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Sample records for abyssal hill topography

  1. Abyssal hills: Influence of topography on benthic foraminiferal assemblages

    NASA Astrophysics Data System (ADS)

    Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.

    2016-11-01

    Abyssal plains, often thought of as vast flat areas, encompass a variety of terrains including abyssal hills, features that constitute the single largest landscape type on Earth. The potential influence on deep-sea benthic faunas of mesoscale habitat complexity arising from the presence of abyssal hills is still poorly understood. To address this issue we focus on benthic foraminifera (testate protists) in the >150-μm fraction of Megacorer samples (0-1 cm layer) collected at five different sites in the area of the Porcupine Abyssal Plain Sustained Observatory (NE Atlantic, 4850 m water depth). Three sites are located on the tops of small abyssal hills (200-500 m elevation) and two on the adjacent abyssal plain. We examined benthic foraminiferal assemblage characteristics (standing stock, diversity, composition) in relation to seafloor topography (hills vs. plain). Density and rarefied diversity were not significantly different between the hills and the plain. Nevertheless, hills do support a higher species density (i.e. species per unit area), a distinct fauna, and act to increase the regional species pool. Topographically enhanced bottom-water flows that influence food availability and sediment type are suggested as the most likely mechanisms responsible for these differences. Our findings highlight the potential importance of mesoscale heterogeneity introduced by relatively modest topography in regulating abyssal foraminiferal diversity. Given the predominance of abyssal hill terrain in the global ocean, we suggest the need to include faunal data from abyssal hills in assessments of abyssal ecology.

  2. Impact of synthetic abyssal hill roughness on resolved motions in numerical global ocean tide models

    NASA Astrophysics Data System (ADS)

    Timko, Patrick G.; Arbic, Brian K.; Goff, John A.; Ansong, Joseph K.; Smith, Walter H. F.; Melet, Angélique; Wallcraft, Alan J.

    2017-04-01

    Global models of seafloor topography have incomplete and inconsistent resolution at horizontal wavelengths less than about 10-20 km, notably due to their inability to resolve abyssal hills in areas unsurveyed by ships (that is, about 90% of the global seafloor). We investigated the impact of this unresolved bottom roughness on global numerical simulations of the HYbrid Coordinate Ocean Model (HYCOM) that are forced exclusively by the M2 and K1 internal tides. Simulations were run with horizontal resolutions of 0.08° and 0.04°, 10 isopycnal layers in the vertical direction, and two versions of bathymetry: one derived from the SRTM30_PLUS global bathymetry model, and one merging SRTM30_PLUS with a synthetic fractal surface simulating the expected roughness of abyssal hills in the 2-10 km horizontal wavelength band. Power spectra of the two bathymetry versions diverge at wavenumbers of order 4*10-4 radians/m and higher (wavelengths of order 15 km and lower), with more pronounced differences evident on the 0.04° grid, as the 0.08° grid has a more limited ability to capture bathymetric details at the abyssal hill scale. Our simulations show an increase in the amount of kinetic and potential energy in higher vertical modes, especially in the 0.04° simulation, when the synthetic roughness is added. Adding abyssal hills to the 0.04° simulation increases the M2 kinetic energy for modes 3 and 4 by 12-18% and the potential energy by 5 - 15%. Adding abyssal hills to the 0.08° simulation yields a reduced, though still measurable, impact on simulated baroclinic tidal energies. Baroclinic tidal energy conversion rates increase by up to 16% in regions of high roughness, and by up to 3.4% in the global integral. The 3.4% increase in global conversion rates in the numerical simulations is less than the 10% increase computed from a linear analysis on a 0.008° grid because of the resolution limitations of the numerical simulations. The results obtained in the present study

  3. Global prediction of abyssal hill roughness statistics for use in ocean models from digital maps of paleo-spreading rate, paleo-ridge orientation, and sediment thickness

    NASA Astrophysics Data System (ADS)

    Goff, John A.; Arbic, Brian K.

    Abyssal hills are the dominant small-scale roughness fabric over much of the ocean floor. Created at mid-ocean ridges by combined volcanic and tectonic processes, they are rafted away by plate spreading and modified through time by mass wasting and sedimentation. Abyssal hills are morphological indicators of spreading rate and direction: they are lineated parallel to the ridge at the time of formation, and their heights and widths are inversely correlated to spreading rate. Knowledge of abyssal hill roughness statistics is important for high-resolution models, including models of internal wave generation and mixing driven by tidal and low-frequency flows over the rough bottom. In this paper we present a prediction of abyssal hill roughness statistical parameters world-wide via relationships for the average statistical properties of abyssal hills as a function of spreading rate and direction, and for the modification to these roughness parameters as a function of sediment thickness. These relationships are constrained by new publicly-available digital maps of paleo-spreading rate and direction, and sediment thickness. We also develop a new method for generating synthetic topography with variable statistical properties over a grid, and present an example of synthetic abyssal hill roughness generated for the North Atlantic on a 1/2-min grid.

  4. Observations on Cretaceous abyssal hills in the northeast Pacific

    USGS Publications Warehouse

    Eittreim, S.L.; Piper, D.Z.; Chezar, H.; Jones, D.R.; Kaneps, A.

    1984-01-01

    An abyssal hills area of 50 ?? 60 km in the northeast Pacific was studied using bottom transponder navigation, closely spaced survey lines, and long-traverse oblique photography. The block-faulted north-south hills are bounded by scarps, commonly with 40?? slopes. On these steep scarps sedimentation is inhibited and pillow basalts often crop out. An ash layer of high acoustic reflectivity at about 7 m subbottom depth blankets the area. This ash occurs in multiple beds altered to phillipsite and is highly consolidated. A 24 m.y. age for the ash is based on ichthyolith dates from samples in the overlying sediments. Acoustically transparent Neogene sediments above the ash are thickest in trough bottoms and are absent or thin on steep slopes. These Neogene sediments are composed of pale-brown pelagic clays of illite, quartz, smectite, chlorite and kaolinite. Dark-brown pelagic clays, rich in smectite and amorphous iron oxides, underlie the Neogene surficial sediments. Manganese nodules cover the bottom in varying percentages. The nodules are most abundant near basement outcrops and where the subbottom ash layer is absent. ?? 1984.

  5. An abyssal hill fractionates organic and inorganic matter in deep-sea surface sediments

    NASA Astrophysics Data System (ADS)

    Turnewitsch, Robert; Lahajnar, Niko; Haeckel, Matthias; Christiansen, Bernd

    2015-09-01

    Current estimates suggest that more than 60% of the global seafloor are covered by millions of abyssal hills and mountains. These features introduce spatial fluid-dynamic "granularity" whose influence on deep-ocean sediment biogeochemistry is unknown. Here we compare biogeochemical surface-sediment properties from a fluid-dynamically well-characterized abyssal hill and upstream plain: (1) In hill sediments, organic-carbon and -nitrogen contents are only about half as high as on the plain while proteinaceous material displays less degradation; (2) on the hill, more coarse-grained sediments (reducing particle surface area) and very variable calcite contents (influencing particle surface charge) are proposed to reduce the extent, and influence compound-specificity, of sorptive organic-matter preservation. Further studies are needed to estimate the representativeness of the results in a global context. Given millions of abyssal hills and mountains, their integrative influence on formation and composition of deep-sea sediments warrants more attention.

  6. A three-dimensional map of tidal dissipation over abyssal hills

    NASA Astrophysics Data System (ADS)

    Lefauve, Adrien; Muller, Caroline; Melet, Angélique

    2015-07-01

    The breaking of internal tides is believed to provide a large part of the power needed to mix the abyssal ocean and sustain the meridional overturning circulation. Both the fraction of internal tide energy that is dissipated locally and the resulting vertical mixing distribution are crucial for the ocean state, but remain poorly quantified. Here we present a first worldwide estimate of mixing due to internal tides generated at small-scale abyssal hills. Our estimate is based on linear wave theory, a nonlinear parameterization for wave breaking and uses quasi-global small-scale abyssal hill bathymetry, stratification, and tidal data. We show that a large fraction of abyssal-hill generated internal tide energy is locally dissipated over mid-ocean ridges in the Southern Hemisphere. Significant dissipation occurs above ridge crests, and, upon rescaling by the local stratification, follows a monotonic exponential decay with height off the bottom, with a nonuniform decay scale. We however show that a substantial part of the dissipation occurs over the smoother flanks of mid-ocean ridges, and exhibits a middepth maximum due to the interplay of wave amplitude with stratification. We link the three-dimensional map of dissipation to abyssal hills characteristics, ocean stratification, and tidal forcing, and discuss its potential implementation in time-evolving parameterizations for global climate models. Current tidal parameterizations only account for waves generated at large-scale satellite-resolved bathymetry. Our results suggest that the presence of small-scale, mostly unresolved abyssal hills could significantly enhance the spatial inhomogeneity of tidal mixing, particularly above mid-ocean ridges in the Southern Hemisphere.

  7. Reconstructed Paleo-topography of the Columbia Hills, Mars

    NASA Astrophysics Data System (ADS)

    Cole, S. B.; Watters, W. A.; Aron, F.; Squyres, S. W.

    2013-12-01

    From June 2004 through March 2010, the Mars Exploration Rover Spirit conducted a detailed campaign examining the Columbia Hills of Gusev Crater. In addition to mineralogical and chemical investigations, Spirit's stereo panoramic (Pancam) and navigation (Navcam) cameras obtained over 7,000 images of geologic targets along the West Spur of the Columbia Hills and Husband Hill, the highest peak. We have analyzed the entirety of this dataset, which includes stereo coverage of several outcrop exposures with apparent bedding. We have measured the bedding plane orientations of hundreds of fine-scale (~1-100cm) features on all of the potentially in-place outcrops using Digital Terrain Models (DTMs) derived from the rover's Pancam stereo image data, and mapped these orientations on a regional HiRISE image and DTM. Assuming that the bedding material was deposited conformably on the topography at the time of emplacement, we reconstruct the paleo-topography of the Columbia Hills. Our reconstructed paleo-topography is similar to the modern shape of Husband Hill, but with steeper slopes, consistent with a substantial amount of erosion since deposition. The Columbia Hills are an irregular, nearly-triangular edifice of uncertain origin, situated near the center of the 160km-diameter crater and hypothesized to be either the remnant of a central peak structure, or overlapping crater rims. They span ~6.6 km in the northerly direction by ~3.6 km in the easterly direction, and rise 90m above the basaltic plains that fill the floor of Gusev Crater and embay the Hills. The topography is as irregular as the perimeter, and is cut by numerous valleys of varying lengths, widths, and directional trends. Along the traverse, Spirit examined several rock classes as defined by elemental abundances from the Alpha Particle X-ray Spectrometer (APXS) and identified remotely by the Miniature Thermal Emission Spectrometer (Mini-TES). Unlike the Gusev Plains, the rocks of the Columbia Hills show

  8. Evidence for enhanced mixing over rough topography in the abyssal ocean

    PubMed

    Ledwell; Montgomery; Polzin; St. Laurent LC; Schmitt; Toole

    2000-01-13

    The overturning circulation of the ocean plays an important role in modulating the Earth's climate. But whereas the mechanisms for the vertical transport of water into the deep ocean--deep water formation at high latitudes--and horizontal transport in ocean currents have been largely identified, it is not clear how the compensating vertical transport of water from the depths to the surface is accomplished. Turbulent mixing across surfaces of constant density is the only viable mechanism for reducing the density of the water and enabling it to rise. However, measurements of the internal wave field, the main source of energy for mixing, and of turbulent dissipation rates, have typically implied diffusivities across surfaces of equal density of only approximately 0.1 cm2 s(-1), too small to account for the return flow. Here we report measurements of tracer dispersion and turbulent energy dissipation in the Brazil basin that reveal diffusivities of 2-4 cm2 s(-1) at a depth of 500 m above abyssal hills on the flank of the Mid-Atlantic Ridge, and approximately 10 cm2 s(-1) nearer the bottom. This amount of mixing, probably driven by breaking internal waves that are generated by tidal currents flowing over the rough bathymetry, may be large enough to close the buoyancy budget for the Brazil basin and suggests a mechanism for closing the global overturning circulation.

  9. EAARL Topography-Sagamore Hill National Historic Site

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Travers, Laurinda J.

    2007-01-01

    This Web site contains lidar-derived bare earth (BE) and first return (FR) topography maps and GIS files for the Sagamore Hill National Historic Site. These lidar-derived topography 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), Northeast Coastal and Barrier 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.

  10. SRTM Colored and Shaded Topography: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001, the Kachchh region in western India suffered the most deadly earthquake in India's history. This shaded topography view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. In this view, the anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the linear feature trending toward the southwest from the image center is an erosion-resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. These features are simple examples of how shaded topography can provide a direct input to geologic studies.

    In this image, colors show the elevation as measured by the Shuttle Radar Topography Mission (SRTM). Colors range from green at the lowest elevations, through yellow and red, to purple at the highest elevations. Elevations here range from near sea level to about 300 meters (about 1000 feet). Shading has been added, with illumination from the north (image top).

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same

  11. Petrological, magnetic and chemical properties of basalt dredged from an abyssal hill in the North-east pacific

    USGS Publications Warehouse

    Luyendyk, B.P.; Engel, C.G.

    1969-01-01

    OVER the years, samples of basalt from the oceanic crust have been taken mainly from seamounts, fracture zones and ridge and rise crests1-6, and rarely from the vast fields of abyssal hills which cover a large part of the deep-sea floor. The basalt sampled from the deeper regions of the oceanic crust (for example, on fault scarps) is a distinct variety of tholeiitic basalt, while alkali basalt is restricted to the volcanic edifices4. Oceanic tholeiitic basalt differs from alkali basalt and continental tholeiite chiefly in having a relatively low percentage of K2O (0.2 weight per cent)4. Some authors have speculated that this type of tholeiitic basalt is the major extrusion from the upper mantle and constitutes the predominant rock type in the upper oceanic crust. ?? 1969 Nature Publishing Group.

  12. Milankovich Sea Level-Change Pumping of Fault Slip May Enhance Abyssal Hill Growth, with Spacing Control by Melt Pumping or Elastic Properties

    NASA Astrophysics Data System (ADS)

    Macdonald, K. C.

    2015-12-01

    Sea level-change pumping of mantle melt to create abyssal hills is a very innovative and elegant hypothesis. However, I see 2 issues: 1. Abyssal hill observations indicate that they are bounded by normal faults in most cases. 2. The resolution of the crustal accretion "tape recorder" and its ability to accurately record cycles as short as 20Kyr and 40Kyr is limited given the width of the zone of crustal accretion. Magnetic anomaly polarity transition widths give us one measure of estimating the resolution of this tape recorder. Based on these measurements, the half-width of the zone of crustal accretion ranges from 1-8 km, with 2-4 km being typical. At a half-spreading rate of 3 cm/yr, a width of 3km of crust is created during the 100Kyr Milankovich cycle, ~1.2 km during the 40Kyr cycle, and 600m during the 20Kyr cycle, so only the 100K signal is likely to be resolvable. In contrast, consider the effect of pressure changes on fault slip. In critically stressed lithosphere, a small change in pressure can produce nearly instantaneous slip. For example, pressure changes of only ~0.1 MPa near injection wells in OK, TX trigger earthquakes at depths of 3-5 km (Mark Zoback, personal comm.). This pressure change is equivalent to a 100 m sea level change. For the 20Kyr and 40Kyr cycles, sea level-change pumping of fault slip may dominate because fault uplift of abyssal hills is not smeared by the time-averaging effects of crustal accretion. The spacing of the abyssal hills in this scenario would be controlled by the elastic thickness and flexural rigidity of young lithosphere. Faulting also can accommodate variations in melt supply, with most of the melt freezing at depth; this would explain why we observe dominantly tectonic rather than constructional volcanic origins of abyssal hills. If abyssal hills are caused by variations in melt production, the crust should be measurably thicker beneath the axes of the hills. If faulting dominates, crustal thickness would be more

  13. Influence of Topography on Root Processes in the Shale Hills-Susquehanna Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Eissenstat, D. M.; Orr, A. S.; Adams, T. S.; Chen, W.; Gaines, K.

    2015-12-01

    Topography can strongly influence root and associated mycorrhizal fungal function in the Critical Zone. In the Shale Hills-Susquehanna Critical Zone Observatory (SSCZO), soil depths range from more than 80 cm deep in the valley floor to about 25 cm on the ridge top. Tree height varies from about 28 m tall at the valley floor to about 17 m tall at the ridge top. Yet total absorptive root length to depth of refusal is quite similar across the hillslope. We find root length density to vary as much at locations only 1-2 m apart as at scales of hundreds of meters across the catchment. Tree community composition also varies along the hillslope, including tree species that vary widely in thickness of their absorptive roots and type of mycorrhiza (arbuscular mycorrhizal and ectomycorrhizal). Studies of trees in a common garden of 16 tree species and in forests near SSCZO indicate that both root morphology and mycorrhizal type can strongly influence root foraging. Species that form thick absorptive roots appear more dependent on mycorrhizal fungi and thin-root species forage more by root proliferation. Ectomycorrhizal trees show more variation in foraging precision (proliferation in a nutrient-rich patch relative to that in an unenriched patch) of their mycorrhizal hyphae whereas AM trees show more variation in foraging precision by root proliferation, indicating alternative strategies among trees of different mycorrhizal types. Collectively, the results provide insight into how topography can influence foraging belowground.

  14. Low-velocity zone and topography as a source of site amplification effect on Tarzana hill, California

    USGS Publications Warehouse

    Graizer, V.

    2009-01-01

    Tarzana station is located in the foothills of the Santa Monica Mountains in California near the crest of a low (<20 m) natural hill with gentle slopes. The hill is about 500 m in length by 130 m in width and is formed of extremely weathered shale at the surface to fresh at depth. Average S-wave is about 250 m/s in the top 17-18 m, and S- and P-wave velocities significantly increase below this depth. According to the NEHRP classification based on VS30???300 m/s it is a site class D. Strong-motion instrumentation at Tarzana consisted of an accelerograph at the top of the hill, a downhole instrument at 60 m depth, and an accelerograph at the base of the hill. More than 20 earthquakes were recorded by at least three instruments at Tarzana from 1998 till 2003. Comparisons of recordings and Fourier spectra indicate strong directional resonance in a direction perpendicular to the strike of the hill. The dominant peaks in ground motion amplification on the top of the hill relative to the base are at frequencies ???3.6 and 8-9 Hz for the horizontal components. Our hypothesis is that the hill acts like a wave trap. This results in an amplification at predominant frequencies f=V/4 h (h is layer's thickness) at f???3.6 Hz for S-waves (using average VS17=246 m/s and h=17 m) and f???7.9 Hz for P-waves (using average VP17=535 m/s and h=17 m). As was shown by Bouchon and Barker [Seismic response of a hill: the example of Tarzana, California. Bull Seism Soc Am 1996;86(1A):66-72], topography of this hill amplifies and polarizes ground motion in the frequency range of 3-5 Hz. Hill acts as a magnifying polarizing glass: It polarizes ground motion in the direction perpendicular to the strike of the hill and also amplifies ground motions that had been also amplified by a low-velocity layer.

  15. Relationship between 'live' and dead benthic foraminiferal assemblages in the abyssal NE Atlantic

    NASA Astrophysics Data System (ADS)

    Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.

    2017-03-01

    Dead foraminiferal assemblages within the sediment mixed layer provide an integrated, time-averaged view of the foraminiferal fauna, while the relationship between dead and live assemblages reflects the population dynamics of different species together with taphonomic processes operating over the last few hundred years. Here, we analysed four samples for 'live' (Rose-Bengal-stained) and dead benthic foraminifera (0-1 cm sediment layer, >150 μm) from four sites in the area of the Porcupine Abyssal Plain Sustained Observatory (PAP-SO; NE Atlantic, 4850 m water depth). Two sites were located on abyssal hills and two on the adjacent abyssal plain. Our results indicate that the transition from live to dead benthic foraminiferal assemblages involved a dramatic loss of delicate agglutinated and organic-walled tests (e.g. Lagenammina, Nodellum, Reophax) with poor preservation potential, and to a lesser extent that of some relatively fragile calcareous tests (mostly miliolids), possibly a result of dissolution. Other processes, such as the transport of tests by bottom currents and predation, are unlikely to have substantially altered the composition of dead faunas. Positive live to dead ratios suggest that some species (notably Epistominella exigua and Bolivina spathulata) may have responded to recent phytodetritus input. Although the composition of live assemblages seemed to be influenced by seafloor topography (abyssal hills vs. plain), no such relation was found for dead assemblages. We suggest that PAP-SO fossil assemblages are likely to be comparable across topographically contrasting sites, and dominated by calcareous and some robust agglutinated forms with calcitic cement (e.g. Eggerella).

  16. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle.

    PubMed

    Milligan, R J; Morris, K J; Bett, B J; Durden, J M; Jones, D O B; Robert, K; Ruhl, H A; Bailey, D M

    2016-05-16

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1-10 km(2)) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km(-2) (95% CI: 601-844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km(-2) respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed.

  17. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle

    NASA Astrophysics Data System (ADS)

    Milligan, R. J.; Morris, K. J.; Bett, B. J.; Durden, J. M.; Jones, D. O. B.; Robert, K.; Ruhl, H. A.; Bailey, D. M.

    2016-05-01

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1–10 km2) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km‑2 (95% CI: 601–844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km‑2 respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed.

  18. High resolution study of the spatial distributions of abyssal fishes by autonomous underwater vehicle

    PubMed Central

    Milligan, R. J.; Morris, K. J.; Bett, B. J.; Durden, J. M.; Jones, D. O. B.; Robert, K.; Ruhl, H. A.; Bailey, D. M.

    2016-01-01

    On abyssal plains, demersal fish are believed to play an important role in transferring energy across the seafloor and between the pelagic and benthic realms. However, little is known about their spatial distributions, making it difficult to quantify their ecological significance. To address this, we employed an autonomous underwater vehicle to conduct an exceptionally large photographic survey of fish distributions on the Porcupine Abyssal Plain (NE Atlantic, 4850 m water depth) encompassing two spatial scales (1–10 km2) on and adjacent to a small abyssal hill (240 m elevation). The spatial distributions of the total fish fauna and that of the two dominant morphotypes (Coryphaenoides sp. 1 and C. profundicolus) appeared to be random, a result contrary to common expectation but consistent with previous predictions for these fishes. We estimated total fish density on the abyssal plain to be 723 individuals km−2 (95% CI: 601–844). This estimate is higher, and likely more precise, than prior estimates from trawl catch and baited camera techniques (152 and 188 individuals km−2 respectively). We detected no significant difference in fish density between abyssal hill and plain, nor did we detect any evidence for the existence of fish aggregations at any spatial scale assessed. PMID:27180728

  19. Topographic height dependence of internal wave generation by tidal flow over random topography

    NASA Astrophysics Data System (ADS)

    Zhao, Jiajun; Zhang, Likun; Swinney, Harry L.

    2015-10-01

    Internal waves (IWs) generated by tidal flow over the seafloor play a critical role in ocean circulation and climate. We determine the dependence of the radiated IW power on topographic parameters in numerical simulations of tidal flow over two-dimensional random topographic profiles that have the spectrum of oceanic abyssal hills. The IW power increases as the horizontal spatial resolution scale is decreased, but below a certain spatial scale the power saturates at a level less than the linear theory prediction. For increasing topographic RMS height Hrms the emergent interference of the tide and the IWs from different generation sites leads to a transition in the IW power dependence on Hrms from quadratic to linear. This transition in the scaling of the IW power depends on the slopes of a valley's nearest neighboring peaks. Our results should guide the modeling of IW generation by tidal flow over small-scale ocean topography.

  20. An Abyssal Current in the Central Labrador Sea

    NASA Astrophysics Data System (ADS)

    Hall, M. M.; Yashayaev, I.; Torres, D. J.

    2012-12-01

    Lowered acoustic Doppler current profiler (LADCP) data collected along the repeat hydrographic section AR7W in the Labrador Sea has unveiled a new abyssal current, confined to a narrow trench extending from NW to SE over the entire abyssal basin and crossing AR7W in the center of the basin at about 57.8°N, 51.3°W. Maximum water depth in the trough is 75 - 100 m greater depth than the surrounding topography, and the current extends from about 160 m above the bottom to the bottom (3610 m), headed in a south to southeasterly direction. Maximum speeds of 10-20 cm s-1 occur in the deepest part of the current, implying a net transport of as much as 0.2 Sv of Denmark Strait Overflow Water (DSOW). Potential temperature and salinity in the bottom-intensified current tend to be well mixed below 3520 m, suggesting that the mixed bottom boundary layer is about 100 m thick. This V-shaped trench is part of the Northwest Atlantic Mid-Ocean Channel (NAMOC), which has been recognized as a turbidity current pathway by petrologists (Chough and Hesse, 1980; Chough et al., 1986). Another small trough intersects the main branch of the NAMOC where the abyssal current is observed, which may account for the varying direction of the current. This network of abyssal channels may provide a pathway for DSOW, entering the Labrador Sea around the southern tip of Greenland, to reach the central Labrador Sea with little delay. Indeed, Yashayaev and Dickson (2008) have noted the rapidity with which signals of hydrographic change in DSOW spread across the entire abyssal basin, reaching the central Labrador Sea within several months after their first appearance at the eastern boundary. Chough, S. K. and R. Hesse (1980). The Northwest Atlantic Mid-Ocean Channel of the Labrador Sea: III. Head spill vs. body spill deposits from turbidity currents on natural levees. J. of Sedimentary Petrology 50, 227-234. Chough, S. K., R. Hesse, and J. Muller (1987). The Northwest Atlantic Mid-Ocean Channel of the

  1. Internal wave structures in abyssal cataract flows

    NASA Astrophysics Data System (ADS)

    Makarenko, Nikolay; Liapidevskii, Valery; Morozov, Eugene; Tarakanov, Roman

    2014-05-01

    We discuss some theoretical approaches, experimental results and field data concerning wave phenomena in ocean near-bottom stratified flows. Such strong flows of cold water form everywhere in the Atlantic abyssal channels, and these currents play significant role in the global water exchange. Most interesting wave structures arise in a powerful cataract flows near orographic obstacles which disturb gravity currents by forced lee waves, attached hydraulic jumps, mixing layers etc. All these effects were observed by the authors in the Romanche and Chain fracture zones of Atlantic Ocean during recent cruises of the R/V Akademik Ioffe and R/V Akademik Sergei Vavilov (Morozov et al., Dokl. Earth Sci., 2012, 446(2)). In a general way, deep-water cataract flows down the slope are similar to the stratified flows examined in laboratory experiments. Strong mixing in the sill region leads to the splitting of the gravity current into the layers having the fluids with different densities. Another peculiarity is the presence of critical layers in shear flows sustained over the sill. In the case under consideration, this critical level separates the flow of near-bottom cold water from opposite overflow. In accordance with known theoretical models and laboratory measurements, the critical layer can absorb and reflect internal waves generated by the topography, so the upward propagation of these perturbations is blocked from above. High velocity gradients were registered downstream in the vicinity of cataract and it indicates the existence of developed wave structures beyond the sill formed by intense internal waves. This work was supported by RFBR (grants No 12-01-00671-a, 12-08-10001-k and 13-08-10001-k).

  2. Orogenic, Ophiolitic, and Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    Bodinier, J.-L.; Godard, M.

    2003-12-01

    "Tectonically emplaced" mantle rocks include subcontinental, suboceanic, and subarc mantle rocks that were tectonically exhumed from the upper mantle and occur:(i) as dispersed ultramafic bodies, a few meters to kilometers in size, in suture zones and mountain belts (i.e., the "alpine," or "orogenic" peridotite massifs - De Roever (1957), Thayer (1960), Den Tex (1969));(ii) as the lower ultramafic section of large (tens of kilometers) ophiolite or island arc complexes, obducted on continental margins (e.g., the Oman Ophiolite and the Kohistan Arc Complex - Coleman (1971), Boudier and Coleman (1981), Burg et al. (1998));(iii) exhumed above the sea level in ocean basins (e.g., Zabargad Island in the Red Sea, St. Paul's islets in the Atlantic and Macquarie Island in the southwestern Pacific - Tilley (1947), Melson et al. (1967), Varne and Rubenach (1972), Bonatti et al. (1981)).The "abyssal peridotites" are samples from the oceanic mantle that were dredged on the ocean floor, or recovered from drill cores (e.g., Bonatti et al., 1974; Prinz et al., 1976; Hamlyn and Bonatti, 1980).Altogether, tectonically emplaced and abyssal mantle rocks provide insights into upper mantle compositions and processes that are complementary to the information conveyed by mantle xenoliths (See Chapter 2.05). They provide coverage to vast regions of the Earth's upper mantle that are sparsely sampled by mantle xenoliths, particularly in the ocean basins and beneath passive continental margins, back-arc basins, and oceanic island arcs.Compared with mantle xenoliths, a disadvantage of some tectonically emplaced mantle rocks for representing mantle compositions is that their original geodynamic setting is not exactly known and their significance is sometimes a subject of speculation. For instance, the provenance of orogenic lherzolite massifs (subcontinental lithosphere versus upwelling asthenosphere) is still debated (Menzies and Dupuy, 1991, and references herein), as is the original setting

  3. Tectonic evolution of the Perth Abyssal Plain's Quiet Zone, Southeast Indian Ocean

    NASA Astrophysics Data System (ADS)

    Ehrlich, Zohar Louis; Granot, Roi; Williams, Simon E.

    2013-04-01

    During the Late Jurassic period, the Greater-Indian plate was torn away from Australia, dissociating East Gondwanaland. The Perth Abyssal Plain (PAP) is the southernmost rift segment along the western Australian margin, and has an onset age of ~136 Ma. New marine magnetic and swath bathymetry data, crossing the entire PAP, were acquired recently on geophysical cruise ss2011v06 aboard the R/V Southern Surveyor. These have lead to the outline of conjugate Indian and Australian M-series isochrons in the east and west PAP, respectively [1]. Yet, most of the PAP was created during the Cretaceous Normal Superchron (CNS, 121-83 Ma), a period of no geomagnetic field reversals, hence no comprehensive tectonic model for the PAP exists . Here we present preliminary findings of an analytic bathymetric and magnetic investigation aimed at elucidating the PAP's quiet zone. Recent discoveries regarding the evolution of the geomagnetic field during the CNS [2] provide new time markers that can be utilized to date the oceanic crust. The magnetic anomaly data exhibit the Q2 anomaly marker (~108 Ma), further constraining the spreading history of the PAP. Together with the ridgelet transform method [3] for automated abyssal hill delineation, we present new constraints on the development of crustal construction processes (spreading location, direction and rates) that took place along the PAP spreading center. References: [1] S.E. Williams, J.M. Whittaker, R. Granot, R.D. Muller (in preparation), New constraints on the seafloor spreading history in the Perth Abyssal Plain. [2] Granot, R., J. Dyment, and Y. Gallet (2012), Geomagnetic field variability during the Cretaceous Normal Superchron, Nature Geoscience, 5(3), 220-223. [3] Downey, N. J. and R. W. Clayton (2007), A ridgelet transform method for constraining tectonic models via abyssal-hill morphology, Geochemistry Geophysics Geosystems, 8, Q03004, doi: 10.1029/2006GC001440.

  4. Red Hill

    EPA Pesticide Factsheets

    Information about the Red Hill Bulk Fuel Storage Facility in Hawaii Administrative Order on Consent (AOC), an enforceable agreement of the Hawaii Department of Health, the Environmental Protection Agency, and the U.S. Navy -- Defense Logistics Agency.

  5. Global variations in abyssal peridotite compositions

    NASA Astrophysics Data System (ADS)

    Warren, Jessica M.

    2016-04-01

    Abyssal peridotites are ultramafic rocks collected from mid-ocean ridges that are the residues of adiabatic decompression melting. Their compositions provide information on the degree of melting and melt-rock interaction involved in the formation of oceanic lithosphere, as well as providing constraints on pre-existing mantle heterogeneities. This review presents a compilation of abyssal peridotite geochemical data (modes, mineral major elements, and clinopyroxene trace elements) for > 1200 samples from 53 localities on 6 major ridge systems. On the basis of composition and petrography, peridotites are classified into one of five lithological groups: (1) residual peridotite, (2) dunite, (3) gabbro-veined and/or plagioclase-bearing peridotite, (4) pyroxenite-veined peridotite, and (5) other types of melt-added peridotite. Almost a third of abyssal peridotites are veined, indicating that the oceanic lithospheric mantle is more fertile, on average, than estimates based on residual peridotites alone imply. All veins appear to have formed recently during melt transport beneath the ridge, though some pyroxenites may be derived from melting of recycled oceanic crust. A limited number of samples are available at intermediate and fast spreading rates, with samples from the East Pacific Rise indicating high degrees of melting. At slow and ultra-slow spreading rates, residual abyssal peridotites define a large (0-15% modal clinopyroxene and spinel Cr# = 0.1-0.6) compositional range. These variations do not match the prediction for how degree of melting should vary as a function of spreading rate. Instead, the compositional ranges of residual peridotites are derived from a combination of melting, melt-rock interaction and pre-existing compositional variability, where melt-rock interaction is used here as a general term to refer to the wide range of processes that can occur during melt transport in the mantle. Globally, ~ 10% of abyssal peridotites are refractory (0

  6. Landscape-scale spatial heterogeneity in phytodetrital cover and megafauna biomass in the abyss links to modest topographic variation.

    PubMed

    Morris, Kirsty J; Bett, Brian J; Durden, Jennifer M; Benoist, Noelie M A; Huvenne, Veerle A I; Jones, Daniel O B; Robert, Katleen; Ichino, Matteo C; Wolff, George A; Ruhl, Henry A

    2016-09-29

    Sinking particulate organic matter (POM, phytodetritus) is the principal limiting resource for deep-sea life. However, little is known about spatial variation in POM supply to the abyssal seafloor, which is frequently assumed to be homogenous. In reality, the abyss has a highly complex landscape with millions of hills and mountains. Here, we show a significant increase in seabed POM % cover (by ~1.05 times), and a large significant increase in megafauna biomass (by ~2.5 times), on abyssal hill terrain in comparison to the surrounding plain. These differences are substantially greater than predicted by current models linking water depth to POM supply or benthic biomass. Our observed variations in POM % cover (phytodetritus), megafauna biomass, sediment total organic carbon and total nitrogen, sedimentology, and benthic boundary layer turbidity, all appear to be consistent with topographically enhanced current speeds driving these enhancements. The effects are detectable with bathymetric elevations of only 10 s of metres above the surrounding plain. These results imply considerable unquantified heterogeneity in global ecology.

  7. Landscape-scale spatial heterogeneity in phytodetrital cover and megafauna biomass in the abyss links to modest topographic variation

    PubMed Central

    Morris, Kirsty J.; Bett, Brian J.; Durden, Jennifer M.; Benoist, Noelie M. A.; Huvenne, Veerle A. I.; Jones, Daniel O. B.; Robert, Katleen; Ichino, Matteo C.; Wolff, George A.; Ruhl, Henry A.

    2016-01-01

    Sinking particulate organic matter (POM, phytodetritus) is the principal limiting resource for deep-sea life. However, little is known about spatial variation in POM supply to the abyssal seafloor, which is frequently assumed to be homogenous. In reality, the abyss has a highly complex landscape with millions of hills and mountains. Here, we show a significant increase in seabed POM % cover (by ~1.05 times), and a large significant increase in megafauna biomass (by ~2.5 times), on abyssal hill terrain in comparison to the surrounding plain. These differences are substantially greater than predicted by current models linking water depth to POM supply or benthic biomass. Our observed variations in POM % cover (phytodetritus), megafauna biomass, sediment total organic carbon and total nitrogen, sedimentology, and benthic boundary layer turbidity, all appear to be consistent with topographically enhanced current speeds driving these enhancements. The effects are detectable with bathymetric elevations of only 10 s of metres above the surrounding plain. These results imply considerable unquantified heterogeneity in global ecology. PMID:27681937

  8. Landscape-scale spatial heterogeneity in phytodetrital cover and megafauna biomass in the abyss links to modest topographic variation

    NASA Astrophysics Data System (ADS)

    Morris, Kirsty J.; Bett, Brian J.; Durden, Jennifer M.; Benoist, Noelie M. A.; Huvenne, Veerle A. I.; Jones, Daniel O. B.; Robert, Katleen; Ichino, Matteo C.; Wolff, George A.; Ruhl, Henry A.

    2016-09-01

    Sinking particulate organic matter (POM, phytodetritus) is the principal limiting resource for deep-sea life. However, little is known about spatial variation in POM supply to the abyssal seafloor, which is frequently assumed to be homogenous. In reality, the abyss has a highly complex landscape with millions of hills and mountains. Here, we show a significant increase in seabed POM % cover (by ~1.05 times), and a large significant increase in megafauna biomass (by ~2.5 times), on abyssal hill terrain in comparison to the surrounding plain. These differences are substantially greater than predicted by current models linking water depth to POM supply or benthic biomass. Our observed variations in POM % cover (phytodetritus), megafauna biomass, sediment total organic carbon and total nitrogen, sedimentology, and benthic boundary layer turbidity, all appear to be consistent with topographically enhanced current speeds driving these enhancements. The effects are detectable with bathymetric elevations of only 10 s of metres above the surrounding plain. These results imply considerable unquantified heterogeneity in global ecology.

  9. Paleotopography of Husband Hill and the West Spur of the Columbia Hills, Gusev Crater, Mars

    NASA Astrophysics Data System (ADS)

    Cole, S. B.; Watters, W. A.; Aron, F. A.; Squyres, S.

    2012-12-01

    From June 2004 through March 2010, Spirit conducted a detailed campaign examining the Columbia Hills of Gusev Crater. The Hills are an irregular, nearly-triangular edifice of uncertain origin, spanning ~8.4 km in the northerly direction by ~4.5 km in the easterly direction, and are embayed by the basaltic plains that fill the floor of Gusev Crater. The topography is as irregular as the perimeter, cut by numerous valleys of varying lengths, widths, and directional trends. Along its traverse, Spirit examined several rock classes as defined by elemental abundances from the Alpha Particle X-ray Spectrometer (APXS). Unlike the Gusev Plains, the rocks of the Columbia Hills show extensive evidence of aqueous alteration. In addition to mineralogical and chemical investigations, Spirit's stereo panoramic (Pancam) and navigation (Navcam) cameras obtained over 7,000 images of the West Spur of the Columbia Hills and Husband Hill, the highest peak. This dataset includes stereo coverage of several outcrop exposures with apparent bedding. In this analysis, we reconstruct a paleo-Digital Elevation Model (paleo-DEM) of the West Spur and Husband Hill based on stereo image data from the Mars Exploration Rover Spirit. We have performed detailed structural and stratigraphic measurements of the outcrops Spirit observed on its traverse across the West Spur and Husband Hill, using digital terrain models derived from Pancam and Navcam data. We compare outcrop bedding orientations to local topography as determined by the HiRISE DEM. While bedding orientations do not conform to the current topography, outcrops within local geographic regions exhibit conformable bedding orientations both within and across the rock classes defined by composition. Assuming that the bedding planes are in-place and were conformable to the local topography at the time of deposition, we reconstruct the ancient topography of the West Spur and Husband Hill.

  10. Spatially heterogeneous diapycnal mixing in the abyssal ocean: A comparison of two parameterizations to observations

    NASA Astrophysics Data System (ADS)

    Decloedt, Thomas; Luther, Douglas S.

    2012-11-01

    The spatial distributions of the diapycnal diffusivity predicted by two abyssal mixing schemes are compared to each other and to observational estimates based on microstructure surveys and large-scale hydrographic inversions. The parameterizations considered are the tidal mixing scheme by Jayne, St. Laurent and co-authors (JSL01) and the Roughness Diffusivity Model (RDM) by Decloedt and Luther. Comparison to microstructure surveys shows that both parameterizations are conservative in estimating the vertical extent to which bottom-intensified mixing penetrates into the stratified water column. In particular, the JSL01 exponential vertical structure function with fixed scale height decays to background values much nearer topography than observed. JSL01 and RDM yield dramatically different horizontal spatial distributions of diapycnal diffusivity, which would lead to quite different circulations in OGCMs, yet they produce similar basin-averaged diffusivity profiles. Both parameterizations are shown to yield smaller basin-mean diffusivity profiles than hydrographic inverse estimates for the major ocean basins, by factors ranging from 3 up to over an order of magnitude. The canonical 10-4 m2 s-1abyssal diffusivity is reached by the parameterizations only at depths below 3 km. Power consumption by diapycnal mixing below 1 km of depth, between roughly 32°S and 48°N, for the RDM and JSL01 parameterizations is 0.40 TW & 0.28 TW, respectively. The results presented here suggest that present-day mixing parameterizations significantly underestimate abyssal mixing. In conjunction with other recently published studies, a plausible interpretation is that parameterizing the dissipation of bottom-generated internal waves is not sufficient to approximate the global spatial distribution of diapycnal mixing in the abyssal ocean.

  11. The Gulf Stream pathway and the impacts of the eddy-driven abyssal circulation and the Deep Western Boundary Current

    NASA Astrophysics Data System (ADS)

    Hurlburt, Harley E.; Hogan, Patrick J.

    2008-08-01

    A hydrodynamic model of the subtropical Atlantic basin and the Intra-Americas Sea (9-47°N) is used to investigate the dynamics of Gulf Stream separation from the western boundary at Cape Hatteras and its mean pathway to the Grand Banks. The model has five isopycnal Lagrangian layers in the vertical and allows realistic boundary geometry, bathymetry, wind forcing, and a meridional overturning circulation (MOC), the latter specified via ports in the northern and southern boundaries. The northward upper ocean branch of the MOC (14 Sv) was always included but the southward Deep Western Boundary Current (DWBC) was excluded in some simulations, allowing investigation of the impacts of the DWBC and the eddy-driven mean abyssal circulation on Gulf Stream separation from the western boundary. The result is resolution dependent with the DWBC playing a crucial role in Gulf Stream separation at 1/16° resolution but with the eddy-driven abyssal circulation alone sufficient to obtain accurate separation at 1/32° resolution and a realistic pathway from Cape Hatteras to the Grand Banks with minimal DWBC impact except southeast of the Grand Banks. The separation from the western boundary is particularly sensitive to the strength of the eddy-driven abyssal circulation. Farther to the east, between 68°W and the Grand Banks, all of the 1/16° and 1/32° simulations with realistic topography (with or without a DWBC) gave similar generally realistic mean pathways with clear impacts of the topographically constrained eddy-driven abyssal circulation versus very unrealistic Gulf Stream pathways between Cape Hatteras and the Grand Banks from otherwise identical simulations run with a flat bottom, in reduced-gravity mode, or with 1/8° resolution and realistic topography. The model is realistic enough to allow detailed model-data comparisons and a detailed investigation of Gulf Stream dynamics. The corresponding linear solution with a Sverdrup interior and Munk viscous western boundary

  12. Abyssal food limitation, ecosystem structure and climate change.

    PubMed

    Smith, Craig R; De Leo, Fabio C; Bernardino, Angelo F; Sweetman, Andrew K; Arbizu, Pedro Martinez

    2008-09-01

    The abyssal seafloor covers more than 50% of the Earth and is postulated to be both a reservoir of biodiversity and a source of important ecosystem services. We show that ecosystem structure and function in the abyss are strongly modulated by the quantity and quality of detrital food material sinking from the surface ocean. Climate change and human activities (e.g. successful ocean fertilization) will alter patterns of sinking food flux to the deep ocean, substantially impacting the structure, function and biodiversity of abyssal ecosystems. Abyssal ecosystem response thus must be considered in assessments of the environmental impacts of global warming and ocean fertilization.

  13. Biogeochemical, Isotopic and Bacterial Distributions Trace Oceanic Abyssal Circulation

    PubMed Central

    Rubino, Angelo; Bensi, Manuel; Hainbucher, Dagmar; Zanchettin, Davide; Mapelli, Francesca; Ogrinc, Nives; Marchetto, Davide; Borin, Sara; Cardin, Vanessa; Fajon, Vesna; Horvat, Milena; Taricco, Carla; Baldi, Franco

    2016-01-01

    We explore the possibility of tracing routes of dense waters toward and within the ocean abyss by the use of an extended set of observed physical and biochemical parameters. To this purpose, we employ mercury, isotopic oxygen, biopolymeric carbon and its constituents, together with indicators of microbial activity and bacterial diversity found in bottom waters of the Eastern Mediterranean. In this basin, which has been considered as a miniature global ocean, two competing sources of bottom water (one in the Adriatic and one in the Aegean seas) contribute to the ventilation of the local abyss. However, due to a recent substantial reduction of the differences in the physical characteristics of these two water masses it has become increasingly complex a water classification using the traditional approach with temperature, salinity and dissolved oxygen alone. Here, we show that an extended set of observed physical and biochemical parameters allows recognizing the existence of two different abyssal routes from the Adriatic source and one abyssal route from the Aegean source despite temperature and salinity of such two competing sources of abyssal water being virtually indistinguishable. Moreover, as the near-bottom development of exogenous bacterial communities transported by convectively-generated water masses in the abyss can provide a persistent trace of episodic events, intermittent flows like those generating abyssal waters in the Eastern Mediterranean basin may become detectable beyond the availability of concomitant measurements. PMID:26761666

  14. Biogeochemical, Isotopic and Bacterial Distributions Trace Oceanic Abyssal Circulation.

    PubMed

    Rubino, Angelo; Bensi, Manuel; Hainbucher, Dagmar; Zanchettin, Davide; Mapelli, Francesca; Ogrinc, Nives; Marchetto, Davide; Borin, Sara; Cardin, Vanessa; Fajon, Vesna; Horvat, Milena; Taricco, Carla; Baldi, Franco

    2016-01-01

    We explore the possibility of tracing routes of dense waters toward and within the ocean abyss by the use of an extended set of observed physical and biochemical parameters. To this purpose, we employ mercury, isotopic oxygen, biopolymeric carbon and its constituents, together with indicators of microbial activity and bacterial diversity found in bottom waters of the Eastern Mediterranean. In this basin, which has been considered as a miniature global ocean, two competing sources of bottom water (one in the Adriatic and one in the Aegean seas) contribute to the ventilation of the local abyss. However, due to a recent substantial reduction of the differences in the physical characteristics of these two water masses it has become increasingly complex a water classification using the traditional approach with temperature, salinity and dissolved oxygen alone. Here, we show that an extended set of observed physical and biochemical parameters allows recognizing the existence of two different abyssal routes from the Adriatic source and one abyssal route from the Aegean source despite temperature and salinity of such two competing sources of abyssal water being virtually indistinguishable. Moreover, as the near-bottom development of exogenous bacterial communities transported by convectively-generated water masses in the abyss can provide a persistent trace of episodic events, intermittent flows like those generating abyssal waters in the Eastern Mediterranean basin may become detectable beyond the availability of concomitant measurements.

  15. The Isotope Geochemistry of Abyssal Peridotites and Related Rocks

    DTIC Science & Technology

    1993-06-01

    Oceanography/ Applied Ocean Science San d E n g in e e r in g ftoo I • •OFTI DOCTORAL DISSERTATION I The Isotope Geochemistry of Abyssal Peridotites and...Related Rocks "- . .. .. .. 1 , ".:i• . Jonathan E. Snow , ’ I .June 1993 I .o. I I I WHOI-93-36 I The Isotope Geochemistry of Abyssal Peridotites and...States Government. This thesis should be cited as: Jonathan E. Snow, 1993. The Isotope Geochemistry of Abyssal Peridotites and Related Rocks. Ph.D

  16. Abyssal benthos of the central Indian Ocean

    NASA Astrophysics Data System (ADS)

    Parulekar, A. H.; Harkantra, S. N.; Ansari, Z. A.; Matondkar, S. G. P.

    1982-12-01

    Quantitative studies of the abyssal benthos (3600 to 5300 m) of the central Indian Ocean show a rich fauna and high standing crops. Density of 3 meiofaunal and 12 macrofaunal taxa are large (2175 to 15233; x = 6441 m -2) Polychaetes (41.6%), peracarid crustaceans (31.7%), ophiuroids (12.2%), echiuroid-bryozoa (9.7%), molluscs (4.8%), and agglutinating rhizopod protozoans form the macrofauna. Meiofaunal taxa are nematodes (69.4%), harpacticoid copepods (26.6%), and ostracods (4%). Meiofauna abundances are positively correlated with distance from shore, whereas the distribution and abundance of macrofauna are independent of variations in depth and distance from the shore. Ratio of macro to meiofauna in the total population is 1 to 31. The benthic standing crop is uniformly high (0.54 to 13.73 g m -2; x = 2.70 g m -2) and many times larger than previously reported for comparable depths in other oceans and from the same region. Biomass values are significantly related to distance from shore and the type of substratum. Contribution of macro and meiofauna to the total standing crop was in the ratio of 31 to 1. High benthic biomass and rich fauna are consequences of high organic production in the euphotic zone. The correlation between biomass of the total oxidizable organic matter in the water column and the benthic standing crop is statistically significant ( r = -0.64) at the P < 0.05 level. Rich fauna and high standing crop were associated with the occurrence of polymetallic nodules.

  17. Structure, stratigraphy, and origin of Husband Hill, Columbia Hills, Gusev Crater, Mars

    USGS Publications Warehouse

    McCoy, T.J.; Sims, M.; Schmidt, M.E.; Edwards, L.; Tornabene, L.L.; Crumpler, L.S.; Cohen, B. A.; Soderblom, L.A.; Blaney, D.L.; Squyres, S. W.; Arvidson, R. E.; Rica, J.W.; Treguier, E.; d'Uston, C.; Grant, J. A.; McSween, H.Y.; Golombek, M.P.; Haldemann, A.F.C.; de Souza, P.A.

    2008-01-01

    The strike and dip of lithologic units imaged in stereo by the Spirit rover in the Columbia Hills using three-dimensional imaging software shows that measured dips (15-32??) for bedding on the main edifice of the Columbia Hill are steeper than local topography (???8-10??). Outcrops measured on West Spur are conformable in strike with shallower dips (7-15??) than observed on Husband Hill. Dips are consistent with observed strata draping the Columbia Hills. Initial uplift was likely related either to the formation of the Gusev Crater central peak or ring or through mutual interference of overlapping crater rims. Uplift was followed by subsequent draping by a series of impact and volcaniclastic materials that experienced temporally and spatially variable aqueous infiltration, cementation, and alteration episodically during or after deposition. West Spur likely represents a spatially isolated depositional event. Erosion by a variety of processes, including mass wasting, removed tens of meters of materials and formed the Tennessee Valley primarily after deposition. This was followed by eruption of the Adirondack-class plains basalt lava flows which embayed the Columbia Hills. Minor erosion, impact, and aeolian processes have subsequently modified the Columbia Hills. Copyright 2008 by the American Geophysical Union.

  18. Barophilic Bacteria Associated with Digestive Tracts of Abyssal Holothurians

    PubMed Central

    Deming, Jody W.; Colwell, Rita R.

    1982-01-01

    Abyssal holothurians and sediment samples were collected at depths of 4,430 to 4,850 m in the Demerara abyssal plain. Bacterial concentrations in progressive sections of the holothurian digestive tract, as well as in surrounding surface sediments, were determined by epifluorescence microscopy. Total bacterial counts in sediments recently ingested by the animals were 1.5- to 3-fold higher than in surrounding sediments at the deepest station. Lowest counts were observed consistently in the foregut, where the digestive processes of the holothurian are believed to occur. In most animals, counts increased 3- to 10-fold in the hindgut. Microbial activity at 3°C and in situ and atmospheric pressure were determined for gut and sediment samples by measuring the utilization of [14C]glutamic acid, the doubling time of the mixed-population of culturable bacteria, and the percentage of the total bacterial count responsive to yeast extract in the presence of nalidixic acid, using epifluorescence microscopy. A barophilic microbial population, showing elevated activity under deep-sea pressure, was detected by all three methods in sediments removed from the hindgut. Transmission electron micrographs revealed intact bacteria directly associated with the intestinal lining only in the hindgut. The bacteria are believed to be carried as an actively metabolizing, commensal gut flora that transforms organic matter present in abyssal sediments ingested by the holothurian. Using data obtained in this study, it was calculated that sediment containing organic matter altered by microbial activity cleared the holothurian gut every 16 h, suggesting that abyssal holothurians and their associated gut flora are important participants in nutrient cycles of the abyssal benthic ocean. Images PMID:16346137

  19. Comment on "Glacial cycles drive variations in the production of oceanic crust".

    PubMed

    Goff, John A

    2015-09-04

    Crowley et al. (Reports, 13 March 2015, p. 1237) propose that abyssal hill topography can be generated by variations in volcanism at mid-ocean ridges modulated by Milankovitch cycle-driven changes in sea level. Published values for abyssal hill characteristic widths versus spreading rate do not generally support this hypothesis. I argue that abyssal hills are primarily fault-generated rather than volcanically generated features.

  20. Mineral compositions of plutonic rocks from the Lewis Hills massif, Bay of Islands ophiolite

    NASA Technical Reports Server (NTRS)

    Smith, Susan E.; Elthon, Don

    1988-01-01

    Mineral compositions of residual and cumulate rocks from the Lewis Hills massif of the Bay of Islands ophiolite complex are reported and interpreted in the context of magnetic processes involved in the geochemical evolution of spatially associated diabase dikes. The mineral compositions reflect greater degrees of partial melting than most abyssal peridotites do and appear to represent the most depleted end of abyssal peridotite compositions. Subsolidus equilibration between Cr-Al spinal and olivine generally has occurred at temperatures of 700 to 900 C. The spinel variations agree with the overall fractionation of basaltic magmas producing spinels with progressively lower Cr numbers. The compositions of clinopyroxenes suggest that the fractionation of two different magma series produced the various cumulate rocks.

  1. Invasion of the abyssal North Atlantic by modern anthropogenic lead

    NASA Astrophysics Data System (ADS)

    Alleman, L. Y.; Véron, A. J.; Church, T. M.; Flegal, A. R.; Hamelin, B.

    While anthropogenic emissions have dramatically elevated lead concentrations in the North Atlantic troposphere and surface waters by orders of magnitude above natural levels [Murozumi et al., 1969; Schaule and Patterson, 1983; Boyle et al., 1986], it has been assumed that the relatively low lead levels in North Atlantic abyssal waters are not yet contaminated [Schaule and Patterson, 1981; Flegal and Patterson, 1983]. That misperception is redressed by the following stable lead isotopic composition data which reveal the advective transport of industrial lead into those deep basin waters through the formation of North Atlantic Deep Water (NADW). Additionally, spatial gradients in the isotopic signatures of anthropogenic lead within the North Atlantic abyss appear to serve as transient tracers of contaminant penetration rates.

  2. Orphan Strontium-87 in Abyssal Peridotites: Daddy Was a Granite

    NASA Astrophysics Data System (ADS)

    Snow, Jonathan E.; Hart, Stanley R.; Dick, Henry J. B.

    1993-12-01

    The 87Sr/86Sr ratios in some bulk abyssal and alpine peridotites are too high to be binary mixtures of depleted mantle and seawater components. The apparent excess, or "orphan," 87Sr appears to be separated from its radioactive parent. Such observations were widely held to be analytical artifacts. Study of several occurrences of orphan 87Sr shows that the orphan component in abyssal peridotite is located in the alteration products of olivine and enstatite in the peridotite. The orphan 87Sr is most likely introduced by infiltration of low-temperature (<200^circC) seawater bearing suspended detrital particulates. These particulates include grains of detrital clay that are partly derived from continental (that is, granitic) sources and thus are highly radiogenic. Orphan 87Sr and other radiogenic isotopes may provide a tracer for low-temperature seawater penetrating into the oceanic crust.

  3. Orphan strontium-87 in abyssal peridotites: daddy was a granite.

    PubMed

    Snow, J E; Hart, S R; Dick, H J

    1993-12-17

    The (87)Sr/(86)Sr ratios in some bulk abyssal and alpine peridotites are too high to be binary mixtures of depleted mantle and seawater components. The apparent excess, or "orphan," (87)Sr appears to be separated from its radioactive parent. Such observations were widely held to be analytical artifacts. Study of several occurrences of orphan (87)Sr shows that the orphan component in abyssal peridotite is located in the alteration products of olivine and enstatite in the peridotite. The orphan (87)Sr is most likely introduced by infiltration of low-temperature (<200 degrees C) seawater bearing suspended detrital particulates. These particulates include grains of detrital clay that are partly derived from continental (that is, granitic) sources and thus are highly radiogenic. Orphan (87)Sr and other radiogenic isotopes may provide a tracer for low-temperature seawater penetrating into the oceanic crust.

  4. Study of abyssal seafloor isolation of contaminated sediments concluded

    SciTech Connect

    Valent, P.

    1998-12-31

    Recognizing the rapidly decreasing availability of disposal sites on land, in 1993 Congress directed the Department of Defense to assess the technical and scientific feasibility of isolating contaminated dredged material on the abyssal seafloor. The Naval Research Laboratory (NRL) conducted and managed the assessment, which was funded during its first year by the Strategic Environmental Research and Development Program and in the following two years by the Defense Advanced Research Projects Agency. NRL carried out the projects in collaboration with participants from academic institutions and industrial organizations. The seafloor isolation concept is an attractive management option for contaminated dredged material because, if abyssal isolation is feasible and environmentally sound, air, land, or water supplies would not be contaminated. The participants concluded that it is technically and environmentally feasible. In ports where shipping costs are high, abyssal seafloor isolation is a cost-competitive strategy. They also outlined the architecture of a system to monitor conditions at the site and to detect and measure possible leaks of contaminated material.

  5. Red Hill Updates

    EPA Pesticide Factsheets

    This and other periodic updates are intended to keep the public informed on major progress being made to protect public health and the environment at the Red Hill Underground Fuel Storage Facility in Hawaii.

  6. David Keynes Hill.

    PubMed

    Huxley, Andrew

    2003-01-01

    David Hill followed his father, A.V. Hill FRS, into the study of muscular contraction. Using a wide range of experimental techniques, he made several important advances of which the most important was the discovery of the 'short-range elastic component', a phenomenon which implied that even in the resting state there was an interaction between the thick (myosin) and thin (actin) filaments. He also studied physical changes in nerve when stimulated.

  7. Can the source–sink hypothesis explain macrofaunal abundance patterns in the abyss? A modelling test

    PubMed Central

    Hardy, Sarah M.; Smith, Craig R.; Thurnherr, Andreas M.

