS)
1969-01-01
This is an aerial view of the deep-sea research submarine 'Ben Franklin' at dock. Named for American patriot and inventor Ben Franklin, who discovered the Gulf Steam, the 50-foot Ben Franklin was built between 1966 and 1968 in Switzerland for deep-ocean explorer Jacques Piccard and the Grumman Aircraft Engineering Corporation. The submersible made a famous 30-day drift dive off the East Coast of the United States and Canada in 1969 mapping the Gulf Stream's currents and sea life, and also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. On July 14, 1969, the Ben Franklin was towed to the high-velocity center of the Stream off the coast of Palm Beach, Florida. With a NASA observer on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. During the course of the dive, NASA conducted exhaustive analyses of virtually every aspect of onboard life. They measured sleep quality and patterns, sense of humor and behavioral shifts, physical reflexes, and the effects of a long-term routine on the crew. The submarine's record-shattering dive influenced the design of Apollo and Skylab missions and continued to guide NASA scientists as they devised future marned space-flight missions.
Currents in monterey submarine canyon
Xu, J. P.; Noble, M.A.
2009-01-01
Flow fields of mean, subtidal, and tidal frequencies between 250 and 3300 m water depths in Monterey Submarine Canyon are examined using current measurements obtained in three yearlong field experiments. Spatial variations in flow fields are mainly controlled by the topography (shape and width) of the canyon. The mean currents flow upcanyon in the offshore reaches (>1000 m) and downcanyon in the shallow reaches (100-m amplitude isotherm oscillations and associated high-speed rectilinear currents. The 15-day spring-neap cycle and a ???3-day??? band are the two prominent frequencies in subtidal flow field. Neither of them seems directly correlated with the spring-neap cycle of the sea level.
NASA Astrophysics Data System (ADS)
Liu, Di; Mo, Xiaoping; Li, Kexun; Liu, Yi; Wang, Junjie; Yang, Tingting
2017-08-01
Nano spinel bulk-like CoGa2O4 prepared via a facile hydrothermal method is used as a high efficient electrochemical catalyst in activated carbon (AC) air-cathode microbial fuel cell (MFC). The maximum power density of the modified MFC is 1911 ± 49 mW m-2, 147% higher than the MFC of untreated AC cathode. Transmission electron microscope (TEM) and X-ray diffraction (XRD) exhibit the morphology and crystal structure of CoGa2O4. Rotating disk electrode (RDE) confirms the four-electron pathway at the cathode during the oxygen reduction reaction (ORR). Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) illustrate that the high rate oxygen vacancy exist in the CoGa2O4. The oxygen vacancy of CoGa2O4 plays an important role in catalytic activity. In a word, the prepared nano spinel bulk-like CoGa2O4 provides an alternative to the costly Pt in air-cathode for power output.
NASA Astrophysics Data System (ADS)
Dominey-Howes, D.; Goff, J. R.
2009-12-01
National economies are increasingly dependent on the global telecommunications system - and in particular, its submarine cable infrastructure. Submarine cable traffic represents about 30% of global GDP so the cost of losing, or even simply slowing, communications traffic is high. Many natural hazards are capable of damaging and destroying this infrastructure but tsunamis are the most significant threat, particularly in waters >1000 m deep. Submarine cables and their shore-based infrastructure (the anchor points), are at risk from direct and indirect tsunami-related effects. During the 2004 Indian Ocean Tsunami in India and Indonesia, cables were broken (direct effect) as the tsunami eroded supporting sediments, and were further damaged by floating/submerged objects and intense nearshore currents. Shore-based infrastructure was also directly damaged in India, Indonesia, and the Maldives. The 1929 Grand Banks earthquake generated a submarine landslide and tsunami off Newfoundland which broke 12 submarine telegraph cables. In 2006, an earthquake in Taiwan generated submarine landslides and a tsunami. These landslides caused one of the largest disruptions of modern telecommunications history when nine cables in the Strait of Luzon were broken disabling vital connections between SE Asia and the rest of the world. Although electronic traffic in and out of Australia was slowed, it did not cease because >70% of our traffic is routed via cables that pass through Hawaii. This is extremely significant because Hawaii is an internationally recognised bottleneck or “choke point” in the global telecommunications network. The fact that Hawaii is a choke point is important because it is regularly affected by numerous large magnitude natural hazards. Any damage to the submarine telecommunications infrastructure routed through Hawaii could result in significant impacts on the electronic flow of data and voice traffic, negatively affecting dependent economies such as Australia
1981-09-29
stressful conditions. Limitation of physical activity, desynchronization of circadian rhythms, adverse work -rest cycles, lack of privacy, and altered...Physical Fitness Aboard Submarines 11 6.2 Disease and Coronary Artery Disease Risk Factors in Submarines 12 6.3 Fatigue, Work -Rest Cycles, and...1974). Stress and disease appear to be related, since organ systems function poorly during periods of stress . Therefore, stress has been viewed as
Peptide synthesis in early earth hydrothermal systems
Lemke, K.H.; Rosenbauer, R.J.; Bird, D.K.
2009-01-01
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 hydrothermal 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 hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal 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 hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems 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.
Impact contribution of prebiotic reactants to Earth
NASA Technical Reports Server (NTRS)
Aggarwal, Hans R.
1993-01-01
A study was performed to explore the effectiveness of comets for chemical evolution. The concentration of amino acids in various terrestrial environments was mathematically explored as there is evidence that amino acids formed as a result of cometary impact. First, the initial concentration of amino acids in surface environment after cometary impact was estimated. The effect of hydrothermal vents, ultra-violet rays, and clays was taken into consideration. Next, the absorption of amino acids by clay particles before degradation by ultra-violet light was analyzed. Finally, the effectiveness of clays, ultra-violet, and hydrothermal vents as sinks for cometary amino acids was compared. A mathematical model was then developed for the production of impact deposits on Earth for the past 2 Ga, and the relative thickness distribution was computed for impact deposits produced in 2 Ga. The reported relative thickness distribution of tillites and diamicites of all ages agrees with the thickness calculated from this impact model. This suggests that many of the ancient tillites and diamicites could be of impact origin. The effectiveness of comets was explored on the chemical evolution of amino acids. The effect of sinks such as clays, submarine vents, and UV light on amino acid concentration was considered. Sites favorable to chemical evolution of amino acids were examined, and it was concluded that chemical evolution could have occurred at or above the surface even during periods of intense bombardment of the Earth more than 3.8 billion years ago.
Impact contribution of prebiotic reactants to Earth
NASA Astrophysics Data System (ADS)
Aggarwal, Hans R.
1993-03-01
A study was performed to explore the effectiveness of comets for chemical evolution. The concentration of amino acids in various terrestrial environments was mathematically explored as there is evidence that amino acids formed as a result of cometary impact. First, the initial concentration of amino acids in surface environment after cometary impact was estimated. The effect of hydrothermal vents, ultra-violet rays, and clays was taken into consideration. Next, the absorption of amino acids by clay particles before degradation by ultra-violet light was analyzed. Finally, the effectiveness of clays, ultra-violet, and hydrothermal vents as sinks for cometary amino acids was compared. A mathematical model was then developed for the production of impact deposits on Earth for the past 2 Ga, and the relative thickness distribution was computed for impact deposits produced in 2 Ga. The reported relative thickness distribution of tillites and diamicites of all ages agrees with the thickness calculated from this impact model. This suggests that many of the ancient tillites and diamicites could be of impact origin. The effectiveness of comets was explored on the chemical evolution of amino acids. The effect of sinks such as clays, submarine vents, and UV light on amino acid concentration was considered. Sites favorable to chemical evolution of amino acids were examined, and it was concluded that chemical evolution could have occurred at or above the surface even during periods of intense bombardment of the Earth more than 3.8 billion years ago.
NASA Astrophysics Data System (ADS)
Chen, S.; Tao, C.; Baker, E. T.; Li, H.
2016-12-01
The Zouyu-1 (14.41°W, 13.25°S) and Zouyu-2 (14.41°W, 13.28°S) hydrothermal fields are located on the neovolcanic Zouyu ridge on axis of a symmetrical spreading ridge, which is on the eastern side of the S14 segment on the southern Mid-Atlantic ridge (the ridge segments were numbered by Chunhui Tao (2016) ). The two hydrothermal fields were found during Chinese 22nd cruise in 2011 and 21st cruise in 2009 on board R/V Dayang YiHao, respectively. We collected data recorded by light-scattering and temperature sensors (Miniature Autonomous Plume Recorder, short for MAPR), and H2S and ORP sensors (Electro-chemical sensor, short for ECS) in multiple years (2009, 2011), yielding the following results: (1) The turbidity anomalies were widely distributed in the Zouyu-1 and Zouyu-2 hydrothermal fields. And the highest turbidity anomalies were concentrated around Zouyu-2 hydrothermal field, with a maximum value of 0.094 △NTU south of Zouyu-2 vent. The horizontal scale of hydrothermal plume maximum was 2.5 km. The plume maximum is offset 500 m east of the Zouyu-2 vent location. (2) ORP anomalies were detected near Zouyu-2 in 2011. Sharp and substantial ORP ( 80 mV) and H2S (2.5 nmol/L) anomalies occurred near 14.412°W,13.28°S for 300 m along the track line 22II-L07. (3)Temperature along the track line 21IV-L04 in the Zouyu-2 field increased by as much as 0.03 ° even as the depth of MAPR was largely unchanged. With the evidence of concomitant fluctuations in turbidity, it showed the temperature increases were hydrothermally induced. Keywords: hydrothermal plume, Zouyu-1 hydrothermal field, Zouyu-2 hydrothermal field
NASA Astrophysics Data System (ADS)
Wei, Yingsan; Wang, Yongsheng
2013-04-01
This study presents the unsteady hydrodynamics of the excitations from a 5-bladed propeller at two rotating speeds running in the wake of a small-scaled submarine and the behavior of the submarine's structure and acoustic responses under the propeller excitations. Firstly, the propeller flow and submarine flows are independently validated. The propulsion of the hull-propeller is simulated using computational fluid dynamics (CFD), so as to obtain the transient responses of the propeller excitations. Finally, the structure and acoustic responses of the submarine under propeller excitations are predicted using a finite element/boundary element model in the frequency domain. Results show that (1) the propeller excitations are tonal at the propeller harmonics, and the propeller transversal force is bigger than vertical force. (2) The structure and acoustic responses of the submarine hull is tonal mainly at the propeller harmonics and the resonant mode frequencies of the hull, and the breathing mode in axial direction as well as the bending modes in vertical and transversal directions of the hull can generate strong structure vibration and underwater noise. (3) The maximum sound pressure of the field points increases with the increasing propeller rotating speed at structure resonances and propeller harmonics, and the rudders resonant mode also contributes a lot to the sound radiation. Lastly, the critical rotating speeds of the submarine propeller are determined, which should be carefully taken into consideration when match the propeller with prime mover in the propulsion system. This work shows the importance of the propeller's tonal excitation and the breathing mode plus the bending modes in evaluating submarine's noise radiation.