    2015-01-01

    Low food availability is a major structuring force in deep-sea benthic communities, sustaining only very low densities of organisms in parts of the abyss. These low population densities may result in an Allee effect, whereby local reproductive success is inhibited, and populations are maintained by larval dispersal from bathyal slopes. This slope–abyss source–sink (SASS) hypothesis suggests that the abyssal seafloor constitutes a vast sink habitat with macrofaunal populations sustained only by an influx of larval ‘refugees' from source areas on continental slopes, where higher productivity sustains greater population densities. Abyssal macrofaunal population densities would thus be directly related to larval inputs from bathyal source populations. We evaluate three predictions derived from the SASS hypothesis: (i) slope-derived larvae can be passively transported to central abyssal regions within a single larval period, (ii) projected larval export from slopes to the abyss reproduces global patterns of macrofaunal abundance and (iii) macrofaunal abundance decreases with distance from the continental slope. We find that abyssal macrofaunal populations are unlikely to be sustained solely through influx of larvae from slope sources. Rather, local reproduction probably sustains macrofaunal populations in relatively high-productivity abyssal areas, which must also be considered as potential larval source areas for more food-poor abyssal regions. PMID:25948686

  8. Can the source-sink hypothesis explain macrofaunal abundance patterns in the abyss? A modelling test.

    PubMed

    Hardy, Sarah M; Smith, Craig R; Thurnherr, Andreas M

    2015-06-07

    Low food availability is a major structuring force in deep-sea benthic communities, sustaining only very low densities of organisms in parts of the abyss. These low population densities may result in an Allee effect, whereby local reproductive success is inhibited, and populations are maintained by larval dispersal from bathyal slopes. This slope-abyss source-sink (SASS) hypothesis suggests that the abyssal seafloor constitutes a vast sink habitat with macrofaunal populations sustained only by an influx of larval 'refugees' from source areas on continental slopes, where higher productivity sustains greater population densities. Abyssal macrofaunal population densities would thus be directly related to larval inputs from bathyal source populations. We evaluate three predictions derived from the SASS hypothesis: (i) slope-derived larvae can be passively transported to central abyssal regions within a single larval period, (ii) projected larval export from slopes to the abyss reproduces global patterns of macrofaunal abundance and (iii) macrofaunal abundance decreases with distance from the continental slope. We find that abyssal macrofaunal populations are unlikely to be sustained solely through influx of larvae from slope sources. Rather, local reproduction probably sustains macrofaunal populations in relatively high-productivity abyssal areas, which must also be considered as potential larval source areas for more food-poor abyssal regions.

  9. Bacon Hill Substation. Bacon Hill, Cecil Co., MD. Sec. 1201, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bacon Hill Substation. Bacon Hill, Cecil Co., MD. Sec. 1201, MP 48.50. - Northeast Railroad Corridor, Amtrak route between District of Columbia/Maryland state line & Maryland/Delaware state line, Baltimore, Independent City, MD

  10. Metasomatizing effects of serpentinization-related hydrothermal fluids in abyssal peridotites: new contributions from Hyblean peridotite xenoliths (southeastern Sicily)

    NASA Astrophysics Data System (ADS)

    Manuella, Fabio Carmelo; Ottolini, Luisa; Carbone, Serafina; Scavo, Lidia

    2016-11-01

    We studied a partially serpentinized peridotite xenolith, found in the diatreme tuff-breccia deposit at Valle Guffari (Hyblean Plateau, southeastern Sicily, Italy), which is representative of the Hyblean peridotite xenolith suite. We also considered all published (21) whole-rock analyses of Hyblean peridotites, to investigate the metasomatizing effects of seawater-related hydrothermal fluids in the Hyblean basement, an in-situ remnant of the ultraslow-spreading Permian Tethys. In detail, we analyzed the serpentine veins by different techniques (scanning electron microscopy-SEM, electron-probe microanalysis-EPMA, micro-Raman spectroscopy, X-ray powder diffraction-XRPD) to determine the crystal-chemical composition and the structure of the veins. In addition, secondary ion mass spectrometry (SIMS) was applied to measure the abundance of trace elements. Serpentine veins are made up of two Fe-rich polytypes, chrysotile 2Mc1 and lizardite 1T. The chondrite-normalized rare earth element compositions of both serpentine polytypes are lower than 1, except for a modest light rare earth element (LREE) enrichment, and also in some fluid-mobile elements (FME: B, Rb, Sr, U). Conversely, the whole-rock composition of the studied peridotite xenolith is enriched with LREE and other trace elements (B, Sr, P, Th, U, Pb), like most Hyblean peridotites. The REE and multi-element patterns of Hyblean peridotites are akin to those of hydrothermal sediments from the Mid-Atlantic Ridge and St. Demetrio hill (northern Hyblean Plateau), and abyssal peridotites (serpentinites) whose trace element abundance is generally ascribed to melt-rock interaction. The integrated interpretation of the data and the documentation of hydrothermal minerals [(Na,S)-rich apatite, carbonates] in serpentine veins indicate that serpentinization-related hydrothermal fluids do have a primary role in metasomatism (mainly for the abundance of LREE and high field strength elements-HFSE) of ancient (Permian Tethys) and

  11. Topography measurements and applications

    NASA Astrophysics Data System (ADS)

    Song, Junfeng; Vorburger, Theodore

    2006-11-01

    Based on auto- and cross-correlation functions (ACF and CCF), a new surface parameter called profile (or topography) difference, D s, has been developed for quantifying differences between 2D profiles or between 3D topographies with a single number. When D s = 0, the two compared 2D profiles or 3D topographies must be exactly the same (point by point). A 2D and 3D topography measurement system was established at NIST. This system includes data acquisition stations using a stylus instrument and a confocal microscope, and a correlation program using the proposed parameters D s and the cross-correlation function maximum CCF max. Applications in forensic science and surface metrology are described; those include profile signature measurements for 40 NIST Standard Reference Material (SRM) 2460 standard bullets, and comparisons of profile measurements with four different techniques. An approach to optimizing the Gaussian filter long wavelength cutoff, λc, is proposed for topography measurements.

  12. Algal pigments in Southern Ocean abyssal foraminiferans indicate pelagobenthic coupling

    NASA Astrophysics Data System (ADS)

    Cedhagen, Tomas; Cheah, Wee; Bracher, Astrid; Lejzerowicz, Franck

    2014-10-01

    The cytoplasm of four species of abyssal benthic foraminiferans from the Southern Ocean (around 51°S; 12°W and 50°S; 39°W) was analysed by High Performance Liquid Chromatography (HPLC) and found to contain large concentrations of algal pigments and their degradation products. The composition of the algal pigments in the foraminiferan cytoplasm reflected the plankton community at the surface. Some foraminiferans contained high ratios of chlorophyll a/degraded pigments because they were feeding on fresher phytodetritus. Other foraminiferans contained only degraded pigments which shows that they utilized degraded phytodetritus. The concentration of algal pigment and corresponding degradation products in the foraminiferan cytoplasm is much higher than in the surrounding sediment. It shows that the foraminiferans collect a diluted and sparse food resource and concentrate it as they build up their cytoplasm. This ability contributes to the understanding of the great quantitative success of foraminiferans in the deep sea. Benthic foraminiferans are a food source for many abyssal metazoans. They form a link between the degraded food resources, phytodetritus, back to the active metazoan food chains.

  13. OpenTopography

    NASA Astrophysics Data System (ADS)

    Baru, C.; Arrowsmith, R.; Crosby, C.; Nandigam, V.; Phan, M.; Cowart, C.

    2012-04-01

    OpenTopography is a cyberinfrastructure-based facility for online access to high-resolution topography and tools. The project is an outcome of the Geosciences Network (GEON) project, which was a research project funded several years ago in the US to investigate the use of cyberinfrastructure to support research and education in the geosciences. OpenTopography provides online access to large LiDAR point cloud datasets along with services for processing these data. Users are able to generate custom DEMs by invoking DEM services provided by OpenTopography with custom parameter values. Users can track the progress of their jobs, and a private myOpenTopo area retains job information and job outputs. Data available at OpenTopography are provided by a variety of data acquisition groups under joint agreements and memoranda of understanding (MoU). These include national facilities such as the National Center for Airborne Lidar Mapping, as well as local, state, and federal agencies. OpenTopography is also being designed as a hub for high-resolution topography resources. Datasets and services available at other locations can also be registered here, providing a "one-stop shop" for such information. We will describe the OpenTopography system architecture and its current set of features, including the service-oriented architecture, a job-tracking database, and social networking features. We will also describe several design and development activities underway to archive and publish datasets using digital object identifiers (DOIs); create a more flexible and scalable high-performance environment for processing of large datasets; extend support for satellite-based and terrestrial lidar as well as synthetic aperture radar (SAR) data; and create a "pluggable" infrastructure for third-party services. OpenTopography has successfully created a facility for sharing lidar data. In the next phase, we are developing a facility that will also enable equally easy and successful sharing of

  14. Dynamic Topography Revisited

    NASA Astrophysics Data System (ADS)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  15. Large-scale patterns in biodiversity of microbial eukaryotes from the abyssal sea floor.

    PubMed

    Scheckenbach, Frank; Hausmann, Klaus; Wylezich, Claudia; Weitere, Markus; Arndt, Hartmut

    2010-01-05

    Eukaryotic microbial life at abyssal depths remains "uncharted territory" in eukaryotic microbiology. No phylogenetic surveys have focused on the largest benthic environment on this planet, the abyssal plains. Moreover, knowledge of the spatial patterns of deep-sea community structure is scanty, and what little is known originates primarily from morphology-based studies of foraminiferans. Here we report on the great phylogenetic diversity of microbial eukaryotic communities of all 3 abyssal plains of the southeastern Atlantic Ocean--the Angola, Cape, and Guinea Abyssal Plains--from depths of 5,000 m. A high percentage of retrieved clones had no close representatives in genetic databases. Many clones were affiliated with parasitic species. Furthermore, differences between the communities of the Cape Abyssal Plain and the other 2 abyssal plains point to environmental gradients apparently shaping community structure at the landscape level. On a regional scale, local species diversity showed much less variation. Our study provides insight into the community composition of microbial eukaryotes on larger scales from the wide abyssal sea floor realm and marks a direction for more detailed future studies aimed at improving our understanding of deep-sea microbes at the community and ecosystem levels, as well as the ecological principles at play.

  16. Derivation of Model Topography

    NASA Technical Reports Server (NTRS)

    Balgovind, R. C.

    1985-01-01

    The Fourth-Order model necessitates representation of the topography. The problem of the representation of the topography at grid points is addressed. The attempted was to derive an envelope topography. The TI is obtained by taking local mean plus one standard deviation at each grid point and sigma filtering it. The method was greatly influenced by large standard deviations at steep mountains. The O1 topography is the local mean. The S1 is obtained by Sigma filtering in both latitude and longitude the mean O1. The S2 is when the operation is applied twice and S3 thrice, the Q3 is the sigma filtered local mean of the upper third quantile of the source data.

  17. Moire topography in odontology

    NASA Astrophysics Data System (ADS)

    Moreno Yeras, A.

    2001-08-01

    For several decades measurement optical techniques have been used in different branches of Science and Technology and in medicine. One of these techniques is the so-called Moire topography that allows the accurate measurement of different parts of the human body topography. This investigation presents the measurement of topographies of teeth and gums using an automated system of shadow moire, with which precision can be reached up to the order of the microns by the phase shift instrumentation in an original way. Advantages and disadvantages of using the Moire topography and its comparison with other techniques used in the optical metrology are presented. Also, some positive and negative aspects of the implementation of this technique are shown in dentistry.

  18. Abyssal Peridotites and Mantle Melting Beneath Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Dick, H. J.; Snow, J. E.; Hellebrand, E.; Shimizu, N.

    2005-12-01

    Studies of abyssal peridotite from ultraslow and slow spreading ridges show significant regional variability; with a strong correlation between the compositions of peridotite averaged by locality and spatially associated MORB reflecting higher degrees of mantle melting near mantle hot spots. Local variability of peridotite compositions, however, is often large, and may equal the regional variability along ocean ridges. The latter is attributed to local melting and melt transport processes such as melt channelization or late-stage melt impregnation in the lithosphere. The observed regional correlation appears only when many samples are averaged to eliminate local and outcrop scale variability. Almost all the peridotites used in these correlations are from transforms, and therefore represent similar thermal and mantle melting histories. Thus, regional differences in mantle composition are preserved. Until recently, little data were available for peridotites away from transforms representing the central mantle environment beneath magmatic segments. This is key, as geophysical and geologic evidence suggest focused melt flow beneath slow spreading ridges. If so, beneath individual magmatic segments there should be a corresponding mantle melting cell in which melt is focused from a broad melting region to a melt transport zone at its mid-point that feeds an overlying crustal magmatic center. High melt fluxes in the transport zone would produce very depleted peridotites stripped of pyroxene by melt-rock reaction during magma ascent. Studies of peridotites far from transforms at ultraslow Gakkel and SW Indian Ridges indicate this is the case: with near-Cpx free intergranular harzburgite and dunite locally abundant in contrast to transform peridotites. Recent mapping of the plutonic foundation of an ancient 35-km long slow spreading ridge segment at the Kane Core Complex also found a narrow 10-km wide zone of focused melt flow through the mantle marked by abundant dunite

  19. Hill In Deuteronilus

    NASA Technical Reports Server (NTRS)

    2004-01-01

    28 December 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an eroded, rounded hill in the Deuteronilus Colles region of Mars, near 40.3oN, 338.8oW. The plains surrounding the hill have been pitted and modified by erosion. Similar pitting is common throughout the middle latitude regions of Mars. Some Mars science investigators have proposed that the pitted materials were ice-rich, and that sublimation of ice has created these textures. However, no similar landforms are found on Earth, thus there is no clear analog that would help scientists better understand the origin of these features. The picture covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the left/lower left.

  20. Black Hills hydrology study

    USGS Publications Warehouse

    Driscoll, D.G.

    1994-01-01

    The Black Hills area of western South Dakota is a valuable resource center. The area has attracted numerous residents and industries because of the availability of mineral, timber, agricultural, recreational, and water resources. The water resources of the area have been stressed locally by increasing population, periodic drought, and development of other resources. In response to residents' concerns about these stresses on the water resources, the Black Hills Hydrology Study was initiated in 1990 as a cooperative effort among the U.S. Geological Survey, the South Dakota Department of Environment and Natural Resources, and the West Dakota Water Development District. West Dakota represents the various local and county cooperators. This report describes the purpose, scope, approach, and status of the study and presents highlights from the first project data report produced for the study.

  1. Nose Hill Artifacts

    ERIC Educational Resources Information Center

    Hansen, Vivian

    2008-01-01

    A Blackfoot woman, caught in the act of adultery, was condemned at this site to have her nose cut off as a penalty for her actions. People do not know her story. The tribe cast it on the ground. And so She, Nose Hill, was named. John Laurie Boulevard holds her mound in a circlet of asphalt, defining the map of her "terra incognita." She…

  2. Last Glacial Maximum and deglacial abyssal seawater oxygen isotopic ratios

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2016-06-01

    An earlier analysis of pore-water salinity (chlorinity) in two deep-sea cores, using terminal constraint methods of control theory, concluded that although a salinity amplification in the abyss was possible during the LGM, it was not required by the data. Here the same methodology is applied to δ18Ow in the upper 100 m of four deep-sea cores. An ice volume amplification to the isotopic ratio is, again, consistent with the data but not required by it. In particular, results are very sensitive, with conventional diffusion values, to the assumed initial conditions at -100 ky and a long list of noise (uncertainty) assumptions. If the calcite values of δ18O are fully reliable, then published enriched values of the ratio in seawater are necessary to preclude sub-freezing temperatures, but the seawater δ18O in pore fluids does not independently require the conclusion.

  3. North Atlantic Abyssal Circulation During Heinrich Event 1

    NASA Astrophysics Data System (ADS)

    Burke, A.; Marchal, O.; Francois, R.

    2007-12-01

    Pa-231/Th-230 ratios in three sediment cores from the North Atlantic have been used to infer changes in the meridional overturning circulation (MOC) over the past 20 kyr. The large Pa-231/Th-230 ratios (approaching the production ratio of the two radionuclides in the water column) during Heinrich Event 1 (H1) in core OCE326-GGC5 off of the Bermuda rise have been interpreted in terms of a reduced export of Pa-231 to the Southern Ocean owing to a slow-down of the MOC (McManus et al., Nature, 2004). Similar observations have been found in core SU81-18 from the Iberian continental margin (Gherardi et al., EPSL, 2005). The Pa-231/Th-230 record for core DAPC2 from the Norwegian Sea also has elevated values during H1, although variations in the flux of biogenic opal might be an important factor in controlling Pa-231/Th-230 ratios in the sediment (Hall et al., GRL, 2006). Here we will use an inverse method to combine Pa-231/Th-230 observations for H1 in these three cores with a model of the abyssal circulation in the North Atlantic basin. Two null hypotheses will be tested. The first null hypothesis is that the Pa-231/Th-230 data are consistent with the modern circulation. The second is that these data are consistent with a state of no flow in the abyssal region. In testing each hypothesis, due regard will be given to the uncertainties in both the Pa-231/Th-230 data and the model equations. By comparing the adjustments in the Pa-231/Th-230 values that are necessary to bring them into consistency with the modern circulation (hypothesis 1) and the state of rest (hypothesis 2), insight into the dynamical information contained in these data will be gained.

  4. 'Columbia Hills' from Orbit

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This view of the 'Columbia Hills' in Gusev Crater was made by draping an image from the Mars Orbiter Camera on NASA's Mars Global Surveyor orbiter (image E0300012 from that camera) over a digital elevation model that was derived from two Mars Orbiter Camera images (E0300012 and R0200357).

    This unique view is helpful to the rover team members as they plan the journey of NASA's Mars Exploration Rover Spirit to the base of the Columbia Hills and beyond. Spirit successfully completed a three-month primary mission, and so far remains healthy in an extended mission of bonus exploration. As of sol 135 (on May 21, 2004), Spirit sits approximately 680 meters (0.4 miles) away from its first target at the western base of the hills, a spot informally called 'West Spur.' The team estimates that Spirit will reach West Spur by sol 146 (June 1, 2004). Spirit will most likely remain there for about a week to study the outcrops and rocks associated with this location.

    When done there, Spirit will head approximately 620 meters (0.38 miles) to a higher-elevation location informally called 'Lookout Point.' Spirit might reach Lookout Point by around sol 165 (June 20, 2004). On the way, the rover will pass by and study ripple-shaped wind deposits that may reveal more information about wind processes on Mars.

    Lookout Point will provide a great vantage point for scientists to remotely study the inner basin area of the Columbia Hills. This basin contains a broad range of interesting geological targets including the informally named 'Home Plate' and other possible layered outcrops. These features suggest that the hills contain rock layers. Spirit might investigate the layers to determine whether they are water-deposited sedimentary rock.

    Once at Lookout Point, Spirit will acquire 360-degree panoramic images of the entire area to help define the rover's next steps. Assuming the rover stays healthy, Spirit will eventually drive down into the basin to get an up

  5. Domains of occupation of abyssal scavengers inferred from baited cameras and traps on the Demerara Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Rowe, Gilbert T.; Sibuet, Myriam; Vangriesheim, Annick

    1986-04-01

    Baited cameras and traps were deployed on the Demerara Abyssal Plain at a depth of 4850 m to assess the behavior, diversity, vertical zonation and abundance of motile near-bottom scavengers. The composition of the fauna that was attracted differed with type of bait and distance from bottom. While several fishes (primarily the ophidiid cf. Barathrites iris) and a penaeid crustacean (cf. Plesiopenaius edwardsi) were attracted to bait on the bottom, only a large mysid (cf. Gnathophausia ingens) gathered to a large tuna bait moored at 200 m off bottom. In no case was the bait utilized extensively. Rates of arrival over time were estimated for each species at each bait. These rates of recruitment were used in a model of "attractant dispersal" to define a "domain of occupation" for each of the common species. The possible ranges in animal abundances, given the uncertainties in the model, have been evaluated for each species.

  6. KISATCHIE HILLS WILDERNESS, LOUISIANA.

    USGS Publications Warehouse

    Haley, Boyd R.; Ryan, George S.

    1984-01-01

    A mineral-resource survey of the Kisatchie Hills Wilderness, Louisiana indicated little promise for the occurrence of mineral resources. There is insufficient data on oil and gas producing formations that underlie the area to evaluate the oil and gas resource potential. All the oil fields of Wilcox age are less than 40 acres in extent; therefore, closer spaced deeper wells might find additional fields in sediments of Wilcox age. Oil and natural gas have been produced from older reservoirs (Cretaceous age) to the northwest of the wilderness, and deeper wells might find oil and natural gas in sediments of Cretaceous and older age in the vicinity of the wilderness.

  7. Deep-sea sipunculans from the Kuril-Kamchatka Trench and adjacent abyssal plain

    NASA Astrophysics Data System (ADS)

    Maiorova, Anastassya S.; Adrianov, Andrey V.

    2015-01-01

    Deep-sea sipunculans collected during the expedition to the Kuril-Kamchatka Trench and adjacent abyssal plain are described and illustrated using differential interference contrast microscopy (DIC) and scanning electron microscopy (SEM). Specimens were sorted from brown silt collected by giant boxcorer (GKG), epibenthic sledge (EBS) and Agassiz trawl (AGT) from the depths 4830-5780 m. Within about 150 valid species of sipunculans only 15 have been known to be abyssal and six of them were found and identified in this KURAMBIO expedition. Eight species of sipunculans have been previously recorded from the Kuril-Kamchatka region but all of them were described based on preserved museum's material collected by bottom dredge and these descriptions are far from to be complete and comparable with other samplings. All KURAMBIO species are described according to a unified protocol to illustrate the most important taxonomic characters. This is the first description and illustrating of abyssal sipunculans in live condition with natural coloration of non-preserved specimens. Abyssal species were for a first time described with SEM facilities and according to a standardized protocol. For a first time for abyssal sipunculans, species accounts also include quantitative characteristics, distribution and specific biotope data. Nephasoma abyssorum is reported for the Kuril-Kamchatka Trench and adjacent abyssal plain for a first time.

  8. Alley Cropping: An Alternative to Slash and Burn in the Slopelands of the Mizo Hills

    ERIC Educational Resources Information Center

    Sailo, Andrew

    2011-01-01

    Population pressure in the Mizo Hills, a small mountainous region in northeast India, has shortened fallow periods of slash-and-burn (S&B) plots substantially, making its practice unsustainable. Conventional farming and modern technology cannot be applied in this remote tropical region due to its topography; hence, most farmers continue…

  9. Insurgency and Counterinsurgency: The Bangladesh Experience in Regional Perspective -- The Chittagong Hill Tracts

    DTIC Science & Technology

    1990-04-11

    T vk-ws expiessed in th13 p:per ame those of the author a,71 ec! ot neem ~ariy reflect the views of the D Fz, ,cntof Dlefense or any of it, agencies...officer in earlier days, R. H. Sneider in 19061 described the topography as "a mass of hill, ravine and cliff covered with dense bamboo, trees and

  10. Abyssal Sequestration of Nuclear Waste in Earth's Crust

    NASA Astrophysics Data System (ADS)

    Germanovich, L. N.; Garagash, D.; Murdoch, L. C.; Robinowitz, M.

    2013-12-01

    This work outlines a new method for disposing of hazardous (e.g., nuclear) waste. The technique is called Abyssal Sequestration, and it involves placing the waste at extreme depths in Earth's crust where it could achieve the geologically-long period of isolation. Abyssal Sequestration involves storing the waste in hydraulic fractures driven by gravity, a process we term gravity fracturing. In short, we suggest creating a dense fluid (slurry) containing waste, introducing the fluid into a fracture, and extending the fracture downward until it becomes long enough to propagate independently. The fracture will continue to propagate downward to great depth, permanently isolating the waste. Storing solid wastes by mixing them with fluids and injecting them into hydraulic fractures is a well-known technology. The essence of our idea differs from conventional hydraulic fracturing techniques only slightly in that it uses fracturing fluid heavier than the surrounding rock. This difference is fundamental, however, because it allows hydraulic fractures to propagate downward and carry wastes by gravity instead of or in addition to being injected by pumping. An example of similar gravity-driven fractures with positive buoyancy is given by magmatic dikes that may serve as an analog of Abyssal Sequestration occurring in nature. Mechanics of fracture propagation in conditions of positive (diking) and negative (heavy waste slurry) buoyancy is similar and considered in this work for both cases. Analog experiments in gelatin show that fracture breadth (horizontal dimension) remains nearly stationary when fracturing process in the fracture 'head' (where breadth is 'created') is dominated by solid toughness, as opposed to the viscous fluid dissipation dominant in the fracture tail. We model propagation of the resulting 'buoyant' or 'sinking' finger-like fracture of stationary breadth with slowly varying opening along the crack length. The elastic response of the crack to fluid loading

  11. Serpentinization Changes Nd, but not Hf Isotopes of Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    Bizimis, M.; Frisby, C. P.; Mallick, S.

    2015-12-01

    Serpentinization of the oceanic lithosphere is a known sink for fluid mobile elements (B, Cl, Li, Sr, etc.), while high field strength elements (HFSE: e.g., Hf, Zr, Ti, Nb) are thought to be unaffected by it. In contrast, the fate of REE during serpentinization is equivocal. Correlations between REE and HFSE concentrations in abyssal peridotites suggest control by magmatic processes (Niu, 2004, J. Pet), while some LREE enrichments in serpentinized peridotites compared to their clinopyroxene (cpx) and Nd, Sr isotope data (Delacour et al., 2008, Chem. Geol.) imply seawater-derived REE addition to the mantle protolith (Paulick et al., 2006, Chem. Geol). To further constrain peridotite-seawater interaction during serpentinization we compare bulk rock and cpx Hf and Nd isotope data in partially (up to ~70%) serpentinized abyssal peridotites (9-16°E South West Indian Ridge). We also present a new method that improves yields in Hf, Nd and Pb separations from depleted (<0.03 ppm Hf) ultramafic rocks, which includes coprecipitation of metals with Al-Fe hydroxides and ether-HCl liquid-liquid exchange for Fe removal. Nd isotopes in the bulk peridotite are up to 7ɛNd units less radiogenic than their cpx (i.e., the magmatic value) while Hf isotopes remain equal to cpx within 1 ɛHf. Melt-rock reaction by the local lavas cannot generate this decoupling. The largest Nd isotopic difference between cpx and bulk is seen in the most LREE-depleted samples, while refertilized samples show little change. Leaching experiments show that 30-60% of REE are mobilized from the rock, but >90% of Hf, Zr, Ti are retained in the residue. LA-ICPMS data shows that serpentine after olivine typically has higher LREE/HREE ratios than cpx, pronounced negative Ce anomalies, high U, Sr concentrations and low HFSE, unlike the coexisting cpx. These data are consistent with some seawater-derived LREE addition to peridotite during serpentinization, localized in the serpentine and other secondary phases

  12. Observations and Modelling of Convective Rolls Over Low Hills

    NASA Astrophysics Data System (ADS)

    Tian, W.; Parker, D. J.; Kilburn, C. A. D.

    Radar and satellite images provide observations of convective rolls and other struc- tures in the convective boundary layer (CBL), but numerical modelling is a neces- sary complement to the observations, to investigate the temporal and spatial evolu- tion of convective rolls. Numerical simulations have been performed to investigate observed convective rolls over the south of England, using BLASIUS, a relatively simple boundary layer code for flow over topography. The principal features of the convective structures can be successfully reproduced by the model, notably the roll orientation and spacing and the basic features of the cloud field. These features are in good agreement for two case studies, one with distinct rolls and the other with more dispersed convective structures and a time-dependent basic state. The presence of low topography (with maximum height of order 30% of the CBL depth) does not significantly change the orientation and spacing, nor the time of initial occurrence of modelled rolls, but local flow anomalies can be related to the hills. These anomalies are related to coherent patterns in the diagnosed cloud fields, with a tendency for more cloud cover upstream and over hills, and cloud clearing in the lee as a result of descent suppressing convective eddies. This kind of control of the shallow convection by the topography is evident in the satellite imagery.

  13. Monte Carlo simulations of adsorption on heterogeneous surfaces with a random topography of surfaces sites

    NASA Astrophysics Data System (ADS)

    Cortes, Joaquin; Araya, Paulo

    1991-11-01

    Making use of Monte Carlo experiments, a simulation has been carried out of the adsorption of a gas on heterogeneous solids characterized by energy distribution and a random topography of the superficial sites. A good interpretation of the results is achieved by means of the theoretical models introduced by Hill, and later by Rudzinsky, for these types of systems.

  14. Diversity and Biogeography of Bathyal and Abyssal Seafloor Bacteria

    PubMed Central

    Bienhold, Christina; Zinger, Lucie; Boetius, Antje; Ramette, Alban

    2016-01-01

    The deep ocean floor covers more than 60% of the Earth’s surface, and hosts diverse bacterial communities with important functions in carbon and nutrient cycles. The identification of key bacterial members remains a challenge and their patterns of distribution in seafloor sediment yet remain poorly described. Previous studies were either regionally restricted or included few deep-sea sediments, and did not specifically test biogeographic patterns across the vast oligotrophic bathyal and abyssal seafloor. Here we define the composition of this deep seafloor microbiome by describing those bacterial operational taxonomic units (OTU) that are specifically associated with deep-sea surface sediments at water depths ranging from 1000–5300 m. We show that the microbiome of the surface seafloor is distinct from the subsurface seafloor. The cosmopolitan bacterial OTU were affiliated with the clades JTB255 (class Gammaproteobacteria, order Xanthomonadales) and OM1 (Actinobacteria, order Acidimicrobiales), comprising 21% and 7% of their respective clades, and about 1% of all sequences in the study. Overall, few sequence-abundant bacterial types were globally dispersed and displayed positive range-abundance relationships. Most bacterial populations were rare and exhibited a high degree of endemism, explaining the substantial differences in community composition observed over large spatial scales. Despite the relative physicochemical uniformity of deep-sea sediments, we identified indicators of productivity regimes, especially sediment organic matter content, as factors significantly associated with changes in bacterial community structure across the globe. PMID:26814838

  15. Abyssal plains heat exchange could explain global deficit

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-07-01

    When researchers measure the amount of heat flowing conductively from the seafloor to the ocean waters and then compare that value against a theoretical prediction of that heat loss, they observe that the global average measured heat flow is lower than expected. Researchers think that advection, a heat transfer mechanism that is difficult to measure, makes up this difference between predicted and observed heat exchange. They suggest that as seawater circulates through the permeable upper layers of the seafloor crust, driven by a thermal gradient, the water accumulates heat, drawing it into the ocean. Scientists have recently proposed that seafloor sediment plays an important role in controlling the geometry of such intraocean crust circulation. In the abyssal plains, the accumulation of millions of years' worth of low permeability sediment limits direct contact between the ocean and the crust. Where the sediment is thin or absent—for example, at outcrops—water is thought to be able to move between the ocean and the crust. Scientists propose that seawater can travel through the crust for tens of kilometers beneath the sediment, moving laterally from outcrop to outcrop.

  16. Toilets in the hills.

    PubMed

    Rosenfield, P; Holcombe, S J

    1990-04-01

    Population and Community Development Association (PDA) in Chieng Rai province in northern Thailand implemented its Environmental Sanitation for the Hill Tribes Project in March 1988 to reduce parasite infection and generate interest in self help development projects. As of early 1990, the hill tribes population growth rate stood at 4.5% compared to 1.5% in lowland Thailand. Other problems included villagers defecating around dwellings, not drinking safe water (since none was available), and not wearing shoes all of which contributed to a high rate of parasite infection. In fact, an analysis of stool samples revealed that parasites infected a mean of almost 70% of the villagers. PDA staff informed villagers about basic environmental health information which influenced them to improve sanitation conditions. They also demonstrated how to build the 1st model latrine. After that, each villager designed and constructed his own latrine. Each villager took out a Baht 150 (US$6) loan to pay for the construction materials (squat casings and cement) provided by PDA. Over the following 10 months, the staff returned to the villages to collect payments and to provide technical assistance. Those villagers that constructed a latrine persuaded others to also construct a latrine. In fact, villagers, not always PDA staff, have even transferred the knowledge to other villages. As of early 1990, villagers and staff have built 1000 squats and 993 latrines. With the health education and latrine use, PDA hoped to see a subsequent reduction in parasite infections. With the help of volunteer contraceptive distributors, PDA has also been able to expand its family planning program to 250 villages. It has also initiated a parasite control pilot project in the area in which infection rates have steadily decreased.

  17. The Dawn Topography Investigation

    NASA Technical Reports Server (NTRS)

    Raymond, C. A.; Jaumann, R.; Nathues, A.; Sierks, H.; Roatsch, T.; Preusker, E; Scholten, F.; Gaskell, R. W.; Jorda, L.; Keller, H.-U.; Zuber, M. T.; Smith, D. E.; Mastrodemos, N.; Mottola, S.

    2011-01-01

    The objective of the Dawn topography investigation is to derive the detailed shapes of 4 Vesta and 1 Ceres in order to create orthorectified image mosaics for geologic interpretation, as well as to study the asteroids' landforms, interior structure, and the processes that have modified their surfaces over geologic time. In this paper we describe our approaches for producing shape models, plans for acquiring the needed image data for Vesta, and the results of a numerical simulation of the Vesta mapping campaign that quantify the expected accuracy of our results. Multi-angle images obtained by Dawn's framing camera will be used to create topographic models with 100 m/pixel horizontal resolution and 10 m height accuracy at Vesta, and 200 m/pixel horizontal resolution and 20 m height accuracy at Ceres. Two different techniques, stereophotogrammetry and stereophotoclinometry, are employed to model the shape; these models will be merged with the asteroidal gravity fields obtained by Dawn to produce geodetically controlled topographic models for each body. The resulting digital topography models, together with the gravity data, will reveal the tectonic, volcanic and impact history of Vesta, and enable co-registration of data sets to determine Vesta's geologic history. At Ceres, the topography will likely reveal much about processes of surface modification as well as the internal structure and evolution of this dwarf planet.

  18. Phylogeography of a pan-Atlantic abyssal protobranch bivalve: implications for evolution in the Deep Atlantic.

    PubMed

    Etter, Ron J; Boyle, Elizabeth E; Glazier, Amanda; Jennings, Robert M; Dutra, Ediane; Chase, Mike R

    2011-02-01

    The deep sea is a vast and essentially continuous environment with few obvious barriers to gene flow. How populations diverge and new species form in this remote ecosystem is poorly understood. Phylogeographical analyses have begun to provide some insight into evolutionary processes at bathyal depths (<3000 m), but much less is known about evolution in the more extensive abyssal regions (>3000 m). Here, we quantify geographical and bathymetric patterns of genetic variation (16S rRNA mitochondrial gene) in the protobranch bivalve Ledella ultima, which is one of the most abundant abyssal protobranchs in the Atlantic with a broad bathymetric and geographical distribution. We found virtually no genetic divergence within basins and only modest divergence among eight Atlantic basins. Levels of population divergence among basins were related to geographical distance and were greater in the South Atlantic than in the North Atlantic. Ocean-wide patterns of genetic variation indicate basin-wide divergence that exceeds what others have found for abyssal organisms, but considerably less than bathyal protobranchs across similar geographical scales. Populations on either side of the Mid-Atlantic Ridge in the North Atlantic differed, suggesting the Ridge might impede gene flow at abyssal depths. Our results indicate that abyssal populations might be quite large (cosmopolitan), exhibit only modest genetic structure and probably provide little potential for the formation of new species.

  19. 3. View of Cherry Hill lettuce shed looking southeast; parking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View of Cherry Hill lettuce shed looking southeast; parking lot in foreground - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  20. 16. Interior view of Cherry Hill lettuce shed looking up ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Interior view of Cherry Hill lettuce shed looking up at the trusses of the second floor - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  1. 22. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. View of second floor of the Cherry Hill lettuce shed looking at double doors - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  2. 18. View of the second floor of the Cherry Hill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. View of the second floor of the Cherry Hill lettuce shed looking at door - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  3. 20. View of second floor to the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. View of second floor to the Cherry Hill lettuce shed looking at floor area - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  4. 12. Partial view of Cherry Hill lettuce shed looking northwest ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Partial view of Cherry Hill lettuce shed looking northwest showing office - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  5. 2. Oblique view of Cherry Hill lettuce shed looking south; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of Cherry Hill lettuce shed looking south; chute building is in background - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  6. 15. Interior view of Cherry Hill lettuce shed showing posts ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Interior view of Cherry Hill lettuce shed showing posts looking towards the chute building - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  7. 21. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. View of second floor of the Cherry Hill lettuce shed looking towards window - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  8. 14. Interior view of Cherry Hill lettuce shed looking towards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Interior view of Cherry Hill lettuce shed looking towards chute building - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  9. 6. Oblique view of Cherry Hill lettuce shed looking northeast, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Oblique view of Cherry Hill lettuce shed looking northeast, with chute building to the right - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  10. 19. View of second floor of the Cherry Hill lettuce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. View of second floor of the Cherry Hill lettuce shed looking at door to stairwell - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  11. 9. View of Cherry Hill lettuce shed looking north, with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. View of Cherry Hill lettuce shed looking north, with chute building on the left - Richmond Hill Plantation, Cherry Hill Lettuce Shed, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA

  12. Origin of salt giants in abyssal serpentinite systems

    NASA Astrophysics Data System (ADS)

    Scribano, Vittorio; Carbone, Serafina; Manuella, Fabio C.; Hovland, Martin; Rueslåtten, Håkon; Johnsen, Hans-K.

    2017-03-01

    Worldwide marine salt deposits ranging over the entire geological record are generally considered climate-related evaporites, derived from the precipitation of salts (mainly chlorides and sulfates) from saturated solutions driven by solar evaporation of seawater. This explanation may be realistic for a salt thickness ≤100 m, being therefore inadequate for thicker (>1 km) deposits. Moreover, sub-seafloor salt deposits in deep marine basins are difficult to reconcile with a surface evaporation model. Marine geology reports on abyssal serpentinite systems provide an alternative explanation for some salt deposits. Seawater-driven serpentinization consumes water and increases the salinity of the associated aqueous brines. Brines can be trapped in fractures and cavities in serpentinites and the surrounding `country' rocks. Successive thermal dehydration of buried serpentinites can mobilize and accumulate the brines, forming highly saline hydrothermal solutions. These can migrate upwards and erupt onto the seafloor as saline geysers, which may form salt-saturated water pools, as are currently observed in numerous deeps in the Red Sea and elsewhere. The drainage of deep-seated saline brines to seafloor may be a long-lasting, effective process, mainly occurring in areas characterized by strong tectonic stresses and/or igneous intrusions. Alternatively, brines could be slowly expelled from fractured serpentinites by buoyancy gradients and, hence, separated salts/brines could intrude vertically into surrounding rocks, forming salt diapirs. Serpentinization is an ubiquitous, exothermic, long-lasting process which can modify large volumes of oceanic lithosphere over geological times. Therefore, buried salt deposits in many areas of the world can be reasonably related to serpentinites.

  13. Antigravity hills are visual illusions.

    PubMed

    Bressan, Paola; Garlaschelli, Luigi; Barracano, Monica

    2003-09-01

    Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.

  14. Edwardsia sojabio sp. n. (Cnidaria: Anthozoa: Actiniaria: Edwardsiidae), a new abyssal sea anemone from the Sea ofJapan

    NASA Astrophysics Data System (ADS)

    Sanamyan, Nadya; Sanamyan, Karen

    2013-02-01

    The paper describes new deep-water edwardsiid sea anemone Edwardsia sojabio sp. n. which is very common on soft muddy bottoms at lower bathyal and upper abyssal depths in the Sea of Japan. It was recorded in high quantity in depths between 2545 and 3550 m and is the second abyssal species of the genus Edwardsia.

  15. Toward optical coherence topography

    NASA Astrophysics Data System (ADS)

    Sayegh, Samir; Jiang, Yanshui

    2012-03-01

    Commercial OCT systems provide pachymetry measurements. Full corneal topographic information of anterior and posterior corneal surfaces for use in cataract surgery and refractive procedures is a desirable goal and would add to the usefulness of anterior and posterior segment evaluation. While substantial progress has been made towards obtaining "average" central corneal power (D Huang), power in different meridians and topography are still missing. This is usually reported to be due to eye movement. We analyze the role of centration, eye movements and develop a model that allows for the formulation of criteria for obtaining reliable topographic data within ¼ diopter.

  16. In situ Os isotopes in abyssal peridotites bridge the isotopic gap between MORBs and their source mantle.

    PubMed

    Alard, Olivier; Luguet, Ambre; Pearson, Norman J; Griffin, William L; Lorand, Jean-Pierre; Gannoun, Abdelmouhcine; Burton, Kevin W; O'Reilly, Suzanne Y

    2005-08-18

    Abyssal peridotites are assumed to represent the mantle residue of mid-ocean-ridge basalts (MORBs). However, the osmium isotopic compositions of abyssal peridotites and MORB do not appear to be in equilibrium, raising questions about the cogenetic relationship between those two reservoirs. However, the cause of this isotopic mismatch is mainly due to a drastic filtering of the data based on the possibility of osmium contamination by sea water. Here we present a detailed study of magmatic sulphides (the main carrier of osmium) in abyssal peridotites and show that the 187Os/188Os ratio of these sulphides is of primary mantle origin and can reach radiogenic values suggesting equilibrium with MORB. Thus, the effect of sea water on the osmium systematics of abyssal peridotites has been overestimated and consequently there is no true osmium isotopic gap between MORBs and abyssal peridotites.

  17. Oxygen Fugacity of Abyssal Peridotites Along the Gakkel Ridge

    NASA Astrophysics Data System (ADS)

    Said, M.; Birner, S.; Cottrell, E.

    2015-12-01

    The oxygen budget of the Earth's mantle is important in understanding how our planet evolves chemically over time. The Gakkel Ridge is the world's slowest spreading ridge [1], and exposes peridotites along its axis that record the activity of oxygen in the upper mantle. Our samples comprise relatively fertile lherzolites and harzburgites (Cr#=0.13-0.17, 3.1-8.3% modal cpx [2]) as well as refractory harzburgites (Cr#=0.43-0.55, 0.2-1.0% modal cpx [2]). Using spinel peridotite oxygen barometry [3], we calculated the oxygen fugacity (fO2) of a suite of 10 peridotites from the Gakkel Ridge in order to investigate how melt processes affect the oxygen budget of the Earth's interior. We show that the low-Cr# lherzolites and harzburgites range from -0.1 to +0.6 log units relative to the QFM buffer, consistent with the global abyssal peridotite array, whereas high-Cr# refractory harzburgites have low fO2 values, ranging from -0.7 to -2.7 log units below QFM, with the most refractory samples falling significantly lower than the global array. Because D'Errico et al. (submitted) interprets the refractory samples as recording ancient melt extraction, the low fO2 recorded by these samples may originate in the geologic past, perhaps even in a different tectonic setting. While LREE enrichment in the refractory harzburgites [2] provides evidence for refertilization by an infiltrating melt that could have recently imprinted reducing conditions, we see no corresponding increase in TiO2 content in the spinels, which weakens this hypothesis. Further research on additional refractory harzburgites is needed to constrain whether the reduced nature of these samples is telling us something about the effect of extreme melt extraction on fO2 at ridges, or whether these samples record a unique history that obscures processes operating at ridges today. [1] Coakley and Cochran, EPSL (1998), [2] D'Errico et al., submitted, [3] Bryndzia and Wood, American Journal of Science (1990)

  18. Varieties of Melt-Rock Interactions in Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    Ross, K.; Elthon, D.

    2003-12-01

    Ocean Drilling Program cores of abyssal peridotite from Hess Deep (Leg 147) and near the Kane Fracture Zone (Leg 153) exhibit features suggesting that a variety of melt-rock interaction processes can influence their compositions. Shallow intrusion into peridotite by melt veins can produce small gabbroic intrusives, with local interaction with the host peridotite, leading to local enrichments in peridotite incompatible element budgets and changes in peridotite modes. This process reveals nothing about proposed reactive porous flow or melt-entrapment processes that might be influencing peridotite geochemistry at greater depth. Given the limited extent of our `outcrop' (one core diameter), it is possible that the gabbroic intrusive could be un-sampled, but that the chemical effects could be present in the core and mistaken for some other type of melt-rock reaction. The presence of these gabbroic veins in both suites of drilled peridotites shows that this type of process has demonstrably changed the geochemistry of parts of these cores. Other processes that could influence the geochemistry of these rocks include: 1. Melt-entrapment; the effects this have on the mode of peridotite will depend on the pressure at which the melt is entrapped and crystallizes and on the composition of the melt; if this occurs at shallow levels, then plagioclase will be present and the occurrence of melt-trapping will be obvious, but if it occurs at greater depths, then the melt will crystallize no plagioclase and the process will be cryptic. 2. Reactive porous flow; this process could also be cryptic, because in the absence of a set of samples that clearly represents simple melt-residues, the baseline against which modal and geochemical changes have occurred is lacking. Both suites of peridotites studied show evidence for Na enrichments, but in different styles. The Kane suite is pervasively enriched in Na above the amount that should be present based on fractional melting models, in

  19. Beach vortices near circular topography

    NASA Astrophysics Data System (ADS)

    Hinds, A. K.; Johnson, E. R.; McDonald, N. R.

    2016-10-01

    Finite-area monopolar vortices which propagate around topography without change in shape are computed for circular seamounts and wells including the limiting cases of each: islands and infinitely deep wells. The time-dependent behaviour of vortex pairs propagating toward circular topography is also examined. Trajectories of point-vortex pairs exterior to the topography are found and compared to trajectories of vortex patches computed using contour dynamics.

  20. RADAR Reveals Titan Topography

    NASA Technical Reports Server (NTRS)

    Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

    2005-01-01

    The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

  1. Topography of Io (color)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The images used to create this color composite of Io were acquired by Galileo during its ninth orbit (C9) of Jupiter and are part of a sequence of images designed to map the topography or relief on Io and to monitor changes in the surface color due to volcanic activity. Obtaining images at low illumination angles is like taking a picture from a high altitude around sunrise or sunset. Such lighting conditions emphasize the topography of the volcanic satellite. Several mountains up to a few miles high can be seen in this view, especially near the upper right. Some of these mountains appear to be tilted crustal blocks. Most of the dark spots correspond to active volcanic centers.

    North is to the top of the picture which merges images obtained with the clear, red, green, and violet filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. . The resolution is 8.3 kilometers per picture element. The image was taken on June 27, 1997 at a range of 817,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  2. An assessment of upper mantle heterogeneity based on abyssal peridotite isotopic compositions

    NASA Astrophysics Data System (ADS)

    Warren, J. M.; Shimizu, N.; Sakaguchi, C.; Dick, H. J. B.; Nakamura, E.

    2009-12-01

    Abyssal peridotites, the depleted solid residues of ocean ridge melting, are the most direct samples available to assess upper oceanic mantle composition. We present detailed isotope and trace element analyses of pyroxene mineral separates from Southwest Indian Ridge abyssal peridotites and pyroxenites in order to constrain the size and length scale of mantle heterogeneity. Our results demonstrate that the mantle can be highly heterogeneous to <1 km and even <0.1 m length scales. Examination of Nd isotopes in relation to modal, trace, and major element compositions indicate that the length scales and amplitudes of heterogeneities in abyssal peridotites reflect both ancient mantle heterogeneity and recent modification by melting, melt-rock reaction and melt crystallization. The isotopic and trace element compositions of pyroxenite veins in this study indicate that they are not direct remnants of recycled oceanic crust, but instead are formed by recent melt crystallization. Combined with existing data sets, the results show that the average global isotopic composition of peridotites is similar to that of mid-ocean ridge basalts, though peridotites extend to significantly more depleted 143Nd/144Nd and 87Sr/86Sr. Standard isotope evolution models of upper mantle composition do not predict the full isotopic range observed among abyssal peridotites, as they do not account adequately for the complexities of ancient and recent melting processes.

  3. Long-term change in the abyssal NE Atlantic: The ‘Amperima Event’ revisited

    NASA Astrophysics Data System (ADS)

    Billett, D. S. M.; Bett, B. J.; Reid, W. D. K.; Boorman, B.; Priede, I. G.

    2010-08-01

    The results from a time series study (1989-2005) at a depth of 4850 m on the Porcupine Abyssal Plain, NE Atlantic, are presented, showing radical changes in the density of large invertebrates (megafauna) over time. Major changes occurred in a number of different taxa between 1996 and 1999 and then again in 2002. One species of holothurian, Amperima rosea, was particularly important, increasing in density by over three orders of magnitude. There were no significant changes in total megafaunal biomass during the same period. Peaks in density were correlated to reductions in mean body size, indicating that the increases were related to large-scale recruitment events. The changes occurred over a wide area of the Porcupine Abyssal Plain. Comparisons made with changes in the density of protozoan and metazoan meiofauna, and with macrofauna, showed that major changes in community structure occurred in all size fractions of the benthic community at the same time. This suggests that the faunal changes were driven by environmental factors rather than being stochastic population imbalances of one or two species. Large-scale changes in the flux of organic matter to the abyssal seafloor have been noted in the time series, particularly in 2001, and may be related to the sudden mass occurrence of A. rosea the following year. Time-varying environmental factors are important in influencing the occurrence of megafauna on the abyssal seafloor.

  4. Unmanned Evaluation of Mares Abyss 22 Navy Open Circuit Scuba Regulator for Cold Water Diving

    DTIC Science & Technology

    2011-05-05

    scuba regulator was conducted, and the results were compared to the U.S. Navy performance limits and goals for use in cold water diving applications...resistive effort; work of breathing; unmanned evaluation; open circuit scuba regulator; cold water diving ; Mares Abyss 22 Navy; UBA; underwater

  5. Eddy-induced variability in Southern Ocean abyssal mixing on climatic timescales

    NASA Astrophysics Data System (ADS)

    Sheen, K. L.; Naveira Garabato, A. C.; Brearley, J. A.; Meredith, M. P.; Polzin, K. L.; Smeed, D. A.; Forryan, A.; King, B. A.; Sallée, J.-B.; St. Laurent, L.; Thurnherr, A. M.; Toole, J. M.; Waterman, S. N.; Watson, A. J.

    2014-08-01

    The Southern Ocean plays a pivotal role in the global ocean circulation and climate. There, the deep water masses of the world ocean upwell to the surface and subsequently sink to intermediate and abyssal depths, forming two overturning cells that exchange substantial quantities of heat and carbon with the atmosphere. The sensitivity of the upper cell to climatic changes in forcing is relatively well established. However, little is known about how the lower cell responds, and in particular whether small-scale mixing in the abyssal Southern Ocean, an important controlling process of the lower cell, is influenced by atmospheric forcing. Here, we present observational evidence that relates changes in abyssal mixing to oceanic eddy variability on timescales of months to decades. Observational estimates of mixing rates, obtained along a repeat hydrographic transect across Drake Passage, are shown to be dependent on local oceanic eddy energy, derived from moored current meter and altimetric measurements. As the intensity of the regional eddy field is regulated by the Southern Hemisphere westerly winds, our findings suggest that Southern Ocean abyssal mixing and overturning are sensitive to climatic perturbations in wind forcing.

  6. Monologue or Dialogue? Stepping Away from the Abyss in Higher Education

    ERIC Educational Resources Information Center

    Stern, Julian

    2009-01-01

    This paper investigates the possibilities of the use of dialogue, and the dangers of the use of monologue, in higher education in the early twenty-first century, in a period facing a number of smaller- and larger-scale crises--each interpreted as an "abyss" of some kind. How does higher education contribute, positively or negatively, to personal…

  7. Zambezi continental margin: compartmentalized sediment transfer routes to the abyssal Mozambique Channel

    NASA Astrophysics Data System (ADS)

    Wiles, E.; Green, A. N.; Watkeys, M. K.; Jokat, W.

    2017-03-01

    Sediment delivery to the abyssal regions of the oceans is an integral process in the source to sink cycle of material derived from adjacent continents and islands. The Zambezi River, the largest in southern Africa, delivers vast amounts of material to the inner continental shelf of central Mozambique. The aim of this contribution is to better constrain sediment transport pathways to the abyssal plains using the latest, regional, high-resolution multibeam bathymetry data available, taking into account the effects of bottom water circulation, antecedent basin morphology and sea-level change. Results show that sediment transport and delivery to the abyssal plains is partitioned into three distinct domains; southern, central and northern. Sediment partitioning is primarily controlled by changes in continental shelf and shelf-break morphology under the influence of a clockwise rotating shelf circulation system. However, changes in sea-level have an overarching control on sediment delivery to particular domains. During highstand conditions, such as today, limited sediment delivery to the submarine Zambezi Valley and Channel is proposed, with increased sediment delivery to the deepwater basin being envisaged during regression and lowstand conditions. However, there is a pronounced along-strike variation in sediment transport during the sea-level cycle due to changes in the width, depth and orientation of the shelf. This combination of features outlines a sequence stratigraphic concept not generally considered in the strike-aligned shelf-slope-abyssal continuum.

  8. Abundance, diversity, and latitudinal gradients of southeastern Atlantic and Antarctic abyssal gastropods

    NASA Astrophysics Data System (ADS)

    Schrödl, M.; Bohn, J. M.; Brenke, N.; Rolán, E.; Schwabe, E.

    2011-03-01

    Mollusca are widely used for deriving concepts on deep-sea biology and biodiversity, yet abyssal collections are limited to only a few regions of the world ocean and biased toward the northern Atlantic. The present study compares gastropod molluscs sampled along a transect through the southern Atlantic from the equator to Antarctica. The DIVA I and II expeditions concentrated on the hardly explored Guinea, Angola, and Cape Basins. Of the 145 deep-sea deployments (5025-5656 m depth) analyzed to date, 20 have yielded 68 specimens of benthic gastropods, representing 27 species. Only five abyssal species were previously known, four of them from the northern Atlantic deep sea; the remainder appear to be undescribed. Interestingly, there is no faunal overlap with the nearby Antarctic deep-sea. Most of these DIVA species (63%) are represented by single individuals, or limited to one or two stations. The rarity (i.e. 0.55 specimens m -2 calculated from quantitative corers) and still undetectable patchiness of southeastern Atlantic abyssal gastropods may indicate "source-sink" dynamics, but comparison is needed with thus far hardly explored regional bathyal faunas. The BRENKE-epibenthic sledge (EBS) may be efficient at surveying the abyssal gastropod species richness, but is shown to drastically underestimate true abundances. Low diversity values throughout the three southern Atlantic ocean basins do further challenge earlier estimates of a hyperdiverse global abyssal macrofauna. Comparative EBS data available from the southern hemisphere indicate a gradient from the equatorial Guinea Basin towards higher gastropod abundances and diversity in Antarctica. This is in clear contrast to the paradigm of a globally strongly decreasing marine diversity from lower to higher latitudes, highlighting the importance of further exploring the southern fauna from the tropics to Antarctica.

  9. Isostasy, flexure, and dynamic topography

    NASA Astrophysics Data System (ADS)

    Gvirtzman, Zohar; Faccenna, Claudio; Becker, Thorsten W.

    2016-06-01

    A fundamental scientific question is, what controls the Earth's topography? Although the theoretical principles of isostasy, flexure, and dynamic topography are widely discussed, the parameters needed to apply these principles are frequently not available. Isostatic factors controlling lithospheric buoyancy are frequently uncertain and non-isostatic factors, such as lithospheric bending towards subduction zones and dynamic topography, are hard to distinguish. The question discussed here is whether a set of simple rules that relate topography to lithospheric structure in various tectonic environments can be deduced in a way that missing parameters can be approximated; or does each area behave differently, making generalizations problematic. We contribute to this issue analyzing the Asia-Africa-Arabia-Europe domain following a top-down strategy. We compile a new crustal thickness map and remove the contribution of the crust from the observed elevation. Then, the challenge is to interpret the residual topography in terms of mantle lithosphere buoyancy and dynamics. Based on systematic relationships between tectonic environments and factors controlling topography, we argue that crustal buoyancy and mantle lithospheric density can be approximated from available geological data and that regions near mantle upwelling or downwelling are easily identified by their extreme residual topography. Yet, even for other areas, calculating lithospheric thickness from residual topography is problematic, because distinguishing variations in mantle lithosphere thickness from sub-lithospheric dynamics is difficult. Fortunately, the area studied here provides an opportunity to examine this issue. Based on the conjunction between the Afar Plume and the mid-ocean ridge in the nearby Gulf of Aden and southern Red Sea, we constrain the maximal amplitude of dynamic topography to 1 km. This estimate is based on a narrow definition of dynamic topography that only includes sub

  10. Trapped internal waves over topography: Non-Boussinesq effects, symmetry breaking and downstream recovery jumps

    NASA Astrophysics Data System (ADS)

    Soontiens, Nancy; Stastna, Marek; Waite, Michael L.

    2013-06-01

    It is well-known that in certain parameter regimes, the steady flow of a density stratified fluid over topography can yield large amplitude internal waves. We discuss an embedded boundary method to solve the Dubreil-Jacotin-Long (DJL) equation for steady-state, supercritical flows over topography in an inviscid, stratified fluid. The DJL equation is equivalent to the full set of stratified steady Euler equations and thus the waves we compute are exact nonlinear solutions. The numerical method presented yields far better scaling with increase in grid size than other iterative methods that have been used to solve this equation, and this in turn allows for a more thorough exploration of parameter space. For waves under the Boussinesq approximation, we contrast the properties of trapped waves over hill-like and valley-like topography, finding that the symmetry of freely propagating solitary waves when the stratification is reflected across the middepth is not present for trapped waves. We extend the derivation of the DJL equation to the non-Boussinesq case and discuss the effect of the new, non-Boussinesq terms on the structure of the trapped waves, finding that the sharp transition between large and small amplitude waves observed under the Boussinesq approximation is much more gradual when the Boussinesq approximation is relaxed. Finally, we demonstrate the existence of asymmetric steady states over hill-like topography where the flow is subcritical upstream of the topography but transitions to supercritical somewhere over the hill. Waves in this new class of exact solutions are related to so-called downstream recovery jumps predicted on the basis of hydrostatic (shallow water) theories, but when breaking does not occur the recovery jump does not stop propagating downstream and an asymmetric state across the topography maximum is reached for long times.