2012-10-24
Figure 6. Haul-Safe Winch System (Spec Rescue International). .................................................. 9 Figure 7. Submarine bridge...illustrating limited deck space for winch system . ............................. 9 vi [THIS PAGE INTENTIONALLY LEFT BLANK] INTRODUCTION U.S...and out the submarine sail for helicopter transport. In addition, a winch system used to lift casualties up and out the sail was also evaluated. 4
NASA Astrophysics Data System (ADS)
Casalbore, D.; Romagnoli, C.; Bosman, A.; De Astis, G.; Lucchi, F.; Tranne, C. A.; Chiocci, F. L.
2018-06-01
The analysis of multibeam bathymetry, seismic profiles, ROV dive and seafloor sampling, integrated with stratigraphic and geological data derived from subaerial field studies, provides information on the multi-stage formation and evolution of La Fossa Caldera at the active volcanic system of Vulcano (Aeolian Islands). The caldera is mostly subaerial and delimited by well-defined rims associated to three different collapse events occurred at about 80, 48-24, and 13-8 ka, respectively. The NE part of the caldera presently lies below the sea-level and is delimited by two partially degraded rim segments, encompassing a depressed and eroded area of approximately 2 km2. We present here further morphological and petrochemical evidence linking the subaerial caldera rims to its submarine counterparts. Particularly, one of the submarine rims can be directly correlated with the subaerial eastern caldera border related to the intermediate (48-24 ka) collapse event. The other submarine rim cannot be directly linked to any subaerial caldera rim, because of the emplacement of the Vulcanello lava platform during the last 2 millennia that interrupts the caldera border. However, morphological interpretation and the trachyte composition of dredged lavas allow us to associate this submarine rim with the younger (13-8 ka) caldera collapse event that truncated the trachyte-rhyolite Monte Lentia dome complex in the NW sector of Vulcano. The diachronicity of the different collapse events forming the La Fossa Caldera can also explain the morpho-structural mismatch of some hundreds of meters between the two submarine caldera rims. A small part of this offset could be also accounted by tectonic displacement along NE-SW trending lineaments breaching and dismantling the submarine portion of the caldera. A network of active erosive gullies, whose headwall arrive up to the coast, is in fact responsible of the marked marine retrogressive erosion affecting the NE part of the caldera, where
Submarine glaciated landscapes of central and northern British Columbia, Canada
NASA Astrophysics Data System (ADS)
Shaw, John; Lintern, Gwyn
2015-04-01
Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also
Submarine landslide: A case study from the southwestern of Taiwan offshore
NASA Astrophysics Data System (ADS)
Hung, Y. H.; Dong, J. J.
2016-12-01
Based on the new multibeam bathymetric data and seismic reflection profiles of the southwestern Taiwan, more and more submarine landslides developed there have been being discovered nowadays. Palm Ridge, located between the boundary of the active and passive margins, is the place where a deformation front passes through. And previous studies suspected that there were old submarine landslides developed here. To learn whether there are old submarine landslides here, a further study is conducted with the collection and analysis of new high-resolution swath-bathymetry and seismic data. Firstly, based on the swath-bathymetry, the topography range of the landslide is mapped and interpreted with the three dimensional model. Then, according to the profile of the mapping, the extending of the sliding surface is predicted. And referred on the properties of soil in adjacent region, the engineering geologic models of the landslide before and after failure are proposed. Thirdly, through a detailed analysis of the seismic data of Taiwan in the past three decades, a magnitude of 7.7 MW is selected as the lower bound of earthquake for the analysis of the trigger of the submarine landslide. And based on the record of earthquakes with 8 MW in the world, some other earthquake magnitudes are also considered in this study. After applying them into STABL 5M, the failure process of the landslide is modeled with its possible deposited ranges being reached. Finally, the sub-bottom and seismic data are used to verify the rationality of the above results. Preliminary result shows that there were at least three landslides occurred in Palm Ridge. The first landslide is largest which covers the approximate range of the study area. The second one is developed in the margin area of the first one, which is resulted by the occurrence of the first one. The third event is caused by the further collapse of the first one due to the loose of its inner structure.