  11. Clarks Hill Lake Water Quality Study.

    DTIC Science & Technology

    1982-06-01

    MACROINVERTEBRATE TAXONOMIC LIST CLARKS HILL LAKE 1981 Phylum Platyhelminthes Order Diptera Class Turbellaria Ablabesmyia parajanta unidentified Planariidae A...HILL LAKE 1981 Phylum Platyhelminthes Order Diptera (continued) Planaria sp.,’ Bezzia sp. 2 unidentified Planariidae Chaoborus punctipennis unidentified

  12. Hill & Knowlton's Two Ethical Dilemmas.

    ERIC Educational Resources Information Center

    Pratt, Cornelius B.

    1994-01-01

    Presents arguments for and against the acceptance, in 1990, of two controversial client accounts by the public relations agency Hill & Knowlton. Examines the ethical implications of both accounts and concludes that whatever ethical infractions may have occurred reflect the agency's dominant public relations practices, not necessarily the "greedy…

  13. SRTM Anaglyph: Haro and Kas Hills

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001 the Kachchh region in western India suffered the most deadly earthquake in India's history. This three-dimensional view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. The anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the curvilinear ridge trending toward the southwest from the image center is an erosion resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. The dike also appears to extend northeast from the image center as a dark line having very little topography. Its location between the tilted block and a smaller anticline to the north (directly east of the larger anticline) probably indicates that the dike fills the fault that separates these contrasting geologic structures. These features are simple examples of how digital elevation data can stereoscopically enhance satellite imagery to provide a direct input to geologic studies.

    The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image (taken just two weeks after the earthquake) over preliminary digital elevation

  14. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  15. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Chalk Hill. 9.52 Section 9... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  16. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  17. 27 CFR 9.52 - Chalk Hill.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Chalk Hill. 9.52 Section 9... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.52 Chalk Hill. (a) Name. The name of the viticultural area described in this section is “Chalk Hill.” (b) Approved...

  18. Internal Wave Breaking in Stratified Flow over Topography

    NASA Astrophysics Data System (ADS)

    Peltier, W. Richard

    2016-11-01

    In both atmosphere and oceans, internal waves generated by stratified flow over topography "break" when a critical Froude number is exceeded. In the oceans, the global field of such waves forced by the flow of the barotropic tide over bottom topography constitutes an "internal tide", the turbulent dissipation of which contributes significantly to the diapycnal diffusivity of mass in the abyss. In the atmosphere, the vertical flux of horizontal momentum in the wave field plays an important role in mediating the strength of the mid-latitude jet streams in the troposphere through the "gravity wave drag" that is applied to the mean zonal flow when the waves break. Early work on the atmospheric problem based upon the application of LES methods demonstrated that, in the restricted case of topographically forces 2-D flows, wave breaking aloft led to the development of an intense low level jet in the lee of the topographic maximum, in which an intense secondary instability of Kelvin-Helmholtz type developed which became intensely turbulent. The same methods were later applied to the oceans, initially to develop an understanding of the tidally induced breaking wave mechanics in the Knight Inlet "flume". Similar dynamical interactions, to those observed in the atmosphere in connection with severe downslope windstorm formation, have been observed to occur in the deep ocean in the lee of ocean bottom topographic extrema. Current work is underway to determine the extent to which DNS methods applied to the oceanographic context are able to recover the phenomenology revealed by the atmospheric LES analyses.

  19. Thermal stability effects on the separated flow over a steep 2-D hill

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Porte-Agel, F.

    2012-12-01

    Transport of momentum and scalars in turbulent boundary-layer flows over complex topography has been of great interest in the atmospheric sciences and wind engineering communities. Applications include but are not limited to weather forecasting, air pollution dispersion, aviation safety control, and wind energy project planning. Linear models have been well accepted to predict boundary-layer flows over topography with gentle slope. However, once the slope of the topography is sufficientlyo steep that flow separation occurs, linear models are not applicable. Modeling the turbulent transport of momentum and scalars in such flows has to be achieved through non-linear models, such as Reynolds-averaged Navier-Stokes solvers and large-eddy simulations (LES). Dynamics of the separated boundary-layer flows over steep topography is affected by the shape and size of the topography, surface characteristics (e.g., roughness and temperature) and atmospheric thermal stability. Most wind-tunnel experiments of boundary-layer flows over idealized topography (e.g. 2-D or 3-D hills, axisymmetric bumps) do not take thermal stability effects into account due to difficulty of physical simulation. We conducted comprehensive experimental investigation of stably- and unstably- stratified boundary layers over a steep 2-D hill in the thermally-controlled boundary-layer wind tunnel at the Saint Anthony Falls Laboratory. The 2-D model hill has a steepest slope of 0.73 and its shape follows a cosine square function: h=Hcos^2 (πx/L) for -L/2 ≤ x ≤ L/2 , where the maximum height H is 7 cm and the total width L is 15 cm. High-resolution Particle Image Velocimetry (PIV) provides dynamic information of the separated shear layer, the recirculation zone and flow reattachment. Turbulent momentum and scalar (heat) fluxes were characterized up to the top of the thermal boundary layer using a triple-wire (cross-wire and cold-wire) anemometer. Results indicate that promoted and suppressed turbulence

  20. Evolution of the Puente Hills Thrust Fault

    NASA Astrophysics Data System (ADS)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  1. New insights into the abyssal sponge fauna of the Kurile-Kamchatka plain and Trench region (Northwest Pacific)

    NASA Astrophysics Data System (ADS)

    Downey, Rachel V.; Janussen, Dorte

    2015-01-01

    The under-explored abyssal depths of the Kurile-Kamchatka region have been re-examined during the KuramBio (Kurile-Kamchatka Biodiversity Study) expedition. Combining new KuramBio data with previous expedition data in this region has enhanced our understanding abyssal sponge fauna, in particular, the patchiness, rarity, and exceptional richness of the Cladorhizidae family. In total, 14 sponge species, from 7 genera, in 5 families, within two classes (Demospongiae and Hexactinellida) were collected. Of the 14 species, 29% (4 spp.) have been found previously in this region, 36% (5 spp.) were new to the regional abyssal fauna, and 21% (3 spp.) were new to science. The number of abyssal species in this region has now been increased by 26% (8 spp.) and genera by nearly 15% (2 genera). Rarity is a prominent feature of this abyssal fauna, with more than half of species only found at one station, and 83% (19 spp.) of species found previously in this region were not re-found during KuramBio. Cladorhizid sponges dominate demosponge species and genera richness in the abyssal Kurile-Kamchatka region; accounting for 87% (20 spp.) of all demosponge species, and accounting for over 60% (5 genera) of all demosponge genera. Sponge richness in this region is potentially aided by the productivity of the ocean waters, the geological age of the Pacific Ocean, low population densities, and the varied topographic features (ridges, trenches, and seamounts) found in this region. Unusually, the dominance of demosponges in the Kurile-Kamchatka sponge faunal composition is not replicated in other well-sampled abyssal regions, which tend to be richer in deep-sea hexactinellid fauna. Broad depth, latitudinal and longitudinal ranges in Kurile-Kamchatka abyssal fauna are a key characteristic of this faunal assemblage. Strong abyssal faunal connectivity is found between the Kurile-Kamchatka region and North Pacific abyssal fauna, with weaker faunal connections found with the adjacent semi

  2. On the origin of Hill's causal criteria.

    PubMed

    Morabia, A

    1991-09-01

    The rules to assess causation formulated by the eighteenth century Scottish philosopher David Hume are compared to Sir Austin Bradford Hill's causal criteria. The strength of the analogy between Hume's rules and Hill's causal criteria suggests that, irrespective of whether Hume's work was known to Hill or Hill's predecessors, Hume's thinking expresses a point of view still widely shared by contemporary epidemiologists. The lack of systematic experimental proof to causal inferences in epidemiology may explain the analogy of Hume's and Hill's, as opposed to Popper's, logic.

  3. GEOCHEMISTRY OF MAJUBA HILL, NEVADA.

    USGS Publications Warehouse

    Wenrich, Karen J.; Mascarenas, Joseph F.; Silberman, Miles L.

    1984-01-01

    Majuba Hill is the erosional remnant of a mineralized volcanic complex of rhyolite porphyry stocks, dikes, sills and irregular masses of breccia intruded into Triassic(? ) argillites. Majuba Hill is best known for its Cu and Sn ore; in addition, it was mineralized with other metals of possible economic significance, most notably, Mo, Ag, and U. Although this is an intrusive complex with no evidence of any extrusive phases, it was intruded sufficiently near the surface to develop a porphyritic texture. Intense sericitic and argillic alteration affected all stages of intrusion. Fresh rocks were not available for K-Ar analyses. Several samples of feldspars and sericite from altered zones yielded K-Ar ages for the alteration of 24. 7 to 25. 5 m. y. The tight clustering of ages suggests that all stages of the complex were altered within less than 1 m. y.

  4. Permian karst topography in the Wichita uplift, southwestern Oklahoma

    SciTech Connect

    Donovan, R.N. Busbey, A.B. . Geology Dept.)

    1993-02-01

    The Wichita uplift in southwestern Oklahoma is one part of a record of Pennsylvania and early Permian deformation that affected the Southern Oklahoma aulacogen. As a result of a partial inversion, the Lower Paleozoic section of this aulacogen was sequentially stripped off an uplift between the Wichita uplift and the Anadarko basin, resulting in the exposure of ultrabasic rocks deep in the Cambrian igneous fill of the aulacogen. Following the late Paleozoic tectonism, the topography of the uplift was entombed beneath Permian sediments and remained essentially undisturbed until exhumation during the present erosional cycle. Modern erosion is gradually exposing this topography, permitting morphometric analysis of the Permian hill forms. Because of the variation of lithology in the uplift, it is possible to isolate the effects of weathering processes such as intense hydrolysis of the igneous rocks (producing, among other features, or topography) and limestone dissolution, in the form of a surface and subsurface karst imprint. The latter process resulted in a network of small caves that are essentially fissures eroded along tectonic fractures. These small caves can be found in all the exposed areas of limestone. They are particularly noteworthy for three reasons: in at least five examples they contain a complex fauna of Permian vertebrates (mostly fragmentary), speleothems in some examples contain hydrocarbon inclusions, derived from the underlying Anadarko basin, some of the caves yield evidence of post burial evolution in the form of clay infiltration from the surface and brine flushing from the underlying Anadarko basin.

  5. A glimpse into the deep of the Antarctic Polar Front - Diversity and abundance of abyssal molluscs

    NASA Astrophysics Data System (ADS)

    Jörger, K. M.; Schrödl, M.; Schwabe, E.; Würzberg, L.

    2014-10-01

    Our knowledge of the biodiversity and distribution patterns of benthic deep-sea faunas is still limited, with large parts of the world's abyss unexplored, lacking α-taxonomic data across oceans basins and especially of biogeographic transition zones between oceans. The Antarctic Polar Frontal Zone has been discussed as major biogeographic barrier hindering faunal exchange between Subantarctic and Antarctic provinces and conserving high rates of endemism in the Southern Ocean benthos. In the present study we report first, exploratory α-taxonomy on the malacofauna sampled by means of an epibenthic sledge from four bathyal respectively abyssal stations (2732-4327 m depth) in the vicinity of the Antarctic Polar Front during the SYSTCO II expedition (SYSTem COupling in the Southern Ocean, RV Polarstern cruise ANT XXVIII/3). We identified 58 distinct molluscan taxa based on external morphology ('morphospecies'); of the 33 taxa successfully assigned to described species 94% were previously reported from the Southern Ocean, but 24% exhibit distribution ranges crossing the Polar Front. One North Atlantic scaphopod is reported for the first time in Antarctic waters. Our study supports that the Antarctic Polar Front does not serve as effective barrier preventing gene flow in deep-sea molluscs. The present dataset shows the general characteristics of deep-sea sampling: patchiness in distribution and a high degree of singletons. Overall molluscan abundances were generally low ranging between 3.60 and 24.65 ind./1000 m², but in comparison with equatorial and subtropic abyssal basins, gastropod species richness and abundance were reaching high values similar to high Antarctic stations. Comparison between high productivity and low productivity zones along the Polar Front suggests increased abundances and species richness in high productivity zones. Intensified sampling is needed, however, to outweigh stochastic errors and to evaluate the influence of carbon flux as driving

  6. Species composition and distribution of bivalves in bathyal and abyssal depths of the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Kamenev, Gennady M.

    2013-02-01

    Twenty-six bivalve species collected by four Russian (1972, 1976, 1985, 2005) and Russian-German (2010) expeditions in the bathyal and abyssal depths of the Sea of Japan (465-3435 m) are listed with the material examined and illustrated. Taxonomic decisions herein: Robaia habei Scarlato, 1981 is synonymized with Nuculana (Robaia) robai (Kuroda, 1929); following Scarlato (1981) and Coan et al. (2000)Dacrydium nipponicum Okutani, 1975 and Dacrydium minimum Okutani and Izumidate, 1992 are synonymized with Dacrydium vitreum (Möller, 1842); Maorithyas yamatotaensis Okutani and Izumidate, 1992 is synonymized with Adontorhina cyclia Berry, 1947; Axinopsida rubiginosa Okutani and Izumidate, 1992 is synonymized with Mendicula ferruginosa (Forbes, 1844); Cardiomya lindbergi batialis Scarlato, 1972 is synonymized with Cardiomya tosaensis (Kuroda, 1948); Cuspidaria sadoensis Okutani and Ito, 1983 is synonymized with Cuspidaria ascoldica Scarlato, 1972; Cyclocardia rjabininae (Scarlato, 1955) recognized as valid and distinct from Cyclocardia ovata (Rjabinina, 1952). The deep-water bivalve fauna of the Sea of Japan is characterized by an impoverished shelf fauna and consists of eurybathic species that extend from the shelf to the bathyal and abyssal zones. Most of them have a wide geographic distribution and inhabit cold water regions of the Northern Atlantic, Northern Pacific, and Arctic Ocean. Only five species are endemic to the Sea of Japan. With increase in depth, the species richness of bivalves decreases. In the depth range from 200 to 1600 m, all species (26) found in the deep Sea of Japan were recorded, while only 10 species were recorded in the lower bathyal slope (1700-3000 m). At depths below 3000 m, only D. vitreum, Delectopecten vancouverensis (Whiteaves, 1893), and Thyasira (Parathyasira) sp. were found. The lack of typical abyssal species of bivalves in the deep Sea of Japan is probably connected with the isolation of this body of water from the Pacific abyssal

  7. Rolling Mill Hill, Nashville, TN

    EPA Pesticide Factsheets

    Rolling Mill Hill was the home to Nashville General Hospital from 1890 to the 1990s and encompassed several buildings and structures. These existing buildings of historical significance were re-used in the form of apartments. The original Trolley Barns on the site are now artists’ lofts and are home to several companies and non-profit offices. Nance Place, which entails additional buildings built on-site, is a Tax Credit Workforce Housing Development and is Platinum LEED certified.

  8. Rocks of the Columbia Hills

    USGS Publications Warehouse

    Squyres, S. W.; Arvidson, R. E.; Blaney, D.L.; Clark, B. C.; Crumpler, L.; Farrand, W. H.; Gorevan, S.; Herkenhoff, K. E.; Hurowitz, J.; Kusack, A.; McSween, H.Y.; Ming, D. W.; Morris, R.V.; Ruff, S.W.; Wang, A.; Yen, A.

    2006-01-01

    The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic or impact in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in Martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present. Copyright 2006 by the American Geophysical Union.

  9. Rocks of the Columbia Hills

    NASA Astrophysics Data System (ADS)

    Squyres, Steven W.; Arvidson, Raymond E.; Blaney, Diana L.; Clark, Benton C.; Crumpler, Larry; Farrand, William H.; Gorevan, Stephen; Herkenhoff, Kenneth E.; Hurowitz, Joel; Kusack, Alastair; McSween, Harry Y.; Ming, Douglas W.; Morris, Richard V.; Ruff, Steven W.; Wang, Alian; Yen, Albert

    2006-02-01

    The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic or impact in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in Martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present.

  10. Demographic indicators of change in a deposit-feeding abyssal holothurian community (Station M, 4000 m)

    NASA Astrophysics Data System (ADS)

    Huffard, Christine L.; Kuhnz, Linda A.; Lemon, Larissa; Sherman, Alana D.; Smith, Kenneth L.

    2016-03-01

    Holothurians are among the most abundant benthic megafauna at abyssal depths, and important consumers and bioturbators of organic carbon on the sea floor. Significant fluctuations in abyssal holothurian density are often attributed to species-specific responses to variable particulate organic carbon flux (food supply) stemming from surface ocean events. We report changes in densities of 19 holothurian species at the abyssal monitoring site Station M in the northeast Pacific, recorded during 11 remotely operated vehicle surveys between Dec 2006 and Oct 2014. Body size demographics are presented for Abyssocucumis abyssorum, Synallactidae sp. 1, Paelopatides confundens, Elpidia sp. A, Peniagone gracilis, Peniagone papillata, Peniagone vitrea, Peniagone sp. A, Peniagone sp. 1, and Scotoplanes globosa. Densities were lower and species evenness was higher from 2006-2009 compared to 2011-2014. Food supply of freshly-settled phytodetritus was exceptionally high during this latter period. Based on relationships between median body length and density, numerous immigration and juvenile recruitment events of multiple species appeared to take place between 2011 and 2014. These patterns were dominated by elpidiids (Holothuroidea: Elasipodida: Elpidiidae), which consistently increased in density during a period of high food availability, while other groups showed inconsistent responses. We considered minimum body length to be a proxy for size at juvenile recruitment. Patterns in density clustered by this measure, which was a stronger predictor of maximum density than median and mean body length.

  11. Distinguishing between the abyssal macrourids Coryphaenoides yaquinae and C. armatus from in situ photography

    NASA Astrophysics Data System (ADS)

    Jamieson, A. J.; Priede, I. G.; Craig, J.

    2012-06-01

    The scavenging fish communities at abyssal depths of the Pacific Ocean are dominated by two species of macrourids; the rough abyssal grenadier Coryphaenoides yaquinaeIwamoto and Stein, 1974 and the abyssal grenadier C. armatus (Hector, 1875). These two species are morphologically very similar, and in the absence of physical specimens are notoriously difficult to distinguish from photographic data. In an era of increasing reliance on imaging technology in the deep sea, we provide an analysis of images of the two species from around the Pacific Rim with supplementary data from the Atlantic and Southern Oceans. Our results show that image-specific morphometric characters are inadequate to distinguish the two species. However, the way in which artificial illumination is reflected from the body is both sufficient, and consistently different to distinguish between the two species. The results are also corroborated by known geographic and bathymetric distributions. This analysis is intended to provide a reliable method of identification from deep-sea imaging systems in the absence of standard fishing techniques.

  12. Abyssal Scavenging Communities attracted to Sargassum and fish in the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Fleury, Aharon G.; Drazen, Jeffrey C.

    2013-02-01

    Deep-sea communities rely on epipelagic surface production as a primary source of energy and food. The flux of phytodetritus drives many abyssal ecological processes but the flux of large particles such as nekton carcasses, macroalgae, and wood may also be important. Recent baited camera experiments noted that some abyssal fish consumed spinach and phytoplankton placed on the seafloor. To evaluate if fish or other scavengers would consume natural plant or macroalgal material falling to the deep-sea floor we conducted camera experiments using Sargassum or mackerel bait in the Sargasso Sea. A benthic community of invertebrates was attracted to Sargassum, which naturally falls to the seafloor in this area. In five instances it was observed that an isopod Bathyopsurus sp. removed a piece of Sargassum from the main clump and left the field of view with it. An ophiuroid is also observed handling a piece of Sargassum. The group of scavengers attracted to mackerel bait was very different and was dominated by large ophidiid fish. In contrast to studies elsewhere in the abyssal North Atlantic, only a small number of rattails are observed, which could be related to water depth or an ichthyofaunal zonal change between oligotrophic and eutrophic regions.

  13. GLORIA side-scan imagery of Aleutian basin, Bering Sea slope and Abyssal plain

    SciTech Connect

    Carlson, P.R.; Cooper, A.K.; Gardner, J.V.; Karl, H.A.; Marlow, M.S.; Stevenson, A.J.; Huggett, Q.; Kenyon, N.; Parson, L.

    1987-05-01

    During July-September 1986, about 700,000 km/sup 2/ of continental slope and abyssal plain of the Aleutian basin, Bering Sea, were insonified with GLORIA (Geological Long Range Inclined Asdic) side-scane sonar. A sonar mosaic displays prominent geomorphic features including the massive submarine canyons of the Beringian and the northern Aleutian Ridge slopes and shows well-defined sediment patterns including large deep-sea channels and fan systems on the Aleutian basin abyssal plain. Dominant erosional and sediment transport processes on both the Beringian and the Aleutian Ridge slopes include varieties of mass movement that range from small debris flows and slides to massive slides and slumps of blocks measuring kilometers in dimension. Sediment-flow patterns that appear to be formed by sheet flow rather than channelized flow extend basinward from the numerous canyons and gullies that incise the slopes of the Beringian margin and of Bowers Ridge and some places along the Aleutian Ridge. These Beringian and Bowers canyon sediment sources, however, appear to have contributed less modern sediment to the Aleutian basin than the large, well-defined channel systems that emanate from Bering, Umnak, and Amchitka submarine canyons and extend for several hundred kilometers across the abyssal plain. This GLORIA imagery emphasizes the important contribution of the Aleutian Ridge to modern sedimentation in the deep Bering Sea.

  14. The man and the hill

    USGS Publications Warehouse

    Leopold, Luna Bergere

    1962-01-01

    He was sitting on a large slab of rock. As he looked at the cloud of dust hanging hazily on the horizon, the piece of antler and the block of flint he held in his hand hung as if they were suspended from their previous rapid motion. The man gazed intently across the swaying grass which rose in wave-like billows across the distant hills. What was that dust - a herd of buffalo, a band of hunters, or were coyotes chasing the antelope again? After watching for a while he started again to chip the flint with a rapid twisting motion of the bone in his right hand. The little chips of flint fell in the grass before him. It is the same hill but the scene has changed. Seated on the same rock, holding the reins of a saddle horse, a man dressed in buckskin took the fur cap off his head and wiped his brow. He was looking intently across a brown and desolate landscape at a cloud of dust on the far horizon. Was it the hostile tribe of Indians? It could be buffalo. Nervously he kicked at the ground with the deerhide moccasin, pushing the flint chips out of the way. He wiped the dust from his long rifle. What a terrible place - no water, practically no grass, everything bare and brown. Now at sunset, slanting across the hills green with springtime, a cowman sits on a big rock, pushes his sombrero back on his head, and looks across the valley at a large but quiet herd of stock, moving slowly as each steer walks from one lush patch of grass to another, nibbling. Suddenly he stood up. Far on the horizon some dark objects were moving. Is it the sheepmen? Could it be the stage coach from Baggs to the Sweetwater Crossing?Same hill - a gray truck was grinding slowly toward the summit. It pulled up near a small fenced enclosure where there were some instruments painted a bright silver color. A man stepped out of the truck and turned to his younger companion, "You've never found an arrowhead? Maybe you have never thought about it correctly. If you want to find where an Indian camped long

  15. Comparative feeding ecology of abyssal and hadal fishes through stomach content and amino acid isotope analysis

    NASA Astrophysics Data System (ADS)

    Gerringer, M. E.; Popp, B. N.; Linley, T. D.; Jamieson, A. J.; Drazen, J. C.

    2017-03-01

    The snailfishes, family Liparidae (Scorpaeniformes), have found notable success in the hadal zone from 6000-8200 m, comprising the dominant ichthyofauna in at least five trenches worldwide. Little is known about the biology of these deepest-living fishes, nor the factors that drive their success at hadal depths. Using recent collections from the Mariana Trench, Kermadec Trench, and neighboring abyssal plains, this study investigates the potential role of trophic ecology in structuring fish communities at the abyssal-hadal boundary. Stomach contents were analyzed from two species of hadal snailfishes, Notoliparis kermadecensis and a newly-discovered species from the Mariana Trench. Amphipods comprised the majority (Kermadec: 95.2%, Mariana: 97.4% index of relative importance) of stomach contents in both species. Decapod crustaceans, polychaetes (N. kermadecensis only), and remains of carrion (squid and fish) were minor dietary components. Diet analyses of abyssal species (families Macrouridae, Ophidiidae, Zoarcidae) collected from near the trenches and the literature are compared to those of the hadal liparids. Stomachs from abyssal fishes also contained amphipods, however macrourids had a higher trophic plasticity with a greater diversity of prey items, including larger proportions of carrion and fish remains; supporting previous findings. Suction-feeding predatory fishes like hadal liparids may find an advantage to descending into the trench - where amphipods are abundant. More generalist feeders and scavengers relying on carrion, such as macrourids, might not benefit from this nutritional advantage at hadal depths. Compound specific isotope analysis of amino acids was used to estimate trophic level of these species (5.3±0.2 Coryphaenoides armatus, 5.2±0.2 C. yaquinae, 4.6±0.2 Spectrunculus grandis, 4.2±0.2 N. kermadecensis, 4.4±0.2 Mariana snailfish). Source amino acid δ15N values were especially high in hadal liparids (8.0±0.3‰ Kermadec, 6.7±0.2

  16. Controls on melting at spreading ridges from correlated abyssal peridotite - mid-ocean ridge basalt compositions

    NASA Astrophysics Data System (ADS)

    Regelous, Marcel; Weinzierl, Christoph G.; Haase, Karsten M.

    2016-09-01

    Variations in the volume and major element composition of basalt erupted along the global mid-ocean ridge system have been attributed to differences in mantle potential temperature, mantle composition, or plate spreading rate and lithosphere thickness. Abyssal peridotites, the residues of mantle melting beneath mid-ocean ridges, provide additional information on the melting process, which could be used to test these hypotheses. We compiled a global database of abyssal peridotite compositions averaged over the same ridge segments defined by Gale et al. (2013). In addition, we calculated the distance of each ridge segment to the nearest hotspots. We show that Cr# in spinel in abyssal peridotites is negatively correlated with Na90 in basalts from the same ridge segments on a global scale. Ridge segments that erupt basalts apparently produced by larger degrees of mantle melting are thus underlain by peridotites from which large amounts of melt have been extracted. We find that near-ridge hotspots have a more widespread influence on mid-ocean ridge basalt (MORB) composition and ridge depth than previously thought. However, when these hotspot-influenced ridge segments are excluded, the remaining segments show clear relationships between MORB composition, peridotite composition, and ridge depth with spreading rate. Very slow-spreading ridges (<20 mm/yr) are deeper, erupt basalts with higher Na90, Al90, K90/Ti90, and lower Fe90, Ca90/Al90, and expose peridotites with lower Cr# than intermediate and fast-spreading ridges. We show that away from hotspots, the spreading-rate dependence of the maximum degree of mantle melting inferred from Cr# in peridotites (FM) and the bulk degree of melting inferred from Na90 in basalts (FB) from the same ridge segments is unlikely to be due to variations in mantle composition. Nor can the effects of dynamic mantle upwelling or incomplete melt extraction at low spreading rates satisfactorily explain the observed compositions of abyssal

  17. Mantle convection, topography and geoid

    NASA Astrophysics Data System (ADS)

    Golle, Olivia; Dumoulin, Caroline; Choblet, Gaël.; Cadek, Ondrej

    2010-05-01

    The internal evolution of planetary bodies often include solid-state convection. This phenomenon may have a large impact on the various interfaces of these bodies (dynamic topography occurs). It also affects their gravity field (and the geoid). Since both geoid and topography can be measured by a spacecraft, and are therefore available for several planetary bodies (while seismological measurements are still lacking for all of them but the Moon and the Earth), these are of the first interest for the study of internal structures and processes. While a classical approach now is to combine gravity and altimetry measurements to infer the internal structure of a planet [1], we propose to complement it by the reverse problem, i.e., producing synthetic geoid and dynamic topography from numerical models of convection as proposed by recent studies (e.g. for the CMB topography of the Earth,[2]). This procedure first include a simple evaluation of the surface topography and geoid from the viscous flow obtained by the 3D numerical tool OEDIPUS [3] modeling convection in a spherical shell. An elastic layer will then be considered and coupled to the viscous model - one question being whether the elastic shell shall be included 'on top' of the convective domain or within it, in the cold 'lithospheric' outer region. What we will present here corresponds to the first steps of this work: the comparison between the response functions of the topography and the geoid obtained from the 3D convection program to the results evaluated by a spectral method handling radial variations of viscosity [4]. We consider the effect of the elastic layer whether included in the convective domain or not. The scale setting in the context of a full thermal convection model overlaid by an elastic shell will be discussed (thickness of the shell, temperature at its base...). References [1] A.M. Wieczorek, (2007), The gravity and topography of the terrestrial planets, Treatise on Geophysics, 10, 165-206. [2

  18. Glacial magnetite dissolution in abyssal NW Pacific sediments - evidence for carbon trapping?

    NASA Astrophysics Data System (ADS)

    Korff, Lucia; von Dobeneck, Tilo; Frederichs, Thomas; Kasten, Sabine; Kuhn, Gerhard; Gersonde, Rainer; Diekmann, Bernhard

    2016-04-01

    The abyssal North Pacific Ocean's large volume, depth, and terminal position on the deep oceanic conveyor make it a candidate site for deep carbon trapping as postulated by climate theory to explain the massive glacial drawdown of atmospheric CO2. As the major basins of the North Pacific have depths of 5500-6500m, far below the modern and glacial Calcite Compensation Depths (CCD), these abyssal sediments are carbonate-free and therefore not suitable for carbonate-based paleoceanographic proxy reconstructions. Instead, paleo-, rock and environmental magnetic methods are generally well applicable to hololytic abyssal muds and clays. In 2009, the international paleoceanographic research cruise SO 202 INOPEX ('Innovative North Pacific Experiment') of the German RV SONNE collected two ocean-spanning EW sediment core transects of the North Pacific and Bering Sea recovering a total of 50 piston and gravity cores from 45 sites. Out of seven here considered abyssal Northwest Pacific piston cores collected at water depths of 5100 to 5700m with mostly coherent shipboard susceptibility logs, the 20.23m long SO202-39-3, retrieved from 5102 m water depth east of northern Shatsky Rise (38°00.70'N, 164°26.78'E), was rated as the stratigraphically most promising record of the entire core transect and selected for detailed paleo- and environmental magnetic, geochemical and sedimentological investigations. This core was dated by correlating its RPI and Ba/Ti records to well-dated reference records and obviously provides a continuous sequence of the past 940 kyrs. The most striking orck magnetic features are coherent magnetite-depleted zones corresponding to glacial periods. In the interglacial sections, detrital, volcanic and even submicron bacterial magnetite fractions are excellently preserved. These alternating magnetite preservation states seem to reflect dramatic oxygenation changes in the deep North Pacific Ocean and hint at large-scale benthic glacial carbon trapping

  19. Keeping pace with Capitol Hill

    USGS Publications Warehouse

    Cooper, C.

    2007-01-01

    At the Capitol Hill, the legislative branch of the United States government, the work is always at pace. Working with Congress is a tough job yet, rewarding. The Congress worked hard together to serve the public interest but many big issues are one small part of what Congress does. However, many US news media do not report what the government does instead, the media report what the government argues about. The media reports the conflicts but story is always incomplete. In order for the people know what is happening to the government, contact the congressional representative to know the complete story.

  20. Unexpectedly higher metazoan meiofauna abundances in the Kuril-Kamchatka Trench compared to the adjacent abyssal plains

    NASA Astrophysics Data System (ADS)

    Schmidt, Christina; Martínez Arbizu, Pedro

    2015-01-01

    We studied meiofauna standing stocks and community structure in the Kuril-Kamchatka Trench and its adjacent abyssal plains in the northwestern Pacific Ocean. In general, the Nematoda were dominant (93%) followed by the Copepoda (4%). Nematode abundances ranged from 87% to 96%; those of copepods from 2% to 7%. The most diverse deployment yielded 17 taxa: Acari, Amphipoda, Annelida, Bivalvia, Coelenterata, Copepoda, Cumacea, Gastrotricha, Isopoda, Kinorhyncha, Loricifera, Nematoda, Ostracoda, Priapulida, Tanaidacea, Tantulocarida, and Tardigrada. Nauplii were also present. Generally, the trench slope and the southernmost deployments had the highest abundances (850-1392 individuals/cm2). The results of non-metric multidimensional scaling indicated that these deployments were similar to each other in meiofauna community structure. The southernmost deployments were located in a zone of higher particulate organic carbon (POC) flux (g Corg m-2 yr-1), whereas the trench slope should have low POC flux due to depth attenuation. Also, POC and abundance were significantly correlated in the abyssal plains. This correlation may explain the higher abundances at the southernmost deployments. Lateral transport was also assumed to explain high meiofauna abundances on the trench slope. Abundances were generally higher than expected from model results. ANOSIM revealed significant differences between the trench slope and the northern abyssal plains, between the central abyssal plains and the trench slope, between the trench slope and the southern abyssal plains, between the central and the southern abyssal plains, and between the central and northern deployments. The northern and southern abyssal plains did not differ significantly. In addition, a U-test revealed highly significant differences between the trench-slope and abyssal deployments. The taxa inhabited mostly the upper 0-3 cm of the sediment layer (Nematoda 80-90%; Copepoda 88-100%). The trench-slope and abyssal did not differ

  1. Long-term maintenance and public exhibition of deep-sea hydrothermal fauna: The AbyssBox project

    NASA Astrophysics Data System (ADS)

    Shillito, Bruce; Ravaux, Juliette; Sarrazin, Jozée; Zbinden, Magali; Sarradin, Pierre-Marie; Barthelemy, Dominique

    2015-11-01

    The AbyssBox project aims to provide the first permanent public exhibition of live deep-sea hydrothermal fauna maintained at in situ pressure. AbyssBox is a pressurized aquarium designed to function permanently. Here we present details of the project after the public exhibition functioned for more than three years at Océanopolis aquarium in Brest, France. We also describe the AbyssBox pressure aquarium, and provide data and observations on vent shrimp (Mirocaris fortunata) and crabs (Segonzacia mesatlantica) that were sampled from 1700 m depth at the Lucky Strike vent field (Mid-Atlantic Ridge) during different cruises. While mortalities exceeded 50% during the first days following sampling, the remaining animals appeared to acclimate fairly well. Some crabs have now been kept for more than 2 years, and some shrimp have spent more than 3 years in captivity. Primarily designed for a public exhibition, the AbyssBox is already used for scientific purposes, since it provides one of the most effective tools for long-term rearing of deep-sea fauna. AbyssBox is a first step towards maintaining a variety of deep-sea fauna year-round at in situ pressure, which will serve both scientific and public interests.

  2. Spirit Rover on 'Husband Hill'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1: Location of Spirit

    Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. Shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image covering approximately 3 kilometers by 3 kilometers (1.9 miles by 1.9 miles) centered on the rover's location at that time in the 'Columbia Hills.'

    'Husband Hill,' the tallest in the range, is just below the center of the image. The image has a resolution of about 50 centimeters (1.6 feet) per pixel. North is up; illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude.

    The image was acquired on Nov. 2, 2005. A white box (see Figure 1) indicates the location of an excerpted portion on which the location of Spirit on that date is marked. Dr. Timothy J. Parker of the Mars Exploration Rover team at the NASA's Jet Propulsion Laboratory, Pasadena, Calif., confirmed the location of the rover in the image. The region toward the bottom of the image shows the area where the rover is currently headed. The large dark patch and other similar dark patches are accumulations of windblown sand and granules.

  3. Parameterizing turbulence over abrupt topography

    NASA Astrophysics Data System (ADS)

    Klymak, Jody

    2016-11-01

    Stratified flow over abrupt topography generates a spectrum of propagating internal waves at large scales, and non-linear overturning breaking waves at small scales. For oscillating flows, the large scale waves propagate away as internal tides, for steady flows the large-scale waves propagate away as standing "columnar modes". At small-scales, the breaking waves appear to be similar for either oscillating or steady flows, so long as in the oscillating case the topography is significantly steeper than the internal tide angle of propagation. The size and energy lost to the breaking waves can be predicted relatively well from assuming that internal modes that propagate horizontally more slowly than the barotropic internal tide speed are arrested and their energy goes to turbulence. This leads to a recipe for dissipation of internal tides at abrupt topography that is quite robust for both the local internal tide generation problem (barotropic forcing) and for the scattering problem (internal tides incident on abrupt topography). Limitations arise when linear generation models break down, an example of which is interference between two ridges. A single "super-critical" ridge is well-modeled by a single knife-edge topography, regardless of its actual shape, but two supercritical ridges in close proximity demonstrate interference of the high modes that makes knife-edfe approximations invalid. Future direction of this research will be to use more complicated linear models to estimate the local dissipation. Of course, despite the large local dissipation, many ridges radiate most of their energy into the deep ocean, so tracking this low-mode radiated energy is very important, particularly as it means dissipation parameterizations in the open ocean due to these sinks from the surface tide cannot be parameterized locally to where they are lost from the surface tide, but instead lead to non-local parameterizations. US Office of Naval Research; Canadian National Science and

  4. 7. Detail of balcony rail. August 1936. Joseph Hill, photographer, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Detail of balcony rail. August 1936. Joseph Hill, photographer, copied from small photo taken by survey member. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  5. 1. Historic American Buildings Survey Joseph Hill, Photographer August 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer August 1936 FIRST ORIGINAL STORE AND POSTOFFICE, COPY OF AN EARLY PHOTOGRAPH. LENT BY EVELYN S. CRAIG - Jansonist Colony, Colony Store & Post Office, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  6. 6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, photographer, copied from small photo taken by survey member. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  7. 3. West and south elevations. Joseph Hill, photographer, copied from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. West and south elevations. Joseph Hill, photographer, copied from photo lent by Evelyn S. Craig. August 1936. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  8. Glaciated appalachian plateau: till shadows on hills.

    PubMed

    Coates, D R

    1966-06-17

    North slopes are twice as steep as south slopes on the hills of central New York. This asymmetry is caused by unequal till thickness-3.6 meters on north slopes and 27.6 meters on south slopes. Previous workers interpreted the hills as being of bedrock sculptured by glacial erosion, with till 0.9 to 3 meters thick.

  9. Report on the Black Hills Alliance.

    ERIC Educational Resources Information Center

    Ryan, Joe

    1979-01-01

    A rally to save the Black Hills from coal- and uranium-greedy energy companies was held on July 6 and over 2,000 joined in a 15-mile walk on July 7 in Rapid City, South Dakota. The Black Hills Alliance, an Indian coalition concerned about energy development proposals in the Great Plains, sponsored the gathering. (NQ)

  10. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake Hills”. For purposes of part 4 of this chapter, “Rattlesnake Hills” is a term of viticultural significance....

  11. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake Hills”. For purposes of part 4 of this chapter, “Rattlesnake Hills” is a term of viticultural significance....

  12. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake Hills”. For purposes of part 4 of this chapter, “Rattlesnake Hills” is a term of viticultural significance....

  13. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Rattlesnake Hills. 9.193... Rattlesnake Hills. (a) Name. The name of the viticultural area described in this section is “Rattlesnake Hills”. For purposes of part 4 of this chapter, “Rattlesnake Hills” is a term of viticultural significance....

  14. Colleges as Shining Cities on a Hill

    ERIC Educational Resources Information Center

    Townsend, Kathleen Kennedy

    2012-01-01

    In this article, the author proposes that the notion of America be reintroduced as the "shining city on a hill," that abiding image from American history. The image of the shining city on a hill captures the imagination because it reflects the abiding truth that people become fully human in society, not outside of it. People need one…

  15. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization

    NASA Astrophysics Data System (ADS)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen

    2016-04-01

    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  16. An abyssal mobilome: viruses, plasmids and vesicles from deep-sea hydrothermal vents.

    PubMed

    Lossouarn, Julien; Dupont, Samuel; Gorlas, Aurore; Mercier, Coraline; Bienvenu, Nadege; Marguet, Evelyne; Forterre, Patrick; Geslin, Claire

    2015-12-01

    Mobile genetic elements (MGEs) such as viruses, plasmids, vesicles, gene transfer agents (GTAs), transposons and transpovirions, which collectively represent the mobilome, interact with cellular organisms from all three domains of life, including those thriving in the most extreme environments. While efforts have been made to better understand deep-sea vent microbial ecology, our knowledge of the mobilome associated with prokaryotes inhabiting deep-sea hydrothermal vents remains limited. Here we focus on the abyssal mobilome by reviewing accumulating data on viruses, plasmids and vesicles associated with thermophilic and hyperthermophilic Bacteria and Archaea present in deep-sea hydrothermal vents.

  17. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata.

    PubMed

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L; Dahlgren, Thomas G

    2016-01-01

    We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

  18. Surface water and groundwater interaction on a hill island

    NASA Astrophysics Data System (ADS)

    Rumph Frederiksen, Rasmus; Rømer Rasmussen, Keld; Christensen, Steen

    2014-05-01

    A number of recent studies have indicated that the hydrological system in stream valleys is often complex and exchange of water takes place through semi-permeable contacts and flow paths may be quite diverse. Yet, surface water and groundwater interaction in one of the major Danish landscapes - the hill islands - is relatively unknown. This study aims at providing new information about the rainfall-runoff processes in hill island landscapes where surface water and groundwater interaction is expected to have a dominant role and hill-slope processes not. Through stream flow measurements, field observations, and existing geological and geophysical data, we have investigated the surface water and groundwater interaction in the Abild Stream catchment (<70 km2) on Skovbjerg hill island in the western part of Denmark. Existing discharge data are limited but the hydrographs downstream Abild Stream appear to be strongly influenced by event flow indicating that shallow control by low permeable sediments is important. Nevertheless irrigation is intensive which indicates that the soil and shallow sediments are permeable. Since July 2014 we have measured stream flow during quarterly campaigns at 11 stations along the stream representing different spatial scales and using Acoustic Doppler techniques (ADCP) as well as current-meters. Furthermore we have mapped topography, soil types, geomorphology, ditches, drains and land use through field observations and digital maps. The shallow subsurface geology has been mapped using abundant well described geological data (boreholes) and geophysical data (airborne TEM). Our stream flow measurements show that the tributaries from west and north dry out during the summer period. Significant drained areas in the NW- and SW-part of the catchment have been observed from old topographical maps as well as in the field. The geological data indicate shallow low permeable sediments primarily on the western side of Abild stream, and the geophysical

  19. Influence of surface topography on the secondary electron yield of clean copper samples.

    PubMed

    Hu, Xiao-Chuan; Cao, Meng; Cui, Wan-Zhao

    2016-11-01

    Secondary electron yield (SEY) due to electron impact depends strongly on surface topography. The SEY of copper samples after Ar-ion bombardment is measured in situ in a multifunctional ultrahigh vacuum system. Increasing the ion energy or duration of ion bombardment can even enlarge the SEY, though it is relatively low under moderate bombardment intensity. The results obtained with scanning electron microscopy and atomic force microscopy images demonstrate that many valley structures of original sample surfaces can be smoothed due to ion bombardment, but more hill structures are generated with stronger bombardment intensity. With increasing the surface roughness in the observed range, the maximum SEY decreases from 1.2 to 1.07 at a surface characterized by valleys, while it again increases to 1.33 at a surface spread with hills. This phenomenon indicates that hill and valley structures are respectively effective in increasing and decreasing the SEY. These obtained results thus provide a comprehensive insight into the surface topography influence on the secondary electron emission characteristics in scanning electron microscopy.

  20. Mars Gravity and Topography Interpretations

    NASA Technical Reports Server (NTRS)

    Zuber, Maria T.; Smith, David E.; Solomon, Sean C.; Phillips, Roger J.

    1999-01-01

    New models of the topography of Mars and its gravity field from the Mars Global Surveyor mission are shedding new light on the structure of the planet and the state of isostatic compensation. Gravity field observations over the flat northern hemisphere plains show a number of anomalies at the 100 to 200 mGal level that have no apparent manifestation in the surface topography. We believe that these anomalies are probably the result of ancient impacts and represent regions of denser material buried beneath the outer depositional crust. Similar anomalies are also found in the region of the north polar ice cap even though a gravity anomaly resulting from the 3 km high icecap has not been uniquely identified. This leads us to speculate that the ice cap is largely compensated and is older than the timescale of isostatic compensation, about 10(exp 15) years.

  1. The absence of sharks from abyssal regions of the world's oceans

    PubMed Central

    Priede, Imants G; Froese, Rainer; Bailey, David M; Bergstad, Odd Aksel; Collins, Martin A; Dyb, Jan Erik; Henriques, Camila; Jones, Emma G; King, Nicola

    2006-01-01

    The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought. PMID:16777734

  2. Calcareous sponges from abyssal and bathyal depths in the Weddell Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Rapp, Hans Tore; Janussen, Dorte; Tendal, Ole S.

    2011-03-01

    Calcareous sponges have traditionally been regarded as shallow-water organisms, a persistent myth created by Hentschel (1925), partly supported by the problematic question of calcareous skeletal secretion under high partial CO 2-pressure below the CCD in the abyss. Up to now, only few species world-wide of the sponge class Calcarea have been described from depths below 2000 m. By far, the largest number of records of Antarctic Calcarea is known from shelf areas between 50 and 400 m depth. They have only been sporadically recorded on the lower shelf and the upper slope from depths between 570 and 850 m. From abyssal depths in the Antarctic there are no previous records of calcareous sponges. It was therefore a big surprise when the first true deep-sea Calcarea from the Antarctic were collected at depths between 1120 and 4400 m during the ANDEEP I, II and III expeditions ( Janussen et al., 2006). To date, five calcareous sponge species have been found, including three species new to science. The three new species belong to the genera Ascaltis, Clathrina and Leucetta. Although calcareous sponges are rare in the Antarctic deep sea, they seem to constitute a constant component of the fauna. Antarctic Calcarea shows all the characteristics of need for revision and further collection and investigation. Still, many new species are likely to be discovered in the Antarctic deep-sea.

  3. Analysis of the community structure of abyssal kinetoplastids revealed similar communities at larger spatial scales

    PubMed Central

    Salani, Faezeh Shah; Arndt, Hartmut; Hausmann, Klaus; Nitsche, Frank; Scheckenbach, Frank

    2012-01-01

    Knowledge of the spatial scales of diversity is necessary to evaluate the mechanisms driving biodiversity and biogeography in the vast but poorly understood deep sea. The community structure of kinetoplastids, an important group of microbial eukaryotes belonging to the Euglenozoa, from all abyssal plains of the South Atlantic and two areas of the eastern Mediterranean was studied using partial small subunit ribosomal DNA gene clone libraries. A total of 1364 clones from 10 different regions were retrieved. The analysis revealed statistically not distinguishable communities from both the South-East Atlantic (Angola and Guinea Basin) and the South-West Atlantic (Angola and Brazil Basin) at spatial scales of 1000–3000 km, whereas all other communities were significantly differentiated from one another. It seems likely that multiple processes operate at the same time to shape communities of deep-sea kinetoplastids. Nevertheless, constant and homogenous environmental conditions over large spatial scales at abyssal depths, together with high dispersal capabilities of microbial eukaryotes, maintain best the results of statistically indistinguishable communities at larger spatial scales. PMID:22071346

  4. Evidence for deep-water deposition of abyssal Mediterranean evaporites during the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Christeleit, Elizabeth C.; Brandon, Mark T.; Zhuang, Guangsheng

    2015-10-01

    Scientific drilling of the abyssal evaporites beneath the deepest parts of the Mediterranean basin gave rise to the idea that the Mediterranean sea completely evaporated at the end of the Messinian. Herein, we show, using new organic geochemical data, that those evaporites were deposited beneath a deep-water saline basin, not in a subaerial saltpan, as originally proposed. Abundant fossil organic lipids were extracted from evaporites in Mediterranean Deep Sea Drilling Project cores. The archaeal lipid distribution and new analyses, using the ACE salinity proxy and TEX86 temperature proxy, indicate that surface waters at the time of evaporite deposition had normal marine salinity, ranging from ∼26 to 34 practical salinity units, and temperatures of 25-28 °C. These conditions require a deep-water setting, with a mixed layer with normal marine salinity and an underlying brine layer at gypsum and halite saturation. After correction for isostatic rebound, our results indicate maximum drawdown of ∼2000 m and ∼2900 m relative to modern sea level in the western and eastern Mediterranean basins, respectively. Our results are consistent with previously proposed scenarios for sea level drawdown based on both subaerial and submarine incision and backfilling of the Rhone and Nile rivers, which require Messinian sea level drops of ∼1300 m and ∼200 m, respectively. This study provides new evidence for an old debate and also demonstrates the importance of further scientific drilling and sampling of deeper part of the abyssal Messinian units.

  5. The absence of sharks from abyssal regions of the world's oceans.

    PubMed

    Priede, Imants G; Froese, Rainer; Bailey, David M; Bergstad, Odd Aksel; Collins, Martin A; Dyb, Jan Erik; Henriques, Camila; Jones, Emma G; King, Nicola

    2006-06-07

    The oceanic abyss (depths greater than 3000 m), one of the largest environments on the planet, is characterized by absence of solar light, high pressures and remoteness from surface food supply necessitating special molecular, physiological, behavioural and ecological adaptations of organisms that live there. Sampling by trawl, baited hooks and cameras we show that the Chondrichthyes (sharks, rays and chimaeras) are absent from, or very rare in this region. Analysis of a global data set shows a trend of rapid disappearance of chondrichthyan species with depth when compared with bony fishes. Sharks, apparently well adapted to life at high pressures are conspicuous on slopes down to 2000 m including scavenging at food falls such as dead whales. We propose that they are excluded from the abyss by high-energy demand, including an oil-rich liver for buoyancy, which cannot be sustained in extreme oligotrophic conditions. Sharks are apparently confined to ca 30% of the total ocean and distribution of many species is fragmented around sea mounts, ocean ridges and ocean margins. All populations are therefore within reach of human fisheries, and there is no hidden reserve of chondrichthyan biomass or biodiversity in the deep sea. Sharks may be more vulnerable to over-exploitation than previously thought.

  6. Threatened by mining, polymetallic nodules are required to preserve abyssal epifauna

    PubMed Central

    Vanreusel, Ann; Hilario, Ana; Ribeiro, Pedro A.; Menot, Lenaick; Arbizu, Pedro Martínez

    2016-01-01

    Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (>25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones. PMID:27245847

  7. Earth rotation and core topography

    NASA Technical Reports Server (NTRS)

    Hager, Bradford H.; Clayton, Robert W.; Spieth, Mary Ann

    1988-01-01

    The NASA Geodynamics program has as one of its missions highly accurate monitoring of polar motion, including changes in length of day (LOD). These observations place fundamental constraints on processes occurring in the atmosphere, in the mantle, and in the core of the planet. Short-timescale (t less than or approx 1 yr) variations in LOD are mainly the result of interaction between the atmosphere and the solid earth, while variations in LOD on decade timescales result from the exchange of angular momentum between the mantle and the fluid core. One mechanism for this exchange of angular momentum is through topographic coupling between pressure variations associated with flow in the core interacting with topography at the core-mantel boundary (CMB). Work done under another NASA grant addressing the origin of long-wavelength geoid anomalies as well as evidence from seismology, resulted in several models of CMB topography. The purpose of work supported by NAG5-819 was to study further the problem of CMB topography, using geodesy, fluid mechanics, geomagnetics, and seismology. This is a final report.

  8. Mapping of sea bottom topography

    NASA Technical Reports Server (NTRS)

    Calkoen, C. J.; Wensink, G. J.; Hesselmans, G. H. F. M.

    1992-01-01

    Under suitable conditions the bottom topography of shallow seas is visible in remote sensing radar imagery. Two experiments were performed to establish which remote sensing technique or combination yields optimal imaging of bottom topography and which hydro-meteorological conditions are favorable. A further goal is to gain experience with these techniques. Two experiments were performed over an area in the North Sea near the measuring platform Meetpost Noordwijk (MPN). The bottom topography in the test area is dominated by sand waves. The crests of the sand waves are perpendicular to the coast line and the dominating (tidal-)current direction. A 4x4 sq km wide section of the test area was studied in more detail. The first experiment was undertaken on 16 Aug. 1989. During the experiment the following remote sensing instruments were used: Landsat-Thematic Mapper, and NASA/JPL Airborne Imaging Radar (AIR). The hydro-meteorological conditions; current, wind, wave, and air and water temperature were monitored by MPN, a ship of Rijkswaterstaat (the OCTANS), and a pitch-and-roll WAVEC-buoy. The second experiment took place on 12 July 1992. During this experiment data were collected with the NASA/JPL polarimetric synthetic aperture radar (SAR), and a five-band helicopter-borne scatterometer. Again the hydro-meteorological conditions were monitored at MPN and the OCTANS. Furthermore, interferometric radar data were collected.

  9. Major Elements Budget Between Abyssal Peridotite And Seawater During The Serpentinization

    NASA Astrophysics Data System (ADS)

    Yu, X.; Dong, Y.; Li, X.; Chu, F.

    2012-12-01

    Water-Rock Interaction is one of the most hot-debated issues among geologists, geophysicists, as well as geochemists. Abyssal peridotites recovered from the seafloor are often greatly affected or alterated by seawater in the form of serpentinization. The alteration to the peridotites makes it difficult to do the straightforward analysis for its primary composition as it was settled in the upper mantle, which confine the usage of these rare direct samples from the mantle in the scientific study, such as mantle dynamics, mantle composition and crust-mantle interaction. Besides, It was revealed recently that the serpentinization of abyssal peridotites may give birth to the hydrothermal activity. The elements migration during the serpentinization may perform a great role on the chemical composition of the hydrothermal fluid, which can support a hidden chemosynthetic ecosystem in the abyssal seabed. The research work focused on the major elements behavior during the serpentinization by studying the partially serpentinized samples of abyssal peridotite from Southwest Indian Ridge. The primary mineral assemblage of peridotite is olivine (Mg2SiO4), orthopyroxene (Mg2Si2O6), clinopyroxene (CaMgSi2O6) and spinel ((Mg,Fe)(Al,Cr)2O4). The major chemical composition are usually as SiO2 (30~45wt.%), MgO (20~45 wt.%), FeO and Fe2O3 (total 5~15 wt.%). Besides there are very few MnO, CaO, Al2O3, Cr2O3, NiO, Na2O, K2O and H2O. While on the other hand the serpentinized peridotite shows a more complicated mineral assemblage, besides the primary minerals there are more alteration minerals, such as serpentine (Mg3[Si2O5](OH)4), magnetite (Fe3O4), talc (Mg3[Si4O10](OH)2), brucite (Mg(OH)2), tremolite (Ca2Mg5[Si8O22](OH)2), chromite (FeCr2O4), chlorite ((Mg,Fe)6[(Si,Al)4O10](OH)8), and other accessary minerals like native metals, sulfides, clay minerals and hornblende. According to the EMPA analysis, the serpentinized sample shows the chemical composition as SiO2(~40 wt.%), MgO(~30 wt

  10. Marius Hills: Surface Roughness from LROC and Mini-RF

    NASA Astrophysics Data System (ADS)

    Lawrence, S.; Hawke, B. R.; Bussey, B.; Stopar, J. D.; Denevi, B.; Robinson, M.; Tran, T.

    2010-12-01

    The Lunar Reconnaissance Orbiter Camera (LROC) Team is collecting hundreds of high-resolution (0.5 m/pixel) Narrow Angle Camera (NAC) images of lunar volcanic constructs (domes, “cones”, and associated features) [1,2]. Marius Hills represents the largest concentration of volcanic features on the Moon and is a high-priority target for future exploration [3,4]. NAC images of this region provide new insights into the morphology and geology of specific features at the meter scale, including lava flow fronts, tectonic features, layers, and topography (using LROC stereo imagery) [2]. Here, we report initial results from Mini-RF and LROC collaborative studies of the Marius Hills. Mini-RF uses a hybrid polarimetric architecture to measure surface backscatter characteristics and can acquire data in one of two radar bands, S (12 cm) or X (4 cm) [5]. The spatial resolution of Mini-RF (15 m/pixel) enables correlation of features observed in NAC images to Mini-RF data. Mini-RF S-Band zoom-mode data and daughter products, such as circular polarization ratio (CPR), were directly compared to NAC images. Mini-RF S-Band radar images reveal enhanced radar backscatter associated with volcanic constructs in the Marius Hills region. Mini-RF data show that Marius Hills volcanic constructs have enhanced average CPR values (0.5-0.7) compared to the CPR values of the surrounding mare (~0.4). This result is consistent with the conclusions of [6], and implies that the lava flows comprising the domes in this region are blocky. To quantify the surface roughness [e.g., 6,7] block populations associated with specific geologic features in the Marius Hills region are being digitized from NAC images. Only blocks that can be unambiguously identified (>1 m diameter) are included in the digitization process, producing counts and size estimates of the block population. High block abundances occur mainly at the distal ends of lava flows. The average size of these blocks is 9 m, and 50% of observed

  11. Descent from the Summit of 'Husband Hill'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Descent from the Summit of 'Husband Hill' (QTVR)

    In late November 2005 while descending 'Husband Hill,' NASA's Mars Exploration Rover Spirit took the most detailed panorama so far of the 'Inner Basin,' the rover's next target destination. Spirit acquired the 405 individual images that make up this 360-degree view of the surrounding terrain using five different filters on the panoramic camera. The rover took the images on Martian days, or sols, 672 to 677 (Nov. 23 to 28, 2005 -- the Thanksgiving holiday weekend).

    This image is an approximately true-color rendering using camera's 750-, 530-, and 430-nanometer filters. Seams between individual frames have been eliminated from the sky portion of the mosaic to better simulate the vista a person standing on Mars would see.

    'Home Plate,' a bright, semi-circular feature scientists hope to investigate, is harder to discern in this image than in earlier views taken from higher up the hill. Spirit acquired this more oblique view, known as the 'Seminole panorama,' from about halfway down the south flank of Husband Hill, 50 meters (164 feet) or so below the summit. Near the center of the panorama, on the horizon, are 'McCool Hill' and 'Ramon Hill,' named, like Husband Hill, in honor of the fallen astronauts of the space shuttle Columbia. Husband Hill is visible behind the rover, on the right and left sides of the panorama. An arc of rover tracks made while avoiding obstacles and getting into position to examine rock outcrops can be traced over a long distance by zooming in to explore the panorama in greater detail.

    Spirit is now significantly farther downhill toward the center of this panorama, en route to Home Plate and other enigmatic soils and outcrop rocks in the quest to uncover the history of Gusev Crater and the 'Columbia Hills.'

  12. Topography, Cell Response, and Nerve Regeneration

    PubMed Central

    Hoffman-Kim, Diane; Mitchel, Jennifer A.; Bellamkonda, Ravi V.

    2010-01-01

    In the body, cells encounter a complex milieu of signals, including topographical cues. Imposed topography can affect cells on surfaces by promoting adhesion, spreading, alignment, morphological changes, and changes in gene expression. Neural response to topography is complex, and depends on the dimensions and shapes of physical features. Looking toward repair of nerve injuries, strategies are being explored to engineer guidance conduits with precise surface topographies. How neurons and other cell types sense and interpret topography remains to be fully elucidated. Studies reviewed here include those of topography on cellular organization and function as well as potential cellular mechanisms of response. PMID:20438370

  13. A SYMPLECTIC INTEGRATOR FOR HILL'S EQUATIONS

    SciTech Connect

    Quinn, Thomas; Barnes, Rory; Perrine, Randall P.; Richardson, Derek C.

    2010-02-15

    Hill's equations are an approximation that is useful in a number of areas of astrophysics including planetary rings and planetesimal disks. We derive a symplectic method for integrating Hill's equations based on a generalized leapfrog. This method is implemented in the parallel N-body code, PKDGRAV, and tested on some simple orbits. The method demonstrates a lack of secular changes in orbital elements, making it a very useful technique for integrating Hill's equations over many dynamical times. Furthermore, the method allows for efficient collision searching using linear extrapolation of particle positions.

  14. Internal Tide Generation by Steep Topography

    DTIC Science & Technology

    2007-09-01

    acting on the barotropic tide ( Foda and Hill 1998) was incomplete. Kunze will put this work in the context of recent internal tide research and...Topographically generated internal waves in the open ocean. J. Geophys. Res., 80, 320-327. Foda , M.A., and D.F. Hill, 1998: Nonlinear energy

  15. Exploring Hill Ciphers with Graphing Calculators.

    ERIC Educational Resources Information Center

    St. John, Dennis

    1998-01-01

    Explains how to code and decode messages using Hill ciphers which combine matrix multiplication and modular arithmetic. Discusses how a graphing calculator can facilitate the matrix and modular arithmetic used in the coding and decoding procedures. (ASK)

  16. Streamlined Hills of Maja Vallis

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 16 May 2003

    Classic catastrophic flood morphology (streamlined hills and longitudinal grooves) is captured in this image of Lunae Planum. Similar features (although much smaller in size) are seen in terrestrial catastrophic flood regions such as Channeled Scabland of Washington state and in Iceland.

    Image information: VIS instrument. Latitude 14.8, Longitude 301.8East (58.2). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. The Igwisi Hills extrusive 'kimberlites'

    NASA Technical Reports Server (NTRS)

    Reid, A. M.; Donaldson, C. H.; Dawson, J. B.; Brown, R. W.; Ridley, W. I.

    1975-01-01

    The petrography and mineral chemistry of volcanic rocks from the Igwisi Hills in Tanzania are discussed. There is considerable evidence to suggest that the Igwisi rocks are extrusive kimberlites: a two-component nature with high P-T minerals in a low P-T matrix; the presence of chrome pyrope, Al enstatite, chrome diopside, chromite and olivine; a highly oxidized, volatile-rich matrix with serpentine, calcite, magnetite, perovskite; high Sr, Zr, and Nb contents; occurrence in a narrow isolated vent within a stable shield area. The Igwisi rocks differ from kimberlite in the lack of magnesian ilmenite, the scarcity of matrix phlogopite, and the overall low alkali content. They apparently contain material from phlogopite-bearing garnet peridotites with a primary mineral assemblage indicative of equilibrium at upper mantle temperatures and pressures. This primary assemblage was brought rapidly to the surface in a gas-charged, carbonate-rich fluid. Rapid upward transport, extrusion, and rapid cooling have tended to prevent reaction between inclusions and the carbonate-rich matrix that might otherwise have yielded a more typical kimberlite.

  18. A perspective on Capitol Hill

    NASA Astrophysics Data System (ADS)

    Hodges, Carroll Ann

    As the AGU Congressional Science Fellow for 1980-1981, I had a unique opportunity to witness the federal engine in action—a remarkable piece of machinery. The American Association for the Advancement of Science organized an excellent orientation program, introducing our class of science fellows (about 30) to the kinds of options available for a year's tenure on Capitol Hill. These include affiliation with a congressman's or senator's staff or with one of the hundred or so standing, select, or joint committees and subcommittees. I arranged to join the personal staff of Congressman Jim Santini (D, Nev.), largely because of his demonstrated interest in Department of Interior affairs in general and the minerals industry in particular. The position of fellow provides no guarantee of work in one's areas of expertise or inclination, however, and I found that my staff assignments included topics ranging from wild horses to peanut subsidies. My principal task involved evaluation of the Air Force proposal to deploy the MX missile in Nevada and the consequent impact of that incredible scheme on the physical and economic environments of the state and the nation, including effects on minerals exploration. I had not expected to become conversant with missile technology, but the exercise provided quite an education.

  19. Seafloor Mapping of the Southeast Iberian Continental Slope and Western Algero-Balearic Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Lastras, G.; Canals, M.; León, C.; Elvira, E.; Pascual, L.; Muñoz, A.; de Cárdenas, E.; Acosta, J.

    2014-12-01

    We present the multibeam bathymetry and derived maps of the southeast Iberian margin from Cabo de Palos to Cabo de Gata, 37º35'N to 35º45'N and 2º10'W to 0º20'E, from the coastline down to the Algero-Balearic abyssal plain at depths exceeding 2,600 m. Data were obtained during different surveys in 2004, 2006 and 2007 on board R/V Vizconde de Eza with a Simrad EM300 multibeam echo-sounder, as part of the CAPESME Project, a collaboration between the Spanish Institute of Oceanography (IEO) and General Secretariat of Fisheries (SGP), aiming at creating maps of the fishing grounds of the Mediterranean continental margins of Spain. The edition of the maps has been carried out within the Complementary Action VALORPLAT (Scientific valorisation of multibeam bathymetry data from the Spanish continental shelf and slope), funded by the Spanish Ministry of Economy and Competitivity. Multibeam bathymetry data from the continental shelf obtained within the ESPACE project, also in a cooperative frame between IEO and SGP, completes the whole picture from the coastline to the deep abyssal plain. The map series is constituted by a general map at 1:400,000 scale and 14 detailed maps at 1:75,000 scale, which include inset maps on slope gradients and seafloor nature (rock or sediment type), the later obtained with rock dredges and Shipeck sediment dredges. Both the detailed maps and the general map are available in paper print, and the whole collection is also distributed in an edited USB. The geological features displayed in the different maps include the continental shelf, with abundant geomorphic features indicative of past sea-level changes, the continental slope carved by a large number of submarine canyons and gullies, including Palos, Tiñoso, Cartagena Este, Cartagena Oeste, Águilas, Almanzora, Alias, Garrucha and Gata submarine canyons, the Mazarrón, Palomares and Al-Mansour escarpments of probable tectonic origin, the Abubácer, Maimonides and Yusuf ridges, the

  20. Os Isotopic Signature of Backarc Abyssal Peridotites from the Godzilla Megamullion

    NASA Astrophysics Data System (ADS)

    Nelson, W. R.; Snow, J. E.; Ohara, Y.; Brandon, A. D.

    2012-12-01

    Backarc seafloor spreading is a unique form of extension intimately tied to subduction zone dynamics. Unlike volcanism at mid-ocean ridges, backarc volcanism evolves from arc-like to MORB-like compositions over the short lifespan (~15 Ma) of the backarc. Our understanding of the evolution of oceanic mantle during backarc extension is limited to exposures of abyssal peridotite and ophiolites. While some ophiolites are thought to have formed in a backarc environment, few direct comparisons of ophiolite and backarc peridotite have been made due to the dearth of documented exposures and limited in situ samples from backarc settings. As a consequence, isotopic investigations have thus far been limited to ophiolite and mid-ocean ridge settings, limiting our understanding of the backarc oceanic mantle. Here we report preliminary Os isotopic data for backarc abyssal peridotites from the Godzilla Megamullion, a massive ~9000 km2 oceanic core complex located in the Parece Vela Basin (Philippine Sea). In this region, Izu-Bonin-Mariana subduction zone is responsible for creating the Parece Vella and Shikoku backarc basins as well as the Mariana Trough. In the last decade, five expeditions have collectively sampled the length of the Godzilla Megamullion. The distal end records early, magmatically productive extension marked by moderately depleted spinel peridotites. This transitions into a less melt-productive medial region characterized by more fertile peridotite. The proximal region represents the most recently exhumed portion of the megamullion and was the focus of the latest (October 2011) mapping and sampling expedition. Ultramafic samples from the proximal region are dominantly spinel lherzolite +/- plagioclase. Spinel grains record high TiO2 and Cr# produced by melt stagnating and interacting with the mantle. Whole rock 187Os/188Os (0.1245-0.1295) ranges from mildly subchondritic to PUM values, consistent with abyssal peridotites from mid-ocean ridge settings. The

  1. Rich and rare—First insights into species diversity and abundance of Antarctic abyssal Gastropoda (Mollusca)

    NASA Astrophysics Data System (ADS)

    Schwabe, Enrico; Michael Bohn, Jens; Engl, Winfried; Linse, Katrin; Schrödl, Michael

    2007-08-01

    The abyssal depths of the polar oceans are thought to be low in diversity compared with the shallower polar shelves and temperate and tropical deep-sea basins. Our recent study on the gastropod fauna of the deep Southern Ocean gives evidence of the existence of a rich gastropod assemblage at abyssal depths. During the ANDEEP I and II expeditions to the southern Drake Passage, Northwestern Weddell Sea, and South Sandwich Trench, gastropods were collected by bottom and Agassiz trawls, epibenthic sledge, and multicorer, at 40 stations in depths between 127 and 5194 m. On the whole, 473 specimens, corresponding to 93 species of 36 families, were obtained. Of those, 414 specimens were caught below 750 m depth and refer to 84 (90%) benthic species of 32 (89%) families. Most families were represented by a single species only. The numerically dominant families were Skeneidae and Buccinidae (with 10 and 11 species, respectively), Eulimidae and Trochidae (with 9 species each), and Turridae (6 species). Thirty-Seven benthic deep-sea species (44%) were represented by a single specimen, and another 20 species (24%) were found at a single station, suggesting that more than two thirds of Antarctic deep-sea gastropod species are very rare or have a very scattered distribution. Of the 27 species occurring at two or more deep-sea stations, 14 were collected with different gear. Approximately half of the deep-water species are new to science or have been recently described. The present investigation increases the total number of recorded benthic Antarctic deep-sea gastropods (below 750 m) from 115 to 177. The previously known depth ranges have been extended, often considerably, for 31 species. The collected deep-sea gastropods comprise both eurybathic shelf species (29%) and apparently true deep-sea species (58%); some of the latter may belong to a so far unknown Antarctic abyssal fauna. Geographical ranges of the collected Antarctic benthic deep-sea gastropod species appear limited

  2. Engineering concepts for the placement of wastes on the abyssal seafloor

    NASA Astrophysics Data System (ADS)

    Valent, Philip J.; Palowitch, Andrew W.; Young, David K.

    1998-05-01

    The Naval Research Laboratory (NRL), with industry and academic participation, has completed a study of the concept of isolating industrial wastes (i.e., sewage sludge, fly ash from municipal incinerators, and dredged material) on the abyssal seafloor. This paper presents results of the technical and economic assessment of this waste management concept. The results of the environmental impacts portion of the study are presented in a companion paper. The technical assessment began with identification of 128 patents addressing waste disposal in the ocean. From these 128 patents, five methods for transporting wastes through the water column and emplacing wastes within an easily monitored area on the abyssal seafloor were synthesized for technical assessment. In one method waste is lowered to the seafloor in a bucket of 190 m 3. In a second method waste is pumped down to the seafloor in pipes, 1.37 m in diameter and 6100 m in length. In a third method waste is free-fallen from the ocean surface in 380-m 3 geosynthetic fabric containers (GFCs). In the fourth and fifth methods, waste is carried to near the seafloor in GFCs transported in (a) a 20,000 metric ton displacement (loaded), unpowered, unmanned submersible glider, or (b) a 2085 metric ton displacement (loaded) disk-shaped transporter traversing to and from the seafloor much like an untethered elevator. In the last two methods the transporter releases the GFCs to free-fall the last few hundred meters to the seafloor. Two reliability analyses, a Fault Tree Analysis (FTA), and a Failure Modes, Effects, and Criticality Analysis (FMECA), showed that the free-fall GFC method posed the least overall relative risk, provided that fabric container and transporter designs eliminate the potential for tearing of the containers on release from the surface transporter. Of the five methods, the three GFC methods were shown to offer cost-effective waste management options when compared with present-day waste management

  3. Implications of spinel compositions for the petrotectonic history of abyssal peridotite from Southwest Indian Ridge (SWIR)

    NASA Astrophysics Data System (ADS)

    Chen, T.; Jin, Z.; Wang, Y.; Tao, C.

    2012-12-01

    Abyssal peridotites generate at mid-ocean ridges. Lherzolite and harzburgite are the main rock types of peridotites in the uppermost mantle. The lherzolite subtype, less depleted and less common in ophiolites, characterizes mantle diapirs and slow-spreading ridges. Along the Earth's mid-ocean ridges, abyssal peridotites undergo hydration reactions to become serpentinite minerals, especially in slow to ultraslow spreading mid-ocean ridges. Spinel is common in small quantities in peridotites, and its compositions have often been used as petrogenetic indicators [1]. The Southwest Indian Ridge (SWIR) is one of the two ultraslow spreading ridges in the world. The studied serpentinized peridotite sample was collected by the 21st Voyage of the Chinese oceanic research ship Dayang Yihao (aka Ocean No. 1) from a hydrothermal field (63.5°E, 28.0°S, and 3660 m deep) in SWIR. The studied spinels in serpentinized lherzolite have four zones with different compositions: relic, unaltered core is magmatic Al-spinels; micro- to nano- sized ferrichromite zoned particles; narrow and discontinuous magnetite rim; and chlorite aureoles. The values Cr# of the primary Al-spinels indicate the range of melting for abyssal peridotites from SWIR extends from ~4% to ~7% [2]. The alteration rims of ferrichromite have a chemical composition characterized by Fe enrichment and Cr# increase indicating chromite altered under greenschist-amphibolite facies. Magnetites formed in syn- and post- serpentinization. Chlorite (clinochlore) formed at the boundary and crack of spinel indicating it had undergone with low-temperature MgO- and SiO2-rich hydrothermal fluids [3]. It suggests that serpentinized lherzolite from SWIR had undergone poly-stage hydration reactions with a wide range of temperature. Acknowledgments: EMPA experiment was carried out by Xihao Zhu and Shu Zheng in The Second Institute of Oceanography and China University of Geosciences, respectively. The work was supported by NSFC

  4. Precision Measurement Of Corneal Topography

    NASA Astrophysics Data System (ADS)

    Yoder, Paul R.; Macri, Timothy F.; Telfair, William B.; Bennett, Peter S.; Martin, Clifford A.; Warner, John W.

    1989-05-01

    We describe a new electro-optical device being developed to provide precise measurements of the three-dimensional topography of the human cornea. This device, called a digital keratoscope, is intended primarily for use in preparing for and determining the effect of corneal surgery procedures such as laser refractive keratectomy, radial keratotomy or corneal transplant on the refractive power of the cornea. It also may serve as an aid in prescribing contact lenses. The basic design features of the hardware and of the associated computer software are discussed, the means for alignment and calibration are described and typical results are given.

  5. The Topography Tub Learning Activity

    NASA Astrophysics Data System (ADS)

    Glesener, G. B.

    2014-12-01

    Understanding the basic elements of a topographic map (i.e. contour lines and intervals) is just a small part of learning how to use this abstract representational system as a resource in geologic mapping. Interpretation of a topographic map and matching its features with real-world structures requires that the system is utilized for visualizing the shapes of these structures and their spatial orientation. To enrich students' skills in visualizing topography from topographic maps a spatial training activity has been developed that uses 3D objects of various shapes and sizes, a sighting tool, a plastic basin, water, and transparencies. In the first part of the activity, the student is asked to draw a topographic map of one of the 3D objects. Next, the student places the object into a plastic tub in which water is added to specified intervals of height. The shoreline at each interval is used to reference the location of the contour line the student draws on a plastic inkjet transparency directly above the object. A key part of this activity is the use of a sighting tool by the student to assist in keeping the pencil mark directly above the shoreline. It (1) ensures the accurate positioning of the contour line and (2) gives the learner experience with using a sight before going out into the field. Finally, after the student finishes drawing the contour lines onto the transparency, the student can compare and contrast the two maps in order to discover where improvements in their visualization of the contours can be made. The teacher and/or peers can also make suggestions on ways to improve. A number of objects with various shapes and sizes are used in this exercise to produce contour lines representing the different types of topography the student may encounter while field mapping. The intended outcome from using this visualization training activity is improvement in performance of visualizing topography as the student moves between the topographic representation and

  6. Photogrammetric portrayal of Mars topography.

    USGS Publications Warehouse

    Wu, S.S.C.

    1979-01-01

    Special photogrammetric techniques have been developed to portray Mars topography, using Mariner and Viking imaging and nonimaging topographic information and earth-based radar data. Topography is represented by the compilation of maps at three scales: global, intermediate, and very large scale. The global map is a synthesis of topographic information obtained from Mariner 9 and earth-based radar, compiled at a scale of 1:25,000,000 with a contour interval of 1 km; it gives a broad quantitative view of the planet. At intermediate scales, Viking Orbiter photographs of various resolutions are used to compile detailed contour maps of a broad spectrum of prominent geologic features; a contour interval as small as 20 m has been obtained from very high resolution orbital photography. Imagery from the Viking lander facsimile cameras permits construction of detailed, very large scale (1:10) topographic maps of the terrain surrounding the two landers; these maps have a contour interval of 1 cm. This paper presents several new detailed topographic maps of Mars.-Author

  7. Deep and abyssal ocean warming from 35 years of repeat hydrography

    NASA Astrophysics Data System (ADS)

    Desbruyères, Damien G.; Purkey, Sarah G.; McDonagh, Elaine L.; Johnson, Gregory C.; King, Brian A.

    2016-10-01

    Global and regional ocean warming deeper than 2000 m is investigated using 35 years of sustained repeat hydrographic survey data starting in 1981. The global long-term temperature trend below 2000 m, representing the time period 1991-2010, is equivalent to a mean heat flux of 0.065 ± 0.040 W m-2 applied over the Earth's surface area. The strongest warming rates are found in the abyssal layer (4000-6000 m), which contributes to one third of the total heat uptake with the largest contribution from the Southern and Pacific Oceans. A similar regional pattern is found in the deep layer (2000-4000 m), which explains the remaining two thirds of the total heat uptake yet with larger uncertainties. The global average warming rate did not change within uncertainties pre-2000 versus post-2000, whereas ocean average warming rates decreased in the Pacific and Indian Oceans and increased in the Atlantic and Southern Oceans.

  8. Deep ocean communities impacted by changing climate over 24 y in the abyssal northeast Pacific Ocean.

    PubMed

    Smith, Kenneth L; Ruhl, Henry A; Kahru, Mati; Huffard, Christine L; Sherman, Alana D

    2013-12-03

    The deep ocean, covering a vast expanse of the globe, relies almost exclusively on a food supply originating from primary production in surface waters. With well-documented warming of oceanic surface waters and conflicting reports of increasing and decreasing primary production trends, questions persist about how such changes impact deep ocean communities. A 24-y time-series study of sinking particulate organic carbon (food) supply and its utilization by the benthic community was conducted in the abyssal northeast Pacific (~4,000-m depth). Here we show that previous findings of food deficits are now punctuated by large episodic surpluses of particulate organic carbon reaching the sea floor, which meet utilization. Changing surface ocean conditions are translated to the deep ocean, where decadal peaks in supply, remineralization, and sequestration of organic carbon have broad implications for global carbon budget projections.

  9. Branimycins B and C, Antibiotics Produced by the Abyssal Actinobacterium Pseudonocardia carboxydivorans M-227.

    PubMed

    Braña, Alfredo F; Sarmiento-Vizcaíno, Aida; Pérez-Victoria, Ignacio; Otero, Luis; Fernández, Jonathan; Palacios, Juan José; Martín, Jesús; de la Cruz, Mercedes; Díaz, Caridad; Vicente, Francisca; Reyes, Fernando; García, Luis A; Blanco, Gloria

    2017-02-24

    Two new antibiotics, branimycins B (2) and C (3), were produced by fermentation of the abyssal actinobacterium Pseudonocardia carboxydivorans M-227, isolated from deep seawater of the Avilés submarine Canyon. Their structures were elucidated by HRMS and NMR analyses. These compounds exhibit antibacterial activities against a panel of Gram-positive bacteria, including Corynebacterium urealyticum, Clostridium perfringens, and Micrococcus luteus, and against the Gram-negative bacterium Neisseria meningitidis. Additionally, branimycin B displayed moderate antibacterial activity against other Gram-negative bacteria such as Bacteroides fragilis, Haemophilus influenzae, and Escherichia coli, and branimycin C against the Gram-positive Enterococcus faecalis and methicillin-sensitive and methicillin-resistant Staphylococcus aureus.

  10. Drought in the Black Hills

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Color-Coded Map

    Despite good rainfall and record-setting snowstorms in the spring of 2005, most of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging SpectroRadiometer (MISR) contrast the appearance of the Black Hills region of northwestern South Dakota on July 12, 2000 (left column), with views acquired four years later, on July 14, 2004 (right column). The natural-color images along the top are from MISR's nadir (downward-looking) camera. The browning that appears in 2004 compared with 2000 indicates that the vigor of green vegetation was significantly diminished in 2004.

    The color-coded maps (along the bottom) provide a quantitative measurement of the sunlight reflected from these surfaces, and the loss of sunlight-absorbing vegetation between the 2000 and 2004 dates. As the vegetation faded with the drought, the albedo at the surface increased. Albedo measures the fraction of incident sunlight that is reflected by a surface, and can vary between zero (if all the incident sunlight is absorbed and none is reflected) and one (if all sunlight is reflected and none is absorbed). Dense forest has a low albedo; bright desert, snow and clouds, have a high albedo. Here, albedo is provided for the wavelengths of sunlight that plants use for photosynthesis (400 - 700 nanometers). This measurement is known as the albedo for Photosynthetically Active Radiation (PAR). Surfaces with greater absorption of PAR appear here in blue hues, whereas surfaces with lower absorption appear as green, yellow, orange or red. Black pixels indicate areas where albedo could not be derived, usually due to the presence of clouds. In July 2004, low albedo areas (blue pixels) are notably reduced in extent, and higher albedo areas (yellow, orange and red pixels) have increased.

    Because incoming sunlight is

  11. Bunker Hill Sediment Characterization Study

    SciTech Connect

    Neal A. Yancey; Debby F. Bruhn

    2009-12-01

    The long history of mineral extraction in the Coeur d’Alene Basin has left a legacy of heavy metal laden mine tailings that have accumulated along the Coeur d’Alene River and its tributaries (U.S. Environmental Protection Agency, 2001; Barton, 2002). Silver, lead and zinc were the primary metals of economic interest in the area, but the ores contained other elements that have become environmental hazards including zinc, cadmium, lead, arsenic, nickel, and copper. The metals have contaminated the water and sediments of Lake Coeur d’Alene, and continue to be transported downstream to Spokane Washington via the Spokane River. In 1983, the EPA listed the Bunker Hill Mining and Metallurgical Complex on the National Priorities List. Since that time, many of the most contaminated areas have been stabilized or isolated, however metal contaminants continue to migrate through the basin. Designation as a Superfund site causes significant problems for the economically depressed communities in the area. Identification of primary sources of contamination can help set priorities for cleanup and cleanup options, which can include source removal, water treatment or no action depending on knowledge about the mobility of contaminants relative to water flow. The mobility of contaminant mobility under natural or engineered conditions depends on multiple factors including the physical and chemical state (or speciation) of metals and the range of processes, some of which can be seasonal, that cause mobilization of metals. As a result, it is particularly important to understand metal speciation (National Research Council, 2005) and the link between speciation and the rates of metal migration and the impact of natural or engineered variations in flow, biological activity or water chemistry.

  12. Source-To-Sink Perspectives On The Mississippi River System, Miocene To Present, Mountain To Abyss

    NASA Astrophysics Data System (ADS)

    Bentley, S. J.; Blum, M. D.

    2013-12-01

    . The objective of this study is to present a synthesis of the Mississippi River source-to-sink system, from montane source to abyssal sink, to elucidate specific geomorphic components and boundaries in the system, controls on mass transfer, and resultant geomorphic and statigraphic development. The Mississippi River source-to-sink system constitutes one of the largest sources, conduits, and depocenters of sediment on Earth, extending from elevations of 3.7 km in the Rocky Mountains to the Gulf of Mexico abyssal plain. Despite being one of the most intensely studied fluvial-marine systems in the world, comprehensive understanding and management of the system's resources remain a challenge. The system is valuable in many ways: it provides navigation and water to the heart of North America, and sustains extensive marine fisheries. The river has built a delta that is home to millions of people and yet is subsiding rapidly. Ancestral Mississippi fluvial-marine deposits continue to yield high-value petroleum resources to exploration. To address the range of temporal and spatial scales over which the system has developed and continues to evolve, we will focus on three geological time spans that display contrasting geologic forcing and response: Miocene, Pleistocene, and late Holocene. The present configuration of source, conduit, and sink were established during the Miocene epoch, when tectonics (via the uplifting southern Rockies, and later the rejuvenated Appalachians) and climate (wet in the east and dry in the west) provided abundant water and sediment to prograde the shelf margin and initiate deep-sea fan growth. Pleistocene continental glaciation, eustasy, and catastrophic drainage events further sculpted the alluvial valley, and extended the shelf margin, and fan. Studies of Modern processes and Holocene delta development have provided keys to both the delta's past and future evolution, in terms of cyclic autogenic lobe-switching, mass-transport events, storm

  13. Vesicomyinae (Bivalvia: Vesicomyidae) of the Kuril-Kamchatka Trench and adjacent abyssal regions

    NASA Astrophysics Data System (ADS)

    Krylova, Elena M.; Kamenev, Gennady M.; Vladychenskaya, Irina P.; Petrov, Nikolai B.

    2015-01-01

    Representatives of the subfamily Vesicomyinae (Bivalvia, Vesicomyidae) are tiny deep-sea molluscs distributed worldwide and reaching huge abundances of hundreds and thousands of specimens in trawl catches. During the German-Russian deep-sea expedition KuramBio (R/V Sonne, 2012) for the first time two vesicomyin species were collected from the abyssal plain adjacent to the Kuril-Kamchatka Trench from the depths of 4861-5787 m, Vesicomya pacifica (Smith, 1885) and "Vesicomya" filatovae sp.n. Two species of vesicomyins, V. sergeeviFilatova, 1971 and V. profundiFilatova, 1971, which were previously reported from the hadal of the Kuril-Kamchatka Trench, were not collected at the abyssal depth despite of the close geographical proximity of the sampling area to their distribution ranges. Altogether nine species of vesicomyins are recorded now from the West and Indo-West Pacific; data on distribution and morpho-anatomical characters of these species are provided. Taxonomic description of V. pacifica is revised including information on its soft part anatomy, new localities and COI sequences. For the first time for a vesicomyin bivalve molecular data is given for a species with an explicit morphological description and unambiguous taxonomic affiliation. Molecular analysis of 160 published COI sequences of vesicomyids and newly obtained molecular data on V. pacifica showed that V. pacifica and two undescribed vesicomyin species forming a monophyletic clade which exhibits sister relationships with the Pliocardiinae, the group of chemosymbiotic vesicomyids. "Vesicomya" filatovae sp.n. is provisionally assigned to the genus Vesicomya (s.l.) until additional morphological and molecular data are obtained. It differs from Vesicomya s.s. by a broader hinge margin with more radiating teeth and the presence of only one pair of demibranchs.

  14. Spectral Topography Generation for Arbitrary Grids

    NASA Astrophysics Data System (ADS)

    Oh, T. J.

    2015-12-01

    A new topography generation tool utilizing spectral transformation technique for both structured and unstructured grids is presented. For the source global digital elevation data, the NASA Shuttle Radar Topography Mission (SRTM) 15 arc-second dataset (gap-filling by Jonathan de Ferranti) is used and for land/water mask source, the NASA Moderate Resolution Imaging Spectroradiometer (MODIS) 30 arc-second land water mask dataset v5 is used. The original source data is coarsened to a intermediate global 2 minute lat-lon mesh. Then, spectral transformation to the wave space and inverse transformation with wavenumber truncation is performed for isotropic topography smoothness control. Target grid topography mapping is done by bivariate cubic spline interpolation from the truncated 2 minute lat-lon topography. Gibbs phenomenon in the water region can be removed by overwriting ocean masked target coordinate grids with interpolated values from the intermediate 2 minute grid. Finally, a weak smoothing operator is applied on the target grid to minimize the land/water surface height discontinuity that might have been introduced by the Gibbs oscillation removal procedure. Overall, the new topography generation approach provides spectrally-derived, smooth topography with isotropic resolution and minimum damping, enabling realistic topography forcing in the numerical model. Topography is generated for the cubed-sphere grid and tested on the KIAPS Integrated Model (KIM).

  15. Wrinkled surface topographies of electrospun polymer fibers

    NASA Astrophysics Data System (ADS)

    Wang, Lifeng; Pai, Chia-Ling; Boyce, Mary C.; Rutledge, Gregory C.

    2009-04-01

    Electrospun polymer fibers are shown to have wrinkled surface topographies that result from buckling instabilities during processing. A glassy shell forms on the surface of the gel-like core during solvent evaporation; continued evaporation leads to a contraction mismatch between the core and shell that triggers buckling of the shell. The wrinkled topographies are quantified in terms of the critical buckling wave number and wavelength. The results explain the observed wrinkled topographies and provide a framework for designing fibers with high specific surface areas and textured/patterned surface topographies to enhance surface dominated properties in fibers and fibrous mats.

  16. High-resolution land topography

    NASA Astrophysics Data System (ADS)

    Massonnet, Didier; Elachi, Charles

    2006-11-01

    After a description of the background, methods of production and some scientific uses of high-resolution land topography, we present the current status and the prospect of radar interferometry, regarded as one of the best techniques for obtaining the most global and the most accurate topographic maps. After introducing briefly the theoretical aspects of radar interferometry - principles, limits of operation and various capabilities -, we will focus on the topographic applications that resulted in an almost global topographic map of the earth: the SRTM map. After introducing the Interferometric Cartwheel system, we will build on its expected performances to discuss the scientific prospects of refining a global topographic map to sub-metric accuracy. We also show how other fields of sciences such as hydrology may benefit from the products generated by interferometric radar systems. To cite this article: D. Massonnet, C. Elachi, C. R. Geoscience 338 (2006).

  17. Venus - Global gravity and topography

    NASA Astrophysics Data System (ADS)

    McNamee, J. B.; Borderies, N. J.; Sjogren, W. L.

    1993-05-01

    A new gravity field determination that has been produced combines both the Pioneer Venus Orbiter (PVO) and the Magellan Doppler radio data. Comparisons between this estimate, a spherical harmonic model of degree and order 21, and previous models show that significant improvements have been made. Results are displayed as gravity contours overlaying a topographic map. We also calculate a new spherical harmonic model of topography based on Magellan altimetry, with PVO altimetry included where gaps exist in the Magellan data. This model is also of degree and order 21, so in conjunction with the gravity model, Bouguer and isostatic anomaly maps can be produced. These results are very consistent with previous results, but reveal more spatial resolution in the higher latitudes.

  18. Engaging Hill-Sachs Defects

    PubMed Central

    Burns, David; Chahal, Jaskarndip; Shahrokhi, Shahram; Henry, Patrick; Wasserstein, David; Whyne, Cari; Theodoropoulos, John S.; Ogilvie-Harris, Darrell; Dwyer, Tim

    2016-01-01

    Objectives: Anatomic studies have demonstrated that bipolar glenoid and humeral bone loss have a cumulative impact on shoulder instability, and that these defects may engage in functional positions depending on their size, location, and orientation, potentially resulting in failure of stabilization procedures. Determining which lesions pose a risk for engagement remains a challenge, with arthroscopic assessment and Itoi’s 3DCT based glenoid track method being the accepted approaches at this time. The purpose of this study was to investigate the interaction of humeral and glenoid bone defects on shoulder engagement in a cadaveric model. Two alternative approaches to predicting engagement were evaluated; 1) CT scanning the shoulder in abduction and external rotation 2) measurement of Bankart lesion width and a novel parameter, the intact anterior articular angle (IAAA), on conventional 2D multi-plane reformats. The results of these two approaches were compared to the results obtained using Itoi’s glenoid track method for predicting engagement. Methods: Hill-Sachs and Bony Bankart defects of varying size were created in 12 cadaveric upper limbs, producing 45 bipolar defect combinations. The shoulders were assessed for engagement using cone beam CT in various positions of function, from 30 to 90 degrees of both abduction and external rotation. The humeral and glenoid defects were characterized by measurement of their size, location, and orientation. Diagnostic performance measures for predicting engagement were calculated for both the abduction external rotation scan and 2D IAAA approaches using the glenoid track method as reference standard. Results: Engagement was predicted by Itoi’s glenoid track method in 24 of 45 specimens (53%). The abduction external rotation CT scan performed at 60 degrees of glenohumeral abduction (corresponding to 90 degrees of abduction relative to the trunk) and 90 degrees of external rotation predicted engagement accurately in 43 of

  19. Taxonomic Notes on the Abyssal Agglutinated Benthic Foraminifera of the HEBBLE (High Energy Benthic Boundary Layer Experiment) Area (Lower Nova Scotian Continental Rise).

    DTIC Science & Technology

    1983-09-01

    Gulf of Mexico . Marine Sciences International, Woods Hole, Ma. Resig, J.M., 1981 Biogeography of benthic foraminifera of the northern Nazca plate and...HD-A133 743 TAXONOMIC NOTES ON THE ABYSSAL AGGLUTINATED BENTHIC t/i FORAMINIFERA OF-THE H..(U) WOODS HOLE OCEANOGRAPHIC INSTITUTION MRN M A KAMINSKI...Notes On The Abyssal Agglutinated Benthic Foraminifera September 1983 Of The HEBBLE Area (Lower Nova Scotian Continental Rise) 7. A41*heeW L Pinforv Mg

  20. Pesticides, Neurodevelopmental Disagreement, and Bradford Hill's Guidelines.

    PubMed

    Shrader-Frechette, Kristin; ChoGlueck, Christopher

    2016-06-27

    Neurodevelopmental disorders such as autism affect one-eighth of all U.S. newborns. Yet scientists, accessing the same data and using Bradford-Hill guidelines, draw different conclusions about the causes of these disorders. They disagree about the pesticide-harm hypothesis, that typical United States prenatal pesticide exposure can cause neurodevelopmental damage. This article aims to discover whether apparent scientific disagreement about this hypothesis might be partly attributable to questionable interpretations of the Bradford-Hill causal guidelines. Key scientists, who claim to employ Bradford-Hill causal guidelines, yet fail to accept the pesticide-harm hypothesis, fall into errors of trimming the guidelines, requiring statistically-significant data, and ignoring semi-experimental evidence. However, the main scientists who accept the hypothesis appear to commit none of these errors. Although settling disagreement over the pesticide-harm hypothesis requires extensive analysis, this article suggests that at least some conflicts may arise because of questionable interpretations of the guidelines.

  1. The Signature of Life in Stabilized Dune Topography

    NASA Astrophysics Data System (ADS)

    Barchyn, T. E.; Hugenholtz, C.

    2012-12-01

    Life dramatically affects aeolian dunes on Earth by modifying dune morphology and immobilizing sediment. Complete immobilization (stabilization) occurs when vegetation growth shelters the surface and eliminates sediment transport (and the capacity of the dune to clear vegetation). In unidirectional dune forms stabilization is usually preceded by a period of transition dominated by pronounced morphological change (e.g., parabolic dunes). Here, we hypothesize that stabilized topography holds previously unidentified clues detailing the kinematics and behavior of vegetation during stabilization (a 'signature'). During stabilization dune ridges advance downwind and 'bulldoze' vegetation in their path. We split dune ridges into a series of wind-parallel 'dune slices' and outline how slipface vegetation could prove to be a 'tipping point' in stabilization for each dune slice. Slipface vegetation sets off a self-reinforcing stabilization feedback, simplifying our treatment and yielding two predictable behaviors: slipfaces either clear vegetation (deposition rate > vegetation deposition tolerance), or succumb to vegetation and become immobilized (deposition rate < vegetation deposition tolerance). We model slipface deposition rates through slipface geometry and show how predictable variations in classical dune forms (i) could be responsible for incipient transformation of barchan to parabolic dunes, (ii) result in a progressive stabilization feedback fundamentally inconsistent with widely used dune activity indices, and (iii) record a quantitative signature of the relative kinematics of sediment flux and vegetation growth in stabilized slipface geometries. To explore the idea in real dune fields, we extract slipface deposition rates through slipface geometry recorded in digital terrain data for three dune fields: (i) Bigstick Sand Hills, SK, Canada, (ii) White Sands, NM, USA, and (iii) Cape Cod, MA, USA. With independent estimates of sediment flux and vegetation deposition

  2. Elk Hills: still out in front

    SciTech Connect

    Rintoul, B.

    1982-07-01

    The producing history and capacity of the Elk Hills Oil and Gas Fields in California are described. Developments in the field are discussed, including waterflooding. The field presently produces ca. 160,000 bpd of oil and 350 mmcfd of natural gas. Gas liquids production totals ca. 683,000 gal/day. Waterflooding is expected to pay an increasingly important role in the production of crude oil. Steaming techniques also are viewed with favor after analysis of results of pilot projects. Exploratory develoment in Elk Hills also continues.

  3. Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria

    PubMed Central

    Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Ikebe, Chiho; Watling, Les; Smith, Craig R; Glover, Adrian G

    2016-01-01

    Abstract Background We present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b). New information Morphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys. PMID:27660533

  4. Investigating the effects of abyssal peridotite alteration on Si, Mg and Zn isotopes

    NASA Astrophysics Data System (ADS)

    Savage, P. S.; Wimpenny, J.; Harvey, J.; Yin, Q.; Moynier, F.

    2013-12-01

    Around 1/3 of Earth's divergent ridge system is now classified as "slow" spreading [1], exposing ultramafic rocks (abyssal peridotites) at the seafloor. Such material is often highly altered by serpentinisation and steatisation (talc formation). It is crucial to understand such processes in order to access the original composition of the mantle, and to quantify any impact on ocean composition. Here we examine the effect of both serpentinisation and steatisation on Si, Mg and Zn isotopes. Hydrothermal alteration and seafloor weathering are both sources of oceanic Si [2] and weathering of abyssal peridotites is a source of oceanic Mg [3]; hence isotopic fractionation as a result of seafloor alteration could affect oceanic Si and Mg isotope composition. Zinc isotopes can provide complimentary information; the magnitude and direction of fractionation is highly dependent on complexing ligand [4] and can provide compositional information on the fluids driving metasomatism. For this study, two cores from the well-characterised abyssal peridotites recovered on ODP Leg 209 were examined [5]. Hole 1274a peridotites exhibit variable serpentinisation at ~200°C, whereas samples from Hole 1268a have been comprehensively serpentinised and then subsequently steatised to talc facies at ~350°C, by a low Mg/Si, low pH fluid. The Si, Mg and Zn isotope compositions of 1274a samples are extremely homogeneous, identical to that of pristine mantle rocks (BSE) i.e., serpentinisation at this locality was predominantly isochemical [5]. In contrast, samples from 1268a show greater isotopic variability. In all samples, Mg is enriched in the heavier isotopes relative to BSE, consistent with formation of isotopically heavy secondary phases [6]. For Si, serpentinised samples are slightly enriched in the lighter isotopes compared to BSE, again consistent with the behaviour of Si during formation of secondary phases [7]. Within the steatised samples, some exhibit enrichments in the lighter Si

  5. Flat Subduction and Dynamic Topography

    NASA Astrophysics Data System (ADS)

    Lithgow-Bertelloni, C. R.; Dávila, F. M.; Eakin, C. M.; Crameri, F.

    2014-12-01

    Mantle dynamics manifests at the surface via the horizontal motions of plates and the vertical deflections that influence topography and the non-hydrostatic geoid. The pioneering work of Mitrovica et al. (1989) and Gurnis (1990) on this dynamic topography revolutionized our understanding of sedimentary basin formation, sea level changes and continental flooding. The temporal evolution of subduction can explain the migration of basins and even the drainage reversal of the Amazon (Shephard et al., 2012; Eakin et al., 2014). Until recently, flat subduction has been seen as enhancing downward deflection of the overriding plate and increasing flooding. However, this interpretation depends crucially on the details of the morphology and density structure of the slab, which controls the loci and amplitude of the deflection. We tend to ignore morphological details in mantle dynamics because flow can smooth out short wavelength variations. We have shown instead that details matter! Using South America as a natural laboratory because of the large changes in morphology of the Nazca slab along strike, we show that downward deflection of the overriding plate and hence basin formation, do not occur over flat segments but at the leading edge, where slabs plunge back into the mantle. This is true in both Argentina and Peru. The temporal evolution from a 'normally' dipplng slab to a flat slab leads to uplift over flat segments rather than enhanced subsidence. Critical for this result is the use of a detailed morphological model of the present-day Nazca slab with a spatial resolution of 50-100 km and based on relocated seismicity and magnetotelluric results. The density structure of the slab, due to age and the presence of overthickened crust from aseismic ridge subduction is essential. Overthickened crust leads to buoyant slabs. We reproduce formation and deposition of the Acres-Solimoes basin and the evolution of the Amazon drainage basin in Peru as well as the Mar Chiquita

  6. Topography and Landforms of Ecuador

    USGS Publications Warehouse

    Chirico, Peter G.; Warner, Michael B.

    2005-01-01

    EXPLANATION The digital elevation model of Ecuador represented in this data set was produced from over 40 individual tiles of elevation data from the Shuttle Radar Topography Mission (SRTM). Each tile was downloaded, converted from its native Height file format (.hgt), and imported into a geographic information system (GIS) for additional processing. Processing of the data included data gap filling, mosaicking, and re-projection of the tiles to form one single seamless digital elevation model. For 11 days in February of 2000, NASA, the National Geospatial-Intelligence Agency (NGA), the German Aerospace Center (DLR), and the Italian Space Agency (ASI) flew X-band and C-band radar interferometry onboard the Space Shuttle Endeavor. The mission covered the Earth between 60?N and 57?S and will provide interferometric digital elevation models (DEMs) of approximately 80% of the Earth's land mass when processing is complete. The radar-pointing angle was approximately 55? at scene center. Ascending and descending orbital passes generated multiple interferometric data scenes for nearly all areas. Up to eight passes of data were merged to form the final processed SRTM DEMs. The effect of merging scenes averages elevation values recorded in coincident scenes and reduces, but does not completely eliminate, the amount of area with layover and terrain shadow effects. The most significant form of data processing for the Ecuador DEM was gap-filling areas where the SRTM data contained a data void. These void areas are a result of radar shadow, layover, standing water, and other effects of terrain, as well as technical radar interferometry phase unwrapping issues. To fill these gaps, topographic contours were digitized from 1:50,000 - scale topographic maps which date from the mid-late 1980's (Souris, 2001). Digital contours were gridded to form elevation models for void areas and subsequently were merged with the SRTM data through GIS and remote sensing image-processing techniques

  7. Abyssal intimacies and temporalities of care: How (not) to care about deformed leaf bugs in the aftermath of Chernobyl.

    PubMed

    Schrader, Astrid

    2015-10-01

    Prompted by a classroom discussion on knowledge politics in the aftermath of the Chernobyl disaster, this article offers a reading of Hugh Raffles' Insectopedia entry on Chernobyl. In that entry, Raffles describes how Swiss science-artist and environmental activist Cornelia Hesse-Honegger collects, studies, and paints morphologically deformed leaf bugs that she finds in the proximity of nuclear power plants. In exploring how to begin to care about beings, such as leaf bugs, this article proposes a notion of care that combines an intimate knowledge practice with an ethical relationship to more-than-human others. Jacques Derrida's notion of 'abyssal intimacy' is central to such a combination. Hesse-Honegger's research practices enact and her paintings depict an 'abyssal intimacy' that deconstructs the oppositions between concerns about human suffering and compassion for seemingly irrelevant insects and between knowledge politics and ethics. At the heart of such a careful knowledge production is a fundamental passivity, based on a shared vulnerability. An abyssal intimacy is not something we ought to recognize; rather, it issues from particular practices of care that do not identify their subjects of care in advance. Caring or becoming affected thus entails the dissociation of affection not only from the humanist subject, but also from movements in time: from direct helping action and from the assumption that advocacy necessarily means speaking for an other, usually assumed to be inferior.

  8. Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata

    PubMed Central

    Glover, Adrian G; Wiklund, Helena; Rabone, Muriel; Amon, Diva J; Smith, Craig R; O'Hara, Tim; Mah, Christopher L

    2016-01-01

    Abstract We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. PMID:26929713

  9. Southern Ocean abyssal heat uptake in fine and coarse resolution climate model simulations

    NASA Astrophysics Data System (ADS)

    Newsom, E. R.; Singh, H.; Bitz, C. M.

    2013-12-01

    The recently observed warming of Antarctic Bottom Water (AABW) represents an important component of accumulated sea level rise and global ocean heat uptake. Yet in simulations of greenhouse warming with coarse resolution climate models (which parameterize ocean eddies), Southern Ocean heat uptake dominantly occurs within near-surface waters, which are subsequently transported northward and subducted at mid-latitudes. Here, we examine the response of the abyssal Southern Ocean to greenhouse forcing within a global climate model run with a fine resolution (eddy-resolving) ocean component, which more faithfully simulates AABW formation than its coarse resolution counterparts. We argue that AABW warming may play a more important role in Southern Ocean heat uptake than is suggested by the CMIP5 ensemble of coarse resolution models. We examine the heat uptake in the Southern Ocean using the Community Climate System Model version 3.5 (CCSM 3.5). The model was run at two resolutions in the ocean and sea ice components: coarse (1 degree), which is a standard resolution of many CMIP5 models, and fine (.1 degree), in which sea ice and AABW is formed more realistically. The atmosphere and land components were fixed throughout at .5 degrees resolution. Each version was forced identically with a 1% ramping of CO2 for 150 years. The fine resolution simulation produces more dense water in the control climate, which sinks to a more realistic depth. We attribute this to the improved simulation of sea ice formation regions granted by increasing the ocean model resolution. The reduction of AABW formation as the climate warms leads to a larger response at depth at fine resolution; below 2000 meters, the fine resolution simulation takes up two orders of magnitude more heat than at coarse resolution. We further propose a framework to weigh the amount of heat taken up at depth in the Southern Ocean by the timescale at which it is sequestered, giving more value to heating of regions with

  10. Suspended particulate loads and transports in the nepheloid layer of the abyssal Atlantic Ocean

    USGS Publications Warehouse

    Biscaye, P.E.; Eittreim, S.L.

    1977-01-01

    Vertical profiles of light scattering from over 1000 L-DGO nephelometer stations in the Atlantic Ocean have been used to calculate mass concentrations of suspended particles based on a calibration from the western North American Basin. From these data are plotted the distributions of particulate concentrations at clear water and in the more turbid near-bottom water. Clear water is the broad minimum in concentration and light scattering that occurs at varying mid-depths in the water column. Concentrations at clear water are as much as one-to-two orders of magnitude lower than those in surface water but still reflect a similar geographic distribution: relatively higher concentrations at ocean margins, especially underneath upwelling areas, and the lowest concentrations underneath central gyre areas. These distributions within the clear water reflect surface-water biogenic productivity, lateral injection of particles from shelf areas and surface circulation patterns and require that the combination of downward vertical and horizontal transport processes of particles retain this pattern throughout the upper water column. Below clear water, the distribution of standing crops of suspended particulate concentrations in the lower water column are presented. The integration of mass of all particles per unit area (gross particulate standing crop) reflects a relative distribution similar to that at the surface and at clear water levels, superimposed on which is the strong imprint of boundary currents along the western margins of the Atlantic. Reducing the gross particulate standing crop by the integral of the concentration of clear water yields a net particulate standing crop. The distribution of this reflects primarily the interaction of circulating abyssal waters with the ocean bottom, i.e. a strong nepheloid layer which is coincident with western boundary currents and which diminishes in intensity equatorward. The resuspended particulate loads in the nepheloid layer of the

  11. Volcanic margin formation and Mesozoic rift propagators in the Cuvier Abyssal Plain off Western Australia

    NASA Astrophysics Data System (ADS)

    Mihut, Dona; Müller, R. Dietmar

    1998-11-01

    The western margin of Australia is characterized by synrift and postrift magmatism which is not well understood. A joint interpretation of magnetic anomaly, satellite gravity anomaly and seismic data from the Cuvier Abyssal Plain and margin shows that the breakup between India and Australia started circa 136 Ma (M14) and was followed by two rift propagation events which transferred portions of the Indian Plate to the Australian Plate. Post breakup magmatism continued with the emplacement of the Wallaby and Zenith plateaus (˜17-18 km thick at their centers) along a transform margin. Two narrow magmatic edifices adjacent to the Wallaby Plateau (Sonne and Sonja ridges) represent an extinct ridge and a pseudofault, respectively. They formed by excess volcanism, probably by lateral migration of buoyant melt along upside-down crustal drainage channels from the melt source underneath the Wallaby Plateau. In a mantle plume scenario a small plume (˜400 km diameter) located underneath the rift could have locally uplifted the Bernier Platform and Exmouth Sub-basin in the Early Cretaceous and left a track consistent with the azimuth of the Wallaby and Zenith plateaus. In this case, ridge-plume interaction would have caused two consecutive ridge propagation events towards the plume while the ridge moved away from the hotspot. The abrupt end of the hotspot track west of the Zenith Plateau would be a consequence of the accelerating south-eastward motion of the spreading ridge relative to the mantle after 120 Ma, leaving the mantle plume underneath the Indian Plate. An alternative nonmantle-plume scenario is based on the observation that between breakup and chron M0 (˜120 Ma) the ocean crust in the southern Cuvier Abyssal Plain was formed while the spreading ridge abutted Indian continental crust. Small-scale convection may have been initiated during rifting in the Early Cretaceous and maintained until the Wallaby-Zenith ridge-transform intersection passed by the eastern edge

  12. Abyssal θ-S Observations at Hawaii Ocean Time-series Station ALOHA

    NASA Astrophysics Data System (ADS)

    Lukas, R.; Santiago-Mandujano, F.; Fumar, C.; McCoy, D.; Deppe, R. W.; Gum, J.; Snyder, J.; Chee, B.; Howe, B. M.; Potemra, J. T.; Duennebier, F. K.

    2014-12-01

    Abyssal θ-S variations observed since June 2011 by the ALOHA Cabled Observatory (ACO) reveal a potential temperature range of 0.025°C, and a salinity range of more than 0.0025 g kg-1. The very large temperature range is associated with episodic cold events (Lukas et al.2001; Alford et al. 2011). The salinity range, while not large in absolute terms, is an order of magnitude larger than the precision of the Sea-Bird Microcat. The absolute salinity is calibrated against simultaneous Hawaii Ocean Time-series (HOT) full-depth CTD profiles that have an accuracy of ~10-3 g kg-1. A slow drift of the SBE-37 conductivity sensor is seen, along with a sudden offset that may have been caused by a nearby glass ball implosion. θ-S variations are dominated by changes in density that are associated with dynamic processes. Large cooling events are associated with increases of salinity ultimately deriving from the neighboring Maui Deep. The slopes of these excursions in θ-S space are consistent with the slopes of HOT CTD depth profiles, suggesting that these are vertical changes due either to gravity currents associated with cold, salty overflow events from the Maui Deep, or to internal seiches within the Kauai Deep. θ-S variations that are nearly isopycnal are also seen during the slow recovery from a major cooling event in 2011. This may be due to diapycnal mixing with fresher waters above the controlling sill depth. It cannot be ruled out that some apparent salinity changes may be associated with sediment resuspension events, with subsequent deviations from the PSS-78 empirical relationship between conductivity, salinity, temperature and pressure. ADCP records show large vacillations of along- and cross-isobath flow. Large vertical current variations are measured that are correlated with horizontal flows, likely due to the bottom slope, even after minimizing correlations to account for the unknown orientation of the ADCP. The primary conclusion is that abyssal dynamics

  13. The Oceanic Lithosphere as Reactive Filter: Implications for MORB and Abyssal Peridotite Compositions

    NASA Astrophysics Data System (ADS)

    Luffi, P. I.; Lee, C.; Antoshechkina, P. M.

    2010-12-01

    Melt-rock reaction in the lithosphere is, as suggested by textural observations and compositional data, a ubiquitous phenomenon capable of generating locally diverse peridotite series, such as those observed at oceanic spreading centers and transform faults, and may represent an important mechanism of creating compositional diversity in MORBs [1]. Whereas our understanding of the principles governing reactive melt transport is supported by basic theories and models, studies that attempt to quantify the physical conditions and mechanisms creating heterogeneities in the oceanic lithosphere are still limited in number [e.g. 2]. Using Adiabat_1ph 3.0 [3] in combination with the pMELTS algorithm [4], we have previously shown that reactive percolation of basaltic melts through depleted harzburgites can generate the dunite-(wehrlite)-harzburgite-lherzolite spectrum observed in the abyssal mantle and ophiolites, and that the amplitude of transformations is a function of thermal boundary layer thickness and amount of available melt [5]. To gain further insight into how melt-rock reactions shape the oceanic lithosphere, here we extend our study to show that the major and trace element variability in the oceanic mantle and rising melts are also significantly influenced by the mechanism of melt transport. If associated with cooling, distributed porous melt percolation (simulated by incremental addition of the same amount of melt) more efficiently converts harzburgites into fertile lherzolites and creates more pronounced compositional gradients in the abyssal mantle than imparted during channelized melt influx (simulated as batch addition of large amounts of melt) under otherwise identical circumstances. To remain within the tholeiitic trend observed in MORB, reacted melts must be released before clinopyroxene precipitation peaks. Further reaction with harzburgite causes liquids to evolve toward boninite-like compositions. As reaction progresses with decreasing temperature, the

  14. Shuttle Radar Topography Mission (SRTM)

    USGS Publications Warehouse

    ,

    2009-01-01

    Under an agreement with the National Aeronautics and Space Administration (NASA) and the Department of Defense's National Geospatial-Intelligence Agency (NGA), the U.S. Geological Survey (USGS) is distributing elevation data from the Shuttle Radar Topography Mission (SRTM). The SRTM is a joint project of NASA and NGA to map the Earth's land surface in three dimensions at an unprecedented level of detail. As part of space shuttle Endeavour's flight during February 11-22, 2000, the SRTM successfully collected data over 80 percent of the Earth's land surface for most of the area between latitudes 60 degrees north and 56 degrees south. The SRTM hardware included the Spaceborne Imaging Radar-C (SIR-C) and X-band Synthetic Aperture Radar (X-SAR) systems that had flown twice previously on other space shuttle missions. The SRTM data were collected with a technique known as interferometry that allows image data from dual radar antennas to be processed for the extraction of ground heights.

  15. Shuttle Radar Topography Mission (SRTM)

    USGS Publications Warehouse

    ,

    2003-01-01

    Under an agreement with the National Aeronautics and Space Administration (NASA) and the Department of Defense's National Imagery and Mapping Agency (NIMA), the U.S. Geological Survey (USGS) is now distributing elevation data from the Shuttle Radar Topography Mission (SRTM). The SRTM is a joint project between NASA and NIMA to map the Earth's land surface in three dimensions at a level of detail unprecedented for such a large area. Flown aboard the NASA Space Shuttle Endeavour February 11-22, 2000, the SRTM successfully collected data over 80 percent of the Earth's land surface, for most of the area between 60? N. and 56? S. latitude. The SRTM hardware included the Spaceborne Imaging Radar-C (SIR-C) and X-band Synthetic Aperture Radar (X-SAR) systems that had flown twice previously on other space shuttle missions. The SRTM data were collected specifically with a technique known as interferometry that allows image data from dual radar antennas to be processed for the extraction of ground heights.

  16. Maps of Mars Global Topography

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Maps of Mars' global topography. The projections are Mercator to 70o latitude and stereographic at the poles with the south pole at left and north pole at right. Note the elevation difference between the northern and southern hemispheres. The Tharsis volcano-tectonic province is centered near the equator in the longitude range 220o E to 300o E and contains the vast east-west trending Valles Marineris canyon system and several major volcanic shields including Olympus Mons (18o N, 225o E), Alba Patera (42o N, 252o E), Ascraeus Mons (12o N, 248o E), Pavonis Mons (0o, 247o E), and Arsia Mons (9o S, 239o E). Regions and structures discussed in the text include Solis Planum (25o S, 270o E), Lunae Planum (10o N, 290o E), and Claritas Fossae (30o S, 255o E). Major impact basins include Hellas (45o S, 70o E), Argyre (50o S, 320o E), Isidis (12o N, 88o E), and Utopia (45o N, 110o E). This analysis uses an areocentric coordinate convention with east longitude positive.

  17. 3. GENERAL VIEW DOWN EAST HILLS DRIVE, BUILDING 20 (ONE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. GENERAL VIEW DOWN EAST HILLS DRIVE, BUILDING 20 (ONE BEDROOM) AND BUILDING 21 (TWO/THREE BEDROOM); ACTIVITY CENTER IN REAR, FACING NORTHEAST. - Aluminum City Terrace, East Hill Drive, New Kensington, Westmoreland County, PA

  18. OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP BUILDINGS, LOOKING SOUTH SOUTHEAST. THE FUNCTION OF THE FLAT AREA AT CENTER RIGHT IS UNKNOWN. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  19. Segment lengths influence hill walking strategies.

    PubMed

    Sheehan, Riley C; Gottschall, Jinger S

    2014-08-22

    Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking.