Estimation of submarine mass failure probability from a sequence of deposits with age dates
Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.
2013-01-01
The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.
ATTICA family of thermal cameras in submarine applications
NASA Astrophysics Data System (ADS)
Kuerbitz, Gunther; Fritze, Joerg; Hoefft, Jens-Rainer; Ruf, Berthold
2001-10-01
Optronics Mast Systems (US: Photonics Mast Systems) are electro-optical devices which enable a submarine crew to observe the scenery above water during dive. Unlike classical submarine periscopes they are non-hull-penetrating and therefore have no direct viewing capability. Typically they have electro-optical cameras both for the visual and for an IR spectral band with panoramic view and a stabilized line of sight. They can optionally be equipped with laser range- finders, antennas, etc. The brand name ATTICA (Advanced Two- dimensional Thermal Imager with CMOS-Array) characterizes a family of thermal cameras using focal-plane-array (FPA) detectors which can be tailored to a variety of requirements. The modular design of the ATTICA components allows the use of various detectors (InSb, CMT 3...5 μm , CMT 7...11 μm ) for specific applications. By means of a microscanner ATTICA cameras achieve full standard TV resolution using detectors with only 288 X 384 (US:240 X 320) detector elements. A typical requirement for Optronics-Mast Systems is a Quick- Look-Around capability. For FPA cameras this implies the need for a 'descan' module which can be incorporated in the ATTICA cameras without complications.
Esposito, Valentina; Andaloro, Franco; Canese, Simonepietro; Bortoluzzi, Giovanni; Bo, Marzia; Di Bella, Marcella; Italiano, Francesco; Sabatino, Giuseppe; Battaglia, Pietro; Consoli, Pierpaolo; Giordano, Patrizia; Spagnoli, Federico; La Cono, Violetta; Yakimov, Michail M; Scotti, Gianfranco; Romeo, Teresa
2018-01-01
The geological, biological and geochemical features of a particular field of hydrothermal vents, discovered in the Panarea Volcanic Complex during a research survey carried out in 2015, are described for the first time. The site, located at 70-80 m depth off the South-western coast of the islet of Basiluzzo, was named Smoking Land for the presence of a large number of wide and high active chimneys and was characterized in terms of dissolved benthic fluxes, associated macrofauna and megafauna communities and preliminary mineralogy and geochemistry of chimney structures. On the whole field, a total of 39 chimneys, different in size and shape, were closely observed and described; 14 of them showed emission of low temperature hydrothermal fluids of marine origin characterized by acidified chemical conditions. The CTD and benthic chamber measurements highlighted that the Smoking Land is able to form a sea water bottom layer characterized by variable acidity and high DIC and trace elements concentrations; these characteristics weaken moving away from the chimney mouths. The SEM-EDS analysis of the collected solid samples revealed a chimney structure principally composed by amorphous and low crystalline Fe-oxyhydroxides of hydrothermal origins. The ROV explorations revealed a wide coverage of red algae (Peyssonnelia spp.) colonized by the green algae Flabiella petiolata and by suspension feeders, mainly sponges, but also bryozoans, and tubicolous polychaetes. Although novent-exclusive species were identified, the benthic communities found in association to the chimneys included more taxa than those observed in the surrounding no-vent rocky areas. These first findings evidence a submarine dynamic habitat where geological, chemical and biological processes are intimately connected, making the Smoking Land an important site in terms of marine heritage that should be safeguarded and protected.
Andaloro, Franco; Canese, Simonepietro; Bo, Marzia; Di Bella, Marcella; Italiano, Francesco; Sabatino, Giuseppe; Battaglia, Pietro; Consoli, Pierpaolo; Giordano, Patrizia; Spagnoli, Federico; La Cono, Violetta; Yakimov, Michail M.; Scotti, Gianfranco; Romeo, Teresa
2018-01-01
The geological, biological and geochemical features of a particular field of hydrothermal vents, discovered in the Panarea Volcanic Complex during a research survey carried out in 2015, are described for the first time. The site, located at 70–80 m depth off the South-western coast of the islet of Basiluzzo, was named Smoking Land for the presence of a large number of wide and high active chimneys and was characterized in terms of dissolved benthic fluxes, associated macrofauna and megafauna communities and preliminary mineralogy and geochemistry of chimney structures. On the whole field, a total of 39 chimneys, different in size and shape, were closely observed and described; 14 of them showed emission of low temperature hydrothermal fluids of marine origin characterized by acidified chemical conditions. The CTD and benthic chamber measurements highlighted that the Smoking Land is able to form a sea water bottom layer characterized by variable acidity and high DIC and trace elements concentrations; these characteristics weaken moving away from the chimney mouths. The SEM-EDS analysis of the collected solid samples revealed a chimney structure principally composed by amorphous and low crystalline Fe-oxyhydroxides of hydrothermal origins. The ROV explorations revealed a wide coverage of red algae (Peyssonnelia spp.) colonized by the green algae Flabiella petiolata and by suspension feeders, mainly sponges, but also bryozoans, and tubicolous polychaetes. Although novent-exclusive species were identified, the benthic communities found in association to the chimneys included more taxa than those observed in the surrounding no-vent rocky areas. These first findings evidence a submarine dynamic habitat where geological, chemical and biological processes are intimately connected, making the Smoking Land an important site in terms of marine heritage that should be safeguarded and protected. PMID:29300784
The impact of glacier geometry on meltwater plume structure and submarine melt in Greenland fjords
NASA Astrophysics Data System (ADS)
Carroll, D.; Sutherland, D. A.; Hudson, B.; Moon, T.; Catania, G. A.; Shroyer, E. L.; Nash, J. D.; Bartholomaus, T. C.; Felikson, D.; Stearns, L. A.; Noël, B. P. Y.; Broeke, M. R.
2016-09-01
Meltwater from the Greenland Ice Sheet often drains subglacially into fjords, driving upwelling plumes at glacier termini. Ocean models and observations of submarine termini suggest that plumes enhance melt and undercutting, leading to calving and potential glacier destabilization. Here we systematically evaluate how simulated plume structure and submarine melt during summer months depends on realistic ranges of subglacial discharge, glacier depth, and ocean stratification from 12 Greenland fjords. Our results show that grounding line depth is a strong control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-trapped plumes that can overcut termini. Due to sustained upwelling velocities, plumes in cold, shallow fjords can induce equivalent depth-averaged melt rates compared to warm, deep fjords. These results detail a direct ocean-ice feedback that can affect the Greenland Ice Sheet.
Kyaw, Zabu; Zhang, Zi-Hui; Liu, Wei; Tan, Swee Tiam; Ju, Zhen Gang; Zhang, Xue Liang; Ji, Yun; Hasanov, Namig; Zhu, Binbin; Lu, Shunpeng; Zhang, Yiping; Sun, Xiao Wei; Demir, Hilmi Volkan
2014-01-13
N-GaN/P-GaN/N-GaN/P-GaN/N-GaN (NPNPN-GaN) junctions embedded between the n-GaN region and multiple quantum wells (MQWs) are systematically studied both experimentally and theoretically to increase the performance of InGaN/GaN light emitting diodes (LEDs) in this work. In the proposed architecture, each thin P-GaN layer sandwiched in the NPNPN-GaN structure is completely depleted due to the built-in electric field in the NPNPN-GaN junctions, and the ionized acceptors in these P-GaN layers serve as the energy barriers for electrons from the n-GaN region, resulting in a reduced electron over flow and enhanced the current spreading horizontally in the n- GaN region. These lead to increased optical output power and external quantum efficiency (EQE) from the proposed device.
2002-05-31
Gary Butterworth, Major Al Alba, Lieutenant Commander John Zuzich, Lieutenant Commander Steve Ruscheinski, and Major Donn Hill were all great sounding...underway and swarm the oceans of the world in a prelude to a third world conflict. However, the lack of a peer competitor for the US did not make the...submarine threat? What nations currently have diesel or nuclear submarines in 3 their inventory? What makes these submarines dangerous? How can
SSN 774 Virginia Class Submarine (SSN 774)
2015-12-01
Selected Acquisition Report ( SAR ) RCS: DD-A&T(Q&A)823-516 SSN 774 Virginia Class Submarine (SSN 774) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 8, 2016 11:22:44 UNCLASSIFIED SSN 774 December 2015 SAR March 8, 2016 11:22:44 UNCLASSIFIED 2...Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost SSN 774 December 2015 SAR March 8
Tolerance and Effectiveness of Forced and Prolonged Smoking Cessation Among French Submariners.