  20. General Education at UNC-Chapel Hill

    ERIC Educational Resources Information Center

    Schalin, Jay; Robinson, Jenna Ashley

    2013-01-01

    The general education program at UNC-Chapel Hill has abandoned the concept of a core curriculum. Instead, students choose their "required" classes from lists of thousands of courses that may be as narrow and idiosyncratic as Love, Sex and Marriage in Soviet Culture (RUSS 277) or The Gardens, Shrines and Temples of Japan (ASIA 586).…

  1. ENHANCED REMEDIATION DEMONSTRATIONS AT HILL AFB: INTRODUCTION

    EPA Science Inventory

    Nine enhanced aquifer remediation technologies were demonstrated side-by-side at a Hill Air Force Base Chemical Disposal Pit/Fire Training Area site. The demonstrations were performed inside 3 x 5 m cells isolated from the surrounding shallow aquifer by steel piling. The site w...

  2. The House on the Hill Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2011-01-01

    In this article, the author suggests a classroom challenge that will engage students in designing a house on the hill. He suggests teachers ask a local builder to come to the school to discuss the kinds of concerns that must be dealt with when building homes in cold environments. The use of dioramas and cardboard scale models would be very useful…

  3. 27 CFR 9.193 - Rattlesnake Hills.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) Approved Maps. The appropriate maps for determining the boundaries of the Rattlesnake Hills viticultural area are eight United States Geological Survey 1:24,000 scale topographic maps. They are titled: (1.... The area's boundary is defined as follows: (1) The beginning point is on the Yakima East map at...

  4. Andoyer construction for Hill and Delaunay variables

    NASA Astrophysics Data System (ADS)

    Laskar, Jacques

    2017-03-01

    Andoyer variables are well known for the study of rotational dynamics. These variables were derived by Andoyer through a procedure that can be also used to obtain the Hill variables of the Kepler problem. Andoyer construction can also forecast the Delaunay variables which canonicity is then obtained without the use of a generating function.

  5. Ocean Hill-Brownsville, 40 Years Later

    ERIC Educational Resources Information Center

    Kahlenberg, Richard D.

    2008-01-01

    Forty years ago--on May 9, 1968--the local school board in Brooklyn's black ghetto of Ocean Hill-Brownsville sent telegrams to 19 unionized educators, informing them that their employment in the district was terminated. Eighteen were white. One black teacher was mistakenly included on the list, but reinstated almost immediately after the error was…

  6. An Unlikely Student Hits Capitol Hill

    ERIC Educational Resources Information Center

    Hoover, Eric

    2009-01-01

    Todd Sollar, a laid-off autoworker from Ohio who is studying for an associate degree in engineering at Sinclair Community College, in Dayton, OH, went to Capitol Hill to help educate lawmakers about the importance of including support for community colleges in the economic-stimulus bill. Mr. Sollar came to Washington with Sinclair's president, and…

  7. The effect of topography on pyroclastic flow mobility

    NASA Astrophysics Data System (ADS)

    Ogburn, S. E.; Calder, E. S.

    2010-12-01

    Pyroclastic flows are among the most destructive volcanic phenomena. Hazard mitigation depends upon accurate forecasting of possible flow paths, often using computational models. Two main metrics have been proposed to describe the mobility of pyroclastic flows. The Heim coefficient, height-dropped/run-out (H/L), exhibits an inverse relationship with flow volume. This coefficient corresponds to the coefficient of friction and informs computational models that use Coulomb friction laws. Another mobility measure states that with constant shear stress, planimetric area is proportional to the flow volume raised to the 2/3 power (A∝V^(2/3)). This relationship is incorporated in models using constant shear stress instead of constant friction, and used directly by some empirical models. Pyroclastic flows from Soufriere Hills Volcano, Montserrat; Unzen, Japan; Colima, Mexico; and Augustine, Alaska are well described by these metrics. However, flows in specific valleys exhibit differences in mobility. This study investigates the effect of topography on pyroclastic flow mobility, as measured by the above mentioned mobility metrics. Valley width, depth, and cross-sectional area all influence flow mobility. Investigating the appropriateness of these mobility measures, as well as the computational models they inform, indicates certain circumstances under which each model performs optimally. Knowing which conditions call for which models allows for better model selection or model weighting, and therefore, more realistic hazard predictions.

  8. SRTM Stereo Pair: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001 the Kachchh region in western India suffered the most deadly earthquake in India's history. This stereoscopic view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. The anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the curvilinear ridge trending toward the southwest from the image center is an erosion resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. The dike also appears to extend northeast from the image center as a dark line having very little topography. Its location between the tilted block and a smaller anticline to the north (directly east of the larger anticline) probably indicates that the dike fills the fault that separates these contrasting geologic structures. These features are simple examples of how digital elevation data can stereoscopically enhance satellite imagery to provide a direct input to geologic studies.

    This stereoscopic image was generated by draping a Landsat satellite image (taken just two weeks after the earthquake) over a preliminary Shuttle Radar Topography Mission (SRTM

  9. Seismicity and seismotectonics of the diffusive Iberian/African plate boundary: Horseshoe Abyssal Plain and Gorringe Bank

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Lange, Dietrich; Matias, Luis

    2014-05-01

    In the area to the west of the Gibraltar Arc the plate boundary between Africa and Iberia is poorly defined. The deformation in the area is forced by the slow NW-SE convergence of 4 mm/yr between the oceanic domains of Iberia/Eurasia and Africa and is accommodated over a 200 km broad tectonically-active deformation zone. The region, however, is also characterized by large earthquakes and tsunamis, such as the 1969 Mw=7.9 Horseshoe Abyssal Plain earthquake and the November 1, 1755 Great Lisbon earthquake with an estimated magnitude of Mw~8.5. The exact location of the source of the 1755 Lisbon earthquake is still unknown. Recent work may suggest that the event occurred in the vicinity of the Horseshoe fault, an oblique thrust fault. However, estimates of tsunami arrival times suggested a source near the Gorringe Bank, a ~180 km-long and ~70 km-wide ridge that has a relieve of ~5000 m. Deep Sea Drilling (DSDP) and rock samples indicated that the bank is mainly composed of serpentinized peridotites with gabbroic intrusions, perhaps being created by overthrusting of the Horseshoe Abyssal Plain onto the Tagus Abyssal Plain in NW direction. Further, the Horseshoe Abyssal Plain is marked by the presence of compressive structures with a roughly NE-SW orientation and E-W trending, segmented, crustal-scale, strike slip faults that extend from the Gorringe Bank to the Gibraltar Arc in the eastern Gulf of Cadiz, which were called "South West Iberian Margin" or SWIM faults. The fault system may mark a developing Eurasia-Africa plate boundary. Two local seismic networks were operated in the area. First, a network of 14 ocean-bottom seismometers (OBS) was operated between April and October 2012 in the vicinity of the Horseshoe fault between 10°W to 11°W, and 35°50'N to 36°10'N. From October 2013 to March 2014 a second network of 15 OBS monitored seismicity at the Gorringe Bank. Both networks benefitted from seismic stations operated in Portugal. The first network provided in

  10. 3. HYDE STREET HILL: View to north looking down the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. HYDE STREET HILL: View to north looking down the Hyde Street hill from Lombard Street. The steepest hill on the present cable railway system, this grade exceeds 20%. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  11. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...). (3) “Los Alamos, Calif.,” edition of 1959. (4) “Santa Rosa Hills, Calif.,” edition of 1959... Hills viticultural area is located in Santa Barbara County, California. The boundary is as follows: (1... the heart of the Santa Rosa Land Grant, T.7N., R. 32W, on the Santa Rosa Hills, Calif., Quadrangle...

  12. View of south boundary of Easter Hill project site, former ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of south boundary of Easter Hill project site, former right of way for Hoffman Boulevard. Note reconstructed Easter Hill Building No. 6 at rear. Looking east - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  13. 78 FR 65962 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of cancellation of meeting of the Black Hills National Forest Advisory Board. SUMMARY: The U. S. Department of Agriculture, Forest Service, Black Hills National Forest cancelled the October 16, 2013 meeting of the...

  14. 77 FR 22755 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: USDA Forest Service. ACTION: Notice of cancellation of meetings of the Black Hills National Forest Advisory Board. SUMMARY: The U. S. Department of Agriculture, Forest Service, Black Hills National Forest was required...

  15. Diversity and distribution of Porifera in the bathyal and abyssal Weddell Sea and adjacent areas

    NASA Astrophysics Data System (ADS)

    Janussen, Dorte; Tendal, Ole Secher

    2007-08-01

    During the ANDEEP I-III expeditions, we obtained a rich and highly diverse sponge collection from the deep Weddell Sea. All the three Poriferan classes, Calcarea, Demospongiae and Hexactinellida, were well represented. Among this material, we have identified a total of 76 species from 47 genera and 30 families. Of these, 17 species (22%) are new to science and 37 (49%) new for the Southern Ocean. Particularly remarkable is the considerable depth of the boundary between bathyal and abyssal sponge faunas. Both Demospongiae and Hexactinellida show a strong shift in their taxonomic composition from a typical shelf assemblage to a more cosmopolitan deep-sea fauna at around 2500 m. Within the Demospongiae, the families Polymastiidae and Cladorhizidae (carnivorous sponges) are particularly abundant and very diverse. The Calcarea are recorded for the first time from the Antarctic deep sea. The type of sampling gear used, especially the epibenthic sledge, was an important factor for the successful collection of deep-sea sponges during the ANDEEP campaigns.

  16. Nitrate respiration associated with detrital aggregates in aerobic bottom waters of the abyssal NE Pacific

    NASA Astrophysics Data System (ADS)

    Wolgast, D. M.; Carlucci, A. F.; Bauer, J. E.

    Rates of nitrate utilization in tube core respirometers (TCR) placed over aggregates on the seafloor at an abyssal site (Station M) in the eastern North Pacific Ocean increased at times of high particle flux. In the presence of aggregates, both oxygen and nitrate were used in respiration. The ratio of O 2 : NO 3 concentrations in ambient waters was 3.9, while O 2 : NO 3 utilization rates in TCR overlying and TCR aggregate pore waters were 2.6 and 0.6, respectively. We postulated that denitrification was occurring in microzones of the particle-rich oxygenated (135 μM) waters. To test this, nitrate respiration was measured aboard a ship in oxygen-minimum (˜26 μM) water supplemented with particulate matter collected by a surface net tow. Dissolved oxygen consumption occurred immediately, followed by nitrate utilization while oxygen was still present. Calculations from cell densities indicated 0.6 μM of the original 42 μM of nitrate was assimilated into bacterial biomass during 36 h of incubation, suggesting the major portion of the utilized nitrate was used in respiration. Nitrate utilization rates in the in situ incubation study and those of the shipboard experiment were 3.1 and 2.7 μM d -1, respectively. The results of the present studies suggest nitrate respiration occurs in microzones of aggregates in oxygenated bottom waters at times of high particle flux and causes some loss of fixed nitrogen.

  17. Mineralogy of the mid-ocean-ridge basalt source from neodymium isotopic composition of abyssal peridotites.

    PubMed

    Salters, Vincent J M; Dick, Henry J B

    2002-07-04

    Inferring the melting process at mid-ocean ridges, and the physical conditions under which melting takes place, usually relies on the assumption of compositional similarity between all mid-ocean-ridge basalt sources. Models of mantle melting therefore tend to be restricted to those that consider the presence of only one lithology in the mantle, peridotite. Evidence from xenoliths and peridotite massifs show that after peridotite, pyroxenite and eclogite are the most abundant rock types in the mantle. But at mid-ocean ridges, where most of the melting takes place, and in ophiolites, pyroxenite is rarely found. Here we present neodymium isotopic compositions of abyssal peridotites to investigate whether peridotite can indeed be the sole source for mid-ocean-ridge basalts. By comparing the isotopic compositions of basalts and peridotites at two segments of the southwest Indian ridge, we show that a component other than peridotite is required to explain the low end of the (143)Nd/(144)Nd variations of the basalts. This component is likely to have a lower melting temperature than peridotite, such as pyroxenite or eclogite, which could explain why it is not observed at mid-ocean ridges.

  18. Evaluation of abyssal meiobenthos in the eastern central Pacific (Clarion-Clipperton fracture zone)

    NASA Astrophysics Data System (ADS)

    Renaud-Mornant, Jeanne; Gourbault, Nicole

    Meiobenthos were sampled from 17 stations in the abyssal deep-sea system of the central Pacific centered around 14°N, 130°W at depths 4960-5154m, during the Nixo 47 R/V Jean Charcot cruise. Meiofaunal density range from 45-89 ind. 10cm 2. Predominant taxa are nematodes (84-100%) and copepods (0-10%). Rotifera, Polychaeta, and Acarina also occur. Nematodes are uniformly distributed spatially with 45 species or so; Monhysteridae is the dominant taxon, and Syringolaimus sp. (Ironidae) co-occurs faithfully. Low biomass (0.4-70.6μg 10cm 2) are attributed to supposed dwarfism of metazoan meiofauna and very high proportion (60-80%) of juveniles and pre-adult forms. The majority of protozoans and metazoans are detritus- or deposit-feeders; in addition symbiotic associations, coprophagy and gardening activities are frequent. In such an oligotrophic environment, low food supply may limit meiofaunal abundance, biomass and maturation, and to a lesser extent species richness.

  19. Distribution and diversity of holothuroids (Echinodermata) on Cascadia Basin and Tufts Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Carney, Robert S.; Carey, Andrew G.

    1982-05-01

    The pattern of diversity, species composition, and inter-sample similarity of the holothuroid fauna was examined for 95 beam trawl samples from below 2000 m on the Cascadia Basin and Tufts Abyssal Plain off Oregon, U.S.A. Abundance as inferred from catch size, diversity, species composition, and zonation all showed major change over the sampled area where there was a depth change. Where depth remained relatively constant across the floor of Cascadia Basin, faunal changes were minor in spite of progressive isolation from land. Overall bathymetric patterns of zonation and diversity were basically like those found for other faunal groups in the deep-sea depth. The distribution of minor species indicated that the holothuroid fauna at the base of the continental slope, the apron of Astoria Fan, and near Cascadia Channel might be slightly different from that at similar depths elsewhere in the sampled area. The marked uniformity of the holothuroid fauna across the basin floor appeared to be restricted to epifaunal sediment-feeding species. Infaunal forms were more abundant at the slope base, similar to previous findings for the macro-infauna.

  20. Abyssal ostracods from the South and Equatorial Atlantic Ocean: Biological and paleoceanographic implications

    USGS Publications Warehouse

    Yasuhara, Moriaki; Cronin, T. M.; Martinez, Arbizu P.

    2008-01-01

    We report the distribution of ostracods from ???5000 m depth from the Southeast and Equatorial Atlantic Ocean recovered from the uppermost 10 cm of minimally disturbed sediments taken by multiple-corer during the R/V Meteor DIVA2 expedition M63.2. Five cores yielded the following major deep-sea genera: Krithe, Henryhowella, Poseidonamicus, Legitimocythere, Pseudobosquetina, and Pennyella. All genera are widely distributed in abyssal depths in the world's oceans and common in Cenozoic deep-sea sediments. The total number of ostracod specimens is higher and ostracod shell preservation is better near the sediment-water interface, especially at the 0-1 cm core depths. Core slices from ???5 to 10 cm were barren or yielded a few poorly preserved specimens. The DIVA2 cores show that deep-sea ostracod species inhabit corrosive bottom water near the carbonate compensation depth (CCD) even though their calcareous valves are rarely preserved as fossils in sediment cores due to postmortem dissolution. Their occurrence at great water depths may partially explain the well-known global distributions of major deep-sea taxa in the world's oceans, although further expeditions using minimal-disturbance sampling devices are needed to fill geographic gaps. ?? 2008 Elsevier Ltd. All rights reserved.

  1. Meiofauna communities along an abyssal depth gradient in the Drake Passage

    NASA Astrophysics Data System (ADS)

    Gutzmann, E.; Martínez Arbizu, P.; Rose, A.; Veit-Köhler, G.

    2004-07-01

    Meiofauna standing stocks and community structure are reported for the first time for abyssal soft-sediment samples in Antarctic waters. At seven stations within a depth range of 2274-5194 m a total of 128 sediment cores were retrieved with a multiple corer (MUC) on board of the R.V. Polarstern during the ANDEEP-1 cruise (ANT XIX/3). The metazoan meiofauna (defined by a lower size limit of 40 μm) was identified and counted, and one core per station was preserved for CPE, C/N, TOM and grain size analyses. Meiofauna densities are in the range of 2731 Ind./10 cm 2 at 2290 m depth and 75 Ind./10 cm 2 at 3597 m depth, with nematodes being the dominant group at all stations. Nematodes account for 84-94% followed by copepods with 2-8% of the total meiofauna. Other frequent taxa found at each station are kinorhynchs, loriciferans, tantulocarids, ostracods and tardigrades. There is a general tendency of decreasing abundances of metazoan meiofauna with increasing depth, but not all higher level taxa displayed this pattern. In addition, a tendency of decreasing higher taxon density with increasing depth was observed. Standing stocks are higher than the average found at similar depths in other oceans.

  2. Genetic topography of brain morphology

    PubMed Central

    Chen, Chi-Hua; Fiecas, Mark; Gutiérrez, E. D.; Panizzon, Matthew S.; Eyler, Lisa T.; Vuoksimaa, Eero; Thompson, Wesley K.; Fennema-Notestine, Christine; Hagler, Donald J.; Jernigan, Terry L.; Neale, Michael C.; Franz, Carol E.; Lyons, Michael J.; Fischl, Bruce; Tsuang, Ming T.; Dale, Anders M.; Kremen, William S.

    2013-01-01

    Animal data show that cortical development is initially patterned by genetic gradients largely along three orthogonal axes. We previously reported differences in genetic influences on cortical surface area along an anterior-posterior axis using neuroimaging data of adult human twins. Here, we demonstrate differences in genetic influences on cortical thickness along a dorsal-ventral axis in the same cohort. The phenomenon of orthogonal gradations in cortical organization evident in different structural and functional properties may originate from genetic gradients. Another emerging theme of cortical patterning is that patterns of genetic influences recapitulate the spatial topography of the cortex within hemispheres. The genetic patterning of both cortical thickness and surface area corresponds to cortical functional specializations. Intriguingly, in contrast to broad similarities in genetic patterning, two sets of analyses distinguish cortical thickness and surface area genetically. First, genetic contributions to cortical thickness and surface area are largely distinct; there is very little genetic correlation (i.e., shared genetic influences) between them. Second, organizing principles among genetically defined regions differ between thickness and surface area. Examining the structure of the genetic similarity matrix among clusters revealed that, whereas surface area clusters showed great genetic proximity with clusters from the same lobe, thickness clusters appear to have close genetic relatedness with clusters that have similar maturational timing. The discrepancies are in line with evidence that the two traits follow different mechanisms in neurodevelopment. Our findings highlight the complexity of genetic influences on cortical morphology and provide a glimpse into emerging principles of genetic organization of the cortex. PMID:24082094

  3. The Shuttle Radar Topography Mission

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Kobrick, M.

    2001-12-01

    The Shuttle Radar Topography Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA, the National Imagery and Mapping Agency, and the German and Italian Space Agencies. The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and better than 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. Data processing will be completed by the end of 2002. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.

  4. The Shuttle Radar Topography Mission

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Kobrick, M.

    2001-05-01

    The Shuttle Radar Topography Mission (SRTM), which flew successfully aboard Endeavour in February 2000, is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA). The mission was designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and 56 degrees south latitude. The DEM will have 30 m horizontal resolution and about 15 m vertical errors. Two ortho-rectified C-band image mosaics are also planned. SRTM used a modification of the radar instrument that comprised the Spaceborne Radar Laboratory that flew twice on the Shuttle Endeavour in 1994. To collect the interferometric data, a 60 m mast, additional C-band antenna, and improved tracking and navigation devices were added. A second X-band antenna was also added by the German Space Agency, and produced higher resolution topographic measurements in strips nested within the full, C-band coverage. First results indicate that the radars and ancillary instruments worked very well. Data played back to the ground during the flight were processed to DEMs and products released hours after acquisition. An extensive program for calibration and verification of the SRTM data is now underway. When complete later this year, systematic processing of the data will begin, with final products emerging a continent at a time. Data processing will be completed by the end of 2002. Products will be transferred to the US Geological Survey's EROS Data Center for civilian archive and distribution. NIMA will handle Department of Defense distribution. * Work performed under contract to NASA.

  5. Genetic and Morphological Divergences in the Cosmopolitan Deep-Sea Amphipod Eurythenes gryllus Reveal a Diverse Abyss and a Bipolar Species

    PubMed Central

    Havermans, Charlotte; Sonet, Gontran; d’Udekem d’Acoz, Cédric; Nagy, Zoltán T.; Martin, Patrick; Brix, Saskia; Riehl, Torben; Agrawal, Shobhit; Held, Christoph

    2013-01-01

    Eurythenes gryllus is one of the most widespread amphipod species, occurring in every ocean with a depth range covering the bathyal, abyssal and hadal zones. Previous studies, however, indicated the existence of several genetically and morphologically divergent lineages, questioning the assumption of its cosmopolitan and eurybathic distribution. For the first time, its genetic diversity was explored at the global scale (Arctic, Atlantic, Pacific and Southern oceans) by analyzing nuclear (28S rDNA) and mitochondrial (COI, 16S rDNA) sequence data using various species delimitation methods in a phylogeographic context. Nine putative species-level clades were identified within E. gryllus. A clear distinction was observed between samples collected at bathyal versus abyssal depths, with a genetic break occurring around 3,000 m. Two bathyal and two abyssal lineages showed a widespread distribution, while five other abyssal lineages each seemed to be restricted to a single ocean basin. The observed higher diversity in the abyss compared to the bathyal zone stands in contrast to the depth-differentiation hypothesis. Our results indicate that, despite the more uniform environment of the abyss and its presumed lack of obvious isolating barriers, abyssal populations might be more likely to show population differentiation and undergo speciation events than previously assumed. Potential factors influencing species’ origins and distributions, such as hydrostatic pressure, are discussed. In addition, morphological findings coincided with the molecular clades. Of all specimens available for examination, those of the bipolar bathyal clade seemed the most similar to the ‘true’ E. gryllus. We present the first molecular evidence for a bipolar distribution in a macro-benthic deep-sea organism. PMID:24086322

  6. Enhanced Characterization of Niobium Surface Topography

    SciTech Connect

    Chen Xu, Hui Tian, Charles Reece, Michael Kelley

    2011-12-01

    Surface topography characterization is a continuing issue for the Superconducting Radio Frequency (SRF) particle accelerator community. Efforts are underway to both to improve surface topography, and its characterization and analysis using various techniques. In measurement of topography, Power Spectral Density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how chemical processes modifiesy the roughnesstopography at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, polycrystalline surfaces with different process histories are sampled with AFM and stylus/white light interferometer profilometryers and analyzed to indicate trace topography evolution at different scales. evolving during etching or polishing. Moreover, Aan optimized PSD analysis protocol will be offered to serve the SRF surface characterization needs is presented.

  7. An estimate of global absolute dynamic topography

    NASA Technical Reports Server (NTRS)

    Tai, C.-K.; Wunsch, C.

    1984-01-01

    The absolute dynamic topography of the world ocean is estimated from the largest scales to a short-wavelength cutoff of about 6700 km for the period July through September, 1978. The data base consisted of the time-averaged sea-surface topography determined by Seasat and geoid estimates made at the Goddard Space Flight Center. The issues are those of accuracy and resolution. Use of the altimetric surface as a geoid estimate beyond the short-wavelength cutoff reduces the spectral leakage in the estimated dynamic topography from erroneous small-scale geoid estimates without contaminating the low wavenumbers. Comparison of the result with a similarly filtered version of Levitus' (1982) historical average dynamic topography shows good qualitative agreement. There is quantitative disagreement, but it is within the estimated errors of both methods of calculation.

  8. Multiscale Study of Currents Affected by Topography

    DTIC Science & Technology

    2015-09-30

    topography on the ocean general circulation is challenging because of the multiscale nature of the flow interactions. Small- scale details of the...topography, and the waves, drag, and turbulence generated at the boundary, from meter scale to mesoscale, interact in the boundary layers to influence the...larger- scale flow. We are using modern modeling and state estimation methods at multiple scales for collaborative study of the interaction of

  9. Corneal topography measurements for biometric applications

    NASA Astrophysics Data System (ADS)

    Lewis, Nathan D.

    The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

  10. Shuttle radar topography mapper (SRTM)

    NASA Astrophysics Data System (ADS)

    Jordan, Rolando L.; Caro, Edward R.; Kim, Yunjin; Kobrick, Michael; Shen, Yuhsyen; Stuhr, Frederick V.; Werner, Marian U.

    1996-12-01

    The use of interferometric SAR (IFSAR) to measure elevation is one of the most powerful and promising capabilities of radar. A properly equipped spaceborne IFSAR system can produce a highly accurate global digital elevation map, including cloud-covered areas, in significantly less time and at significantly lower cost than with other systems. For accurate topography, the interferometric measurements must be performed simultaneously in physically sperate receive system, since measurements made at different times with the same system suffer significant decorrelation. The US/German/Italian spaceborne imaging radar C/X-band SAR (SIR-C/X-SAR), successfully flown twice in 1994 aboard the Space Shuttle Endeavor, offers a unique opportunity for global multifrequency elevation mapping by the year 2000. With appropriate augmentation, SIR-C/X-SAR is capable of producing an accurate elevation map covering 80 percent of the Earth's land surface in a single 10-day Shuttle flight. The existing US SIR-C SCANSAR mode provides a 225-km swath at C-band, which makes this coverage possible. Addition of a C-band receive antenna, extended from the Shuttle bay on a mast and operating in concert with the existing SIR-C antenna, produces an interferometric pair. Accuracy is enhanced by utilizing the SIR-C dual polarizations simultaneously to form separate SCANSAR beams. Due to the practical limitation of approximately 60 meters for the mast length, the longer SIR-C L-band wavelength does not produce useful elevation measurement accuracy. IFSAR measurements can also be obtained by the German/Italian X-SAR, simultaneously with SIR-C, by utilizing an added outboard antenna at X-band to produce a swath coverage of about 50 km. Accuracy can be enhanced at both frequencies by processing both ascending and descending data takes. It is estimated that the 90 percent linear absolute elevation error achievable is less that 16 meters for elevation postings of 30 meters. This will be the first use of

  11. 3D time-domain airborne EM forward modeling with topography

    NASA Astrophysics Data System (ADS)

    Yin, Changchun; Qi, Yanfu; Liu, Yunhe; Cai, Jing

    2016-11-01

    The time-domain finite-difference method has been widely used in simulation of the electromagnetic field diffusion. However, this method is severely restricted by the mesh size and time step. To overcome the defect, we adopted edge finite-element method for unstructured grid with Backward Euler method to conduct 3D airborne electromagnetic forward modeling directly in time-domain. The tetrahedral meshes provide the flexibility required for representing the rugged topography and complex-shape anomalous bodies. We simulated the practical shape, size and attitude of transmitting source by directly setting the loop into the well-generated grids. The characteristic properties of vector basic functions guarantee automatic satisfaction of divergence-free property of electric fields. The Galerkin's method is used to discretize the governing equations and a direct solver is adopted to solve the large sparse linear system. We adopted an algorithm with constant step in each time segment to speed up the forward modeling. Further we introduced the local mesh strategy to reduce the calculations, in which an optimized grid is designed for each sounding station. We check the accuracy of our 3D modeling results against the solution for a homogenous half-space and those for a buried vertical plate model using integral equation. The numerical experiments for a hill, a valley or undulating topography model with buried anomalous bodies were further studied that show that the topography has a serious effect on airborne EM data.

  12. Uranium series dating of Allan Hills ice

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.

    1986-01-01

    Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

  13. Morgan Hill, California Earthquake, April 1984

    USGS Publications Warehouse

    Spall, Henry

    1987-01-01

    The Morgan Hill earthquake, a moderate-size (Mg=6.1, ML =6.2, M=6.2) event, was felt throughout central California on April 24, 1984. The epicenter of the earthquake was located near Halls Valley southwest of Mount Hamilton, and the event is presumed to have occurred on the Calaveras fault. Damage, however, was concentrated near the south end of the Anderson Reservoir and in the town of Morgan Hill. A preliminary assessment by the California Office of Emergency Services estimated damage to private property at \\$7.0 million and to local-government facilities at \\$0.5 million, for a total of \\$7.5 million in damage. 

  14. Abyssal and deep circulation in the Eastern Mediterranean Sea (Ionian Sea)

    NASA Astrophysics Data System (ADS)

    Artale, Vincenzo; Bensi, Manuel; Falcini, Federico; Marullo, Salvatore; Rubino, Angelo

    2016-04-01

    In the mid-1990s, experimental evidences on the Eastern Mediterranean Transient (EMT) were presented and it was shown that the Mediterranean abyssal circulation is not in a steady state but can be subjected to episodic sudden changes (Roether et al., 1996). In the last 10 years the Ionian Sea, the central and deepest part of the Mediterranean Sea, was subjected to relevant scientific interests from a theoretical and experimental point of view. Among these, there is the discovery of the BiOS (Bimodal Oscillating System), one new mechanism that drives a periodic (almost decadal) redistribution of surface and subsurface waters in the Eastern Mediterranean, with considerable feedbacks in the variability of the deep-water formation both in the southern Adriatic and in the Levantine and Aegean sub-basins (Gačić et al., 2010). In the Ionian Sea, numerous recent observational campaigns have been conducted to investigate the behaviour of deep and abyssal waters, at depths between 2000-4000m that are comparable to the mean global ocean depth (Rubino and Hainbucher, 2007; Bensi et al., 2013). There, advection, diffusion and vertical stability of the water masses can assume an important role on the internal quasi-periodical variability, creating the preconditions for catastrophic events such as the EMT or reversals of the Ionian circulation (Pisacane et al., 2006). Since there are no significant deep heat sources in the world ocean, waters that fill the deep ocean can only return to the sea surface as a result of downward mixing of heat from the sea surface to the bottom and vice versa and this occurs through eddy diffusion. Along our presentation, mainly through the analysis of the deepest CTD casts taken from 2009 to 2011 in the eastern basins and in particular in the Ionian Sea, we will show a significant change in the deep thermohaline structure (including its biogeochemical and hydrological characteristics), giving an indication on the time scale of the renewal of deep

  15. Possible Meteorites in the Martian Hills

    NASA Technical Reports Server (NTRS)

    2006-01-01

    From its winter outpost at 'Low Ridge' inside Gusev Crater, NASA's Mars Exploration Rover Spirit took this spectacular, color mosaic of hilly, sandy terrain and two potential iron meteorites. The two light-colored, smooth rocks about two-thirds of the way up from the bottom of the frame have been labeled 'Zhong Shan' and 'Allan Hills.'

    The two rocks' informal names are in keeping with the rover science team's campaign to nickname rocks and soils in the area after locations in Antarctica. Zhong Shang is an Antarctic base that the People's Republic of China opened on Feb. 26, 1989, at the Larsemann Hills in Prydz Bay in East Antarctica. Allan Hills is a location where researchers have found many Martian meteorites, including the controversial ALH84001, which achieved fame in 1996 when NASA scientists suggested that it might contain evidence for fossilized extraterrestrial life. Zhong Shan was the given name of Dr. Sun Yat-sen (1866-1925), known as the 'Father of Modern China.' Born to a peasant family in Guangdong, Sun moved to live with his brother in Honolulu at age 13 and later became a medical doctor. He led a series of uprisings against the Qing dynasty that began in 1894 and eventually succeeded in 1911. Sun served as the first provisional president when the Republic of China was founded in 1912.

    The Zhong Shan and Allan Hills rocks, at the left and right, respectively, have unusual morphologies and miniature thermal emission spectrometer signatures that resemble those of a rock known as 'Heat Shield' at the Meridiani site explored by Spirit's twin, Opportunity. Opportunity's analyses revealed Heat Shield to be an iron meteorite.

    Spirit acquired this approximately true-color image on the rover's 872nd Martian day, or sol (June 16, 2006), using exposures taken through three of the panoramic camera's filters, centered on wavelengths of 600 nanometers, 530 nanometers, and 480 nanometers.

  16. Hill Ciphers over Near-Fields

    ERIC Educational Resources Information Center

    Farag, Mark

    2007-01-01

    Hill ciphers are linear codes that use as input a "plaintext" vector [p-right arrow above] of size n, which is encrypted with an invertible n x n matrix E to produce a "ciphertext" vector [c-right arrow above] = E [middle dot] [p-right arrow above]. Informally, a near-field is a triple [left angle bracket]N; +, *[right angle bracket] that…

  17. Autonomous Legged Hill and Stairwell Ascent

    DTIC Science & Technology

    2011-11-01

    environments with little burden to a human operator. Keywords: autonomous robot, hill climbing, stair climbing, sequential composition, hexapod, self...simulation studies [11], with almost all empirical work confined to the traversal of a single flight and yaw control on the stairs (summarized in [4]). The...only prior report we have found documenting empirical work over multiple flights of stairs assumed a very specific, simple landing geometry [12]; we

  18. A Reverse Taxonomic Approach to Assess Macrofaunal Distribution Patterns in Abyssal Pacific Polymetallic Nodule Fields

    PubMed Central

    Janssen, Annika; Kaiser, Stefanie; Meißner, Karin; Brenke, Nils; Menot, Lenaick; Martínez Arbizu, Pedro

    2015-01-01

    Heightened interest in the exploitation of deep seafloor minerals is raising questions on the consequences for the resident fauna. Assessing species ranges and determination of processes underlying current species distributions are prerequisites to conservation planning and predicting faunal responses to changing environmental conditions. The abyssal central Pacific nodule belt, located between the Clarion and Clipperton Fracture Zones (CCZ), is an area prospected for mining of polymetallic nodules. We examined variations in genetic diversity and broad-scale connectivity of isopods and polychaetes across the CCZ. Faunal assemblages were studied from two mining claims (the eastern German and French license areas) located 1300 km apart and influenced by different productivity regimes. Using a reverse taxonomy approach based on DNA barcoding, we tested to what extent distance and large-scale changes in environmental parameters lead to differentiation in two macrofaunal taxa exhibiting different functions and life-history patterns. A fragment of the mitochondrial gene Cytochrome Oxidase Subunit 1 (COI) was analyzed. At a 97% threshold the molecular operational taxonomic units (MOTUs) corresponded well to morphological species. Molecular analyses indicated high local and regional diversity mostly because of large numbers of singletons in the samples. Consequently, variation in composition of genotypic clusters between sites was exceedingly large partly due to paucity of deep-sea sampling and faunal patchiness. A higher proportion of wide-ranging species in polychaetes was contrasted with mostly restricted distributions in isopods. Remarkably, several cryptic lineages appeared to be sympatric and occurred in taxa with putatively good dispersal abilities, whereas some brooding lineages revealed broad distributions across the CCZ. Geographic distance could explain variation in faunal connectivity between regions and sites to some extent, while assumed dispersal

  19. Links between surface productivity and deep ocean particle flux at the Porcupine Abyssal Plain sustained observatory

    NASA Astrophysics Data System (ADS)

    Frigstad, H.; Henson, S. A.; Hartman, S. E.; Omar, A. M.; Jeansson, E.; Cole, H.; Pebody, C.; Lampitt, R. S.

    2015-10-01

    In this study we present hydrography, biogeochemistry and sediment trap observations between 2003 and 2012 at Porcupine Abyssal Plain (PAP) sustained observatory in the Northeast Atlantic. The time series is valuable as it allows for investigation of the link between surface productivity and deep ocean carbon flux. The region is a perennial sink for CO2, with an average uptake of around 1.5 mmol m-2 day-1. The average monthly drawdowns of inorganic carbon and nitrogen were used to quantify the net community production (NCP) and new production. Seasonal NCP and new production were found to be 4.57 ± 0.85 mol C m-2 and 0.37 ± 0.14 mol N m-2, respectively. The C : N ratio was high (12) compared to the Redfield ratio (6.6), and the production calculated from carbon was higher than production calculated from nitrogen, which is indicative of carbon overconsumption. The export ratio and transfer efficiency were 16 and 4 %, respectively, and the site thereby showed high flux attenuation. Particle tracking was used to examine the source region of material in the sediment trap, and there was large variation in source regions, both between and within years. There were higher correlations between surface productivity and export flux when using the particle-tracking approach, than by comparing with the mean productivity in a 100 km box around the PAP site. However, the differences in correlation coefficients were not significant, and a longer time series is needed to draw conclusions on applying particle tracking in sediment trap analyses.

  20. An abyssal carbonate compensation depth overshoot in the aftermath of the Palaeocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Penman, Donald E.; Turner, Sandra Kirtland; Sexton, Philip F.; Norris, Richard D.; Dickson, Alexander J.; Boulila, Slah; Ridgwell, Andy; Zeebe, Richard E.; Zachos, James C.; Cameron, Adele; Westerhold, Thomas; Röhl, Ursula

    2016-08-01

    During the Palaeocene-Eocene Thermal Maximum (PETM) about 56 million years ago, thousands of petagrams of carbon were released into the atmosphere and ocean in just a few thousand years, followed by gradual sequestration over approximately 200,000 years. If silicate weathering is one of the key negative feedbacks that removed this carbon, a period of seawater calcium carbonate saturation greater than pre-event levels would be expected during the event's recovery phase. In marine sediments, this should be recorded as a temporary deepening of the depth below which no calcite is preserved -- the calcite compensation depth (CCD). Previous and new sedimentary records from sites that were above the pre-PETM CCD show enhanced carbonate accumulation following the PETM. A new record from an abyssal site in the North Atlantic that lay below the pre-PETM CCD shows a period of carbonate preservation beginning about 70,000 years after the onset of the PETM, providing the first direct evidence for an over-deepening of the CCD. This record confirms an overshoot in ocean carbonate saturation during the PETM recovery. Simulations with two earth system models support scenarios for the PETM that involve a large initial carbon release followed by prolonged low-level emissions, consistent with the timing of CCD deepening in our record. Our findings indicate that sequestration of these carbon emissions was most likely the result of both globally enhanced calcite burial above the CCD and, at least in the North Atlantic, an over-deepening of the CCD.

  1. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    NASA Astrophysics Data System (ADS)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  2. Reproductive patterns of the abyssal asteroid Styracaster elongatus from the N.E. Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Benítez-Villalobos, Francisco; Díaz-Martínez, Julia P.

    2010-01-01

    We analysed the reproductive biology of the asteroid species Styracaster elongatus based on time-series samples from a 5000-m-deep site on the Porcupine Abyssal Plain (N.E. Atlantic). The ratio of males to females, the gonadosomatic index (GI), and pyloric caecum index (PCI) were determined and the results were corroborated by histological examination of the gonads. Fecundity and oocyte-size distribution were determined by histological and image analyses. Styracaster elongatus is a gonochoric asteroid and the ratio of males to females was not significantly different throughout the year. Oogenesis was asynchronous. The previtellogenic oocytes grew to a size of ˜230 μm before undergoing vitellogenesis. Maximum oocyte size was ˜620 μm. The ovary volume was mainly occupied by small previtellogenic oocytes (100-150 μm) at any one time. Mean GI was 6.38±3.30 for females and 9.04±4.1 for males. Mean PCI was 7.44±1.66 for females and 7.66±1.46 for males. Mean fecundity was 16,373±5988 oocites per female. There were no seasonal variations in GI and fecundity. There was evidence of a pyiloric caecum seasonal development for females and males. For S. elongatus there is no direct relationship among seasonal primary production at the surface and production of vitellogenic oocytes. Nevertheless, this species takes advantage of the pulse of phytodetritus to the seabed by increasing the storage of nutrients in the pyloric caecum in order to maintain a constant production of eggs and sperm.

  3. Moored observation of abyssal flow and temperature near a hydrothermal vent on the Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Liao, Guanghong; Zhou, Beifeng; Liang, Chujin; Zhou, Huaiyang; Ding, Tao; Wang, Yuan; Dong, Changming

    2016-01-01

    Four moorings were deployed near "Dragon Flag," an active hydrothermal vent in the valley of the Southwest Indian Ridge. The goal was to examine the variability of currents and temperature, which will guide the trajectory of spreading plumes. The mean current was cross-isobath, and the circulation was characterized by a submesoscale circulation. Observed currents also showed fluctuations with periods of 1-15 days. The inferred phase speed and wavelength for the wave with a period of 4.4 day are 10.4 km d-1 and 45.8km, respectively, which are consistent with the topographic Rossby wave theory. The persistent warming tendency with corresponding variation of salinity based on background θ-S properties may be caused by background circulation and divergence of the water column. The warming or cooling episodes were most likely as signatures of isopycnal surface depression or uplifting induced by the moving of mesoscale eddies. Well-resolved rotary spectra exhibited important nonlinear interactions between inertial and semidiurnal tide in the velocity and temperature records. Amplification of near-inertial currents in the near bottom is also exposed. These discoveries provided new evidence for the nonlinear interaction and trapped near-inertial waves by the ridge, which occurred in the deep ocean of the Southern Hemisphere. Such nonlinear interaction may represent a significant energy loss pathway for the internal waves, and part of the decay of such motion would likely result in increased mixing to maintain the abyssal stratification. Enhanced near-inertial motions can play a major role for the local advection of hydrothermal plumes.

  4. The Rocks of the Columbia Hills

    NASA Technical Reports Server (NTRS)

    Squyres, Steven W.; Arvidson, Raymond E.; Blaney, Diana L.; Clark, Benton C.; Crumpler, Larry; Farrand, William H.; Gorevan, Stephen; Herkenhoff, Kenneth; Hurowitz, Joel; Kusack, Alastair; McSween, Harry Y.; Ming, Douglas W.; Morris, Richard V.; Ruff, Steven W.; Wang, Alian; Yen, Albert

    2006-01-01

    The Mars Exploration Rover Spirit has identified five distinct rock types in the Columbia Hills of Gusev crater. Clovis Class rock is a poorly-sorted clastic rock that has undergone substantial aqueous alteration. We interpret it to be aqueously-altered ejecta deposits formed by impacts into basaltic materials. Wishstone Class rock is also a poorly-sorted clastic rock that has a distinctive chemical composition that is high in Ti and P and low in Cr. Wishstone Class rock may be pyroclastic in origin. Peace Class rock is a sedimentary material composed of ultramafic sand grains cemented by significant quantities of Mg- and Ca-sulfates. Peace Class rock may have formed when water briefly saturated the ultramafic sands, and evaporated to allow precipitation of the sulfates. Watchtower Class rocks are similar chemically to Wishstone Class rocks, and have undergone widely varying degrees of near-isochemical aqueous alteration. They may also be ejecta deposits, formed by impacts into Wishstone-rich materials and altered by small amounts of water. Backstay Class rocks are basalt/trachybasalt lavas that were emplaced in the Columbia Hills after the other rock classes were, either as impact ejecta or by localized volcanic activity. The geologic record preserved in the rocks of the Columbia Hills reveals a period very early in martian history in which volcanic materials were widespread, impact was a dominant process, and water was commonly present.

  5. Miocene cercopithecoidea from the Tugen Hills, Kenya.

    PubMed

    Gilbert, Christopher C; Goble, Emily D; Hill, Andrew

    2010-11-01

    Miocene to Pleistocene fossiliferous sediments in the Tugen Hills span the time period from at least 15.5 Ma to 0.25 Ma, including time periods unknown or little known elsewhere in Africa. Consequently, the Tugen Hills deposits hold the potential to inform us about crucial phylogenetic events in African faunal evolution and about long-term environmental change. Among the specimens collected from this region are a number of discoveries already important to the understanding of primate evolution. Here, we describe additional cercopithecoid material from the Miocene deposits in the Tugen Hills sequence, including those from securely dated sites in the Muruyur Beds (16-13.4 Ma), the Mpesida Beds (7-6.2 Ma) and the Lukeino Formation (∼ 6.2-5.7 Ma). We also evaluate previously described material from the Ngorora Formation (13-8.8 Ma). Identified taxa include Victoriapithecidae gen. et sp. indet., cf. Parapapio lothagamensis, and at least two colobines. Specimens attributed to cf. Pp. lothagamensis would extend the species' geographic range beyond its type locality. In addition, we describe specimens sharing derived characters with modern African colobines (Tribe: Colobina), a finding that is congruent with previous molecular estimates of colobine divergence dates. These colobine specimens represent some of the earliest known members of the modern African colobine radiation and, in contrast to previous hypotheses, suggest that early African colobines were mainly arboreal and that semi-terrestrial Late Miocene and Plio-Pleistocene colobine taxa were secondarily derived in their locomotor adaptations.

  6. Late Permian topography at the southern margin of the Northern Permian Basin: Paleogeography inferred from 3D seismic analysis

    NASA Astrophysics Data System (ADS)

    Clausen, Ole R.; Andresen, Katrine J.; Rasmussen, Jens A.

    2013-04-01

    The Top Pre Zechstein (TPZ) surface in the North Sea Basin is often mapped because it reveals the total basement tectonics in the area. In areas where Zechstein salt is present halokinetic processes, differential subsidence, and Mesozoic faulting however significantly alter the TPZ surface. The study area is located at the southern margin of the Northern Permian Basin in the eastern North Sea at the northern flank of the Ringkøbing-Fyn High. This area occurs approximately at the pinch-out line of the late Permian Zechstein salt and constitutes an excellent theater illustrating a range of salt-related problems. The TPZ surface is characterized by an overall NNW-ward dip defining the northern flank of the RFH and is transected by a set of NNW-SSE striking faults, and a E-W striking set of minor faults. Salt structures in the northern part of the study area introduce velocity pull-up (artefacts) at the TPZ surface and furthermore cause intense faulting of the Mesozoic and Cenozoic cover sediments. Pronounced isolated topographic highs similar to hills can be observed in the southern part of the study area where no to very little Zechstein evaporites are present. In the central part where Zechstein evaporites are present, small topographic highs similar to ridges can be observed at the footwall crest of minor faults. The Zechstein evaporites generally onlap towards the south in the study area but in the transitional zone around the hills, onlap from all directions onto the hills is observed. This suggests that the hills reflect paleo-topography developed during sub-aerial exposure before and perhaps during the deposition of the Zechstein sediments. The internal reflections within the hills show that they are composed of southward dipping sediments and very evident erosional truncations can be observed. The hills are aligned parallel to the major E-W striking basement fault, but are not directly associated to faults offsetting the TPZ surface. However, the alignment

  7. Inter-annual species-level variations in an abyssal polychaete assemblage (Sta. M, NE Pacific, 4000 m)

    NASA Astrophysics Data System (ADS)

    Laguionie-Marchais, Claire; Paterson, Gordon L. J.; Bett, Brian J.; Smith, Kenneth L.; Ruhl, Henry A.

    2016-01-01

    Understanding the dynamics of abyssal community structure and function has become increasingly important as deep-sea resource exploitation and climate change pressures are expected to ramp up. This time-series study investigates macrofaunal polychaete dynamics at a station in the North East Pacific (Sta. M; 35° N 123° W, 4000 m, 1991-2011). Infaunal polychaete species were identified and their proxy biomass and proxy energy use rate estimated. The assemblage comprised 167 species, having a composition consistent with other abyssal areas globally. Significant changes in univariate and multivariate parameters (rank abundance distribution, Simpson's diversity index, and species and functional group composition) were detected across 1991-2011. However, no change in biomass or energy use rate was apparent through the time-series. The largest changes in the polychaete assemblage coincided with both an increase in sinking particulate organic carbon flux to the seafloor in 2007, and a 40 km relocation of the sampling location to a site 100 m shallower, preventing a conclusive assessment of which might drive the observed variation. Analyses prior to the change of sampling location showed that the polychaete assemblage composition dynamics were primary driven by food supply variation. Changes in several species were also lagged to changes in POC flux by 4-10 months. The polychaete fauna exhibited a significant positive relationship between total density and total energy use rate, suggesting population-level tracking of a common resource (e.g. POC flux food supply). Neither compensatory nor energetic zero-sum dynamics were detected among the polychaete assemblage, but the results suggest that the latter occur in the macrofaunal community as a whole. The results do indicate (a) potential control of species composition, and the density of individual key species, by food supply, when the time-series prior to the sampling location was analysed separately, and (b) generally

  8. Structure and variability of the abyssal water masses in the Ionian Sea in the period 2003-2010

    NASA Astrophysics Data System (ADS)

    Bensi, Manuel; Rubino, Angelo; Cardin, Vanessa; Hainbucher, Dagmar; Mancero-Mosquera, Isaac

    2013-02-01

    This study presents aspects of the spatial and temporal variability of abyssal water masses in the Ionian Sea, as derived from recent temperature, salinity, dissolved oxygen and velocity observations and from comparisons between these and former observations. Previous studies showed how in the Southern Adriatic Sea the Adriatic Deep Water (AdDW) became fresher (ΔS ≈ -0.08) and colder (ΔT ≈ -0.1°C) after experiencing warming and salinification between 2003 and 2007. Our data, collected from October 2009 to July 2010 from two bottom moorings, one within the Strait of Otranto and the other in the northern Ionian, confirm this tendency: a bottom vein of southward-flowing AdDW, whose temperature and salinity continuously decreased during the observation time, was detected there. Typically, the vein travel time between the two stations ranged between 45 and 50 days. This gave us a temporal estimate for AdDW anomaly propagation towards the Ionian abyss from their Adriatic generation region. The density excess of the observed vein was always enough to enable its existence as a bottom-arrested current. This evidence confirms that, at that time (2009 and 2010), the Adriatic Sea was greatly contributing to the formation of Eastern Mediterranean Deep Water (EMDW), the bottom water of the Eastern Mediterranean. Hence, based on these results and on the evidence that, from 2003 to 2009, abyssal Ionian waters became saltier and warmer under the time-lagged influence of AdDW, possible future changes in the EMDW characteristics, as a response to Adriatic variability, are discussed.

  9. Growth, reproduction and possible recruitment variability in the abyssal brittle star Ophiocten hastatum (Ophiuroidea: Echinodermata) in the NE Atlantic

    NASA Astrophysics Data System (ADS)

    Gage, John D.; Anderson, Roslyn M.; Tyler, Paul A.; Chapman, Rachel; Dolan, Emily

    2004-06-01

    Growth was studied from skeletal growth markers in the cosmopolitan abyssal brittle star Ophiocten hastatm. Samples for analysis were taken at five sites located in the southern (2900 m) and central (2000 m) Rockall Trough, at ca. 3000 and 4000 m in the Porcupine Seabight, and at 4850 m on the Porcupine Abyssal Plain. Growth bands were assumed to reflect an annual cycle in skeletal growth. Band measurements on arm vertebrae, standardised to disc diameter, were used to provide size-at-age data and size-increment data that took into account overgrowth of early bands in older individuals. The Richards growth function marginally provides best fit to pooled size-at-age data, although the asymptote-less Tanaka function and the Gompertz growth function also provided good fit to size-at-age data which showed a rather linear growth pattern with little indication of a growth asymptote. Log e transformed size-increment data were linearised by applying the Ford-Walford method to approximate Gompertz growth so that growth could be compared at the five sites. Grouped linear regression and analysis of covariance showed no significant differences between growth at the sites and a common fitted regression. However, pairwise comparisons suggest growth differences with increasing bathymetric separation. Oocyte size frequencies measured from histological preparations of the gonad of specimens from the Porcupine Abyssal Plain indicate marked reproductive periodicity, with spawn-out in late winter that is likely followed by planktotrophic early development in spring with benthic settlement in summer. Although usually rare in the trawl and epibenthic sled samples, several years of successful recruitment followed by a period when recruitment was low or absent might explain size structure observed in a single unusually large sample from the Rockall Trough. This is consistent with previous observations during the late 1990s of a large population increase on the Porcupine Abyssal Plain

  10. Character, paleoenvironment, rate of accumulation, and evidence for seismic triggering of Holocene turbidites, Canada Abyssal Plain, Arctic Ocean

    USGS Publications Warehouse

    Grantz, A.; Phillips, R.L.; Mullen, M.W.; Starratt, S.W.; Jones, Glenn A.; Naidu, A.S.; Finney, B.P.

    1996-01-01

    Four box cores and one piston core show that Holocene sedimentation on the southern Canada Abyssal Plain for the last 8010??120 yr has consisted of a continuing rain of pelagic organic and ice-rafted elastic sediment with a net accumulation rate during the late Holocene of ???10 mm/1000 yr, and episodically emplaced turbidites 1-5 m thick deposited at intervals of 830 to 3450 yr (average 2000 yr). The average net accumulation rate of the mixed sequence of turbidites and thin pelagite interbeds in the cores is about 1.2 m/1000 yr. Physiography suggests that the turbidites originated on the Mackenzie Delta or its clinoform, and ??13C values of -27 to - 25??? in the turbidites are compatible with a provenance on a delta. Extant displaced neritic and lower slope to basin plain calcareous benthic foraminifers coexist in the turbidite units. Their joint occurence indicates that the turbidites originated on the modern continental shelf and entrained sediment from the slope and rise enroute to their final resting place on the Canada Abyssal Plain. The presence of Middle Pleistocene diatoms in the turbidites suggests, in addition, that the turbidites may have originated in shallow submarine slides beneath the upper slope or outer shelf. Small but consistent differences in organic carbon content and ??13C values between the turbidite units suggest that they did not share an identical provenance, which is at least compatible with an origin in slope failures. The primary provenance of the ice-rafted component of the pelagic beds was the glaciated terrane of northwestern Canada; and the provenance of the turbidite units was Pleistocene and Holocene sedimentary deposits on the outer continental shelf and upper slope of the Mackenzie Delta. Largely local derivation of the sediment of the Canada Abyssal Plain indicates that sediment accumulation rates in the Arctic Ocean are valid only for regions with similar depositional sources and processes, and that these rates cannot be

  11. Electronic Cigarette Topography in the Natural Environment.

    PubMed

    Robinson, R J; Hensel, E C; Morabito, P N; Roundtree, K A

    2015-01-01

    This paper presents the results of a clinical, observational, descriptive study to quantify the use patterns of electronic cigarette users in their natural environment. Previously published work regarding puff topography has been widely indirect in nature, and qualitative rather than quantitative, with the exception of three studies conducted in a laboratory environment for limited amounts of time. The current study quantifies the variation in puffing behaviors among users as well as the variation for a given user throughout the course of a day. Puff topography characteristics computed for each puffing session by each subject include the number of subject puffs per puffing session, the mean puff duration per session, the mean puff flow rate per session, the mean puff volume per session, and the cumulative puff volume per session. The same puff topography characteristics are computed across all puffing sessions by each single subject and across all subjects in the study cohort. Results indicate significant inter-subject variability with regard to puffing topography, suggesting that a range of representative puffing topography patterns should be used to drive machine-puffed electronic cigarette aerosol evaluation systems.

  12. Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.; Downs, R. T.; Morrison, S. M.; Fendrich, K. V.; Yen, A. S.; Grotzinger, J.; Crisp, J. A.; Bristow, T. F.; Sarrazin, P. C.; Farmer, J. D.; Des Marais, D. J.; Stolper, E. M.; Morookian, J. M.; Wilson, M. A.; Spanovich, N.; Anderson, R. C.

    2015-01-01

    The Mars Science Laboratory (MSL) rover Curiosity recently completed its fourth drill sampling of sediments on Mars. The Confidence Hills (CH) sample was drilled from a rock located in the Pahrump Hills region at the base of Mt. Sharp in Gale Crater. The CheMin X-ray diffractometer completed five nights of analysis on the sample, more than previously executed for a drill sample, and the data have been analyzed using Rietveld refinement and full-pattern fitting to determine quantitative mineralogy. Confidence Hills mineralogy has several important characteristics: 1) abundant hematite and lesser magnetite; 2) a 10 angstrom phyllosilicate; 3) multiple feldspars including plagioclase and alkali feldspar; 4) mafic silicates including forsterite, orthopyroxene, and two types of clinopyroxene (Ca-rich and Ca-poor), consistent with a basaltic source; and 5) minor contributions from sulfur-bearing species including jarosite.

  13. Martian wrinkle ridge topography: Evidence for subsurface faults from MOLA

    NASA Astrophysics Data System (ADS)

    Golombek, M. P.; Anderson, F. S.; Zuber, M. T.

    2001-10-01

    Mars Orbiter Laser Altimeter (MOLA) topography shows distinct elevation offsets across wrinkle ridges that can be explained simply by subsurface thrust faults. MOLA has provided the first reliable topographic data of wrinkle ridges to test models for their origin; although previous work has shown that wrinkle ridges result from compressional folding and faulting of near-surface units, the role of thrust faulting and its depth penetration have been argued. Topographic profiles across wrinkle ridges in Solis Planum, Lunae Planum, Tempe Terra, Xanthe Terra, Arcadia, Terra Sirenum, Thaumasia Planum, Arabia Terra, Syrtis Major, and Hesperia Planum show characteristic features such as superposed hills, crenulations, and elevation offsets between the plains on either side of the ridge. The characteristic elevation offsets between plains surfaces on either side of the ridges shown by MOLA are easily explained by subsurface thrust faults that underlie the ridges and produce the offset. In Solis Dorsa, wrinkle ridges are 10-20 km wide (well resolved by the 300 m spaced MOLA elevations), have a total relief of 80-250 m, and have elevation offsets of 50-180 m (well above the uncertainty in the MOLA elevations). MOLA topography shows that the plains decrease in elevation toward the southeast and are deformed into folds or arches not visible in images that are parallel to and in between the ridges. The elevations of the plains on either side of the ridges in Solis and Lunae Plana are characteristically down to the southeast and east, respectively, suggesting that faults beneath the wrinkle ridges offset the plains. This offset indicates underlying thrust faults that dip to the northwest and west, respectively, and systematically lower the southeast side of the plains. The observation that the elevation offsets across the ridges are maintained to the next ridge implies that the thrust fault penetrates to depths of tens of kilometers and thus well into the mechanical lithosphere

  14. Development of benthic biological monitoring criteria for disposal of low-level radioactive waste in the abyssal deep sea. Final report

    SciTech Connect

    Smith, C.R.; Present, T.M.C.; Jumars, P.A.

    1988-09-01

    In order to develop recommendations for monitoring low-level radioactive waste dumpsites in the abyss, the report attempts a synthesis of information from three overlapping topical areas. First, U.S. Regulations governing the dumping and monitoring of wastes in the ocean are interpreted in a deep-sea context. Second, significant attention is given to experiences obtained from past dumping of low-level radioactive wastes in marine environments, both shallow-water and deep-sea. Third, the report attempts to apply the monitoring Requirements and conceptual approaches selected to the abyssal seafloor, based on present understandings of the deep-sea ecosystem.

  15. Moiré topography in odontology

    NASA Astrophysics Data System (ADS)

    Moreno Yeras, A.