Derkenne, Clément; Bylicki, Olivier; Darléguy, Adrien; Garnier, Mathieu; Baert, Patrice; Lamblin, Antoine
2016-05-01
This study investigates nicotine withdrawal symptoms and resumption rates of tobacco abuse among French submariners during and after a 7-week mission without using tobacco. A prospective study was conducted in 2010 during two missions aboard nuclear-powered ballistic missile submarines. Over a 6-month follow-up, the study subjects completed five standardized questionnaires (Fagerström test, Hospital Anxiety Depression, and the Minnesota Nicotine Withdrawal Scale). Out of 222 prospective study subjects, 168 were included, 52 of whom were smokers. For 84.9% of the smokers, the Fagerström test score was lower than 2 (no dependency). Additionally, 92% of the smokers did not experience withdrawal symptoms following an abrupt and mandatory cessation of cigarette smoking. Two-thirds of the smokers resumed their addiction within 2 months, 78% of whom did so the first day they had the opportunity. In the physically and mentally constraining environment of submarines, the behavioral component of cigarette dependency largely dominates over the psychological and physical components of nicotine dependence. This phenomenon occurs because the behavioral component of addiction is the source of smoking resumption and, therefore, must be better addressed to achieve sustained withdrawal. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.
Submarine canyon and fan systems of the California Continental Borderland
Normark, W.R.; Piper, D.J.W.; Romans, B.W.; Covault, J.A.; Dartnell, P.; Sliter, R.W.
2009-01-01
Late Quaternary turbidite and related gravity-flow deposits have accumulated in basins of the California Borderland under a variety of conditions of sediment supply and sea-level stand. The northern basins (Santa Barbara, Santa Monica, and San Pedro) are closed and thus trap virtually all sediment supplied through submarine canyons and smaller gulley systems along the basin margins. The southern basins (Gulf of Santa Catalina and San Diego Trough) are open, and, under some conditions, turbidity currents flow from one basin to another. Seismic-reflection profiles at a variety of resolutions are used to determine the distribution of late Quaternary turbidites. Patterns of turbidite-dominated deposition during lowstand conditions of oxygen isotope stages 2 and 6 are similar within each of the basins. Chronology is provided by radiocarbon dating of sediment from two Ocean Drilling Program sites, the Mohole test-drill site, and large numbers of piston cores. High-resolution, seismic-stratigraphic frameworks developed for Santa Monica Basin and the open southern basins show rapid lateral shifts in sediment accumulation on scales that range from individual lobe elements to entire fan complexes. More than half of the submarine fans in the Borderland remain active at any given position of relative sea level. Where the continental shelf is narrow, canyons are able to cut headward during sea-level transgression and maintain sediment supply to the basins from rivers and longshore currents during highstands. Rivers with high bedload discharge transfer sediment to submarine fans during both highstand and lowstand conditions. ?? 2009 The Geological Society of America.
Hydrothermal synthesis of ammonium illite
Šucha, Vladimír; Elsass, F.; Eberl, D.D.; Kuchta, L'.; Madejova, J.; Gates, W.P.; Komadel, P.
1998-01-01
Synthetic gel and glass of illitic composition, natural kaolinite, and mixed-layer illite-smectite were used as starting materials for hydrothermal synthesis of ammonium illite. Ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300??C. The onset of crystallization began within 3 h, and well-crystallized ammonium illite appeared at 24 h. Increasing reaction time (up to four weeks) led to many illite layers per crystal. In the presence of equivalent proportions of potassium and ammonium, the gel was transformed to illite with equimolar contents of K and NH4. In contrast, synthesis using glass under the same conditions resulted in a mixture of mixed-layer ammonium illite-smectite with large expandability and discrete illite. Hydrothermal treatments of the fine fractions of natural kaolinite and illite-smectite produced ammonium illite from kaolinite but the illite-smectite remained unchanged.
Examination of the constructional processes of submarine Cerro Azul and the Galapagos Platform
NASA Astrophysics Data System (ADS)
Lambert, M. K.; Harpp, K. S.; Geist, D. J.; Fornari, D. J.; Kurz, M. D.; Koleszar, A. M.; Rollins, N. A.
2004-05-01
One of the primary goals of the 2001 Drift04 cruise was to examine the constructional processes responsible for the Galapagos platform and to investigate the relationship between the platform and the overlying volcanoes. Cerro Azul volcano is located above the steep escarpment that marks the southwestern limit of the Galapagos platform, at the leading edge of the hotspot. This area is of particular interest in light of a recent seismic tomography experiment by Toomey, Hooft, et al., which suggests that the root of the Galapagos plume is centered between Cerro Azul and adjacent Fernandina Island. During the Drift04 cruise, detailed bathymetric and sidescan sonar studies were carried out across the submarine sector of Cerro Azul and 14 dredges were collected from the same area. Major element analyses of the submarine lavas indicate that the lavas from the platform edge and the subaerial Cerro Azul lavas constitute a suite of petrologically-related lavas. The dredged glasses of the Drift04 cruise have MgO contents of <7.5% and are indistinguishable from published data on Cerro Azul. Whole rock analyses include a highly primitive sample (20 wt% MgO), which probably contains accumulated olivine. All the submarine and subaerial lavas define coherent trends in major element space that are consistent with variable amounts of olivine and olivine+cpx fractionation. Incompatible trace element (ITE) ratios indicate that the mantle source for the submarine platform flows is intermediate in composition between the magmas supplying Fernandina and Cerro Azul. Previous researchers have proposed that two mantle endmembers are interacting across the leading edge of the plume, one focused at Fernandina and the other at Floreana Island. The intermediate ITE ratios of the submarine and subaerial Cerro Azul lavas are consistent both geographically and compositionally with this hypothesis. Naumann and co-workers concluded that the lavas erupted at Cerro Azul were stored in small
Hydrothermal systems as environments for the emergence of life
NASA Technical Reports Server (NTRS)
Shock, E. L.
1996-01-01
Analysis of the chemical disequilibrium provided by the mixing of hydrothermal fluids and seawater in present-day systems 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 hydrothermal systems because it depends only on catalysis of thermodynamically favourable, exergonic reactions. It follows that hydrothermal systems may be the most favourable environments for life on Earth. This fact makes hydrothermal systems 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 hydrothermal systems on the early Earth would correspond to the presence of liquid water. Evidence that hydrothermal systems 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 hydrothermal systems. 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 hydrothermal system.
Comparative safety assessment of surface versus submarine plutonium shipments
DOE Office of Scientific and Technical Information (OSTI.GOV)
Knepper, D.S.; Feltus, M.A.
1993-01-01
The recent shipment of plutonium from France to Japan aboard the freighter Akatsuki Maru touched off protests from environmental and antinuclear organizations. These protests arose from the fear of an accidental sinking of the vessel that would release its cargo to the sea, as well as the threat of a terrorist nation highjacking the ship for its cargo to produce atomic weapons. The sinking of a merchant ship is not uncommon, as illustrated by the famous losses of the tankers Amoco Cadiz and Exxon Valdez. The highjacking of a lightly armed freighter such as the Akatsuki Maru is possible andmore » would not be unduly difficult for a well-equipped terrorist nation. The combined threats of weapons proliferation and environmental damage arising from the diversion or destruction of a sea vessel carrying plutonium will continue to abound as the reprocessing of spent nuclear fuel increases. An alternate method for the transportation with reduced risks of both diversion and destruction needs to be developed. The shipment aboard the Akatsuki Maru was originally proposed to be flown from France to Japan over the continental United States. This proposal was rejected by the Reagan administration in 1988. A third alternative to the current ideas of air transport and surface transport is subsurface transport. This research project investigates the transportation of plutonium by submarine and compares it to the current method of transportation by freighter. This analysis involves a study of the military threat to a submarine by a terrorist nation and comparable threat to a surface vessel. To study the nonmilitary aspects of plutonium shipping, a fault-tree evaluation is performed for transportation by submarine and compared with the current risk analysis performed for surface vessels.« less
Li, Chunxing; Wang, Xingdong; Zhang, Guangyi; Yu, Guangwei; Lin, Jingjiang; Wang, Yin
2017-06-15
To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C-220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0-11.0 by adding Ca(OH) 2 . The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH) 2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO. Copyright © 2017 Elsevier Ltd. All rights reserved.
Ancient Hydrothermal Springs in Arabia Terra, Mars
NASA Technical Reports Server (NTRS)
Oehler, Dorothy Z.; Allen, Carlton C.
2008-01-01
Hydrothermal springs are important astrobiological sites for several reasons: 1) On Earth, molecular phylogeny suggests that many of the most primitive organisms are hyperthermophiles, implying that life on this planet may have arisen in hydrothermal settings; 2) on Mars, similar settings would have supplied energy- and nutrient-rich waters in which early martian life may have evolved; 3) such regions on Mars would have constituted oases of continued habitability providing warm, liquid water to primitive life forms as the planet became colder and drier; and 4) mineralization associated with hydrothermal settings could have preserved biosignatures from those martian life forms. Accordingly, if life ever developed on Mars, then hydrothermal spring deposits would be excellent localities in which to search for morphological or chemical remnants of that life. Previous attempts to identify martian spring deposits from orbit have been general or limited by resolution of available data. However, new satellite imagery from HiRISE has a resolution of 28 cm/pixel which allows detailed analysis of geologic structure and geomorphology. Based on these new data, we report several features in Vernal Crater, Arabia Terra that we interpret as ancient hydrothermal springs.
Calibrated Hydrothermal Parameters, Barrow, Alaska, 2013
Atchley, Adam; Painter, Scott; Harp, Dylan; Coon, Ethan; Wilson, Cathy; Liljedahl, Anna; Romanovsky, Vladimir
2015-01-29
A model-observation-experiment process (ModEx) is used to generate three 1D models of characteristic micro-topographical land-formations, which are capable of simulating present active thaw layer (ALT) from current climate conditions. Each column was used in a coupled calibration to identify moss, peat and mineral soil hydrothermal properties to be used in up-scaled simulations. Observational soil temperature data from a tundra site located near Barrow, AK (Area C) is used to calibrate thermal properties of moss, peat, and sandy loam soil to be used in the multiphysics Advanced Terrestrial Simulator (ATS) models. Simulation results are a list of calibrated hydrothermal parameters for moss, peat, and mineral soil hydrothermal parameters.