    2003-07-01

    For several decades, measurement of optical techniques has been used in different branches of science and technology. One of these techniques is the so-called moiré topography (MT) that enables the accurate measurement of different parts of the human body topography. This investigation presents the measurement of topographies of teeth and gums using an automated system of shadow moiré and the phase shift method in an original way. The fringe patterns used to compute the shape and the shape matrix itself are presented in the article. The phase shift method ensures precisions up to the order of microns. Advantages and disadvantages of using the MT are included. Besides, some positive and negative aspects concerned with the implementation of this technique in odontology are shown in the article.

  16. Topography Restoration of Historic City Research

    NASA Astrophysics Data System (ADS)

    ho, L. Sung; soo, H. Dong

    2015-08-01

    The preservation of historic cities requires a balance between conservation and development because the urban structures of the old and new city are interwoven on same space. Existing restoration plans rely on old records and excavation reports and are based on the present topography. However, historic cities have undergone significant natural and anthropogenic topographic changes such as alluvial sediment accumulation and uneven terrain construction. Therefore, considering only the present topography is misleading. Thus, to understand a historic city's structure more appropriately, it is necessary to comprehend the ancient geographic environment. This study provides an analysis and GIS visualization of the ancient topography of a historic city, Sabi capital city of the Baekje Dynasty, which collapsed 1,500 years ago.

  17. Three-dimensional potential flow over hills and oval mounds

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1976-01-01

    An analysis was made of the potential flow behavior for an initially uniform flow passing over a single axisymmetric hill, an oval mound, and a combination of two hills. Small perturbation theory was used, and the resulting Laplace equation for the perturbation velocity potential was solved by using either a product solution or a Green's function. The three dimensional solution is of interest in calculating the pressure distribution around obstacles, the flow of pollutants carried by the wind, and the augmentation of wind velocity for windmill siting. The augmentation in velocity at the top of a hill was found to be proportional to the hill height relative to a characteristic width dimension of the hill. An axisymmetric hill produced about 20 percent less velocity increase than a two dimensional ridge having the same cross-sectional profile.

  18. Columbia Hills, Mars: aeolian features seen from the ground and orbit

    USGS Publications Warehouse

    Greeley, Ronald; Whelley, Patrick L.; Neakrase, Lynn D.V.; Arvidson, Raymond E.; Bridges, Nathan T.; Cabrol, Nathalie A.; Christensen, Philip R.; Di, Kaichang; Foley, Daniel J.; Golombek, Matthew P.; Herkenhoff, Kenneth; Knudson, Amy; Kuzmin, Ruslan O.; Li, Ron; Michaels, Timothy; Squyres, Steven W.; Sullivan, Robert; Thompson, Shane D.

    2008-01-01

    Abundant wind-related features occur along Spirit's traverse into the Columbia Hills over the basaltic plains of Gusev Crater. Most of the windblown sands are probably derived from weathering of rocks within the crater, and possibly from deposits associated with Ma'adim Vallis. Windblown particles act as agents of abrasion, forming ventifacts, and are organized in places into various bed forms. Wind-related features seen from orbit, results from atmospheric models, and considerations of topography suggest that the general wind patterns and transport pathways involve: (1) winter nighttime winds that carry sediments from the mouth of Ma'adim Vallis into the landing site area of Spirit, where they are mixed with locally derived sediments, and (2) winter daytime winds that transport the sediments from the landing site southeast toward Husband Hill; similar patterns occur in the summer but with weaker winds. Reversals of daytime flow out of Gusev Crater and nighttime wind flow into the crater can account for the symmetry of the bed forms and bimodal orientations of some ventifacts.

  19. Columbia Hills, Mars: Aeolian features seen from the ground and orbit

    USGS Publications Warehouse

    Greeley, R.; Whelley, P.L.; Neakrase, L.D.V.; Arvidson, R. E.; Bridges, N.T.; Cabrol, N.A.; Christensen, P.R.; Di, K.; Foley, D.J.; Golombek, M.P.; Herkenhoff, K.; Knudson, A.; Kuzmin, R.O.; Li, R.; Michaels, T.; Squyres, S. W.; Sullivan, R.; Thompson, S.D.

    2008-01-01

    Abundant wind-related features occur along Spirit's traverse into the Columbia Hills over the basaltic plains of Gusev Crater. Most of the windblown sands are probably derived from weathering of rocks within the crater, and possibly from deposits associated with Ma'adim Vallis. Windblown particles act as agents of abrasion, forming ventifacts, and are organized in places, into various bed forms. Wind-related features seen from orbit, results from atmospheric models, and considerations of topography suggest that the general wind patterns and transport pathways involve: (1) winter nighttime winds that carry sediments from the mouth of Ma'adim. Vallis into the landing site area of Spirit, where they are mixed with locally derived sediments, and (2) winter daytime winds that transport the sediments from the landing site southeast toward Husband Hill; similar patterns occur in the summer but with weaker winds. Reversals of daytime flow out of Gusev Crater and nighttime wind flow into the crater can account for the symmetry of the bed forms and bimodal orientations of some ventifacts. Copyright 2008 by the American Geophysical Union.

  20. Effects of patterned topography on biofilm formation

    NASA Astrophysics Data System (ADS)

    Vasudevan, Ravikumar

    2011-12-01

    Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference

  1. Late-glacial and postglacial history of the hill'', Norwich University campus, Northfield, Vermont

    SciTech Connect

    Larsen, F.D. . Dept. of Geology)

    1993-03-01

    The central part of the Norwich University campus at Northfield is built on a kame about 60 ft high on the side of the Dog River valley. Significant excavations made between 1979 and 1991 in the flank of the hill provide details about its glacial origin. Collapsed ice-contact lake deposits on the northwestern flank of the kame are overlain by undisturbed lake sediments formed by turbidity currents that moved southward in glacial Lake Roxbury. Lake Roxbury formed when the retreating ice margin blocked the north-draining Dog River valley and caused melt water to drain south over a 1,010-foot threshold at Roxbury. The lowest deposits exposed on the southeast flank of the kame are highly deformed and include a chaotic slide breccia overlain by progressively less deformed lake-bottom sediments. Northward retreat of the ice margin permitted Lake Roxbury to drop 80 ft to the level of glacial Lake Winooski, which still left 80 ft of lake water over the top of the hill''. Following the lowering of Lake Winooski, stream terraces were cut on the west flank of the hill''. The terraces are underlain by imbricated pebble gravel deposited by the north-flowing Dog River that probably was graded to a lower glacial lake in the Winooski River valley to the north. Downcutting by the Dog River and subsequent lateral migration of its meanders produced the topography the authors see today. The late-glacial and postglacial history can be summarized as follows: (1) deposition of lake sediments in contact with buried ice, (2) collapse and continued deposition of lake sediments during melting of buried ice, (3) deposition of undeformed lake sediments, (4) drainage of glacial lakes, and (5) development of stream terraces and the modern flood plain.

  2. Effects of topography and atmospheric structure on volcano infrasound

    NASA Astrophysics Data System (ADS)

    Marcillo, O. E.; Johnson, J. B.

    2009-12-01

    Proper interpretation of infrasonic waves produced by volcanic explosions requires understanding of weather and topographic effects. We have studied infrasound produced by two different volcanoes (Kilauea and Tungurahua) to determine the influence of topographic and atmospheric conditions on the infrasonic records corresponding to several weeks of eruptive activity. This analysis is necessary to understand and correct for phase and amplitude responses in order to properly perform waveform modeling. For instance, these corrections are necessary to obtain a better estimate of volume flux from the volcanic vent. The first case study is a dataset acquired during June of 2008 at Kilauea volcano in Hawaii, focused on the active Halemaumau Vent. Several days of infrasonic tremor were recorded by a 3-station infrasound network. These records show a strong influence of wind and topography in one of the three stations of the network. This station was located 2370 m from the vent, at a comparable distance to the other stations, but line of sight to the vent was obstructed by a 50-meter high crater edge, which introduced diffraction effects. Periods when wind blew in the vent-station direction are correlated with increase in infrasonic energy in the 0.5 - 1 Hz bandwidth. The second case focuses on a campaign conducted in June 2009 at Tungurahua Volcano, Ecuador. This study implemented two infrasonic arrays located on the flanks of the volcano 6000m north of the vent and on the flanks of an adjacent hill, 11,500m northeast. Compared to the proximal array a distinctive attenuation is evident at certain frequencies (0.5-1.5 Hz) at the distal array. This degree of attenuation is time-variant and is mostly likely related to changing atmospheric structure. An alternative explanation for the apparent spectral differences between near and far stations (and their evolution over time) is a complex (and changing) source geometry due to non-compact sources.

  3. PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL STA. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PLANS AND SECTIONS. WEIR SPILLWAY. TEXAS HILL CANAL - STA. 132+82.15. TEXAS HILL CANAL AND DISTRIBUTION SYSTEM. United States Department of Interior, Bureau of Reclamation; Gila Project, Arizona, Wellton-Mohawk Division. Drawing No. 50-D-3200, dated February 7, 1955, Denver, Colorado - Wellton-Mohawk Irrigation System, Relift Station, Texas Hill Canal 2.5, Northern Terminus of Avenue 51 East, approximately .5 mile south of Union Pacific Railroad, Wellton, Yuma County, AZ

  4. MODOO: A modular and mobile deep ocean observatory and its application to the Porcupine Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Karstensen, Johannes; Greinert, Jens; Lampitt, Richard; Grant, Fiona; Priede, Monty; Pagnani, Maureen

    2010-05-01

    Many of todays scientific questions require to observe the various processes in the ocean in parallel and from the air/sea interface to the sea-floor interior. Moreover, socioeconomic as well as scientific requirements may even demand to excess data in real time - for example for marine safety or to adapt the instrumentation to episodic environmental conditions. Here we describe a muti-disciplinary deep ocean observatory that has been designed within the European FP6 ESONET Network of Excellence to meet todays scientific and socioeconomic requirements for ocean observatories. MODOO, the Modular and mObile Deep Ocean Observatory, combines underwater acoustic modules with a surface telecommunication module to access and combine a variety of instrumentation from the sea surface to below the sea floor. MODOO's first application will be at the Porcupine Abyssal Plain: here a BOBO deep sea lander will be connected to a full water depth (4800m) deep sea mooring with meteorological package that belongs to the European FP7 EuroSITES network. The main scientific mission of this MODOO configuration is to investigate physical and biogeochemical processes that control the propagation and impact of near surface events (e.g. chlorophyll bloom) to the deep sea. For this mission we make use of physical (T/S recorder, current meters/profilers) and biogeochemical sensors (nitrate, fluorescence, oxygen, turbidity, particle flux/composition) combined with deep sea photography. Scientific guest missions will be seismic records and passive acoustics to detect deep sea marine life. The first MODOO installation is planned to be installed by the end of May 2010 for a three month test. The MODOO instrumentation is not simply mounted together but part of the MODOO concept is to add a common time stamp to the individual instrumentations data set. All instrumentation that is directly connected to the acoustic modems - for the PAP application this will be T/S/turbidity, ADCP, seismometer, oxygen

  5. Southern Ocean abyssal oxygenation linked to the air-sea partitioning of carbon throughout the last glacial cycle

    NASA Astrophysics Data System (ADS)

    Jaccard, S.; Galbraith, E. D.; Martinez-Garcia, A.; Anderson, R. F.

    2015-12-01

    Although no single mechanism can account for the full amplitude of past atmospheric CO2 variability over glacial interglacial cycles, a build-up of biologically-stored carbon in the deep ocean has emerged as a central mechanism for low CO2 during the Last Glacial Maximum (LGM). However, the mechanisms for which this deeply sequestered carbon was released, and the relative importance it played in the history of atmospheric CO2 prior to the LGM, remain subjects of debate. Here, we present new redox-sensitive trace metal records from the Antarctic Zone of the Southern Ocean that provide an unprecedented reconstruction of transient changes in deep ocean oxygenation and, by inference, respired carbon storage throughout the last glacial cycle. Our results show that respired carbon was removed from the abyssal Southern Ocean during the northern hemisphere cold phases of the deglaciation, when atmospheric CO2 rose rapidly, due to a combination of dwindling iron fertilization by dust and enhanced deep ocean ventilation. Furthermore, our new records show that the correlation between atmospheric CO2 and abyssal Southern Ocean oxygenation was maintained throughout most of the prior 80 kyrs, consistent with a unifying role of the Southern Ocean through a coupled control on deep ocean circulation and iron fertilization.

  6. Acoustic structure and echo character of surficial sediments of the northern Hatteras Abyssal Plain. [LLW Ocean Disposal Program

    SciTech Connect

    McCreery, C.J.; Laine, E.P.

    1986-05-01

    A study has been made of the high frequency acoustic response of abyssal plain depositional facies. Piston cores have been obtained at six stations and deep hydrophone recordings at three stations on the northern Hatteras Abyssal Plain. 3.5 kHz seismic profiles indicate acoustically transparent lobes of surficial sediment which thicken towards the Hatteral Transverse Canyon and Sohm Gap/Wilmington Fan. Physical property data from piston cores indicate a higher percentage of coarse sediment in the areas of transparent acoustic response. Many of the characteristics normally used in mapping of conventional 3.5 kHz profiler acoustic response varied only slightly in the study area. Regions of diffuse 3.5 kHz surface echoes, similar to prolonged echoes attributed to high percent sand beds, have been identified in the study area. High trace to trace variation in deep hydrophone/pinger recordings in these areas suggests that the diffuse echo returns are due to unresolved microtopography and are not necessarily associated with a sandy seafloor.

  7. Diversity and large-scale biogeography of Paramesochridae (Copepoda, Harpacticoida) in South Atlantic Abyssal Plains and the deep Southern Ocean

    NASA Astrophysics Data System (ADS)

    Gheerardyn, Hendrik; Veit-Köhler, Gritta

    2009-10-01

    Multicorer samples for meiofaunal study were obtained within the framework of the international project CeDAMar, at 21 stations occupied during the DIVA and ANDEEP campaigns (2000, 2002 and 2005) to the southern Atlantic Ocean (Guinea, Angola and Cape Basins) and the Southern Ocean (Weddell and Scotia Seas), respectively. A total of 311 adult Paramesochridae Lang, 1944 (Copepoda, Harpacticoida) was extracted from 437 cores obtained during 83 deployments of the corer at depths between 1107 and 5655 m. All specimens were determined to species based on morphological characteristics. They belonged to 19 species and four genera ( Kliopsyllus Kunz, 1962, Leptopsyllus T. Scott, 1894, Paramesochra T. Scott, 1892 and Scottopsyllus Kunz, 1962). Eleven species were restricted to single regions, whereas the others showed a much wider distribution. For example, Kliopsyllus andeep Veit-Köhler, 2004 and Kliopsyllus diva Veit-Köhler, 2005, were both collected from Guinea, Angola and Weddell Abyssal Plains, and Kliopsyllus schminkei Veit-Köhler & Drewes, 2009 occurred in the three West-African basins. This study provides a first insight into the large-scale biogeography of deep-sea harpacticoids, represented by the Paramesochridae, and indicates that distribution ranges, at least in this family, may extend across South Atlantic and Southern Ocean Abyssal Plains.

  8. Novel benthic foraminifera are abundant and diverse in an area of the abyssal equatorial Pacific licensed for polymetallic nodule exploration

    PubMed Central

    Goineau, Aurélie; Gooday, Andrew J.

    2017-01-01

    The benthic biota of the Clarion–Clipperton Zone (CCZ, abyssal eastern equatorial Pacific) is the focus of a major research effort linked to possible future mining of polymetallic nodules. Within the framework of ABYSSLINE, a biological baseline study conducted on behalf of Seabed Resources Development Ltd. in the UK-1 exploration contract area (eastern CCZ, ~4,080 m water depth), we analysed foraminifera (testate protists), including ‘live’ (Rose Bengal stained) and dead tests, in 5 cores (0–1 cm layer, >150-μm fraction) recovered during separate megacorer deployments inside a 30 by 30 km seafloor area. In both categories (live and dead) we distinguished between complete and fragmented specimens. The outstanding feature of these assemblages is the overwhelming predominance of monothalamids, a group often ignored in foraminiferal studies. These single-chambered foraminifera, which include agglutinated tubes, spheres and komokiaceans, represented 79% of 3,607 complete tests, 98% of 1,798 fragments and 76% of the 416 morphospecies (live and dead combined) in our samples. Only 3.1% of monothalamid species and 9.8% of all species in the UK-1 assemblages are scientifically described and many are rare (29% singletons). Our results emphasise how little is known about foraminifera in abyssal areas that may experience major impacts from future mining activities. PMID:28382941

  9. Intensity of pelagic-benthic coupling in different regions along the Antarctic Polar Front - Clues from abyssal megafauna

    NASA Astrophysics Data System (ADS)

    Würzberg, Laura; Zinkann, Ann-Christine; Brandt, Angelika; Janussen, Dorte; Bohn, Jens M.; Schwabe, Enrico

    2014-10-01

    The zone surrounding the Antarctic Polar Front is a region characterized by elevated seasonal primary production. Studies on the implications for the fauna inhabiting the underlying deep-sea floor, however, are rare. The present study focuses on the abundance of megafaunal organisms caught by means of an Agassiz Trawl during the SYSTem COupling in the Southern Ocean II (SYSTCO II) expedition (RV Polarstern cruise ANT XXVIII/3). Biomass estimates in terms of volume as well as species richness of echinoderms were additionally taken into account. Abyssal stations (ca. 4000 m depth) located in three different regions along the Antarctic Polar Front characterized by different primary production regimes and oceanographic features were sampled. One shallower station (337 m depth) was used as reference station. Highest megafaunal abundances were found at the shallow station (147 individuals per 1000 m2). Megafaunal abundances were low to moderate at the abyssal stations (7.2-23.5 individuals per 1000 m2) with the exception of the region northwest of South Georgia, where distinctly higher abundances were found (up to 119.7 individuals per 1000 m2). The same pattern was observed for biomass estimates. At the other regions, magnitude of megafaunal abundances and echinoderm biomasses were found not to be linked to the surface levels of primary production. This indicates that strong pelagic-benthic coupling likely occurs only downstream of South Georgia. Echinoderm species richness does not appear to be directly related to the environmental conditions as it does not differ statistically between the considered areas.

  10. Temporal and depth-related differences in prokaryotic communities in abyssal sediments associated with particulate organic carbon flux

    NASA Astrophysics Data System (ADS)

    Moeseneder, M. M.; Smith, K. L.; Ruhl, H. A.; Jones, D. O. B.; Witte, U.; Prosser, J. I.

    2012-12-01

    Particulate organic carbon (POC) flux is hypothesized to be the most important parameter influencing activity and biomass of prokaryotic and faunal communities in the abyssal seafloor, but there is little evidence of POC-related changes in community composition of prokaryotes. This hypothesis was tested by 16S rRNA-gene-based analysis of prokaryotic DNA and RNA extracted from abyssal seafloor sediments during periods of low and high POC flux. Fingerprint analysis of prokaryotic communities indicated that approximately 50% of the phylotypes were identical at each sediment horizon, regardless of the temporal variations in POC flux. However, phylotypes were also detected that represented a relatively dynamic component of these communities and were probably strongly influenced by the prevalent POC flux regime. These patterns were also detected in deeper sediment horizons. DNA- and RNA-based community profiles differed, although both approaches had similar community dynamics. Crenarchaeota showed the strongest shift in community composition in response to availability of labile POC, indicating that POC flux may have a more pronounced impact on crenarchaeal communities than on bacterial communities. The high number of phylotypes common to each sample time suggests that both standing stock and active prokaryotic communities are stable.

  11. Morphological and ontogenetic stratification of abyssal and hadal Eurythenes gryllus sensu lato (Amphipoda: Lysianassoidea) from the Peru-Chile Trench

    NASA Astrophysics Data System (ADS)

    Eustace, Ryan M.; Ritchie, Heather; Kilgallen, Niamh M.; Piertney, Stuart B.; Jamieson, Alan J.

    2016-03-01

    The globally ubiquitous lysianassoid amphipod, Eurythenes gryllus, has been shown to consist of multiple genetically distinct cryptic taxa, with depth considered a major driver of speciation and morphological divergence. Here we examine morphological variation of E. gryllus sensu lato through a continuous depth distribution that spans from abyssal (3000-6000 m) into hadal depths (>6000 m) in the Peru-Chile Trench (SE Pacific Ocean). Three distinct morphospecies were identified: one was confirmed as being E. magellanicus (4602-5329 m) based on DNA sequence and morphological similarity. The other two morphologically distinct species were named based upon depth of occurrence; Abyssal (4602-6173 m) and Hadal (6173-8074 m). The three Eurythenes morphospecies showed vertical ontogenetic stratification across their bathymetric range, where juveniles were found shallower in their depth range and mature females deeper. Potential ecological and evolutionary drivers that explain the observed patterns of intra and inter-specific structure, such as hydrostatic pressure and topographical isolation, are discussed.

  12. Correlates of simulated hill climb cycling performance.

    PubMed

    Davison, R C; Swan, D; Coleman, D; Bird, S

    2000-02-01

    The aim of this study was to assess the relationship between several commonly used aerobic and anaerobic cycle ergometer tests and performance during a treadmill cycling hill climb. Eight competitive cyclists (age 27+/-7 years; body mass 73.2+/-5.2 kg; height 177+/-6 cm; mean +/- s) completed six tests in random order: a lactate minimum test; a Wingate anaerobic power test; and two 6-km climbs at 6% and two 1-km climbs at 12% gradient performed on a motorized treadmill. The mean times and power outputs for the 6-km and 1-km climbs were 16:30+/-1:08 min: s and 330+/-17.8 W, and 4:19+/-0:27 min: s and 411+/-24.4 W, respectively. The best individual predictor of 6-km and 1-km performance times was the time for the corresponding climb at the other distance (r = 0.97). The next strongest predictor of both hill climb performances was the average power produced during the Wingate test divided by body mass. Stepwise regression analysis showed that the two variables contributing most to the prediction equation for both climbs were the Wingate average power per unit of body mass and maximal aerobic power divided by total mass (rider + bike), which together accounted for 92 and 96% of the variability in the 6-km and 1-km climbs. In conclusion, among competitive cyclists, the Wingate average power per unit of body mass was the best single predictor of simulated cycling hill climb performance at the distance and gradient used.

  13. Corneal topography and the hirschberg test.

    PubMed

    Brodie, S E

    1992-07-01

    A simple trigonometric analysis of the Hirschberg test with the assumption that the corneal surface is spherical predicts a sinusoidal dependence of the corneal reflex displacement on the angle of ocular rotation. A comparison with corneal reflex photographs demonstrates that at angles larger than 50 prism diopters (26 deg) the reflex displacements are larger than predicted by the spherical model. This discrepancy may be accounted for by incorporating a more general description of the corneal topography into the geometric analysis. The linear Hirschberg relation that is seen in typical data is accounted for by a relative flattening of the peripheral cornea by ~ 20% of the apical curvature. This geometric analysis of the functional dependence of the Hirschberg relation on the corneal topography can be expressed as an integral equation. Differentiation yields a second-order differential equation for the corneal topography in terms of the Hirschberg data. If the Hirschberg relation is assumed to be linear, a quadratic dependence is found for the corneal curvature. A similar differential approach can be formulated for the Placido disk. In this sense the corneal topography problem given in terms of Placido disk data is shown to be wellformulated. The relative simplicity of the Hirschberg geometry is seen to stem from the alignment of the light source with the eye of the observer.

  14. Spike voltage topography in temporal lobe epilepsy.

    PubMed

    Asadi-Pooya, Ali A; Asadollahi, Marjan; Shimamoto, Shoichi; Lorenzo, Matthew; Sperling, Michael R

    2016-07-15

    We investigated the voltage topography of interictal spikes in patients with temporal lobe epilepsy (TLE) to see whether topography was related to etiology for TLE. Adults with TLE, who had epilepsy surgery for drug-resistant seizures from 2011 until 2014 at Jefferson Comprehensive Epilepsy Center were selected. Two groups of patients were studied: patients with mesial temporal sclerosis (MTS) on MRI and those with other MRI findings. The voltage topography maps of the interictal spikes at the peak were created using BESA software. We classified the interictal spikes as polar, basal, lateral, or others. Thirty-four patients were studied, from which the characteristics of 340 spikes were investigated. The most common type of spike orientation was others (186 spikes; 54.7%), followed by lateral (146; 42.9%), polar (5; 1.5%), and basal (3; 0.9%). Characteristics of the voltage topography maps of the spikes between the two groups of patients were somewhat different. Five spikes in patients with MTS had polar orientation, but none of the spikes in patients with other MRI findings had polar orientation (odds ratio=6.98, 95% confidence interval=0.38 to 127.38; p=0.07). Scalp topographic mapping of interictal spikes has the potential to offer different information than visual inspection alone. The present results do not allow an immediate clinical application of our findings; however, detecting a polar spike in a patient with TLE may increase the possibility of mesial temporal sclerosis as the underlying etiology.

  15. Internal Tide Generation by Steep Topography

    DTIC Science & Technology

    2016-06-07

    ridges and the continental slope (Kunze and Llewellyn Smith 2004). A prominent interaction which creates large currents and temperature fluctuations that...S.G. Llewellyn Smith , 2004: The role of smallscale topography in turbulent mixing of the global ocean. Oceanography, 17(1), 51-60. E. Kunze, E

  16. Quasigeostrohpic flow over isolated elongated topography

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.

    1982-09-01

    The finite amplitude perturbations to a uniform stream caused by the presence of elongated topography is considered using two simple models. The first considers elliptic seamounts with scales L and l ( L ⪖ l) and gives a smooth interpolation between axisymmetric models L ; l at one extreme and infinite ridges of fixed cross-section L å l at the other. Basing the Rossby number of the flow on the shorter scale gives blocking heights of order unity for all elongations, whereas it is the longer scale that determines the horizontal extent of the region affected by the topography. The second model considers greatly elongated topography (L å l) of variable cross section showing that the topographic velocity parallel to the ridges is given by ƒ A∗/2d , where A∗ is the local cross-section area, d the depth, and f the Coriolis parameter. The component perpendicular to the ridge is obtained directly from the parallel component via a linear transform. Topographically generated velocities may thus be obtained rapidly from contours of bottom topography and an example is given using the seamount 'Brontosaurus Bump' from GOULD, HENDRY AND HUPPERT (Deep-Sea Research, 28, 409-440, 1981).

  17. Lateglacial geomorphology in the Tweedsmuir Hills, Scotland - Implications for retreat patterns, glacier reconstruction and chronology.

    NASA Astrophysics Data System (ADS)

    Pearce, D.; Rea, B.; McDougall, D.

    2012-04-01

    The Tweedsmuir Hills, Southern Uplands, Scotland, contain excellent assemblages of glacial landforms, including hummocky moraine, classically associated with a Lateglacial deglaciation (c. 14.7 - 11.7 cal. ka BP) in the UK. Although initially documented in 1855, a detailed systematic geomorphological investigation has never been undertaken in the region, meaning reconstructions are patchy, outdated and lacking chronological control. This has resulted in conflicting styles of glaciation being inferred, with both plateau icefield and valley glaciers reconstructed in the Tweedsmuir Hills. Importantly, comprehensive numerical modelling experiments for the period, c. 38 -10.4 ka BP, predict a significant body of ice for the Tweedsmuir Hills at the onset and throughout the Younger Dryas (c. 12.9 - 11.7 cal. ka. BP). Field data, which at present, are missing means that the numerical modelling remains untested. Given the emerging evidence that ice-masses survived, during or throughout the Lateglacial in a number of regions in Scotland, the glacial geomorphology and reconstructions for this area will provide a key input of palaeo-glacier data for subsequent investigation of wider patterns of Lateglacial ice-mass distribution and climate gradients across the UK and NW Europe. Geomorphological mapping followed a morphostratigraphic approach using a combination of aerial photos, NEXTMapTM and mapping in the field using a ruggedized tablet PC, with built in GPS and ArcGIS 9.3. The glacial landforms indicate two separate landsystems. The first is characterised by elongate subglacial bedforms overriding the topography, trending SW to NE, suggested to be attributable to the Devensian glaciation. The second landsystem is characterised by closely spaced sharp crested moraines, oblique to the valley axis and confined by the topography, meltwater channels and single terrace systems, which are likely to have formed in a subsequent period of renewed glaciation i.e. Lateglacial. The

  18. Exploring the Influence of Topography on Belowground C Processes Using a Coupled Hydrologic-Biogeochemical Model

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Davis, K. J.; Eissenstat, D. M.; Kaye, J. P.; Duffy, C.; Yu, X.; He, Y.

    2014-12-01

    Belowground carbon processes are affected by soil moisture and soil temperature, but current biogeochemical models are 1-D and cannot resolve topographically driven hill-slope soil moisture patterns, and cannot simulate the nonlinear effects of soil moisture on carbon processes. Coupling spatially-distributed physically-based hydrologic models with biogeochemical models may yield significant improvements in the representation of topographic influence on belowground C processes. We will couple the Flux-PIHM model to the Biome-BGC (BBGC) model. Flux-PIHM is a coupled physically-based land surface hydrologic model, which incorporates a land-surface scheme into the Penn State Integrated Hydrologic Model (PIHM). The land surface scheme is adapted from the Noah land surface model. Because PIHM is capable of simulating lateral water flow and deep groundwater, Flux-PIHM is able to represent the link between groundwater and the surface energy balance, as well as the land surface heterogeneities caused by topography. The coupled Flux-PIHM-BBGC model will be tested at the Susquehanna/Shale Hills critical zone observatory (SSHCZO). The abundant observations, including eddy covariance fluxes, soil moisture, groundwater level, sap flux, stream discharge, litterfall, leaf area index, above ground carbon stock, and soil carbon efflux, make SSHCZO an ideal test bed for the coupled model. In the coupled model, each Flux-PIHM model grid will couple a BBGC cell. Flux-PIHM will provide BBGC with soil moisture and soil temperature information, while BBGC provides Flux-PIHM with leaf area index. Preliminary results show that when Biome- BGC is driven by PIHM simulated soil moisture pattern, the simulated soil carbon is clearly impacted by topography.

  19. Parameterizing surface wind speed over complex topography

    NASA Astrophysics Data System (ADS)

    Helbig, N.; Mott, R.; Herwijnen, A.; Winstral, A.; Jonas, T.

    2017-01-01

    Subgrid parameterizations are used in coarse-scale meteorological and land surface models to account for the impact of unresolved topography on wind speed. While various parameterizations have been suggested, these were generally validated on a limited number of measurements in specific geographical areas. We used high-resolution wind fields to investigate which terrain parameters most affect near-surface wind speed over complex topography under neutral conditions. Wind fields were simulated using the Advanced Regional Prediction System (ARPS) on Gaussian random fields as model topographies to cover a wide range of terrain characteristics. We computed coarse-scale wind speed, i.e., a spatial average over the large grid cell accounting for influence of unresolved topography, using a previously suggested subgrid parameterization for the sky view factor. We only require correlation length of subgrid topographic features and mean square slope in the coarse grid cell. Computed coarse-scale wind speed compared well with domain-averaged ARPS wind speed. To further statistically downscale coarse-scale wind speed, we use local, fine-scale topographic parameters, namely, the Laplacian of terrain elevations and mean square slope. Both parameters showed large correlations with fine-scale ARPS wind speed. Comparing downscaled numerical weather prediction wind speed with measurements from a large number of stations throughout Switzerland resulted in overall improved correlations and distribution statistics. Since we used a large number of model topographies to derive the subgrid parameterization and the downscaling framework, both are not scale dependent nor bound to a specific geographic region. Both can readily be implemented since they are based on easy to derive terrain parameters.

  20. Sea bottom topography imaging with SAR

    NASA Technical Reports Server (NTRS)

    Vanderkooij, M. W. A.; Wensink, G. J.; Vogelzang, J.

    1992-01-01

    It is well known that under favorable meteorological and hydrodynamical conditions the bottom topography of shallow seas can be mapped with airborne or spaceborne imaging radar. This phenomenon was observed for the first time in 1969 by de Loor and co-workers in Q-band Side Looking Airborne Radar (SLAR) imagery of sandwaves in the North Sea. It is now generally accepted that the imaging mechanism consists of three steps: (1) interaction between (tidal) current and bottom topography causes spatial modulations in the surface current velocity; (2) modulations in the surface current velocity give rise to variations in the spectrum of wind-generated waves, as described by the action balance equation; and (3) variations in the wave spectrum show up as intensity modulations in radar imagery. In order to predict radar backscatter modulations caused by sandwaves, an imaging model, covering the three steps, was developed by the Dutch Sea Bottom Topography Group. This model and some model results will be shown. On 16 Aug. 1989 an experiment was performed with the polarimetric P-, L-, and C-band synthetic aperture radar (SAR) of NASA/JPL. One scene was recorded in SAR mode. On 12 Jul. 1991 another three scenes were recorded, of which one was in the ATI-mode (Along-Track Interferometer). These experiments took place in the test area of the Sea Bottom Topography Group, 30 km off the Dutch coast, where the bottom topography is dominated by sand waves. In-situ data were gathered by a ship in the test area and on 'Measuring Platform Noordwijk', 20 km from the center of the test area. The radar images made during the experiment were compared with digitized maps of the bottom. Furthermore, the profiles of radar backscatter modulation were compared with the results of the model. During the workshop some preliminary results of the ATI measurements will be shown.

  1. New type of hill-top inflation

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.; Kamenshchik, A. Yu.; Nesterov, D. V.

    2016-01-01

    We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters epsilon and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R2-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

  2. The Goodwin model: behind the Hill function.

    PubMed

    Gonze, Didier; Abou-Jaoudé, Wassim

    2013-01-01

    The Goodwin model is a 3-variable model demonstrating the emergence of oscillations in a delayed negative feedback-based system at the molecular level. This prototypical model and its variants have been commonly used to model circadian and other genetic oscillators in biology. The only source of non-linearity in this model is a Hill function, characterizing the repression process. It was mathematically shown that to obtain limit-cycle oscillations, the Hill coefficient must be larger than 8, a value often considered unrealistic. It is indeed difficult to explain such a high coefficient with simple cooperative dynamics. We present here molecular models of the standard Goodwin model, based on single or multisite phosphorylation/dephosphorylation processes of a transcription factor, which have been previously shown to generate switch-like responses. We show that when the phosphorylation/dephosphorylation processes are fast enough, the limit-cycle obtained with a multisite phosphorylation-based mechanism is in very good quantitative agreement with the oscillations observed in the Goodwin model. Conditions in which the detailed mechanism is well approximated by the Goodwin model are given. A variant of the Goodwin model which displays sharp thresholds and relaxation oscillations is also explained by a double phosphorylation/dephosphorylation-based mechanism through a bistable behavior. These results not only provide rational support for the Goodwin model but also highlight the crucial role of the speed of post-translational processes, whose response curve are usually established at a steady state, in biochemical oscillators.

  3. Spirit's Express Route to 'Columbia Hills'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This map illustrates the Mars Exploration Rover Spirit's position as of sol 112 (April 26, 2004), near the crater called 'Missoula.' Like a train on a tight schedule, Spirit will make regular stops along the way to its ultimate destination, the 'Columbia Hills.' At each stop, or 'station,' the rover will briefly analyze the area's rocks and soils. Each tick mark on the rover's route represents one sol's worth of travel, or about 60 to 70 meters (200 to 230 feet). Rover planners estimate that Spirit will reach the hills around mid-June. Presently, the rover is stopped at a site called 'Plains Station.'

    The color thermal data show how well different surface features hold onto heat. Red indicates warmth; blue indicates coolness. Areas with higher temperatures are more likely to be rocky, as rocks absorb heat. Lower temperatures denote small particles and fewer rocks. During its traverse, Spirit will document the causes of these temperature variations.

    The map comprises data from the camera on NASA's Mars Global Surveyor orbiter and the thermal emission imaging system on NASA's Mars Odyssey orbiter.

  4. Spirit's Express Route to 'Columbia Hills'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This map illustrates the Mars Exploration Rover Spirit's position as of sol 112 (April 26, 2004), near the crater called 'Missoula.' Like a train on a tight schedule, Spirit will make regular stops along the way to its ultimate destination, the 'Columbia Hills.' At each stop, or 'station,' the rover will briefly analyze the area's rocks and soils. Each tick mark on the rover's route represents one sol's worth of travel, or about 60 to 70 meters (200 to 230 feet). Rover planners estimate that Spirit will reach the hills around mid-June. Presently, the rover is stopped at a site called 'Plains Station.'

    The color thermal data show how well different surface features hold onto heat. Red indicates a higher thermal inertia associated with rocky terrain (cooler in the day, warmer at night); blue indicates a lower thermal inertia associated with smaller particles and fewer rocks (warmer at night, cooler in the day). During its traverse, Spirit will document the causes of these thermal variations.

    The map comprises data from the camera on NASA's Mars Global Surveyor orbiter and the thermal emission imaging system on NASA's Mars Odyssey orbiter.

  5. New type of hill-top inflation

    SciTech Connect

    Barvinsky, A.O.; Kamenshchik, A.Yu.; Nesterov, D.V.

    2016-01-20

    We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters ϵ and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R{sup 2}-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

  6. New type of hill-top inflation

    SciTech Connect

    Barvinsky, A.O.; Nesterov, D.V.; Kamenshchik, A.Yu. E-mail: Alexander.Kamenshchik@bo.infn.it

    2016-01-01

    We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial conditions for inflation are set up by cosmological instantons describing underbarrier oscillations in the vicinity of the inflaton potential maximum. These periodic oscillations of the inflaton field and cosmological scale factor are obtained within the approximation of two coupled oscillators subject to the slow roll regime in the Euclidean time. This regime is characterized by rapid oscillations of the scale factor on the background of a slowly varying inflaton, which guarantees smallness of slow roll parameters ε and η of the following inflation stage. A hill-like shape of the inflaton potential is shown to be generated by logarithmic loop corrections to the tree-level asymptotically shift-invariant potential in the non-minimal Higgs inflation model and R{sup 2}-gravity. The solution to the problem of hierarchy between the Planckian scale and the inflation scale is discussed within the concept of conformal higher spin fields, which also suggests the mechanism bringing the model below the gravitational cutoff and, thus, protecting it from large graviton loop corrections.

  7. Spirit on 'Husband Hill,' with 2004 Comparison

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. On Nov. 2, 2005, shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image centered on the rover's location in the 'Columbia Hills.' The location of Spirit on that date is circled on the image on the right. On the left, for comparison, is an image from Jan. 10, 2004, when few dreamed that the Spirit would ever reach the hills from its landing site about three kilometers (two miles) away.

    The newer image has a resolution of about 50 centimeters (1.6 feet) per pixel. North is up; illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude. Dr. Timothy J. Parker of the Mars Exploration Rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., confirmed the location of the rover in the 2005 image. The scale bar is 50 meters (164 feet).

  8. Spirit's Neighborhood in 'Columbia Hills,' in Stereo

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. On Nov. 2, 2005, shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image covering approximately 3 kilometers by 3 kilometers (1.9 miles by 1.9 miles) centered on the rover's location in the 'Columbia Hills.'

    The tinted portion of this image gives a stereo, three-dimensional view when observed through 3-D glasses with a red left eye and blue right eye. The tallest peak is 'Husband Hill,' which was climbed by Spirit during much of 2005. The region south (toward the bottom) of these images shows the area where the rover is currently headed. The large dark patch and other similar dark patches in these images are accumulations of windblown sand and granules. North is up; illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude.

  9. Epibenthic megacrustaceans from the continental margin, slope and abyssal plain of the Southwestern Gulf of Mexico: Factors responsible for variability in species composition and diversity

    NASA Astrophysics Data System (ADS)

    Escobar-Briones, Elva G.; Gaytán-Caballero, Adriana; Legendre, Pierre

    2008-12-01

    The community structure of megacrustaceans (orders Lophogastrida, Isopoda, and Decapoda) collected in trawls on the continental margin, upper slope and abyssal plain of the southern Gulf of Mexico was studied to determine to what extent broad-scale variation in community composition and diversity was influenced by geographic regions environmental variability and depth. Trawls were collected in the Mexican Ridges, the Campeche Bank, and the Sigsbee abyssal plain. There was variability in species composition, density and diversity among geographic regions and along the depth gradient. A total of 106 species were identified and grouped in three orders; five infraorders, 40 families, and 70 genera. This study extends the known geographic ranges of the species Homolodromia monstrosa and Ephyrina benedicti. The largest number of species was recorded in the Mexican Ridges and on the upper continental shelf; lower values were found on the continental margin and in the abyssal plain. The largest densities were recorded on the continental margin in the Mexican Ridges. Megacrustaceans show in general low frequencies and low abundances in trawls, characterizing them as rare components of benthic assemblages. Contrary to an accepted paradigm about deep-sea biodiversity, the highest H' diversity values were recorded in the Sigsbee abyssal plain, followed by values from the upper continental slope; diversity values were correlated with evenness. Canonical Redundancy analysis results showed a significant affinity to regions for 18 crustacean species; 33 species showed a significant affinity to both regions and depth zones within regions.

  10. "First" abyssal record of Stenosemus exaratus (G.O. Sars, 1878) (Mollusca, Polyplacophora) in the North-Atlantic Ocean.

    PubMed

    Allcock, Louise; Schwabe, Enrico

    2013-01-01

    The first proven abyssal record of Stenosemus exaratus (G.O. Sars, 1878) is presented on the basis of an ROV study in the Irish Sea. For the first time in situ images of the species and data on the environmental parameters are provided.

  11. Heat flow in the western abyssal plain of the Gulf of Mexico: Implications for thermal evolution of the old oceanic lithosphere

    SciTech Connect

    Nagihara, S.; Sclater, J.G.; Phillips, J.D.; Behrens, E.W.

    1996-02-10

    This report discusses the heat flow and constraints on the heat flux from the lithosphere under the thick sedimentary layer of the western abyssal plain of the Gulf of Mexico. This paper developes the best estimates for the lithospheric heat loss that is free from near-surface disturbance.

  12. 186Os-187Os and highly siderophile element abundance systematics of the mantle revealed by abyssal peridotites and Os-rich alloys

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Walker, Richard J.; Warren, Jessica M.

    2017-03-01

    Abyssal peridotites are oceanic mantle fragments that were recently processed through ridges and represent residues of both modern and ancient melting. To constrain the nature and timing of melt depletion processes, and the composition of the mantle, we report high-precision Os isotope data for abyssal peridotites from three ocean basins, as well as for Os-rich alloys, primarily from Mesozoic ophiolites. These data are complemented by whole-rock highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re), trace- and major-element abundances for the abyssal peridotites, which are from the Southwest Indian (SWIR), Central Indian (CIR), Mid-Atlantic (MAR) and Gakkel Ridges. The results reveal a limited role for melt refertilization or secondary alteration processes in modifying abyssal peridotite HSE compositions. The abyssal peridotites examined have experienced variable melt depletion (2% to >16%), which occurred >0.5 Ga ago for some samples. Abyssal peridotites typically exhibit low Pd/Ir and, combined with high-degrees of estimated total melt extraction, imply that they were relatively refractory residues prior to incorporation into their present ridge setting. Recent partial melting processes and mid-ocean ridge basalt (MORB) generation therefore played a limited role in the chemical evolution of their precursor mantle domains. The results confirm that many abyssal peridotites are not simple residues of recent MORB source melting, having a more complex and long-lived depletion history. Peridotites from the Gakkel Ridge, SWIR, CIR and MAR indicate that the depleted MORB mantle has 186Os/188Os of 0.1198356 ± 21 (2SD). The Phanerozoic Os-rich alloys yield an average 186Os/188Os within uncertainty of abyssal peridotites (0.1198361 ± 20). Melt depletion trends defined between Os isotopes and melt extraction indices (e.g., Al2O3) allow an estimate of the primitive mantle (PM) composition, using only abyssal peridotites. This yields 187Os/188Os (0.1292 ± 25), and 186Os

  13. 83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM OF 3RD AVENUE EL SHOWING THE SOUTHBOUND TRACK APPROACH INTO GUN HILL STATION. 7TH AVENUE EXPRESS EL ABOVE. - Interborough Rapid Transit Company, Third Avenue Elevated Line, Borough of the Bronx, New York County, NY

  14. Accounting for imperfect detection in Hill numbers for biodiversity studies

    USGS Publications Warehouse

    Broms, Kristin M.; Hooten, Mevin B.; Fitzpatrick, Ryan M.

    2015-01-01

    The occupancy-based Hill number estimators are always at their asymptotic values (i.e. as if an infinite number of samples have been taken for the study region), therefore making it easy to compare biodiversity between different assemblages. In addition, the Hill numbers are computed as derived quantities within a Bayesian hierarchical model, allowing for straightforward inference.

  15. "This Delightfull Garden": "Rabbit Hill" and the Pastoral Tradition.

    ERIC Educational Resources Information Center

    Jordan, Anne Devereaux

    1997-01-01

    Contends that Robert Lawson's children's book "Rabbit Hill" (1944) falls within the genre of pastoral literature, in the tradition of Edmund Spenser's "Faerie Queen." Examines the history of the genre and finds reasons for classifying Lawson's book as pastoral. Cites classic elements in "Rabbit Hill." Gives five…

  16. View of sports field and Easter Hill at west side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field and Easter Hill at west side of project site. Looking southwest - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  17. View of sports field from Easter Hill looking at intersection ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field from Easter Hill looking at intersection of South Twenty-Sixth Street and Foothill Avenue at left center rear. Buildings No. 36, 35, 25, 27, and 29, from left to right. Looking northeast - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  18. View of sports field and Easter Hill at west side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of sports field and Easter Hill at west side of project site. Looking west - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  19. VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, FROM AMMUNITION (IGLOO) HILL. (Part 2 of a 3 view panorama; see also CA-2398-J-1 and CA-2398-16.) - Hamilton Field, East of Nave Drive, Novato, Marin County, CA

  20. 1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT AREA LOOKING SOUTH. PLANT DRY IS IN CENTER FOREGROUND, SLAG FUMING PLANT IS IN RIGHT FOREGROUND, AND BAG HOUSE IS IN RIGHT BACKGROUND. VARIOUS PLANT STACKS ARE ALSO VISIBLE. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  1. Spectral parameter power series representation for Hill's discriminant

    SciTech Connect

    Khmelnytskaya, K.V.; Rosu, H.C.

    2010-11-15

    We establish a series representation of the Hill discriminant based on the spectral parameter power series (SPPS) recently introduced by Kravchenko. We also show the invariance of the Hill discriminant under a Darboux transformation and employing the Mathieu case the feasibility of this type of series for numerical calculations of the eigenspectrum.

  2. View of south boundary of Easter Hill project site for ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of south boundary of Easter Hill project site for right of way for Hoffman Boulevard. Buildings No. 11 and 14 at right in trees. Looking west - Easter Hill Village, Bordered by South Twenty-sixth Street, South Twenty-eighth Street, Hinkley Avenue, Foothill Avenue & Corto Square, Richmond, Contra Costa County, CA

  3. VIEW LOOKING WEST TOWARD RESERVOIR HILL. THE SPRR HOTEL WAS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW LOOKING WEST TOWARD RESERVOIR HILL. THE SPRR HOTEL WAS LOCATED IN THE STRIPED AREA AT THE BOTTOM OF THE IMAGE, AND THE TRACK RAN BETWEEN THE HILL AND THE HOTEL. - Southern Pacific Railroad Water Settling Reservoir, Yuma Crossing, south bank of Colorado River at foot of Madison Avenue, Yuma, Yuma County, AZ

  4. 78 FR 21098 - Black Hills National Forest Advisory Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board) will... Committee Act of 1972 (5 U.S.C. App. II) (FACA); and the Forest and Rangeland Renewable Resources...

  5. Drawing entitled "Sketch of proposed site for Pine Hills Patrol ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Drawing entitled "Sketch of proposed site for Pine Hills Patrol Station, Cleveland National Forest, San Diego County, California. Surveyed by Norman McClean, U.S.F.S., January, 1934. - Pine Hills Station, Barracks, West Side of Boulder Creek Road at Engineers Road, Julian, San Diego County, CA

  6. 3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO THE SOUTHWEST. BUILDINGS NOTED IN ID-29-2 APPEAR, IN ADDITION TO DRY ORE PLANT AND BONNOT COAL PULVERIZING EQUIPMENT BUILDING ON THE RIGHT. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  7. 2. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO THE SOUTH. IN FOREGROUND, PLANT DRY, SLAG FUMING PLANT, BLAST FURNACE, SMELTER OFFICE, LEAD AND SILVER REFINERIES ARE VISIBLE, L. TO R. HIGH VELOCITY FLUE LEADS FROM LOWER PLANT TO BAG HOUSE AND STACKS AT TOP OF SMELTING FACILITY. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  8. Axillary shoulder with exaggerated rotation: the Hill-Sachs defect.

    PubMed

    Rafert, J A; Long, B W; Hernandez, E M; Kreipke, D L

    1990-01-01

    One of the most common fractures of the humeral head resulting from an anterior dislocation is the Hill-Sachs defect. Other special radiographic positions to demonstrate this injury may prove difficult for the patient to assume and maintain. An axillary shoulder projection with exaggerated external rotation is easy to position and clearly demonstrates the Hill-Sachs defect.

  9. AmeriFlux US-Blk Black Hills

    DOE Data Explorer

    Meyers, Tilden [NOAA/ARL

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Blk Black Hills. Site Description - The Black Hills tower was established by the Institute for Atmospheric Studies of the South Dakota School of Mines and Technology.

  10. OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC MINE LOOKING EAST. THE OPENING TO THE TALC MINE IS IN THE DARK AREA AT CENTER LEFT EDGE. WARM SPRINGS CAMP IS OUT OF FRAME TO THE RIGHT. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  11. Abyssal macrofauna of the Kuril-Kamchatka Trench area (Northwest Pacific) collected by means of a camera-epibenthic sledge

    NASA Astrophysics Data System (ADS)

    Brandt, A.; Elsner, N. O.; Malyutina, M. V.; Brenke, N.; Golovan, O. A.; Lavrenteva, A. V.; Riehl, T.

    2015-01-01

    Abyssal macrofaunal composition of 21 epibenthic sledge hauls from twelve stations taken in the Kuril-Kamchatka Trench (KKT) and at the adjacent abyssal plain, Northwest Pacific, is presented. Sampling with the fine meshed epibenthic sledge yielded higher abundances and species richness than was reported from previous expeditions from board of RV Vityaz. In total 84,651 invertebrates were sampled with RV Sonne between July and September of 2012 (31,854 invertebrates if standardised for 1000 m2 trawled distances) from 41 taxa of different taxonomic ranks (15 phyla, 28 classes, 7 orders) were sampled from a trawled area of 53,708 m² and have been analyzed. Few taxa were frequent and most taxa were rare in the samples, twelve taxa occurred with more than 1% frequency. Of these, the Polychaeta were most abundant followed by the benthic Copepoda and Isopoda. Total numbers of individuals varied between stations and were highest with 4238 individuals at station 2-10 close to the KKT in 4865 m depth and lowest with 374 individuals at station 6-11 in 5305 m depth. At this station also the lowest number of taxa occurred (18 taxa) while the highest number occurred with 31 taxa at station 3-9 in 4991 m depth. Numbers of individuals decreased with increasing depth between 4830 and 5780 m. Crustaceans of the superorder Peracarida were one of the dominating taxa with four orders occurring frequently in most samples. In total, Isopoda were most important and occurred with 59% of all peracarid orders sampled, followed by Amphipoda with 21%, Tanaidacea with 11%, Cumacea with 9%, and Mysidacea with <1%. The communities of the stations (and hauls) of the KKT abyssal area differ in terms of taxon composition from each other. A cluster analysis (nMDS) performed for all sampled stations revealed no clear pattern of community similarity between stations or hauls. All hauls close to the trench (2-9 and 2-10 close to the eastern slope of the KKT; and 3-9 and 4-3 at the western slope) were

  12. Can LREE Enriched Patterns in Clinopyroxenes in Abyssal Peridotites be Produced by Melting of a Depleted Mantle Source?

    NASA Astrophysics Data System (ADS)

    LIU, B.; Liang, Y.

    2015-12-01

    The enrichment of LREE in clinopyroxenes in abyssal peridotites has often been attributed to shallow level melt refertilization. Here we show an alternative mechanism that involves diffusive fractionation of REE during disequilibrium mantle melting. We present a simple model for trace element fractionation during disequilibrium melting in an upwelling steady-state column. We use linear kinetics to approximate crystal-melt mass exchange rate and obtain analytical solutions for cases of perfect fractional melting and batch melting. A key parameter determining the extent of chemical disequilibrium during partial melting is an element specific dimensionless ratio (ɛ) defined as the melting rate relative to the solid-melt chemical exchange rate for the trace element of interest. In the case of diffusion in mineral limited exchange, ɛ is inversely proportional to diffusivity of the element of interest. Disequilibrium melting is important for the trace element when e is comparable to or greater than the bulk solid-melt partition coefficient for the element (k). The disequilibrium fractional melting model is reduced to the equilibrium perfect fractional melting model when e is much smaller than k. Hence highly incompatible trace elements with slower mobilities in minerals are more susceptible to disequilibrium melting than moderately incompatible elements. Effect of chemical disequilibrium is to hinder the extent of fractionation between residual solid and partial melt, making the residual solid less depleted and the accumulated melt more enriched in incompatible trace element abundances relative the case of equilibrium melting. Application of the disequilibrium fractional melting model to REE abundances in clinopyroxene in abyssal peridotites from the Central Indian Ridge and the Vema Lithospheric Section, Mid-Atlantic Ridge revealed a positive correlation between the disequilibrium parameter ɛ and the degree of melting, which can be explained by an increase in melting

  13. The Os isotopic variation of abyssal peridotites revised: A study from the ultra-slow spreading Gakkel Ridge

    NASA Astrophysics Data System (ADS)

    Büchl, A.; Snow, J. E.

    2003-04-01

    It is generally thought that the Os isotopic variation of abyssal peridotites (187Os/188Os varies from 0.120 to 0.129 after [1,2,3,4]) only exceeds the chondritic value of 0.127 [5] because of secondary alteration by seawater. In contrast supra-chondritic 187Os/188Os ratios in peridotites from ophiolites [6] and xenoliths from a subduction zone setting [7] have been ascribed to exchange of Os with radiogenic melts. We analysed the Os isotopic composition of 16 peridotites from the ultra-slow spreading Gakkel Ridge. The samples are unusually fresh for abyssal peridotites. The Os isotopic composition varies from 0.1208 to 0.1344 in the spinel-lherzolites, from 0.1176 to 0.1360 in the harzburgites and from 0.1325 to 0.1400 in the dunites. The reason for the supra-chondritic Os isotopic ratios could be (a) secondary alteration by seawater, (b) radiogenic ingrowth due to the decay of Re to Os, or (c) exchange with a radiogenic magmatic component. The fact that the degree of alteration does not correlate with Os isotopic composition, together with the high Os concentration in the peridotites compared with seawater, implies that the supra-chondritic 187Os/188Os ratios cannot be explained by secondary alteration processes. The similar and low Re and high Os concentrations in all samples rule out the ingrowth of 187Os as source for the supra-chondritic values. World-wide volcanic rocks mostly have supra-chondritic 187Os/188Os ratios. In addition it was shown recently that during melt percolation the peridotites can inherit the signature of percolating melts [6]. This suggests that the supra-chondritic 187Os/188Os ratios are due to the exchange with a magmatic component. This is supported by the observation that the dunites, which are expected to have the highest melt/rock ratio of all lithologies, have the most radiogenic signatures. We therefore suggest that the 187Os/188Os variation of abyssal peridotites is much larger than previously considered. However the origin of

  14. A Geo-traverse at a Passive Continental Margin: the Tagus Abyssal Plain, West Iberia

    NASA Astrophysics Data System (ADS)

    Afilhado, A.; Matias, L.; Mendes-Victor, L.

    2006-12-01

    transitional domain suggests a layered structure for the lithospheric mantle. The location of the main features and trend changes seen on the magnetic anomaly and the Bouguer anomaly maps are compatible to the seismically defined transition to the oceanic domain. Both magnetic and free air profiles modeling are also consistent to a major rock property contrast at this location. Minor features within the oceanic domain indicate some variability of the mass and magnetic dipoles distribution that might be related to different cross cutting of the segment axis and/or non stationary thermo-mechanical conditions of the sea floor spreading process. From 9.4W to the foot of the continental slope, at 10.2W, in a 65km distance, the Bouguer anomaly strongly increases due both to continental crust thinning and Moho shallowing. Magnetic anomalies having peak to peak values of 30 to 90nT and wave length of at least 30km plus the high density blocks modeled at shallow levels, indicate that dense and magnetic rocks should be present at the continental margin. A large body of exhumed continental mantle at the OCT is hardly supported by the data. Even so, the eastern 35km segment of the abyssal plain adjacent to the continental margin is a mass excess segment, bordered by significant magnetic anomalies, in good agreement to an intruded and partly ultramafic lower transitional crust, as suggested by the seismic data.

  15. Characteristics of sinking particles in the upper ocean at the Porcupine Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Riley, Jennifer; Sanders, Richard; Achterberg, Eric

    2010-05-01

    Sinking particles play an important role in the biological carbon pump, transferring carbon from the surface to the deep ocean. Data from deep ocean sediment traps suggest biominerals influence particle settling velocity, by increasing their density. However it is unclear whether this biomineral facilitated sinking applies to the upper ocean and if shape also plays a critical role on the rate at which particles sink. Measurements of particle settling velocity, density and drag were made in order to determine their influences on the particle sinking rate in the upper water column. Samples were taken during a cruise in summer 2009 from the Porcupine Abyssal Plain (PAP site) in the northwest Atlantic. Particles were collected from the base of the mixed layer (approximately 50m) using the Marine Snow Catcher. This instrument samples 100L of water and collects any settling particles in a 5L base chamber over 2 - 3 hours. After settling, the top 95L of water was drained off and any particles collected in the base chamber were transferred to the lab. Particles were individually picked using a Pasteur pipette and subdivided, into categories on the basis of appearance. Settling experiments were conducted in a 2L glass measuring cylinder filled with surface sea water, kept at a constant temperature of 15° C. After each experiment particles were preserved individually in buffered formalin for high quality image analysis back on land. Calculations of both excess density and drag were undertaken using data from microscopic measurements. Five main particle categories were identified; (1) diffuse fluff aggregates, (2) dense fluff aggregates, (3) centred particles (fluff aggregated around a central biomineral test), (4) organisms (biomineralising protists including foraminifera) and (5) calcareous tests. Statistical analysis suggested a significant difference in the rate at which the centred and calcareous particles sank (approximately 248 m day-1 and 1070 m day-1respectively) in

  16. Bait attending fishes of the abyssal zone and hadal boundary: Community structure, functional groups and species distribution in the Kermadec, New Hebrides and Mariana trenches

    NASA Astrophysics Data System (ADS)

    Linley, T. D.; Stewart, A. L.; McMillan, P. J.; Clark, M. R.; Gerringer, M. E.; Drazen, J. C.; Fujii, T.; Jamieson, A. J.