30 years of Arctic sea ice thickness measurements by Royal Navy submarines
NASA Astrophysics Data System (ADS)
Wadhams, P.; Hughes, N.; Rodrigues, J. M.; Toberg, N.
2009-12-01
Royal Navy submarines fitted with upward-looking sonars have been collecting sea ice thickness data in the Arctic Ocean since the early 1970s. These data sets provide unique information on the Arctic sea ice thickness distribution and the way it has been changing in the past decades. In March 2007 HMS Tireless conducted a transect of the Arctic Ocean from Fram Strait to the western Beaufort Sea which gave the opportunity to measure the thickness of the sea ice cover during the winter immediately preceding the exceptional retreat of summer 2007. Three years earlier, in April 2004, a voyage by the same submarine took sea ice thickness data in the regions of Fram Strait, the Lincoln Sea and the North Pole. We report on the ice draft, pressure ridge and lead distributions obtained in these two cruises and analyse the evolution of the ice cover from 2004 to 2007 in areas of coincident tracks. In the region from north of Fram Strait to Ellesmere Island (about 85°N, 0-70°W) we find no change in mean drafts between 2004 and 2007 although there is a change in ice composition, with more ridging in 2007 and a slight reduction of modal draft. This agrees with the concept of young ice being driven towards Fram Strait. The region north of Ellesmere Island continues to be a "redoubt" of very thick deformed multiyear ice. In 2007 the submarine profiled extensively under the DAMOCLES ice camp at about 85°N 64°W and under the SEDNA ice camp at about 73°N 145°W. The latter is in the same location as the 1976 AIDJEX ice camp and a sonar survey done by a US submarine in April 1976. We found that a large decrease in mean draft had occurred (32%) over 31 years and that in 2007 the SEDNA region contained the thinnest ice of any part of the Arctic surveyed by the submarine. Under the DAMOCLES ice camp about 200km of topographic sea ice data were gathered with a Kongsberg EM3002 multibeam (MB) sonar, making this the largest continuous data set of its kind. The MB data produce high
Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.
2017-09-12
A combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) system 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.
Study on dynamic response measurement of the submarine pipeline by full-term FBG sensors.
Zhou, Jinghai; Sun, Li; Li, Hongnan
2014-01-01
The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG) is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG) sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement.
NASA Astrophysics Data System (ADS)
Wang, S. C.; Hutchings, L.; Chang, C. C.; Lee, C. S.
2017-12-01
The Tatun volcanic group (TVG) and the Keelung submarine volcano (KSV) are active volcanoes and surrounding three nuclear plant sites in north Taiwan. The famous Jinshan-Wanli hot springs locates between TVG and KSV, moreover, the geochemical anomalies of acidic boiling springs on the seacoast infer that the origin is from magmatic fluids, sea water and meteoric water mixture, strongly implying that mantle fluids ascends into the shallow crust. The evidence for a magma chamber, submarine volcano, and boiling springs have a close spatial relationship. Based on UNECE specifications to Geothermal Energy Resources (2016), the Jinshan-Wanli geothermal area could be classified as Known Geothermal Energy Source for geothermal direct use and Potential Geothermal Energy Source for conventional geothermal system. High resolution reservoir exploration and modeling in Jinshan-Wanli geothermal area is developing for drilling risk mitigation. The geothermal team of National Taiwan Ocean University and local experts are cooperating for further exploration drilling and geothermal source evaluation. Keywords: geothermal resource evaluation, Jinshan-Wanli geothermal area, submarine volcano
Study on Dynamic Response Measurement of the Submarine Pipeline by Full-Term FBG Sensors
Zhou, Jinghai; Sun, Li; Li, Hongnan
2014-01-01
The field of structural health monitoring is concerned with accurately and reliably assessing the integrity of a given structure to reduce ownership costs, increase operational lifetime, and improve safety. In structural health monitoring systems, fiber Bragg grating (FBG) is a promising measurement technology for its superior ability of explosion proof, immunity to electromagnetic interference, and high accuracy. This paper is a study on the dynamic characteristics of fiber Bragg grating (FBG) sensors applied to a submarine pipeline, as well as an experimental investigation on a laboratory model of the pipeline. The dynamic response of a submarine pipeline under seismic excitation is a coupled vibration of liquid and solid interaction. FBG sensors and strain gauges are used to monitor the dynamic response of a submarine pipeline model under a variety of dynamic loading conditions and the maximum working frequency of an FBG strain sensor is calculated according to its dynamic strain responses. Based on the theoretical and experimental results, it can be concluded that FBG sensor is superior to strain gauge and satisfies the demand of dynamic strain measurement. PMID:24971391