    2017-03-01

    Baited landers were deployed at 83 stations at four locations in the west Pacific Ocean from bathyal to hadal depths: The Kermadec Trench, the New Hebrides Trench, the adjoining South Fiji Basin and the Mariana Trench. Forty-seven putative fish species were observed. Distinct fish faunal groups were identified based on maximum numbers and percentage of observations. Both analyses broadly agreed on the community structure: A bathyal group at <3000 m in the New Hebrides and Kermadec trenches, an abyssal group (3039 - 4692 m) in the Kermadec Trench, an abyssal-hadal transition zone (AHTZ) group (Kermadec: 4707-6068 m, Mariana: 4506-6198 m, New Hebrides: 2578-6898 m, South Fiji Basin: 4074-4101 m), and a hadal group of endemic snailfish in the Kermadec and Mariana trenches (6750-7669 m and 6831-8143 m respectively). The abyssal and hadal groups were absent from the New Hebrides Trench. Depth was the single factor that best explained the biological variation between samples (16%), the addition of temperature and average surface primary production for the previous year increased this to 36% of variation. The absence of the abyssal group from the New Hebrides Trench and South Fiji Basin was due to the absence of macrourids (Coryphaenoides spp.), which defined the group. The macrourids may be energetically limited in these areas. In their absence the species of the AHTZ group appear released of competition with the macrourids and are found far shallower at these sites. The fish groups had distinct feeding strategies while attending the bait: The bathyal and abyssal groups were almost exclusively necrophagous, the AHTZ group comprised predatory and generalist feeders, while the hadal snailfishes were exclusively predators. With increasing depth, predation was found to increase while scavenging decreased. The data suggest scavenging fish fauna do not extend deeper than the hadal boundary.

  17. Decay of isolated hills and saddles on Si(001)

    NASA Astrophysics Data System (ADS)

    Kirschbaum, Pierre; Brendel, Lothar; Roos, Kelly R.; Horn-von Hoegen, Michael; Heringdorf, Frank-J. Meyer zu

    2016-08-01

    We discuss the high temperature decay of isolated hills and saddle points on Si(001). Using in situ dark-field imaging in low energy electron microscopy, we track the movement of individual steps during high temperature annealing. We find different temperature dependent decay rates for the top of the hill compared to a saddle point with low step density that is present in the vicinity of the hill. The decay rate of the hill is always higher than the decay rate at the saddle. The two rates converge with increasing temperature and become equal at temperatures above 1060 °C. We also report an alternating fast and low decay rate for the layer-by-layer decay of the hills. This surprising finding is independent of temperature and is explained by macroscopic strain in the sample.

  18. Comparisons of calculated and measured helicopter noise near instrument hill

    NASA Technical Reports Server (NTRS)

    Bass, Henry E.; You, Chulsoo

    1993-01-01

    The polar parabolic equation (POPE) method solves for the diffraction of sound by a curved surface including a realistic sound speed profile. POPE is outlined briefly to describe diffraction which propagates the field over a hill. Experimental data are compared with POPE predictions using the measured sound speed profile and ground impedance. Two trial cases are considered for the comparisons: the helicopter located at the base of the hill and far away from the base of the hill, respectively. The physical mechanisms for sound propagation over a hill are examined with and of POPE calculations and experimental data. The shedding of rays from the hillside gives an interference effect with a wave along the flat surface beyond the base of a hill.

  19. The 'Ice Hill': An example of 'retarded deglaciation' in siberia

    NASA Astrophysics Data System (ADS)

    Astakhov, Valery I.; Isayeva, Lia L.

    The geological structure of one of the southernmost sites of thick ice beds in the Yenisei valley near the Arctic Circle is discussed. The erosion contacts of the foliated and contorted ice, abundance of glacial debris and the position between the basal till and ablation cover indicate a glacial origin for the ice layer. The ice occurs in the cores of arcuate accretion ridges built of ablation materials. The overlying sequence consists of a series of diamicton flows alternating with lacustrine and outwash sediments. Laterally the ice-rock complex changes into thick lacustrine rhythmites underlain by basal tills. The ice-containing hummocky terrain is often lower than the adjacent lacustrine plain. Therefore inversion of ice-controlled topography is suggested. Several stages of glaciokarst development are supposed to have occurred after an eastward moving ice lobe stagnated more than 50 ka BP. The main depositional events are associated with the Middle Weichselian draining of ice-dammed Lake Igarka, and with Early Holocene topographic inversion. The Holocene warming apparently caused diapiric deformation of the buried ice probably because of the density and thickness differences between the ice and the overburden. The long history of burial and preservation of the remnants of basal glacier ice was controlled by Pleistocene permafrost. Landscape evolution in Northern Siberia is governed by such 'retarded deglaciation', in contrast with Atlantic environments. The thick ablation sequence may be described in terms of a Spitsbergen model, but the Siberian basal tills, because of their position within the permafrost, must be regarded as exfoliated layers of debris-rich ice according to Shantzer-Lavrushin's model. The occurrence of buried glacier ice and the mode of distribution of the permafrost shows the relict nature of the latter. In areas of modern and former retarded deglaciation intermittent diamicton flows are supposed to mark episodes of climatic amelioration like

  20. Spatial Fourier Transform Analysis of Polishing Pad Surface Topography

    NASA Astrophysics Data System (ADS)

    Khajornrungruang, Panart; Kimura, Keiichi; Okuzono, Takahisa; Suzuki, Keisuke; Kushida, Takashi

    2012-05-01

    The spatial Fourier transform analysis is proposed to quantitatively evaluate the irregular topography of the conditioned chemical mechanical polishing (CMP) pad surface. We discuss the power spectrum in the spatial wavelengths of the surface topographies corresponding to polishing time. We conclude that the spatial wavelength of less than 5 µm in the topography yielded high material removal rates.

  1. Impact of watershed topography on hyporheic exchange

    NASA Astrophysics Data System (ADS)

    Caruso, Alice; Ridolfi, Luca; Boano, Fulvio

    2016-08-01

    Among the interactions between surface water bodies and aquifers, hyporheic exchange has been recognized as a key process for nutrient cycling and contaminant transport. Even though hyporheic exchange is strongly controlled by groundwater discharge, our understanding of the impact of the regional groundwater flow on hyporheic fluxes is still limited because of the complexity arising from the multi-scale nature of these interactions. In this work, we investigate the role of watershed topography on river-aquifer interactions by way of a semi-analytical model, in which the landscape topography is used to approximate the groundwater head distribution. The analysis of a case study shows how the complex topographic structure is the direct cause of a substantial spatial variability of the aquifer-river exchange. Groundwater upwelling along the river corridor is estimated and its influence on the hyporheic zone is discussed. In particular, the fragmentation of the hyporeic corridor induced by groundwater discharge at the basin scale is highlighted.

  2. New null screen design for corneal topography

    NASA Astrophysics Data System (ADS)

    Campos-García, Manuel; Estrada-Molina, Amilcar; Díaz-Uribe, Rufino

    2011-09-01

    In this work we report the design of a null screen for corneal topography. Here we assume that the corneal surface is an ellipsoid with a diameter of 12 mm and a curvature radius of 7.8 mm. To avoid the difficulties in the alignment of the test system due to the face contour (eyebrows, nose, or eyelids), we design a conical null-screen with spots (similar to ellipses) drawn on it in such a way that its image, which is formed by reflection on the test surface, becomes an exact radial array of circular spots if the surface is perfect. Additionally, we performed a numerical simulation introducing Gaussian random errors in the coordinates of the centroids of the spots on the image plane, and in the coordinates of the sources (spots on the null-screen) in order to obtain the conical null-screen that reduces the error in the evaluation of the topography.

  3. Operational teledermatology in Broken Hill, rural Australia.

    PubMed

    See, Adrian; Lim, Adrian C; Le, Katie; See, Jo-Ann; Shumack, Stephen P

    2005-08-01

    From January 2001 to January 2002, Broken Hill, New South Wales, served as a trial site for teledermatology as one method of access to dermatologists. Fourteen participating general practitioners referred 46 patients making up 48 teledermatology cases. The mean diagnostic agreement between general practitioners and dermatologists was 35% and 50% for primary and differential diagnoses, respectively. Teledermatology patients formed 12% of the collectively referred dermatology patients (outpatients and teledermatology). In this project, high patient and general practitioner acceptability and positive medical outcomes confirm the value of rural teledermatology. However, this project also revealed unexpected barriers and pitfalls in the effective operation of rural teledermatology. Lack of education of participants, inertia among potential users and patient inconvenience are issues that may adversely affect the effective implementation of rural teledermatology.

  4. Seeing sodomy: Fanny Hill's blinding vision.

    PubMed

    Kopelson, K

    1992-01-01

    One of the oddest and most erotic moments in Cleland's Fanny Hill occurs when Fanny is knocked "senseless" by a voyeuristic vision of two young men having anal intercourse. This sodomitical passage demonstrates a dominant culture's strong phobic attraction to a socially peripheral Other against which it defines itself. The passage also represents two types of transgression. On one level, it records an inversion of sex, gender, and class paradigms that structure bourgeois subjectivity. On another level, the passage also transgresses signification itself, exploding as well as inverting those paradigms, in a movement that recalls Barthes's distinction between the coded "studium" of the pornographic and the uncoded "punctum" of the erotic. This transgressive exemption from meaning might well be read, in a Barthesian sense, as true sexual enfranchisement in that, for Barthes, the liberation of sexuality requires the release of sexuality from meaning, and from transgression as meaning.

  5. The 1984 Morgan Hill, California, earthquake

    USGS Publications Warehouse

    Bakun, W.H.; Clark, M.M.; Cockerham, R.S.; Ellsworth, W.L.; Lindh, A.G.; Prescott, W.H.; Shakal, A.F.; Spudich, P.

    1984-01-01

    The Morgan Hill, California, earthquake (magnitude 6.1) of 24 April 1984 ruptured a 30-kilometer-long segment of the Calaveras fault zone to the east of San Jose. Although it was recognized in 1980 that an earthquake of magnitude 6 occurred on this segment in 1911 and that a repeat of this event might reasonably be expected, no short-term precursors were noted and so the time of the 1984 earthquake was not predicted. Unilateral rupture propagation toward the south-southeast and an energetic late source of seismic radiation located near the southeast end of the rupture zone contributed to the highly focused pattern of strong motion, including an exceptionally large horizontal acceleration of 1.29g at a site on a dam abutment near the southeast end of the rupture zone.

  6. Motivations of female Black Hills deer hunters

    USGS Publications Warehouse

    Gigliotti, Larry M.; Covelli Metcalf, Elizabeth

    2016-01-01

    State fish and wildlife agencies are particularly interested in attracting female participation because of the potential to offset declining participation in hunting. Understanding female hunters’ motivations will be critical for designing effective recruitment and retention programs for women hunters. Although female participation in hunting is increasing, males still outnumber females by about tenfold. Gender differences in deer hunters were explored by comparing ratings of eight motivations (social, nature, excitement, meat, challenge, trophy, extra hunting opportunity, and solitude). Hunter types were defined by hunters’ selection of the most important motivation for why they like Black Hills deer hunting. Overall, females and males were relatively similar in their ratings of the eight motivations, and we found 85% gender similarity in the selection of the most important motivation. Women were slightly more motivated by the food aspect of the hunt while men placed slightly more value on the hunt as a sporting activity.

  7. AGU climate scientists visit Capitol Hill

    NASA Astrophysics Data System (ADS)

    Hankin, Erik

    2012-02-01

    On 1 February 2012, AGU teamed with 11 other scientific societies to bring 29 scientists researching various aspects of climate change to Washington, D. C., for the second annual Climate Science Day on Capitol Hill. The participants represented a wide range of expertise, from meteorology to agriculture, paleoclimatology to statistics, but all spoke to the reality of climate change as demonstrated in their scientific research. With Congress debating environmental regulations and energy policy amid tight fiscal pressures, it is critical that lawmakers have access to the best climate science to help guide policy decisions. The scientists met with legislators and their staff to discuss the importance of climate science for their districts and the nation and offered their expertise as an ongoing resource to the legislators.

  8. After Conquering 'Husband Hill,' Spirit Moves On

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The first explorer ever to scale a summit on another planet, NASA's Mars Exploration Rover Spirit has begun a long trek downward from the top of 'Husband Hill' to new destinations. As shown in this 180-degree panorama from east of the summit, Spirit's earlier tracks are no longer visible. They are off to the west (to the left in this view). Spirit's next destination is 'Haskin Ridge,' straight ahead along the edge of the steep cliff on the right side of this panorama.

    The scene is a mosaic of images that Spirit took with the navigation camera on the rover's 635th Martian day, or sol, (Oct. 16, 2005) of exploration of Gusev Crater on Mars. This view is presented in a cylindrical projection with geometric seam correction.

  9. Planetary stations and Abyssal Benthic Laboratories: An overview of parallel approaches for long-term investigation in extreme environments

    NASA Technical Reports Server (NTRS)

    Dipippo, S.; Prendin, W.; Gasparoni, F.

    1994-01-01

    In spite of the apparent great differences between deep ocean and space environment, significant similarities can be recognized when considering the possible solutions and technologies enabling the development of remote automatic stations supporting the execution of scientific activities. In this sense it is believed that mutual benefits shall be derived from the exchange of experiences and results between people and organizations involved in research and engineering activities for hostile environments, such as space, deep sea, and polar areas. A significant example of possible technology transfer and common systematic approach is given, which describes in some detail how the solutions and the enabling technologies identified for an Abyssal Benthic Laboratory can be applied for the case of a lunar or planetary station.

  10. Ash and Steam, Soufriere Hills Volcano, Monserrat

    NASA Technical Reports Server (NTRS)

    2002-01-01

    International Space Station crew members are regularly alerted to dynamic events on the Earth's surface. On request from scientists on the ground, the ISS crew observed and recorded activity from the summit of Soufriere Hills on March 20, 2002. These two images provide a context view of the island (bottom) and a detailed view of the summit plume (top). When the images were taken, the eastern side of the summit region experienced continued lava growth, and reports posted on the Smithsonian Institution's Weekly Volcanic Activity Report indicate that 'large (50-70 m high), fast-growing, spines developed on the dome's summit. These spines periodically collapsed, producing pyroclastic flows down the volcano's east flank that sometimes reached the Tar River fan. Small ash clouds produced from these events reached roughly 1 km above the volcano and drifted westward over Plymouth and Richmond Hill. Ash predominately fell into the sea. Sulfur dioxide emission rates remained high. Theodolite measurements of the dome taken on March 20 yielded a dome height of 1,039 m.' Other photographs by astronauts of Montserrat have been posted on the Earth Observatory: digital photograph number ISS002-E-9309, taken on July 9, 2001; and a recolored and reprojected version of the same image. Digital photograph numbers ISS004-E-8972 and 8973 were taken 20 March, 2002 from Space Station Alpha and were provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  11. Multiscale Study of Currents Affected by Topography

    DTIC Science & Technology

    2013-09-30

    understand the effects of topography on the ocean general circulation with a focus on the wide range of scales in the interactions. The small-scale...influence the larger-scale flow. We will study these issues through ocean model simulations, adjoint sensitivity experiments, and state estimation...using measurements in the region surrounding an island in the westward-flowing limb of the subtropical gyre . OBJECTIVES The objectives of this

  12. Diffraction imaging (topography) with monochromatic synchrotron radiation

    NASA Technical Reports Server (NTRS)

    Steiner, Bruce; Kuriyama, Masao; Dobbyn, Ronald C.; Laor, Uri

    1988-01-01

    Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In the review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

  13. Topography over South America from ERS altimetry

    NASA Technical Reports Server (NTRS)

    Brenner, Anita; Frey, Herb; DiMarzio, John; Tsaoussi, Lucia

    1997-01-01

    The results of the surface topography mapping of South America during the ERS-1 geodetic mission are presented. The altimeter waveforms, the range measurement, and the internal and Doppler range corrections were obtained. The atmospheric corrections and solid tides were calculated. Comparisons between Shuttle laser altimetry and ERS-1 altimetry grid showed good agreement. Satellite radar altimetry data can be used to improve the topographic knowledge of regions for which only poor elevation data currently exist.

  14. ATM Coastal Topography-Mississippi, 2001

    USGS Publications Warehouse

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived first-surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Mississippi coastline, from Lakeshore to Petit Bois Island, acquired September 9-10, 2001. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative scanning lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning lidar system that measures high-resolution topography of the land surface and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser-ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS

  15. ATM Coastal Topography-Alabama 2001

    USGS Publications Warehouse

    Nayegandhi, Amar; Yates, Xan; Brock, John C.; Sallenger, A.H.; Bonisteel, Jamie M.; Klipp, Emily S.; Wright, C. Wayne

    2009-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of the Alabama coastline, acquired October 3-4, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface, and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft. Elevation measurements were collected over the survey area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of Lidar data in an interactive or batch mode. Modules for pre-survey flight line definition, flight path plotting, Lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have been developed to extract the range to the first and last significant return within each waveform. ALPS is routinely used to create maps that

  16. EAARL topography: Cape Cod National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Travers, Laurinda J.

    2007-01-01

    This Web site contains 90 Lidar-derived bare earth topography maps and GIS files for the Cape Cod National Seashore. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS), Northeast Coastal and Barrier 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 coastal resource managers.

  17. Neurofunctional topography of the human hippocampus

    PubMed Central

    Robinson, Jennifer L.; Barron, Daniel S.; Kirby, Lauren A. J.; Bottenhorn, Katherine L.; Hill, Ashley C.; Murphy, Jerry E.; Katz, Jeffrey S.; Salibi, Nouha; Eickhoff, Simon B.; Fox, Peter T.

    2015-01-01

    Much of what we assume about the functional topography of the hippocampus was derived from a single case study over half a century ago. Given advances in the imaging sciences, a new era of discovery is underway, with potential to transform our understanding of healthy processing as well as our ability to treat disorders. We employed coactivation based parcellation, a meta-analytic approach, and ultra-high field, high-resolution functional and structural neuroimaging to characterize the neurofunctional topography of the hippocampus. Data revealed strong support for an evolutionarily preserved topography along the long-axis. Specifically, the left hippocampus was segmented into three distinct clusters: an emotional processing cluster supported by structural and functional connectivity to the amygdala and parahippocampal gyrus, a cognitive operations cluster, with functional connectivity to the anterior cingulate and inferior frontal gyrus, and a posterior perceptual cluster with distinct structural connectivity patterns to the occipital lobe coupled with functional connectivity to the precuneus and angular gyrus. The right hippocampal segmentation was more ambiguous, with plausible 2- and 5-cluster solutions plausible. Segmentations shared connectivity with brain regions known to support the correlated processes. This represents the first neurofunctional topographic model of the hippocampus using a robust, bias-free, multi-modal approach. PMID:26350954

  18. Evolution of Neogene Dynamic Topography in Africa

    NASA Astrophysics Data System (ADS)

    Paul, Jonathan; Roberts, Gareth; White, Nicky

    2013-04-01

    The characteristic basins and swells of Africa's surface topography probably reflect patterns of convective circulation in the sub-lithospheric mantle. We have interrogated drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~560 longitudinal river profiles were extracted from a digital elevation model of Africa. An inverse model is then used to minimise the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~22 to ~5. Our results suggest that Africa's topography began to grow most rapidly after ~30 Ma at peak uplift rates of 0.1-0.15 mm/yr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Angolan Dome). Uplift rate histories are shown to vary significantly from swell to swell. The calculated magnitudes, timing, and location of uplift agree well with local independent geological constraints, such as intense volcanism at Hoggar (42-39 Ma) and Afar (31-29 Ma), uplifted marine terraces, and warped peneplains. We have also calculated solid sediment flux histories for major African deltas which have persisted through time. This onshore record provides an important indirect constraint on the history of vertical motions at the surface, and agrees well with the offshore flux record, obtained from mapping isopachs of deltaic sediments. Our modelling and reconstructed sedimentary flux histories indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  19. Long wavelength gravity and topography anomalies

    NASA Technical Reports Server (NTRS)

    Watts, A. B.; Daly, S. F.

    1981-01-01

    It is shown that gravity and topography anomalies on the earth's surface may provide new information about deep processes occurring in the earth, such as those associated with mantle convection. Two main reasons are cited for this. The first is the steady improvement that has occurred in the resolution of the long wavelength gravity field, particularly in the wavelength range of a few hundred to a few thousand km, mainly due to increased coverage of terrestrial gravity measurements and the development of radar altimeters in orbiting satellites. The second reason is the large number of numerical and laboratory experiments of convection in the earth, including some with deformable upper and lower boundaries and temperature-dependent viscosity. The oceans are thought to hold the most promise for determining long wavelength gravity and topography anomalies, since their evolution has been relatively simple in comparison with that of the continents. It is also shown that good correlation between long wavelength gravity and topography anomalies exists over some portions of the ocean floor

  20. Solutions of barotropic trapped waves over topography

    NASA Astrophysics Data System (ADS)

    Zavala Sanson, Luis

    2010-05-01

    Solutions of free, barotropic waves over variable topography are derived. In particular, we examine two cases: waves around axisymmetric seamounts and waves along a sloping bottom. Even though these types of oscillations have been studied before, we revisit the problem because of two main reasons: (i) The linear, barotropic, shallow-water equations with a rigid lid are now solved with no further approximations, in contrast with previous studies. (ii) The solutions are applied to a wide family of seamounts and bottom slopes with profiles proportional to exp(rs) and ys, respectively, where r is the radial distance from the centre of the mountain, y is the direction perpendicular to the slope, and s is an arbitrary positive real number. Most of previous works on seamounts are restricted to the special case s = 2. By varying the shape parameter one can study trapped waves around flat-topped seamounts or guyots (s > 2) or sharp, cone-shaped topographies (s < 2). Similarly, most of previous studies on sloping bottoms report cases with s = 1 (linear slopes), whilst the present results are applied to more general bottom profiles. The resulting dispersion relation in both cases possess a remarkable simplicity that reveals a number of wave characteristics as a function of the topography shape.

  1. EAARL topography: Assateague Island National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Travers, Laurinda J.

    2007-01-01

    This Web site contains 58 lidar-derived bare earth topography maps and GIS files for the Assateague Island National Seashore. These lidar-derived topography 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.

  2. EAARL topography: Thomas Stone National Historic Site

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2007-01-01

    This Web site contains Lidar-derived topography (first return and bare earth) maps and GIS files for Thomas Stone National Historic Site in Maryland. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, 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.

  3. EAARL topography: George Washington Birthplace National Monument

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2007-01-01

    This Web site contains Lidar-derived topography (first return and bare earth) maps and GIS files for George Washington Birthplace National Monument in Virginia. These lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, the National Park Service (NPS), Northeast Coastal and Barrier 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 coastal resource managers.

  4. EAARL topography: Gulf Islands National Seashore: Florida

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

    2007-01-01

    This Web site contains 33 lidar-derived bare earth topography maps and GIS files for the Gulf Islands National Seashore-Florida. These lidar-derived topography 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), Gulf Coast Network, 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.

  5. EAARL topography: Gateway National Recreation Area

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2007-01-01

    This Web site contains Lidar-derived topography (bare earth) maps and GIS files for the Sandy Hook Unit within Gateway National Recreation Area in New Jersey. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, FISC St. Petersburg, 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.

  6. EAARL Topography-Padre Island National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

    2007-01-01

    This Web site contains 116 Lidar-derived bare earth topography maps and GIS files for Padre Island National Seashore-Texas. These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Florida Integrated Science Center (FISC) St. Petersburg, Florida, the National Park Service (NPS) Gulf Coast 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.

  7. EAARL topography: Gulf Islands National Seashore: Mississippi

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Patterson, Matt; Wilson, Iris; Travers, Laurinda J.

    2007-01-01

    This Web site contains 30 lidar-derived bare earth topography maps and GIS files for the Gulf Islands National Seashore-Mississippi. These lidar-derived topography 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) Gulf Coast 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.

  8. Curvature sensor for the measurement of the static corneal topography and the dynamic tear film topography in the human eye

    NASA Astrophysics Data System (ADS)

    Gruppetta, Steve; Koechlin, Laurent; Lacombe, François; Puget, Pascal

    2005-10-01

    A system to measure the topography of the first optical surface of the human eye noninvasively by using a curvature sensor is described. The static corneal topography and the dynamic topography of the tear film can both be measured, and the topographies obtained are presented. The system makes possible the study of the dynamic aberrations introduced by the tear film to determine their contribution to the overall ocular aberrations in healthy eyes, eyes with corneal pathologies, and eyes wearing contact lenses.

  9. Petrological significance of the abyssal peridotites from the ophiolite belt of Indo-Myanmar Range, northeastern India

    NASA Astrophysics Data System (ADS)

    Maibam, B.; Foley, S.

    2009-04-01

    The ophiolite belt of the Indo-Myanmar Range of northeastern India is regarded as the continental extension of the Indonesia island arc. The ophiolite sequence forms a belt extending about 200 km from Pukhpur (Nagaland state) in the north to Moreh (Manipur state) in the south. Here we report preliminary mineralogical and phase geochemical data of peridotites collected from the ophiolite sequences of the Ukhrul district in Manipur. Primary minerals are clinopyroxene, orthopyroxene and spinel with scarce relicts of olivine. Andraditic garnet present in a few samples is of secondary origin. The clinopyroxene and orthopyroxene show limited compositional range. Well's (1977) single clinopyroxene thermometry yielded variable equilibrium temperature between 780-1250oC. The lower temperature value suggests post-crystallisation re-equilibration. Equilibrium pressure estimates based on Nimis and Ulmer's single clinopyroxene (1998) and Köhler and Brey's (1990) olivine-spinel geobarometries range from 19 to 25 kbars. Oxygen fugacity expressed in terms of quartz-fayalite-magnetite (Delta QFM) value is calculated as -1.32. Spinel Cr# (Cr/(Cr+Al)) of the peridotites reflects mantle residues after low degree of melting (F = 0.5 - 11%) if derived from primitive mantle. Mineral composition tectonomagmatic discrimination diagrams confirm the studied samples to be abyssal peridotites. Laser Ablation ICPMS analyses of the rare earth element patterns of clinopyroxene in the peridotites show depleted light rare earth element with flat middle and heavy rare earth element patterns, similar to the reported abyssal peridotites. References Wells P.R.A. (1977) CMP, 62, 129-139. Nimis P., Ulmer P. (1998) CMP, 133, 122-135. Köhler T., Brey G.P. (1990) GCA, 54, 2375-2388.

  10. Descending into the abyss: Bathymetric patterns of diversity in decapod crustaceans shift with taxonomic level and life strategies

    NASA Astrophysics Data System (ADS)

    Rosa, Rui; Boavida-Portugal, Joana; Trübenbach, Katja; Baptista, Miguel; Araújo, Ricardo; Calado, Ricardo

    2012-06-01

    The aim of this study was to examine the depth-related changes in the diversity of decapod crustaceans from the intertidal to abyssal zones off Madeira Archipelago, a chain of islands in the subtropical North East Atlantic Ocean. The bathymetric gradient in species richness was evaluated using the reported ranges of 175 out of approximately 186 decapod species known in this archipelago. The depth-related changes at different taxonomic (order, sub-orders and families) and life strategy (pelagic, benthopelagic and benthic) levels were investigated and different ecological hypotheses (species-energy, mid-domain and Rapoport's effects) were tested to explain the observed patterns. No unimodal trend of Decapoda diversity was revealed and, instead, a monotonic decrease towards the abyss was observed, mainly as a consequence of the depth-related changes in the benthic diversity of the suborder Pleocyemata. Nonetheless, all bathymetric gradients of pelagic diversity (at order and suborder levels) displayed parabolic trends. There was also a general increase in bathymetric range towards greater depth, and the major faunal break was identified within the continental shelf area. All species richness-depth patterns were significantly nested, but there was a clear increasing trend in randomness from the benthic to the pelagic realm. The present study shows for the first time that even within the same taxonomic group and geographic region different bathymetric patterns of diversity can be observed, depending on the taxonomic level and, more importantly, on the group's life strategies. Moreover, our analysis supports the species-energy hypothesis, implicating a combination of temperature and food availability as the main causal predictors explaining diversity variation.

  11. Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping

    NASA Astrophysics Data System (ADS)

    Korff, Lucia; Dobeneck, Tilo; Frederichs, Thomas; Kasten, Sabine; Kuhn, Gerhard; Gersonde, Rainer; Diekmann, Bernhard

    2016-05-01

    The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a "blank spot" in ocean and climate history. Paleomagnetic and rock magnetic, geochemical, and sedimentological methods were combined to date and analyze seven middle to late Pleistocene northwest Pacific sediment cores from water depths of 5100 to 5700 m. Besides largely coherent tephra layers, the most striking features of these records are nearly magnetite-free zones corresponding to glacial marine isotope stages (MISs) 22, 12, 10, 8, 6, and 2. Magnetite depletion is correlated with organic carbon and quartz content and anticorrelated with biogenic barite and opal content. Within interglacial sections and mid-Pleistocene transition glacial stages MIS 20, 18, 16, and 14, magnetite fractions of detrital, volcanic, and bacterial origin are all well preserved. Such alternating successions of magnetic iron mineral preservation and depletion are known from sapropel-marl cycles, which accumulated under periodically changing bottom water oxygen and redox conditions. In the open central northwest Pacific Ocean, the only conceivable mechanism to cause such abrupt change is a modified glacial bottom water circulation. During all major glaciations since MIS 12, oxygen-depleted Antarctic Bottom Water (AABW)-sourced bottom water seems to have crept into the abyssal northwest Pacific below ~5000 m depth, thereby changing redox conditions in the sediment, trapping and preserving dissolved and particulate organic matter and, in consequence, reducing and dissolving both, biogenic and detrital magnetite. At deglaciation, a downward progressing oxidation front apparently remineralized and released these sedimentary carbon reservoirs without replenishing the magnetite losses.

  12. Interferometer for measuring dynamic corneal topography

    NASA Astrophysics Data System (ADS)

    Micali, Jason Daniel

    The cornea is the anterior most surface of the eye and plays a critical role in vision. A thin fluid layer, the tear film, coats the outer surface of the cornea and serves to protect, nourish, and lubricate the cornea. At the same time, the tear film is responsible for creating a smooth continuous surface where the majority of refraction takes place in the eye. A significant component of vision quality is determined by the shape of the cornea and stability of the tear film. It is desirable to possess an instrument that can measure the corneal shape and tear film surface with the same accuracy and resolution that is currently performed on common optical elements. A dual interferometer system for measuring the dynamic corneal topography is designed, built, and verified. The completed system is validated by testing on human subjects. The system consists of two co-aligned polarization splitting Twyman-Green interferometers designed to measure phase instantaneously. The primary interferometer measures the surface of the tear film while the secondary interferometer simultaneously tracks the absolute position of the cornea. Eye motion, ocular variation, and a dynamic tear film surface will result in a non-null configuration of the surface with respect to the interferometer system. A non-null test results in significant interferometer induced errors that add to the measured phase. New algorithms are developed to recover the absolute surface topography of the tear film and corneal surface from the simultaneous interferometer measurements. The results are high-resolution and high-accuracy surface topography measurements of the in vivo cornea that are captured at standard camera frame rates. This dissertation will cover the development and construction of an interferometer system for measuring the dynamic corneal topography of the human eye. The discussion starts with the completion of an interferometer for measuring the tear film. The tear film interferometer is part of an

  13. OpenTopography: Enabling Online Access to High-Resolution Lidar Topography Data and Processing Tools

    NASA Astrophysics Data System (ADS)

    Crosby, Christopher; Nandigam, Viswanath; Baru, Chaitan; Arrowsmith, J. Ramon

    2013-04-01

    High-resolution topography data acquired with lidar (light detection and ranging) technology are revolutionizing the way we study the Earth's surface and overlying vegetation. These data, collected from airborne, tripod, or mobile-mounted scanners have emerged as a fundamental tool for research on topics ranging from earthquake hazards to hillslope processes. Lidar data provide a digital representation of the earth's surface at a resolution sufficient to appropriately capture the processes that contribute to landscape evolution. The U.S. National Science Foundation-funded OpenTopography Facility (http://www.opentopography.org) is a web-based system designed to democratize access to earth science-oriented lidar topography data. OpenTopography provides free, online access to lidar data in a number of forms, including the raw point cloud and associated geospatial-processing tools for customized analysis. The point cloud data are co-located with on-demand processing tools to generate digital elevation models, and derived products and visualizations which allow users to quickly access data in a format appropriate for their scientific application. The OpenTopography system is built using a service-oriented architecture (SOA) that leverages cyberinfrastructure resources at the San Diego Supercomputer Center at the University of California San Diego to allow users, regardless of expertise level, to access these massive lidar datasets and derived products for use in research and teaching. OpenTopography hosts over 500 billion lidar returns covering 85,000 km2. These data are all in the public domain and are provided by a variety of partners under joint agreements and memoranda of understanding with OpenTopography. Partners include national facilities such as the NSF-funded National Center for Airborne Lidar Mapping (NCALM), as well as non-governmental organizations and local, state, and federal agencies. OpenTopography has become a hub for high-resolution topography

  14. Descent from the Summit of 'Husband Hill' (False Color)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In late November 2005 while descending 'Husband Hill,' NASA's Mars Exploration Rover Spirit took the most detailed panorama so far of the 'Inner Basin,' the rover's next target destination. Spirit acquired the 405 individual images that make up this 360-degree view of the surrounding terrain using five different filters on the panoramic camera. The rover took the images on Martian days, or sols, 672 to 677 (Nov. 23 to 28, 2005 -- the Thanksgiving holiday weekend).

    This image is a false-color rendering using camera's 750-, 530-, and 430-nanometer filters, emphasizing some colors more than others to enhance striking but subtle color differences among rocks, soils, hills, and plains.

    'Home Plate,' a bright, semi-circular feature scientists hope to investigate, is harder to discern in this image than in earlier views taken from higher up the hill. Spirit acquired this more oblique view, known as the 'Seminole panorama,' from about halfway down the south flank of Husband Hill, 50 meters (164 feet) or so below the summit. Near the center of the panorama, on the horizon, are 'McCool Hill' and 'Ramon Hill,' named, like Husband Hill, in honor of the fallen astronauts of the space shuttle Columbia. Husband Hill is visible behind the rover, on the right and left sides of the panorama. An arc of rover tracks made while avoiding obstacles and getting into position to examine rock outcrops can be traced over a long distance by zooming in to explore the panorama in greater detail.

    Spirit is now significantly farther downhill toward the center of this panorama, en route to Home Plate and other enigmatic soils and outcrop rocks in the quest to uncover the history of Gusev Crater and the 'Columbia Hills.'

  15. Evidence for Repeated Early Miocene Glaciation and the Cutting of Upper Taylor Valley from the Friis Hills, Antarctica

    NASA Astrophysics Data System (ADS)

    Lewis, A.; Ashworth, A. C.; Marchant, D. R.; Hemming, S. R.

    2009-12-01

    The Friis Hills, located at the head of Taylor Valley in the the McMurdo Dry Valleys, hold a sequence of stacked tills at least Early Miocene in age. Sedimentology, clast lithology and bedrock striations indicate these tills were deposited from wet-based glaciers that flowed southeastward down a shallow paleovalley toward the Ferrar trough. Interbedded paleosols, fluvial, and glaciolacustrine deposits register ice-free periods when the valley held small streams and ponds. Exceptionally well-preserved fossil biota suggests mild conditions during at least two of these interglacial episodes. Proglacial lacustrine deposits that include dropstones and debris flows mark the return of glacial conditions but fossil leaves and wood of Nothofagus suggest conditions during the initial phase of ice advance were also relatively mild. Geomorphic relationships show that major valley incision must have taken place after deposition of these sediments as the Friis Hills is today a flat-topped inselberg, about 5 km across, isolated from nearby topography by the deep glacial troughs of the Taylor Valley drainage. A second suite of tills, directly overlying the first, registers a reorganized glacial system with ice streaming eastward, roughly parallel to Taylor Valley. Like the first, these tills were deposited during repeated ice advances but glaciers never fully inundated the Friis Hills and ice-free periods are marked by only weak weathering surfaces and thin glaciolacustrine deposits. We interpret the changing glacial pattern to reflect headward cutting in upper Taylor Valley and the capture of ice from the Ferrar drainage. A volcanic ash interbed dated by Ar-Ar at 19.76 (±0.11) Ma occurs in a Taylor Valley-oriented drift near the eastern edge of the Friis Hills plateau. Based on its stratigraphic position, the older suite of tills and fossil-bearing interbeds are >19.76 Ma. Underlying bedrock striations show that ice flow had been redirected into Taylor Valley by this time. The

  16. Seismic waveform sensitivity to global boundary topography

    NASA Astrophysics Data System (ADS)

    Colombi, Andrea; Nissen-Meyer, Tarje; Boschi, Lapo; Giardini, Domenico

    2012-09-01

    We investigate the implications of lateral variations in the topography of global seismic discontinuities, in the framework of high-resolution forward modelling and seismic imaging. We run 3-D wave-propagation simulations accurate at periods of 10 s and longer, with Earth models including core-mantle boundary topography anomalies of ˜1000 km spatial wavelength and up to 10 km height. We obtain very different waveform signatures for PcP (reflected) and Pdiff (diffracted) phases, supporting the theoretical expectation that the latter are sensitive primarily to large-scale structure, whereas the former only to small scale, where large and small are relative to the frequency. PcP at 10 s seems to be well suited to map such a small-scale perturbation, whereas Pdiff at the same frequency carries faint signatures that do not allow any tomographic reconstruction. Only at higher frequency, the signature becomes stronger. We present a new algorithm to compute sensitivity kernels relating seismic traveltimes (measured by cross-correlation of observed and theoretical seismograms) to the topography of seismic discontinuities at any depth in the Earth using full 3-D wave propagation. Calculation of accurate finite-frequency sensitivity kernels is notoriously expensive, but we reduce computational costs drastically by limiting ourselves to spherically symmetric reference models, and exploiting the axial symmetry of the resulting propagating wavefield that collapses to a 2-D numerical domain. We compute and analyse a suite of kernels for upper and lower mantle discontinuities that can be used for finite-frequency waveform inversion. The PcP and Pdiff sensitivity footprints are in good agreement with the result obtained cross-correlating perturbed and unperturbed seismogram, validating our approach against full 3-D modelling to invert for such structures.

  17. Topography Influences Adherent Cell Regulation of Osteoclastogenesis.

    PubMed

    Nagasawa, M; Cooper, L F; Ogino, Y; Mendonca, D; Liang, R; Yang, S; Mendonca, G; Uoshima, K

    2016-03-01

    The importance of osteoclast-mediated bone resorption in the process of osseointegration has not been widely considered. In this study, cell culture was used to investigate the hypothesis that the function of implant-adherent bone marrow stromal cells (BMSCs) in osteoclastogenesis is influenced by surface topography. BMSCs isolated from femur and tibia of Sprague-Dawley rats were seeded onto 3 types of titanium surfaces (smooth, micro, and nano) and a control surface (tissue culture plastic) with or without osteogenic supplements. After 3 to 14 d, conditioned medium (CM) was collected. Subsequently, rat bone marrow-derived macrophages (BMMs) were cultured in media supplemented with soluble receptor activator of NF-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) as well as BMSC CM from each of the 4 surfaces. Gene expression levels of soluble RANKL, osteoprotegerin, tumor necrosis factor α, and M-CSF in cultured BMSCs at different time points were measured by real-time polymerase chain reaction. The number of differentiated osteoclastic cells was determined after tartrate-resistant acid phosphatase staining. Analysis of variance and t test were used for statistical analysis. The expression of prominent osteoclast-promoting factors tumor necrosis factor α and M-CSF was increased by BMSCs cultured on both micro- and nanoscale titanium topographies (P < 0.01). BMSC CM contained a heat-labile factor that increased BMMs osteoclastogenesis. CM from both micro- and nanoscale surface-adherent BMSCs increased the osteoclast number (P < 0.01). Difference in surface topography altered BMSC phenotype and influenced BMM osteoclastogenesis. Local signaling by implant-adherent cells at the implant-bone interface may indirectly control osteoclastogenesis and bone accrual around endosseous implants.

  18. Macromolecular Topography Leaps into the Digital Age

    NASA Technical Reports Server (NTRS)

    Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

    2003-01-01

    A low-cost, real-time digital topography system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the topography images. With this development macromolecular topography finally comes into the digital age.

  19. EAARL Coastal Topography - Sandy Hook 2007

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), Northeast Coastal and Barrier Network, Kingston, RI; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate datasets of Gateway National Recreation Area's Sandy Hook Unit in New Jersey, acquired on May 16, 2007. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL) was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then

  20. Welcome to Surface Topography: Metrology and Properties

    NASA Astrophysics Data System (ADS)

    Leach, Richard

    2013-11-01

    I am delighted to welcome readers to this inaugural issue of Surface Topography: Metrology and Properties (STMP). In these days of citation indexes and academic reviews, it is a tough, and maybe a brave, job to start a new journal. But the subject area has never been more active and we are seeing genuine breakthroughs in the use of surfaces to control functional performance. Most manufactured parts rely on some form of control of their surface characteristics. The surface is usually defined as that feature on a component or device, which interacts with either the environment in which it is housed (or in which the device operates), or with another surface. The surface topography and material characteristics of a part can affect how fluids interact with it, how the part looks and feels and how two bearing parts will slide together. The need to control, and hence measure, surface features is becoming increasingly important as we move into a miniaturized world. Surface features can become the dominant functional features of a part and may become large in comparison to the overall size of an object. Research into surface texture measurement and characterization has been carried out for over a century and is now more active than ever, especially as new areal surface texture specification standards begin to be introduced. The range of disciplines for which the function of a surface relates to its topography is very diverse; from metal sheet manufacturing to art restoration, from plastic electronics to forensics. Until now, there has been no obvious publishing venue to bring together all these applications with the underlying research and theory, or to unite those working in academia with engineering and industry. Hence the creation of Surface Topography: Metrology and Properties . STMP will publish the best work being done across this broad discipline in one journal, helping researchers to share common themes and highlighting and promoting the extraordinary benefits this

  1. Carbon contamination topography analysis of EUV masks

    SciTech Connect

    Fan, Y.-J.; Yankulin, L.; Thomas, P.; Mbanaso, C.; Antohe, A.; Garg, R.; Wang, Y.; Murray, T.; Wuest, A.; Goodwin, F.; Huh, S.; Cordes, A.; Naulleau, P.; Goldberg, K. A.; Mochi, I.; Gullikson, E.; Denbeaux, G.

    2010-03-12

    The impact of carbon contamination on extreme ultraviolet (EUV) masks is significant due to throughput loss and potential effects on imaging performance. Current carbon contamination research primarily focuses on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on absorbing features and the printed images, as well as impacting the efficiency of cleaning process. In this work, several different techniques were used to determine possible contamination topography. Lithographic simulations were also performed and the results compared with the experimental data.

  2. 18. Historic American Buildings Survey Joseph Hill, Photographer May 26, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. Historic American Buildings Survey Joseph Hill, Photographer May 26, 1936 FIREPLACE IN DINING ROOM, The Davenport House, Rock Island Arsenal - Rock Island Arsenal, Building No. 346, Davenport Drive, Arsenal Grounds, Rock Island, Rock Island County, IL

  3. 258. Dennis Hill, Photographer April 1998 VIEW OF CANTILEVER TRUSS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    258. Dennis Hill, Photographer April 1998 VIEW OF CANTILEVER TRUSS ANCHOR ARM AT PIERS E- AND E-2, SOUTH SIDE, FACING NORTH. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  4. 81. VIEW NORTH ON WEST SIDE OF GUN HILL PLATFORM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    81. VIEW NORTH ON WEST SIDE OF GUN HILL PLATFORM SHOWING LAMP STANDARDS FOR NIGHT LIGHTNING. - Interborough Rapid Transit Company, Third Avenue Elevated Line, Borough of the Bronx, New York County, NY

  5. 28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ABOVE EAST TOWER. NOTE SWAY CABLES ON EACH SIDE OF THE WALKWAY. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  6. 184. Dennis Hill, Photographer June 1998 DETAIL VIEW OF UPPER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    184. Dennis Hill, Photographer June 1998 DETAIL VIEW OF UPPER DECK EXPANSION JOINT AT PIER W-2, FACING WEST-SOUTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  7. 2. Historic American Buildings Survey Joseph Hill, Photographer May 10, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Joseph Hill, Photographer May 10, 1936 CAST IRON GATE AT 1352 W. Washington Blvd., Chicago - Chicago Ironwork, William M. Strong Estate (Cast Iron House & Gate), 1352 West Washington Boulevard, Chicago, Cook County, IL

  8. 1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 FENCE RAILING 1133 WEST WASHINGTON BLVD. - Chicago Ironwork, 1133 West Washington Boulevard (Cast Iron Fence & Railing), 1133 West Washington Boulevard, Chicago, Cook County, IL

  9. 1. Historic American Buildings Survey Joseph Hill, Photographer July, 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer July, 1936 PORCH RAILING, 1149 W. WASHINGTON Blvd. - Chicago Ironwork, 1149 West Washington Boulevard (Cast Iron Stair Railing), 1149 West Washington Boulevard, Chicago, Cook County, IL

  10. 6. Historic American Buildings Survey Joseph Hill, Photographer April 1, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey Joseph Hill, Photographer April 1, 1936 MANTEL 1352 W. Washington Blvd., Chicago - Chicago Ironwork, William M. Strong Estate (Cast Iron House & Gate), 1352 West Washington Boulevard, Chicago, Cook County, IL

  11. Context view looking west from hill with tree in foreground. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Context view looking west from hill with tree in foreground. Entist Mountains are in distance. - Badger Mountain Lookout, .125 mile northwest of Badger Mountain summit, East Wenatchee, Douglas County, WA

  12. Modal comparison of Yamato and Allan Hills polymict eucrites

    NASA Technical Reports Server (NTRS)

    Delaney, J. S.; Prinz, M.; Takeda, H.

    1983-01-01

    Seven Yamato and six Allan Hills polymict eucrite specimens were compared by modal analysis. The analyses reveal differences of plagioclase and pyroxene content between the two groups. The Yamato suite has more 'pigeonitic' pyroxene and less plagioclase and low-calcium pyroxene than the Allan Hills suite. Variations within each suite are small and three sections of Allan Hills A78040 are more variable than the Allen Hills suite considered as a group. Modal data provides a basis for pairing polymict eucrite specimens when used together with mineralogical and petrographic criteria. Modal data furthermore confirms the presence of several rock types previously identified using pyroxene crystallography and hints at the presence of an augite-rich component.

  13. 12. ARROYO SECO PARKWAY SEEN FROM RADIO TOWER HILL. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. ARROYO SECO PARKWAY SEEN FROM RADIO TOWER HILL. NOTE PARALLEL SURFACE STREET AT LEFT AND AVENUE 43 BRIDGE AT RIGHT. LOOKING 342° NNW. - Arroyo Seco Parkway, Los Angeles to Pasadena, Los Angeles, Los Angeles County, CA

  14. View looking east over coal tipple toward Friendship Hill, home ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking east over coal tipple toward Friendship Hill, home of Albert Gallatin, in right background behine bridge. - Monongahela Railroad, New Geneva Bridge, Spanning Monongahela River, South of Lock & Dam No. 7, New Geneva, Fayette County, PA

  15. 117. Dennis Hill, Photographer April 1998 VIEW UP ESSEX STREET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    117. Dennis Hill, Photographer April 1998 VIEW UP ESSEX STREET AT UPPER DECK OFF-RAMP, FACING NORTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  16. 132. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    132. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP FROM NATOMA STREET BETWEEN FIRST AND SECOND STREETS, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  17. 122. Dennis Hill, Photographer January 1998 VIEW OF UPPER DECK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    122. Dennis Hill, Photographer January 1998 VIEW OF UPPER DECK OFF-RAMP AND TRANSBAY TERMINAL BUS LOOP, SOUTHWEST OF FIRST STREET, FACING NORTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  18. 139. Dennis Hill, Photographer January 1998 ELEVATION VIEW OF TRANSBAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    139. Dennis Hill, Photographer January 1998 ELEVATION VIEW OF TRANSBAY TERMINAL BUS LOOP CROSSING OVER HARRISON STREET, FACING NORTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  19. 127. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TRANSBAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    127. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TRANSBAY TERMINAL BUS LOOP CROSSING OVER HOWARD STREET NORTHEAST OF BEALE STREET, FACING WEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  20. 124. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    124. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP CROSSING OVER FREMONT STREET, FACING NORTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  1. 137. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    137. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP AT SPLIT, FACING NORTH. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  2. 129. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    129. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP FROM HOWARD STREET NORTHEAST OF BEALE STREET, FACING NORTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  3. 136. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    136. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP AT SPLIT (FROM GROUND LEVEL), FACING SOUTH-SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  4. 135. Dennis Hill, Photographer December 1997 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    135. Dennis Hill, Photographer December 1997 VIEW OF TRANSBAY TERMINAL BUS LOOP AT SPLIT, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  5. 134. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    134. Dennis Hill, Photographer April 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP NEAR SPLIT, WITH SUSPENSION BRIDGE IN DISTANT BACKGROUND, FACING EAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  6. 234. Dennis Hill, Photographer July 1998 VIEW OF BUS STOP, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    234. Dennis Hill, Photographer July 1998 VIEW OF BUS STOP, UPPER DECK OF YERBA BUENA EAST VIADUCT, FACING WEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  7. 125. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    125. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP CROSSING OVER BEALE STREET BETWEEN FOLSOM AND HOWARD STREETS, FACING NORTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  8. 119. Dennis Hill, Photographer January 1998 VIEW OF UNDERSIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    119. Dennis Hill, Photographer January 1998 VIEW OF UNDERSIDE OF UPPER DECK OFF-RAMP AND TRANSBAY TERMINAL BUS LOOP NEAR FOLSOM STREET, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  9. 123. Dennis Hill, Photographer January 1998 VIEW OF UPPER DECK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    123. Dennis Hill, Photographer January 1998 VIEW OF UPPER DECK OFF-RAMP DESCENDING TO FREMONT STREET, WITH TRANSBAY TERMINAL BUS LOOP BEHIND, FACING NORTH. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  10. 133. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    133. Dennis Hill, Photographer January 1998 VIEW OF TRANSBAY TERMINAL BUS LOOP FROM HOWARD STREET BETWEEN FIRST AND SECOND STREETS, FACING EAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  11. 128. Dennis Hill, Photographer January 1998 VIEW OF UNDERSIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    128. Dennis Hill, Photographer January 1998 VIEW OF UNDERSIDE OF TRANSBAY TERMINAL BUS LOOP CROSSING OVER HOWARD STREET NORTHEAST OF BEALE STREET, FACING NORTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  12. EXTERIOR, A view looking northwest from far hill toward the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR, A view looking northwest from far hill toward the Mounds complex and the HH Building - Department of Energy, Mound Facility, Hydrolysis House Building (HH Building), One Mound Road, Miamisburg, Montgomery County, OH

  13. 233. Dennis Hill, Photographer April 1998 VIEW OF LOWER DECK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    233. Dennis Hill, Photographer April 1998 VIEW OF LOWER DECK AND KEY SYSTEM STATION CANOPY, YERBA BUENA EAST VIADUCT, FACING NORTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  14. 215. Dennis Hill, Photographer May 1998 DETAIL VIEW OF STRAND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    215. Dennis Hill, Photographer May 1998 DETAIL VIEW OF STRAND SHOES AND STORM CABLE EYE BARS IN YERBA BUENA ANCHORAGE, FACING EAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  15. 266. Dennis Hill, Photographer June 1998 DETAIL VIEW OF TENSION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    266. Dennis Hill, Photographer June 1998 DETAIL VIEW OF TENSION EYE BARS AND COMPRESSION MEMBERS ABOVE UPPER DECK, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  16. 265. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TENSION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    265. Dennis Hill, Photographer April 1998 DETAIL VIEW OF TENSION EYE BARS AT CANTILEVER TRUSS, FACING SOUTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  17. 22. TRANSMISSION MAIN, PLAN AND PROFILE, INDEX SHEET. Leeds, Hill, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. TRANSMISSION MAIN, PLAN AND PROFILE, INDEX SHEET. Leeds, Hill, Barnard & Jewett drawing, no date, no number. - Salinas River Project, Cuesta Tunnel, Southeast of U.S. 101, San Luis Obispo, San Luis Obispo County, CA

  18. 23. CUESTA TUNNEL, PORTAL STRUCTURES. Leeds, Hill, Barnard & Jewett ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. CUESTA TUNNEL, PORTAL STRUCTURES. Leeds, Hill, Barnard & Jewett drawing, no number, revised 10/10/41. - Salinas River Project, Cuesta Tunnel, Southeast of U.S. 101, San Luis Obispo, San Luis Obispo County, CA

  19. 12. Historic American Buildings Survey Joseph Hill, Photographer Spring 1937 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Historic American Buildings Survey Joseph Hill, Photographer Spring 1937 DETAIL OF CORNICE AND SECOND FLOOR WINDOW TRIM. - Rock Island Arsenal, Building No. 346, Davenport Drive, Arsenal Grounds, Rock Island, Rock Island County, IL

  20. 170. Credit SHS. Northern California Power Company substation, Bully Hill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    170. Credit SHS. Northern California Power Company substation, Bully Hill Mine area. Note lack of vegetation, caused by nearby copper smelting works. - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  1. 24. VIEW FORM NORTHWEST, WHERE HOUSE RECEDES INTO HILL, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. VIEW FORM NORTHWEST, WHERE HOUSE RECEDES INTO HILL, SHOWING ROOF, CHIMNEY AND OCTAGONAL SKYLIGHT TO KITCHEN IN CENTER - Isaac N. Hagan House, Kentuck Knob, U.S. Route 40 vicinity (Stewart Township), Chalkhill, Fayette County, PA

  2. 1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 STAIR RAILING, 66 WEST OAK STREET - Chicago Ironwork, 66 West Oak Street (Cast Iron Stair Railing), 66 West Oak Street, Chicago, Cook County, IL

  3. 1. Historic American Buildings Survey Joseph Hill, Photographer October 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer October 1936 #12 EARLY RED BRICK HOUSE, Elk and Prospect Sts., Galena, Illinois - Galena Doorways, Red Brick House, Elk & Prospect Streets, Galena, Jo Daviess County, IL

  4. 46. LINED SECTION OF AQUEDUCT LOOKING NORTH TO ALABAMA HILLS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. LINED SECTION OF AQUEDUCT LOOKING NORTH TO ALABAMA HILLS - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  5. 1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF OLD PHOTOGRAPH LOANED BY THE COMMANDANT, EARLY PHOTO OF HOUSE DATE UNKNOWN. - Rock Island Arsenal, Building No. 346, Davenport Drive, Arsenal Grounds, Rock Island, Rock Island County, IL

  6. 1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer July 1936 COPIED FROM AN OLD PHOTOGRAPH LOANED BY MRS. NELLY MUNRO - Old Baptist Parsonage, Snyder & Virginia Streets, Sublette, Lee County, IL

  7. 1. Historic American Buildings Survey Copied by Joseph Hill from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Copied by Joseph Hill from an old photograph loaned by Alice Snyder, Galena, Illinois. SOUTH EAST ELEVATION - Grace Episcopal Church, South Prospect Street, Galena, Jo Daviess County, IL

  8. 2. Historic American Buildings Survey Copied by Joseph Hill from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Copied by Joseph Hill from photograph loaned by the Illinois Bell Telephone Co. SOUTH EAST ELEVATION - Grace Episcopal Church, South Prospect Street, Galena, Jo Daviess County, IL

  9. 2. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF AN OLD PHOTOGRAPH LOANED BY THE COMMANDANT, ARSENAL ISLAND 1870 - Rock Island Arsenal, Rock Island, Rock Island County, IL

  10. 1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF PHOTOGRAPH LOANED BY THE COMMANDANT, FORT ARMSTRONG 1819 FROM A MODEL IN ARSENAL MUSEUM - Fort Armstrong, Rock Island, Rock Island County, IL

  11. 19. Historic American Buildings Survey Joseph Hill, Photographer COL. DAVENPORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Historic American Buildings Survey Joseph Hill, Photographer COL. DAVENPORT Copy of an old photograph loaned by the commandant. - Rock Island Arsenal, Building No. 346, Davenport Drive, Arsenal Grounds, Rock Island, Rock Island County, IL

  12. 4. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF OLD PHOTOGRAPH LOANED BY THE COMMANDANT, FORT ARMSTRONG ARSENAL ISLAND 1819 - Fort Armstrong, Rock Island, Rock Island County, IL

  13. 5. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF OLD PHOTOGRAPH LOANED BY THE COMMANDANT. DATE UNKNOWN - Rock Island Arsenal, Building No. 346, Davenport Drive, Arsenal Grounds, Rock Island, Rock Island County, IL

  14. 1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Joseph Hill, Photographer May 1936 COPY OF AN OLD PHOTOGRAPH LOANED BY THE COMMANDANT, EARLY BRIDGE ACROSS MISSISSIPPI RIVER, DATE UNKNOWN. - Bridge Spanning Mississippi River, Rock Island, Rock Island County, IL

  15. 12. VIEW FROM PARKWAY MEDIAN TO SPORT HILL ROAD BRIDGE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW FROM PARKWAY MEDIAN TO SPORT HILL ROAD BRIDGE, Copy of photograph ca. 1940. Collection Connecticut Department of Transportation. - Merritt Parkway, Bridge No. 744, Spanning Merritt Parkway at Route 59, Fairfield, Fairfield County, CT

  16. 3. Historic American Buildings Survey Joseph Hill, Photographer August 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Joseph Hill, Photographer August 1936 BRONZE TABLET HISTORICAL MARKER - Hobson Grist Mill (Monument & Millstones), DuPage County Pioneer Park, Naperville, Du Page County, IL

  17. 2. Historic American Buildings Survey Joseph Hill, Photographer July 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Joseph Hill, Photographer July 1936 BALCONY RAILING, 945 NO. DEARBORN ST. JUDGE CARPENTER'S HOME - Chicago Ironwork, Judge Carpenter House (Cast Iron Balcony Railing), 945 North Dearborn Street, Chicago, Cook County, IL

  18. 3. Historic American Buildings Survey Joseph Hill, Photographer June, 1936 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey Joseph Hill, Photographer June, 1936 DETAIL OF BALCONY RAILING, 945 NO. DEARBORN ST. JUDGE CARPENTER'S HOME - Chicago Ironwork, Judge Carpenter House (Cast Iron Balcony Railing), 945 North Dearborn Street, Chicago, Cook County, IL

  19. 12. Historic American Buildings Survey Joseph Hill, Photographer July 10, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Historic American Buildings Survey Joseph Hill, Photographer July 10, 1936 SOUTH ELEVATION (Copied from student's drawing, Dept. of Architecture, Armour Institute of Technology. Chicago) - Keating House, U.S. Highway 430, Fayville, Alexander County, IL

  20. 126. Dennis Hill, Photographer January 1998 DETAIL VIEW OF SUPPORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    126. Dennis Hill, Photographer January 1998 DETAIL VIEW OF SUPPORT STRUCTURE FOR TRANSBAY TERMINAL BUS LOOP CROSSING OVER BEALE STREET, FACING WEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  1. 154. Dennis Hill, Photographer April 1998 DETAIL VIEW OF ENTRY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    154. Dennis Hill, Photographer April 1998 DETAIL VIEW OF ENTRY DOOR TO SAN FRANCISCO ANCHORAGE AT BEALE STREET, FACING SOUTHWEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  2. 158. Dennis Hill, Photographer June 1998 VIEW DOWN BEALE STREET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    158. Dennis Hill, Photographer June 1998 VIEW DOWN BEALE STREET TOWARD HARRISON STREET BRIDGE, WITH SAN FRANCISCO ANCHORAGE AND CONTINUOUS SPAN IN BACKGROUND, FACING SOUTHEAST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  3. 305. Dennis Hill, Photographer June 1998 DETAIL VIEW OF UPPER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    305. Dennis Hill, Photographer June 1998 DETAIL VIEW OF UPPER DECK GUARDRAIL AT DECK TRUSS SPANS, FACING WEST. - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  4. Steamboat Hills exploratory slimhole: Drilling and testing

    SciTech Connect

    Finger, J.T.; Jacobson, F.D.; Hickox, C.E.; Eaton, R.R.

    1994-10-01

    During July-September, 1993, Sandia National Laboratories, in cooperation with Far West Capital, drilled a 4000 feet exploratory slimhole (3.9 inch diameter) in the Steamboat Hills geothermal field near Reno, Nevada. This well was part of Sandia`s program to evaluate slimholes as a geothermal exploration tool. During and after drilling the authors performed four series of production and injection tests while taking downhole (pressure-temperature-spinner) and surface (wellhead pressure and temperature, flow rate) data. In addition to these measurements, the well`s data set includes: continuous core (with detailed log); borehole televiewer images of the wellbore`s upper 500 feet; daily drilling reports from Sandia and from drilling contractor personnel; daily drilling fluid record; numerous temperature logs; and comparative data from production and injection wells in the same field. This report contains: (1) a narrative account of the drilling and testing, (2) a description of equipment used, (3) a brief geologic description of the formation drilled, (4) a summary and preliminary interpretation of the data, and (5) recommendations for future work.

  5. Bunker Hill Superfund site: Ecological restoration program

    SciTech Connect

    Brown, S.; Chaney, R.; Henry, C.L.; Compton, H.

    1998-12-31

    Bunker Hill ID was the site of mining and smelting activities for many decades. As a result of these activities, soils on the hillsides adjacent to the site became contaminated with Pb, Zn, and Cd. In addition to metal contamination, pH of the soils became highly acidic. Native vegetation has died off and the soils have become highly erosive. An application of municipal biosolids in combination with wood ash and log yard wood waste was made to test the potential of this remediation mixture to reduce erosion, correct soil pH, and support a self sustaining vegetative cover. Biosolids improve soil physical properties and provide macro and micro nutrients. Wood ash serves as a lime substitute and a source of nutrients. Log yard waste improves physical properties and has a high C:N ratio that reduces the potential for N leaching. Initial results are promising. A healthy stand of grasses and legumes has been established. In addition, the application mixture has proven itself to be highly resistant to erosion.

  6. ICP-AE and cluster analysis investigation of the distribution of major and trace element in manganese nodules, micronodules and abyssal clay collected from the Clarion-Clipperton abyssal plain, Northeast Pacific

    NASA Astrophysics Data System (ADS)

    Duliu, O. G.; Alexe, V. E.; Moutte, J.; Szobotca, S. A.

    2009-04-01

    The concentrations of seven major components (Ti, Fe, Mg, Ca, Na, K and P as oxides) and 15 trace elements (Sc, V, Cr, Ni, Cu, Sr, Y, Zr, Ba, La, Ce, Nd, Eu, Yb and Th) were determined by ICP-AE spectrometry in 27 samples of manganese nodules, micronodules and abyssal clay collected by dredging during the 1984 cruise of the R/V Akademik Alexandr Karpinski in the Clarion-Clipperton Province of the North Pacific (12° N-12° 40' N and 137° 40' W-138° 50' W) at a depth of about 4,500 m. Cluster analysis was used to compare among individual as well as pooled datasets, in addition to different indicators such as La/Th, Ni/Cu and LREE/HREE ratios for the Clarion-Clipperton samples, as well as between these and corresponding values for the upper continental crust (UCC), North America Shale Composite (NASC), and igneous Indian and Pacific Mid-Ocean Ridge Basalts (MORBs). The results evidenced the existence of significant positive correlations between major components in the Clarion-Clipperton samples and Pacific Ocean MORB, whereas trace elements (excepting Ni and Cu) correlate better with the UCC and NASC. There was also evidenced a depletion in LREEs which, together with a Ce negative anomaly for all Clarion-Clipperton samples, pointed towards a hydrothermal origin of the all REE, this fact being sustained by a La/Th ratio between 5 and 7, different from UCC (2.80) and NASC (2.50), but closer to Pacific (8.8) and Indian (11.25) Oceans MORBs. On the other hand, on a Sc-La-Th ternary diagram, all Clarion-Clipperton samples grouped together closer UCC and NASC and far away from both Pacific and Indian Oceans MORBs. At the same time, all investigated samples showed more significant clusters such as phosphorous pentoxide and all REE excepting Ce, or Ni and Cu. Compared to abyssal clay, the nodule as well as micronodules show significant enrichment in Ni and Cu while a constant Ni/Cu ratio indicated that all samples come from the sediment surface. In this way, the

  7. After runaway: The trans-Hill stage of planetesimal growth

    SciTech Connect

    Lithwick, Yoram

    2014-01-01

    When planetesimals begin to grow by coagulation, they first enter an epoch of runaway, during which the biggest bodies grow faster than all the others. The questions of how runaway ends and what comes next have not been answered satisfactorily. We show that runaway is followed by a new stage—the 'trans-Hill stage'—that commences when the bodies that dominate viscous stirring ('big bodies') become trans-Hill, i.e., when their Hill velocity matches the random speed of the small bodies they accrete. Subsequently, the small bodies' random speed grows in lockstep with the big bodies' sizes, such that the system remains in the trans-Hill state. Trans-Hill growth is crucial for determining the efficiency of growing big bodies, as well as their growth timescale and size spectrum. Trans-Hill growth has two sub-stages. In the earlier one, which occurs while the stirring bodies remain sufficiently small, the evolution is collisionless, i.e., collisional cooling among all bodies is irrelevant. The efficiency of forming big bodies in this collisionless sub-stage is very low, ∼10α << 1, where α ∼ 0.005(a/AU){sup –1} is the ratio between the physical size of a body and its Hill radius. Furthermore, the size spectrum is flat (equal mass per size decade, i.e., q = 4). This collisionless trans-Hill solution explains results from previous coagulation simulations for both the Kuiper Belt and the asteroid belt. The second trans-Hill sub-stage commences once the stirring bodies grow big enough (>α{sup –1} × the size of the accreted small bodies). After that time, collisional cooling among small bodies controls the evolution. The efficiency of forming big bodies rises and the size spectrum becomes more top heavy. Trans-Hill growth can terminate in one of two ways, depending on the sizes of the small bodies. First, mutual accretion of big bodies can become significant and conglomeration proceeds until half of the total mass is converted into big bodies. This mode of growth

  8. Stormwater Management Plan for the Arden Hills Army Training Site, Arden Hills, Minnesota

    SciTech Connect

    Carr, Adrianne E.; Wuthrich, Kelsey K.; Ziech, Angela M.; Bowen, Esther E.; Quinn, John

    2013-03-01

    This stormwater management plan focuses on the cantonment and training areas of the Arden Hills Army Training Site (AHATS). The plan relates the site stormwater to the regulatory framework, and it summarizes best management practices to aide site managers in promoting clean site runoff. It includes documentation for a newly developed, detailed model of stormwater flow retention for the entire AHATS property and adjacent upgradient areas. The model relies on established modeling codes integrated in a U.S. Department of Defense-sponsored software tool, the Watershed Modeling System (WMS), and it can be updated with data on changes in land use or with monitoring data.

  9. 27 CFR 9.162 - Sta. Rita Hills.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...). (3) “Los Alamos, Calif.,” edition of 1959. (4) “Santa Rosa Hills, Calif.,” edition of 1959... the heart of the Santa Rosa Land Grant, T.7N., R. 32W, on the Santa Rosa Hills, Calif., Quadrangle U.S... the northeastern part of the Santa Rosa Land Grant, T.7N, R. 32W, on the Los Alamos,...

  10. 1. General view of Fort Hill Farm, view looking southsoutheast. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. General view of Fort Hill Farm, view looking south-southeast. From left to right, buildings visible are (B) two-story hall-and-parlor house; (k) small barn; (A) mansion' (G( shed; (H) shed; (I) log tobacco barn; (H and D) shed and center chimney four-room cabin; (E and (A) one-room cabin in front of mansion; (J) hay barn. - Fort Hill Farm, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  11. 2. General view of Fort Hill Farm, view looking north ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. General view of Fort Hill Farm, view looking north from (F) two-room cabin. From left to right, buildings visible are (I) log tobacco barn; (H and D) shed and center chimney four-room cabin; (E and (A) one-room cabin in front of mansion; (J) hay barn. - Fort Hill Farm, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  12. 3. General view of Fort Hill Farm, view looking west ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. General view of Fort Hill Farm, view looking west from (B) two-story hall-and-parlor house. Buildings visible, from left to right, are (B) parlor house porch; (E) one-room cabin; (D) center chimney four-room cabin; (J) hay barn; (I) log tobacco barn; (A) mansion, obscured by trees; (M) stable; (K) small barn. - Fort Hill Farm, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

  13. 4. BUNKER HILL LEAD SMELTER. VIEW IS FROM RIDGE ABOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. BUNKER HILL LEAD SMELTER. VIEW IS FROM RIDGE ABOVE GOVERNMENT GULCH LOOKING TO THE EAST. IN THE RIGHT MID GROUND, CARPENTER SHOP BUILDINGS AND FRAMING SHEDS ARE VISIBLE. THE BACKGROUND FACILITIES VISIBLE FROM L. TO R. ARE: SMELTER OFFICE, REFINERIES, SLAG FUMING STACKS, HIGH VELOCITY FLUE, BAG HOUSE, 200-FOOT STACK, AND 715-FOOT STACK. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

  14. Water Quality Studies: Richard B. Russell and Clarks Hill Lakes.

    DTIC Science & Technology

    1986-12-01

    studies at Richard B. Russell and Clarks Hill lakes , Georgia and South Carolina. The study objectives were to document water quality conditions in each...Monitoring Program - Richard B. Russell Dam and Lake , Georgia and South Carolina" (Intra-Army Order No. PD-EI-84-07). Portions of these studies were...by the U. S. Army Corps of Engi- neers, is situated between Hartwell and Clarks Hill Lakes . 7. Concerns over the potential environmental and water

  15. SOUTH ELEVATION OF GOLD HILL MILL, LOOKING NORTH. THE PRIMARY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTH ELEVATION OF GOLD HILL MILL, LOOKING NORTH. THE PRIMARY ORE BIN IS A CENTER, WITH A JAW CRUSHER JUST TO THE RIGHT. A CONVEYOR (MISSING) WAS USED TO CARRY CRUSHED ORE UP AND INTO THE SECONDARY ORE BIN. THE STONE RAMP TO THE LEFT OF THE ORE BIN WAS USED TO DRIVE TRUCKS UP TO DUMPING LEVEL. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

  16. [Compositional characteristics and roles of soil mineral substances in depressions between hills in karst region].

    PubMed

    Han, Mei-Rong; Song, Tong-Qing; Peng, Wan-Xia; Huang, Guo-Qin; Du, Hu; Lu, Shi-Yang; Shi, Wei-Wei

    2012-03-01

    Based on the investigation and analysis of seven soil mineral substance variables, nine vegetation factors, four topographical factors, and ten soil physicochemical factors in the 200 m x 40 m dynamic monitoring plots in farmland, forest plantation, secondary forest, and primary forest in the depressions between hills in karst region, and by using traditional statistical analysis, principal component analysis (PCA), and canonical correlation analysis (CCA), this paper studied the compositional characteristics and roles of soil mineral substances as well as the coupling relationships between the mineral substances and the vegetation, topography, and other soil properties. In the depressions, soil mineral substances were mainly composed of SiO2, Al2O3, K2O, and Fe2O3, whose contents were obviously lower than the mean background values of the soils in the world and in the zonal red soils at the same latitudes. The soil CaO and MgO contents were at medium level, while the soil MnO content was very low. The composition of soil mineral substances and their variation degrees varied with the ecosystems, and the soil development degree also varied. There was a positive correlation between vegetation origin and soil origin, suggesting the potential risk of rock desertification. Due to the high landscape heterogeneity of the four ecosystems, PCA didn't show good effect in lowering dimension. In all of the four ecosystems, soil mineral substances were the main affecting factors, and had very close relationships with vegetation, topography, and other soil properties. Especially for SiO2, CaO, and MnO, they mainly affected the vegetation species diversity and the soil organic matter, total nitrogen, and total potassium. This study indicated that soil mineral substances were the one of the factors limiting the soil fertility and vegetation growth in the depressions between hills in karst region. To effectively use the soil mineral resources and rationally apply mineral nutrients

  17. Support of long-wavelength topography on Mercury inferred from MESSENGER measurements of gravity and topography

    NASA Astrophysics Data System (ADS)

    James, Peter B.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.

    2015-02-01

    To explore the mechanisms of support of surface topography on Mercury, we have determined the admittances and correlations of topography and gravity in Mercury's northern hemisphere from measurements obtained by NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. These admittances and correlations can be interpreted in the context of a number of theoretical scenarios, including flexural loading and dynamic flow. We find that long-wavelength (spherical harmonic degree l < 15) surface topography on Mercury is primarily supported through a combination of crustal thickness variations and deep mass anomalies. The deep mass anomalies may be interpreted either as lateral variations in mantle density or as relief on compositional interfaces. Domical topographic swells are associated with high admittances and are compensated at 300-400 km depth in the lower reaches of Mercury's mantle. Quasi-linear topographic rises are primarily associated with shallow crustal compensation and are weakly correlated with positive mass anomalies in the mantle. The center of the Caloris basin features some of the thinnest crust on the planet, and the basin is underlain by a large negative mass anomaly. We also explore models of dynamic flow in the presence of compositional stratification above the liquid core. If there is substantial compositional stratification in Mercury's solid outer shell, relaxation of perturbed compositional interfaces may be capable of creating and sustaining long-wavelength topography.

  18. Gravity/Topography Admittances and Lithospheric Evolution on Mars: The Importance of Finite-Amplitude Topography

    NASA Technical Reports Server (NTRS)

    McGovern, Patrick J.; Solomon, Sean C.; Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Head, J. W., III; Phillips, Roger J.; Simons, Mark

    2001-01-01

    We calculate localized gravity/topography admittances for Mars, in order to estimate elastic lithosphere thickness. A finite-amplitude correction to modeled gravity is required to properly interpret admittances in high-relief regions of Mars. Additional information is contained in the original extended abstract.

  19. Measurement of the topography of human cadaver lenses using the PAR corneal topography system

    NASA Astrophysics Data System (ADS)

    Fernandez, Viviana; Manns, Fabrice; Zipper, Stanley; Sandadi, Samith; Hamaoui, Marie; Tahi, Hassan; Ho, Arthur; Parel, Jean-Marie A.

    2001-06-01

    To measure the radius of curvature and asphericity of the anterior and posterior surfaces of crystalline lenses of human Eye-Bank eyes using the PAR Corneal Topography System. The measured values will be used in an optical model of the eye for lens refilling procedures.

  20. EAARL Topography-Colonial National Historical Park

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Nayegandhi, Amar; Stevens, Sara; Travers, Laurinda J.

    2008-01-01

    These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, Florida Integrated Science Center (FISC) St. Petersburg, the National Park Service (NPS) Inventory and Monitoring Program, Northeast Coastal and Barrier Network, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility. One objective of this research is to create techniques to survey coral reefs, barrier islands, and various nearshore coastal environments 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 coastal resource managers.

  1. Evaluation of facial palsy by moire topography

    NASA Astrophysics Data System (ADS)

    Inokuchi, Ikuo; Kawakami, Shinichiro; Maeta, Manabu; Masuda, Yu

    1991-08-01

    Society of Facial Research is used frequently. It is of great value clinically, but the method has several weak points concerning objective and quantitative assessment. This study uses moire topography to solve these problems. mA moire camera, FM3013, of the lattice irradiation type was used for measurement of the face. Five moire photographs were taken: at rest, wrinkling the forehead, closing the eyes lightly, blowing out the cheeks and grinning. The degree of facial palsy was determined by the Asymmetry Index (AI) as a measure of the degree of facial deviation. Total AI was expressed as the average AI based on calculations of the measurement in 5 photos. Severe paralysis is represented by an AI of more than 20%. Partial paralysis has a range of 20-8%. Nearly normal is judged to be less than 8%. Ten normal individuals are measured as control and show an AI of 3% or less. Moire topography is useful in assessing the recovery process because it has the benefit of making the site and grade of palsy easily achieved by the AI and the deviation in its patterns. The authors propose that the moire method is better for an objective and quantitative evaluation than the society's method.

  2. Uncertainty in measurement of surface topography

    NASA Astrophysics Data System (ADS)

    Haitjema, Han

    2015-09-01

    The 2.5-dimensional (2.5D) roughness parameters were standardized in 2012. With their increasing use in science and industry, the request for traceability and uncertainty evaluation for these parameters follows logically. This paper gives an overview of the problems and possibilities that appear when uncertainties have to be associated with values that are derived from a measured surface topography, such as the Ra-value of a periodic specimen, the RSm value of a type-D standard, and the Sa-value of a single cutoff length of a type D standard. It is shown that straightforward implementation of the methods described in the ‘Guide to the Expression of Uncertainty in Measurement’ (GUM) leads to impossible and impracticable equations because of the correlations between some millions of measurement points. A practical solution is found by considering the main aspects of uncertainty, as these are given in the recent ISO 25178 standards series, and applying these to a measured surface topography as a whole.

  3. EAARL Coastal Topography - Northern Gulf of Mexico

    USGS Publications Warehouse

    Nayegandhi, Amar; Brock, John C.; Sallenger, Abby; Wright, C. Wayne; Travers, Laurinda J.; Lebonitte, James

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived coastal topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. One objective of this research is to create techniques to survey areas for the purposes of geomorphic change studies following major storm events. The USGS Coastal and Marine Geology Program's National Assessment of Coastal Change Hazards project is a multi-year undertaking to identify and quantify the vulnerability of U.S. shorelines to coastal change hazards such as effects of severe storms, sea-level rise, and shoreline erosion and retreat. Airborne Lidar surveys conducted during periods of calm weather are compared to surveys collected following extreme storms in order to quantify the resulting coastal change. Other applications of high-resolution topography include habitat mapping, ecological monitoring, volumetric change detection, and event assessment. The purpose of this project is to provide highly detailed and accurate datasets of the northern Gulf of Mexico coastal areas, acquired on September 19, 2004, immediately following Hurricane Ivan. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Airborne Advanced Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532 nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking RGB (red-green-blue) digital camera, a high-resolution multi

  4. Deep-sea epibiotic hydroids from the abyssal plain adjacent to the Kuril-Kamchatka Trench with description of Garveia belyaevi sp. nov. (Hydrozoa, Bougainvilliidae)

    NASA Astrophysics Data System (ADS)

    Stepanjants, Sofia D.; Chernyshev, Alexey V.

    2015-01-01

    Examination of material collected by the German-Russian KuramBio Deep-Sea Expedition to the abyssal plain adjacent to the Kuril-Kamchatka Trench revealed about 17 hydroid species, including two species presumably new to science. Before the KuramBio Expedition only fragments of the unidentified hydroids and Cryptolaria sp. were collected in the Kuril-Kamchatka Trench from depths exceeding 3000 m. Descriptions of three species of epibiotic hydroids (including one new species, Garveia belyaevi sp. nov.) are presented herein. A colony of G. belyaevi sp. nov. (the third deep-sea and deepest species of the wide distributed genus Garveia) was attached to the spines of unidentified irregular sea urchins from depths 5217 to 5229 m. Нalitholus (?) sp. (Hydrozoa, Anthoathecata) colonized the skin of spoon worms (Echiura) but could not be identified to species level because the mature medusa stage was absent in the material. An unidentified juvenile polyp (Pandeidae) was found on the bryozoan Tricitella minini attached to spines of irregular sea urchins Echinosigra amphora. Colonial sedentary organisms inhabiting abyssal plains with soft bottoms may colonize invertebrates which are seldom used as substrates for epibiota in shallow waters. Epibiosis among abyssal colonial invertebrates, though extremely poorly studied, appears to be rather frequent.

  5. Bait-attending fauna of the Kermadec Trench, SW Pacific Ocean: Evidence for an ecotone across the abyssal-hadal transition zone

    NASA Astrophysics Data System (ADS)

    Jamieson, A. J.; Kilgallen, N. M.; Rowden, A. A.; Fujii, T.; Horton, T.; Lörz, A.-N.; Kitazawa, K.; Priede, I. G.

    2011-01-01

    The bait-attending fauna of the abyssal-hadal transition zone of the Kermadec Trench, SW Pacific Ocean (4329-7966 m), was investigated using a baited camera and a trap lander. The abyssal stations (4329-6007 m) revealed a typical scavenging fish community comprising macrourids and synaphobranchid eels, as well as natantian decapods. At the hadal depths of 7199 and 7561 m, the endemic liparid Notoliparis kermadecensis was observed aggregating at the bait reaching surprisingly high numbers of 5 and 13, respectively. A total of 3183 invertebrate samples were collected (mean deployment time=16 h) of which 97.8% were of the order Amphipoda (nine families, 16 species). Ten of the amphipod species represent new distributional records for the Kermadec Trench and the New Zealand Exclusive Economic Zone; this includes the shallowest known record of the endemic hadal amphipod Hirondellea dubia (6000, 6007 m). Using amphipods to statistically examine the compositional change across the abyssal-hadal boundary, an ecotone between depths <6007 and >6890 m was found, indicating that there is an ecologically distinct bait-attending fauna in this trench.

  6. Geologic and paleoecologic studies of the Nebraska Sand Hills

    USGS Publications Warehouse

    Ahlbrandt, Thomas S.; Fryberger, S.G.; Hanley, John H.; Bradbury, J. Platt

    1980-01-01

    PART A: The Nebraska Sand Hills are an inactive, late Quaternary, most probably Holocene, dune field (covering 57,000 km 2 ) that have been eroded along streams and in blowouts, resulting in excellent lateral and vertical exposures of the stratification of dune and interdune sediments. This paper presents new data on the geometry, primary sedimentary structures, modification of sedimentary structures, direction of sand movement, and petrography of these eolian deposits. Eolian deposits of the Sand Hills occur as relatively thin (9-24 m) 'blanket' sands, composed of a complex of dune and discontinuous, diachronous interdune deposits unconformably overlying fluviolacustrine sediments. The internal stratification of large dunes in the Sand Hills (as high as 100 m), is similar to the internal stratification of smaller dunes of the same type in the Sand Hills, differing only in scale. Studies of laminae orientation in the Sand Hills indicate that transverse, barchan, and blowout dunes can be differentiated in rocks of eolian origin using both the mean dip angle of laminae and the mean angular deviation of dip direction. A variety of secondary structures modify or replace primary eolian stratification in the Sand Hills, the more common of which are dissipation structures and bioturbation. Dissipation structures in the Sand Hills may develop when infiltrating water deposits clay adjacent to less permeable layers in the sand, or along the upper margins of frozen layers that form in the sands during winter. Cross-bed measurements from dunes of the Nebraska Sand Hills necessitate a new interpretation of the past sand transport directions. The data from these measurements indicate a general northwest-to-southeast drift of sand, with a more southerly drift in the southeast part of the Sand Hills. A large area of small dunes < 100 m high) described by Smith (1965) as linear or seif in the central part of the Sand Hills was interpreted by him on the basis of morphology only. We

  7. Fatty acid compositions and trophic relationships of shelled molluscs from the Kuril-Kamchatka Trench and the adjacent abyssal plain

    NASA Astrophysics Data System (ADS)

    Kharlamenko, Vladimir I.; Würzberg, Laura; Peters, Janna; Borisovets, Evgeny E.

    2015-01-01

    Fatty acid (FA) compositions of 12 species of shelled molluscs (gastropods, bivalves, and scaphopods) from the Kuril-Kamchatka Trench and the adjacent abyssal plain were studied. According to the results of multivariate statistical analysis, molluscs were divided into three groups. Group I consisted of three scaphopod species, the bivalve Nucula profundorum and the gastropod Solariella delicata. FA compositions of this group were characterized by high levels of 20:4(n-6). We suggest that the FA pattern found in scaphopods with high values of 20:4(n-6) is most likely typical for that of benthic organisms feeding preferentially on foraminiferans. Group II included the bivalves Neilonella politissima, Bentharca asperula, and Rhinoclama filatovae. Bivalves from the second group had elevated concentrations of 22:6(n-3), and the ratio of 20:4(n-6) to 20:5(n-3) was lower than 1. Bivalves from the second group had elevated concentrations of 22:6(n-3). We propose that high concentrations of this FA can be used as a specific marker for a carnivorous feeding mode of deep-sea benthic invertebrates. The bivalve Bathyspinula calcarella as well as the scaphopod Polyschides sakuraii could not unambiguously be assigned to one group. Within the similarity analysis they rather clustered together with the foraminiferans feeders (group I), but forming an own subgroup. In the PCA on the other hand, P. sakuraii showed a position close to the other bivalves, while B. calcarella had an intermediate position between all three groups. Group III consisted of the gastropods Tacita holoserica and Paracteocina sp., which contained high concentrations of 20:5(n-3) and 22:5(n-3). Both are known to exhibit a carnivorous/scavenging feeding strategy. The very low content of DHA in both species is on first sight not consistent with the suggested carnivorous feeding behavior. A characteristic feature of Paracteocina sp. and T. holoserica was a high level of 22:5(n-3), and HUFA ratios indicate that DHA

  8. Late Quaternary paleoenvironmental changes revealed by multi-proxy records from the Chukchi Abyssal Plain, western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Wang, Rujian; Xiao, Wenshen; März, Christian; Li, Qianyu

    2013-09-01

    Late Quaternary paleoenvironmental changes in the western Arctic Ocean are revealed by multi-proxy records of core 03M03 from the Chukchi Abyssal Plain (CAP). Proxy parameters include lithology, grain size fractions, and mineralogy and petrology of ice-rafted detritus (IRD), element contents, biogenic components, δ18O, δ13C and Mg/Ca of planktonic foraminifera Neogloboquadrina pachyderma (sin.) (Nps). Seven IRD (> 250 μm) peaks are interpreted as marking detrital input by rafting sea ice or icebergs during MIS 3 interstadials and early MIS 1. High MnO, CaO and MgO contents and high Ca/Al and Mg/Al ratios during MIS 3 and MIS 1 correspond to increases in ice-rafted detrital carbonates and the synchronous declines in siliciclastic elements (e.g., Al2O3, Fe2O3). Therefore, these warmer periods were characterized by a high detrital carbonate input entrained in icebergs from the Canadian Arctic Archipelago coeval with an increased input of Mn through rivers and/or coastal erosion. Relatively stable contents of siliciclastic elements and their ratios in the grayish sediment units are interpreted from turbid surface water plumes or nepheloid flows delivered by meltwater and/or brine rejection from ice-sheet margins at the Arctic Ocean periphery. Relatively stable clay- and silt-sized fractions were attributed mainly to sea ice entrainment over glacial-interglacial cycles. High foraminiferal abundances in the brown units during MIS 3 and 1 are related to enhanced calcareous plankton productivity under more open water conditions and/or the incremental input of Atlantic water masses. Relatively high TOC and opal contents in the grayish units of MIS 3 appear to have accumulated by lateral transport of organic matter from the Chukchi shelf to the deep abyssal plain. Lower contents of biogenic material in the brown units probably result from increased dilution by rapid IRD deposition, and from early diagenetic degradation. Depletions in Nps-δ18O and -δ13C concurrent with

  9. Simple models for disequilibrium fractional melting and batch melting with application to REE fractionation in abyssal peridotites

    NASA Astrophysics Data System (ADS)

    Liang, Yan; Liu, Boda

    2016-01-01

    Disequilibrium melting arises when the kinetics of chemical exchange between a residual mineral and partial melt is sluggish compare to the rate of melting. To better understand the role of a finite crystal-melt exchange rate on trace element fractionation during mantle melting, we have developed a disequilibrium melting model for partial melting in an upwelling steady-state column. We use linear kinetics to approximate crystal-melt mass exchange rate and obtain simple analytical solutions for cases of perfect fractional melting and batch melting. A key parameter determining the extent of chemical disequilibrium during partial melting is an element specific dimensionless ratio (ε) defined as the melting rate relative to the solid-melt chemical exchange rate for the trace element of interest. In the case of diffusion in mineral limited chemical exchange, ε is inversely proportional to diffusivity of the element of interest. Disequilibrium melting is important for the trace element when ε is comparable to or greater than the bulk solid-melt partition coefficient for the trace element (k). The disequilibrium fractional melting model is reduced to the equilibrium perfect fractional melting model when ε is much smaller than k. Hence highly incompatible trace elements with smaller mobilities in minerals are more susceptible to disequilibrium melting than moderately incompatible and compatible trace elements. Effect of chemical disequilibrium is to hinder the extent of fractionation between residual solid and partial melt, making the residual solid less depleted and the accumulated melt more depleted in incompatible trace element abundances relative the case of equilibrium melting. Application of the disequilibrium fractional melting model to REE and Y abundances in clinopyroxene in abyssal peridotites from the Central Indian Ridge and the Vema Lithospheric Section, Mid-Atlantic Ridge revealed a positive correlation between the disequilibrium parameter ε and the

  10. Seismotectonics of the Gulf of Cadiz and Horseshoe Abyssal Plain - active faulting in continental and oceanic mantle

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Matias, Luis

    2013-04-01

    In the area to the west of the Gibraltar Arc the plate boundary between Africa and Iberia is poorly defined. The deformation in the area is forced by the slow NW-SE convergence of 4 mm/yr between the oceanic domains of Iberia/Eurasia and Africa and is accommodated over a 200 km broad tectonically-active deformation zone. The region, however, is also characterized by large earthquakes and tsunamis, such as the 1969 Mw=7.9 Horseshoe Abyssal Plain earthquake and the November 1, 1755 Great Lisbon earthquake with an estimated magnitude of Mw~8.5. The exact location of the source of the 1755 Lisbon earthquake is still unknown. Recent work, however, may suggest that the event occurred in the vicinity of the Horseshoe fault, an oblique thrust fault. Further, the area is marked by the presence of compressive structures with a roughly NE-SW orientation and E-W trending, segmented, crustal-scale, strike slip faults that extend from the Gorringe Bank to the Gibraltar arc in the eastern Gulf of Cadiz, which were called "South West Iberian Margin" or SWIM faults. The fault system may mark a developing Eurasia-Africa plate boundary. Two local seismic networks were operated in the area. First, within the framework of TOPOE-EUROPE, a network of 24 ocean bottom seismometers (OBS) monitored the seismicity between January and July 2010 in the northern Gulf of Cadiz to the north of 36°N between 9°30'W and ~7 °W. The second network operated between April and October 2012 14OBS in the vicinity of the Horseshoe fault between 10°W to 11°W, and 35°50'N to 36°10'N. Recordings from the both deployments were supplemented by land stations operated in Portugal and the Gibraltar Arc. The networks provided in the order of 100 locale earthquakes occurring with the networks. In the Gulf of Cadiz, the two largest events of Mw~3.6 where thrust faulting events occurring in the vicinity of the Portimao Bank. With a depth of 40-50 km these events, among others, occurred within the continental

  11. The Impact of Source Distribution on Scalar Transport over Forested Hills

    NASA Astrophysics Data System (ADS)

    Ross, Andrew N.; Harman, Ian N.

    2015-08-01

    Numerical simulations of neutral flow over a two-dimensional, isolated, forested ridge are conducted to study the effects of scalar source distribution on scalar concentrations and fluxes over forested hills. Three different constant-flux sources are considered that span a range of idealized but ecologically important source distributions: a source at the ground, one uniformly distributed through the canopy, and one decaying with depth in the canopy. A fourth source type, where the in-canopy source depends on both the wind speed and the difference in concentration between the canopy and a reference concentration on the leaf, designed to mimic deposition, is also considered. The simulations show that the topographically-induced perturbations to the scalar concentration and fluxes are quantitatively dependent on the source distribution. The net impact is a balance of different processes affecting both advection and turbulent mixing, and can be significant even for moderate topography. Sources that have significant input in the deep canopy or at the ground exhibit a larger magnitude advection and turbulent flux-divergence terms in the canopy. The flows have identical velocity fields and so the differences are entirely due to the different tracer concentration fields resulting from the different source distributions. These in-canopy differences lead to larger spatial variations in above-canopy scalar fluxes for sources near the ground compared to cases where the source is predominantly located near the canopy top. Sensitivity tests show that the most significant impacts are often seen near to or slightly downstream of the flow separation or reattachment points within the canopy flow. The qualitative similarities to previous studies using periodic hills suggest that important processes occurring over isolated and periodic hills are not fundamentally different. The work has important implications for the interpretation of flux measurements over forests, even in

  12. Stargazing at 'Husband Hill Observatory' on Mars

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit continues to take advantage of extra solar energy by occasionally turning its cameras upward for night sky observations. Most recently, Spirit made a series of observations of bright star fields from the summit of 'Husband Hill' in Gusev Crater on Mars. Scientists use the images to assess the cameras' sensitivity and to search for evidence of nighttime clouds or haze. The image on the left is a computer simulation of the stars in the constellation Orion. The next three images are actual views of Orion captured with Spirit's panoramic camera during exposures of 10, 30, and 60 seconds.

    Because Spirit is in the southern hemisphere of Mars, Orion appears upside down compared to how it would appear to viewers in the Northern Hemisphere of Earth. 'Star trails' in the longer exposures are a result of the planet's rotation. The faintest stars visible in the 60-second exposure are about as bright as the faintest stars visible with the naked eye from Earth (about magnitude 6 in astronomical terms). The Orion Nebula, famous as a nursery of newly forming stars, is also visible in these images. Bright streaks in some parts of the images aren't stars or meteors or unidentified flying objects, but are caused by solar and galactic cosmic rays striking the camera's detector. Spirit acquired these images with the panoramic camera on Martian day, or sol, 632 (Oct. 13, 2005) at around 45 minutes past midnight local time, using the camera's broadband filter (wavelengths of 739 nanometers plus or minus 338 nanometers).

  13. Origin of bending in uncoated microcantilever - Surface topography?

    SciTech Connect

    Lakshmoji, K.; Prabakar, K.; Tripura Sundari, S. Jayapandian, J.; Tyagi, A. K.; Sundar, C. S.

    2014-01-27

    We provide direct experimental evidence to show that difference in surface topography on opposite sides of an uncoated microcantilever induces bending, upon exposure to water molecules. Examination on opposite sides of the microcantilever by atomic force microscopy reveals the presence of localized surface features on one side, which renders the induced stress non-uniform. Further, the root mean square inclination angle characterizing the surface topography shows a difference of 73° between the opposite sides. The absence of deflection in another uncoated microcantilever having similar surface topography confirms that in former microcantilever bending is indeed induced by differences in surface topography.

  14. Is long-term change in the abyssal Northeast Atlantic driven by qualitative changes in export flux? Evidence from selective feeding in deep-sea holothurians

    NASA Astrophysics Data System (ADS)

    Wigham, in deep-sea holothurians [review article] B. D.; Hudson, I. R.; Billett, D. S. M.; Wolff, G. A.

    2003-12-01

    The Porcupine Abyssal Plain (NE Atlantic) time-series has shown large, wide-scale, changes in the composition of the benthic community at 4800 m depth (48°50‧N, 16°30‧W). The abundance of holothurians has increased significantly since 1996 and one species in particular, Amperimarosea, has increased in abundance by three orders of magnitude. Environmental forcing in the form of phytodetrital food supply to the benthos is believed to be driving these changes. Chlorophyll and carotenoid pigments were determined from the gut sediments of seven species of abyssal holothurian, sampled from the Porcupine Abyssal Plain during Autumn 2000 and Spring 2002. These two samples fell either side of the main phytoplankton bloom in the NE Atlantic, providing an opportunity for seasonal comparisons. Significant inter-species differences in pigment profiles were observed among the seven species. Seasonal differences were noted among four species sampled in both time periods. All seven species were collected from the same geographical area and depth. As algal pigments cannot be synthesised by the holothurians, they provide good biomarkers for the composition of the phytodetritus. Differences in pigments from gut sediment profiles are indicative of selective feeding among the holothurians. A.rosea had a gut profile dominated by the pigments zeaxanthin, chlorophyll a/echineone and β-carotene; these pigments were all present in significantly smaller quantities in the other species. The high quantities of these pigments are indicative of a diet rich in cyanobacteria. The gut sediments of A. rosea also lacked many chloropigments characteristic of other phytoplankton groups, which were observed in the guts of other holothurian species. Ovarian tissue for the five species taken in the pre-spring bloom 2002 sample were examined. All species showed similar carotenoid profiles, dominated by zeaxanthin, echinenone and β-carotene, all of which are important compounds for reproductive

  15. Chemistry and mineralogy of pyrite-enriched sediments at a passive margin sulfide brine seep: abyssal Gulf of Mexico

    USGS Publications Warehouse

    Commeau, R.F.; Paull, C.K.; Commeau, J.A.; Poppe, L.J.

    1987-01-01

    Pyrite is rapidly accumulating at the contact between the Cretaceous limestones of the Florida Platform and the hemipelagic sediments of the abyssal Gulf of Mexico. Sediments sampled with the submersible "Alvin" in 3266 m of water are associated with a dense community of organisms that depend on chemosynthetic primary production as a food source. Analysis of the chemistry, mineralogy, and textural composition of these sediments indicate that iron sulfide mineralization is occurring at the seafloor within an anoxic micro-habitat sustained by the advection of hydrogen sulfide-charged saline brines from the adjacent platform. The chemosynthetic bacteria that directly overlie the sediments oxidize hydrogen sulfide for energy and provide elemental sulfur that reacts with iron monosulfide to form some of the pyrite. The sediments are mixtures of pyrite (??? 30 wt.%), BaSr sulfates (??? 4 wt.%), clays, and locally derived biogenic carbonates and are progressively being cemented by iron sulfides. Oxidation of hydrogen sulfide produces locally acidic conditions that corrode the adjacent limestones. Potential sources of S, H2S, Fe, Ba, and Sr are discussed. ?? 1987.

  16. Neotectonic morphotructures in the junction zone of the Cape Verde Rise and Cape Verde Abyssal Plain, Central Atlantic

    NASA Astrophysics Data System (ADS)

    Skolotnev, S. G.; Kolodyazhny, S. Yu.; Tsukanov, N. V.; Chamov, N. P.; Sokolov, S. Yu.

    2009-01-01

    Acoustic profiling carried out with an Edgetech 3300 prophilograph in the junction zone of the Cape Verde Rise, Cape Verde Abyssal Plain, and Grimaldi and Bathymetrists seamounts in the Central Atlantic during Cruise 23 of the R/V Akademik Nikolaj Strakhov allowed us to obtain new data on neotectonic deformations in the ocean and to propose their interpretation. It has been established that neotectonic movements occurred in the discrete manner: blocks of undeformed rocks alternate with linear zones of intense deformation spatially related to paleotransform fracture zones, where anticlines, horsts, diapir-like morphostructures, and grabens were formed. The Cape Verde Ridge is a large horst. Its sedimentary cover is disturbed by thrust (?), reverse, and normal faults, steeply dipping fracture zones, and folds. Three stages of tectonic movements—Oligocene-early Miocene, pre-Quaternary, and Holocene—are recognized. The tectonic deformations occurred largely under near-meridional compression. Extension setting was characteristic of the Cape Verde Ridge and the Carter Rise in the Holocene.

  17. Triticella minini - a new ctenostome bryozoan from the abyssal plain adjacent to the Kuril-Kamchatka Trench

    NASA Astrophysics Data System (ADS)

    Grischenko, Andrei V.; Chernyshev, Alexei V.

    2015-01-01

    A new species of ctenostome bryozoan, Triticella minini sp. nov., is described from the abyssal plain adjacent to the Kuril-Kamchatka Trench, based on material collected by the Russian-German deep-sea expedition KuramBio 2012. Colonies of T. minini sp. nov. were found attached to the oral spines of irregular sea urchin Echinosigra (Echinogutta) amphoraMironov, 1974 by means of rhizoid fibers that penetrated the substratum through circular borings. The specimens were examined by light microscopy, scanning electron microscopy, and confocal laser scanning microscopy with phalloidin and nuclear labeling. The description of T. minini sp. nov. combines a general taxonomic description with a description of the anatomy of the muscular system. The new species differs from congeners in lacking a stolon. It has an intertentacular organ. T. minini sp. nov. is the eleventh species described in the genus TriticellaDalyell, 1848, and the first record for this genus from the northwestern Pacific. The new species is the fifth ctenostome bryozoan known to occur in 5001-5500 m depth interval worldwide, and the deepest record reported for Triticella.

  18. Links between surface productivity and deep ocean particle flux at the Porcupine Abyssal Plain (PAP) sustained observatory

    NASA Astrophysics Data System (ADS)

    Frigstad, H.; Henson, S. A.; Hartman, S. E.; Omar, A. M.; Jeansson, E.; Cole, H.; Pebody, C.; Lampitt, R. S.

    2015-04-01

    In this study we present hydrography, biogeochemistry and sediment trap observations between 2003 and 2012 at Porcupine Abyssal Plain (PAP) sustained observatory in the northeast Atlantic. The time series is valuable as it allows for investigation of the link between surface productivity and deep ocean carbon flux. The region is a perennial sink for CO2, with an average uptake of around 1.5 mmol m-2 d-1. The average monthly drawdowns of inorganic carbon and nitrogen were used to quantify the net community production (NCP) and new production, respectively. Seasonal NCP and new production were found to be 4.57 ± 0.27 mol C m-2 and 0.37 ± 0.14 mol N m-2. The Redfield ratio was high (12), and the production calculated from carbon was higher than production calculated from nitrogen, which is indicative of carbon overconsumption. The export ratio and transfer efficiency were 16 and 4%, respectively, and the site thereby showed high flux attenuation. Particle tracking was used to examine the source region of material in the sediment trap, and there was large variation in source regions, both between and within years. There were higher correlations between surface productivity and export flux when using the particle-tracking approach, than by comparing with the mean productivity in a 100 km box around the PAP site. However, the differences in correlation coefficients were not significant, and a longer time series is needed to draw conclusions on applying particle tracking in sediment trap analyses.

  19. Biogeochemical variations at the Porcupine Abyssal Plain Sustained Observatory (PAP-SO) in the northeast Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Hartman, Susan; Lampitt, Richard; Schuster, Ute; Jiang, Zongpei; Frigstad, Helene; Ostle, Clare

    2016-04-01

    We examine high-resolution autonomous measurements of carbon dioxide partial pressure p(CO2) taken in situ at the FixO3 Porcupine Abyssal Plain sustained observatory (PAP-SO) site in the northeast Atlantic (49° N, 16.5° W; water depth of 4850 m) for the period 2010 to 2012. Measurements of p(CO2) made at 30 m depth on a sensor frame are compared with other autonomous biogeochemical measurements at that depth (including chlorophyll a-fluorescence and nitrate concentration data) to analyze weekly to seasonal controls on p(CO2) flux in the inter-gyre region of the North Atlantic. Comparisons are also made with in situ regional time-series data from a ship of opportunity and mixed layer depth (MLD) measurements from profiling Argo floats. There is a persistent under saturation of CO2 in surface waters throughout the year which gives rise to a perennial CO2 sink. Comparison with an earlier dataset collected at the site (2003 to 2005) confirms seasonal and inter-annual changes in surface seawater chemistry. There is year-to-year variability in the timing of deep winter mixing and the intensity of the spring bloom.

  20. Early India-Australia spreading history revealed by newly detected Mesozoic magnetic anomalies in the Perth Abyssal Plain

    NASA Astrophysics Data System (ADS)

    Williams, Simon E.; Whittaker, Joanne M.; Granot, Roi; Müller, Dietmar R.

    2013-07-01

    seafloor within the Perth Abyssal Plain (PAP), offshore Western Australia, is the only section of crust that directly records the early spreading history between India and Australia during the Mesozoic breakup of Gondwana. However, this early spreading has been poorly constrained due to an absence of data, including marine magnetic anomalies and data constraining the crustal nature of key tectonic features. Here, we present new magnetic anomaly data from the PAP that shows that the crust in the western part of the basin was part of the Indian Plate—the conjugate flank to the oceanic crust immediately offshore the Perth margin, Australia. We identify a sequence of M2 and older anomalies in the west PAP within crust that initially moved with the Indian Plate, formed at intermediate half-spreading rates (35 mm/yr) consistent with the conjugate sequence on the Australian Plate. More speculatively, we reinterpret the youngest anomalies in the east PAP, finding that the M0-age crust initially formed on the Indian Plate was transferred to the Australian Plate by a westward jump or propagation of the spreading ridge shortly after M0 time. Samples dredged from the Gulden Draak and Batavia Knolls (at the western edge of the PAP) reveal that these bathymetric features are continental fragments rather than igneous plateaus related to Broken Ridge. These microcontinents rifted away from Australia with Greater India during initial breakup at ~130 Ma, then rifted from India following the cessation of spreading in the PAP (~101-103 Ma).

  1. Three new species and one new genus of abyssal Cumacea (Crustacea, Malacostraca, Peracarida) from the Kuril-Kamchatka Trench area

    NASA Astrophysics Data System (ADS)

    Lavrenteva, Anna V.; Mühlenhardt-Siegel, Ute

    2015-01-01

    Only two species of crustacean Cumacea have been reported in publications for the Kuril-Kamchatka Trench area after nine expeditions on board of the RV "Vityaz". During the KuramBio expedition 2012 to the Kuril-Kamchatka Trench and the adjacent abyssal plain at depths 4830-5780 m no less than 72 species of cumaceans from 23 genera and 6 families were sampled. Five genera were recorded for the first time in the studied region: the genera Pseudoleptostyloides and Platycuma were detected for the first time for the Pacific Ocean; Cyclaspoides, Bathylamprops and Styloptocuma were firstly sampled in North Pacific. About 90% of the sampled species appear to be new to science. Three new deep-sea cumacean species and one new genus from the Kurile Kamchatka area are described in the present paper: Abyssoleucon tzarevae gen. n., sp. n. belonging to the family Leuconidae, Cyclaspoides borisovetsi sp. n. and Bathycuma sonne sp. n. of the family Bodotriidae. A distribution map for the species of the genus Cyclaspoides is provided.

  2. Hydrocarbon potential, organic matter diagenesis, sedimentology, and paleoenvironment of upper Mesozoic dark shales, northern Himalayas and Argo abyssal plain

    SciTech Connect

    Thurow, J.; Gibling, M.

    1989-03-01

    The Late Jurassic was a time favorable for the deposition of black shale-type sediments in shallow environments as known from circum-North Atlantic basins, North Sea, and Himalayan Tethys regions. Locally these shales have excellent hydrocarbon source potential. The site of the Spiti shales in the Thakkola region of north-central Nepal provides the opportunity to study a long-term (Oxfordian-Tithonian) stable, shallow, and oxygen-depleted environment. Strata with calcareous benthic communities show that the environment was not anoxic. Organic geochemical and sedimentological analyses on the Spiti shales (Oxfordian-Valanginian) were done to understand the hydrocarbon potential, organic matter diagenesis, sedimentology, and paleoenvironment of this sequence. The depositional environment changed, driven by tectono-eustatic and climatic events, from an open shelf (approximately 250 m) with low amounts of detrital input and rich macrofossil communities to an extremely shallow, partly continental environment with intercalations of quartzose channel fill, silty shales, rare lumachelle layers, and coal seams. Paleocurrents suggest a north-facing continental margin bordering the Tethys Sea. The organic matter changed from marine (Jurassic) to terrestrial in the Cretaceous. Analysis of coeval strata, deposited in the deep-marine environment off the northern Indian shelf (contiguous with the present-day Argo abyssal plain), demonstrates the changing shallow to deep-water hydrocarbon potential. It reflects the more advanced organic matter maturation of the onshore material due to Himalayan tectonics and allows tracing the transport of the organic matter.

  3. Hyalinecia (sic) Edwardsi Roule, 1898-the enigmatic ghost from abyssal depths-redescribed as Nothria edwardsi (Annelida: Onuphidae).

    PubMed

    Arias, Andrés; Paxton, Hannelore

    2016-08-02

    The deep sea is one of the largest ecosystems on earth, extending from 200 m, where sunlight becomes inadequate for photosynthesis, to the deepest trenches. However, it is still one of the least explored. Polychaetes are among the dominant groups in these environments worldwide and play a critical role in the deep sea food chain. Within polychaetes, the onuphids are one the best represented families from 2000 m deep to the hadal zone, with 46 recorded species (Paterson et al. 2009). Hyalinoecia edwardsi Roule, 1898 is one of the early described abyssal onuphids. The species was described from the Talisman station 136, located between the Azores archipelago and the Iberian Peninsula (referred as "l'Espagne") at 4255 m depth (Roule 1898). The original description is rather brief without illustrations and the species was characterised as follows: thick antennae, lateral ones reaching chaetiger 3; first chaetiger twice as long as second one; parapodia of first chaetiger with thick falcate hooks; parapodia of second chaetiger with bidentate hooks; parapodia of third chaetiger with limbate chaetae; following chaetigers with limbate, pectinate chaetae and subacicular hooks; oval tube looking flattened and covered by small particles, mainly quartzites of different colours (Roule 1898).

  4. Numerical errors in the presence of steep topography: analysis and alternatives

    SciTech Connect

    Lundquist, K A; Chow, F K; Lundquist, J K

    2010-04-15

    It is well known in computational fluid dynamics that grid quality affects the accuracy of numerical solutions. When assessing grid quality, properties such as aspect ratio, orthogonality of coordinate surfaces, and cell volume are considered. Mesoscale atmospheric models generally use terrain-following coordinates with large aspect ratios near the surface. As high resolution numerical simulations are increasingly used to study topographically forced flows, a high degree of non-orthogonality is introduced, especially in the vicinity of steep terrain slopes. Numerical errors associated with the use of terrainfollowing coordinates can adversely effect the accuracy of the solution in steep terrain. Inaccuracies from the coordinate transformation are present in each spatially discretized term of the Navier-Stokes equations, as well as in the conservation equations for scalars. In particular, errors in the computation of horizontal pressure gradients, diffusion, and horizontal advection terms have been noted in the presence of sloping coordinate surfaces and steep topography. In this work we study the effects of these spatial discretization errors on the flow solution for three canonical cases: scalar advection over a mountain, an atmosphere at rest over a hill, and forced advection over a hill. This study is completed using the Weather Research and Forecasting (WRF) model. Simulations with terrain-following coordinates are compared to those using a flat coordinate, where terrain is represented with the immersed boundary method. The immersed boundary method is used as a tool which allows us to eliminate the terrain-following coordinate transformation, and quantify numerical errors through a direct comparison of the two solutions. Additionally, the effects of related issues such as the steepness of terrain slope and grid aspect ratio are studied in an effort to gain an understanding of numerical domains where terrain-following coordinates can successfully be used and

  5. EAARL topography: Dry Tortugas National Park

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd

    2008-01-01

    This lidar-derived submarine topography map was produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, 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 for the purposes of habitat mapping, ecological monitoring, change detection, ad event assessment (for example: bleaching, hurricanes, disease outbreaks). 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 water depth and conducting 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 managers of coastal tropical habitats.

  6. EAARL submarine topography: Biscayne National Park

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayegandhi, Amar; Patterson, Judd; Harris, Melanie S.; Mosher, Lance

    2006-01-01

    This lidar-derived submarine topography map was produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, 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 for the purposes of habitat mapping, ecological monitoring, change detection, and event assessment (for example: bleaching, hurricanes, disease outbreaks). 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 water depth and conducting 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 managers of coastal tropical habitats.

  7. Architecture and development of olivocerebellar circuit topography

    PubMed Central

    Reeber, Stacey L.; White, Joshua J.; George-Jones, Nicholas A.; Sillitoe, Roy V.

    2013-01-01

    The cerebellum has a simple tri-laminar structure that is comprised of relatively few cell types. Yet, its internal micro-circuitry is anatomically, biochemically, and functionally complex. The most striking feature of cerebellar circuit complexity is its compartmentalized topography. Each cell type within the cerebellar cortex is organized into an exquisite map; molecular expression patterns, dendrite projections, and axon terminal fields divide the medial-lateral axis of the cerebellum into topographic sagittal zones. Here, we discuss the mechanisms that establish zones and highlight how gene expression and neural activity contribute to cerebellar pattern formation. We focus on the olivocerebellar system because its developmental mechanisms are becoming clear, its topographic termination patterns are very precise, and its contribution to zonal function is debated. This review deconstructs the architecture and development of the olivocerebellar pathway to provide an update on how brain circuit maps form and function. PMID:23293588

  8. Topographies of forensic practice in Imperial Germany.

    PubMed

    Engstrom, Eric J

    2014-01-01

    This article examines the topography and "cultural machinery" of forensic jurisdictions in Imperial Germany. It locates the sites at which boundary disputes between psychiatric and legal professionals arose and explores the strategies and practices that governed the division of expert labor between them. It argues that the over-determined paradigms of 'medicalization' and 'biologization' have lost much of their explanatory force and that historians need to refocus their attention on the institutional and administrative configuration of forensic practices in Germany. After first sketching the statutory context of those practices, the article explores how contentious jurisdictional negotiations pitted various administrative, financial, public security, and scientific interests against one another. The article also assesses the contested status of psychiatric expertise in the courtroom, as well as post-graduate forensic psychiatric training courses and joint professional organizations, which drew the two professional communities closer together and mediated their jurisdictional disputes.

  9. Assimilation of altimeter topography into oceanic models

    NASA Technical Reports Server (NTRS)

    Demey, Pierre; Menard, Yves; Pinardi, Nadia; Schroeter, J.; Verron, J.

    1991-01-01

    The primary goals of the authors are to build an intuition for assimilation techniques and to investigate the impact of variable altimeter topography on simple or complex oceanic models. In particular, applying various techniques and sensitivity studies to model and data constraints plays a key role. We are starting to use quasi-geostrophic, semigeostrophic, and primitive-equation (PE) models and to test the schemes in regions of interest to the World Ocean Circulation Experiment (WOCE), as well as in the northeast Atlantic and the Mediterranean. The impact of scatterometer wind forcing on the results is also investigated. The use of Geosat, European Remote Sensing satellite (ERS-1), and TOPEX/POSEIDON altimetry data is crucial in fine tuning the models and schemes to the selected areas of interest.

  10. Mean Dynamic Topography of the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Farrell, Sinead Louise; Mcadoo, David C.; Laxon, Seymour W.; Zwally, H. Jay; Yi, Donghui; Ridout, Andy; Giles, Katherine

    2012-01-01

    ICESat and Envisat altimetry data provide measurements of the instantaneous sea surface height (SSH) across the Arctic Ocean, using lead and open water elevation within the sea ice pack. First, these data were used to derive two independent mean sea surface (MSS) models by stacking and averaging along-track SSH profiles gathered between 2003 and 2009. The ICESat and Envisat MSS data were combined to construct the high-resolution ICEn MSS. Second, we estimate the 5.5-year mean dynamic topography (MDT) of the Arctic Ocean by differencing the ICEn MSS with the new GOCO02S geoid model, derived from GRACE and GOCE gravity. Using these satellite-only data we map the major features of Arctic Ocean dynamical height that are consistent with in situ observations, including the topographical highs and lows of the Beaufort and Greenland Gyres, respectively. Smaller-scale MDT structures remain largely unresolved due to uncertainties in the geoid at short wavelengths.

  11. EAARL topography: Fire Island National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayagandhi, Amar; Patterson, Judd

    2007-01-01

    This Web site contains 31 LIDAR-derived first return topography maps and GIS files for Fire Island National Seashore. These lidar-derived topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. The aims of the partnership that created this product are to develop advanced survey techniques for mapping barrier island geomorphology and habitats, and to enable the monitoring of ecological and geological change within National Seashores. This product is based on data from an innovative airborne lidar instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Advanced Airborne Research Lidar (EAARL).

  12. Mesozoic and Cenozoic structural geology of the CP Hills, Nevada Test Site, Nye County, Nevada; and regional implications

    SciTech Connect

    Caskey, S.J.

    1991-08-01

    Detailed mapping and structural analysis of upper Proterozoic and Paleozoic rocks in the CP Hills of the Nevada Test Site, together with analysis of published maps and cross sections and a reconnaissance of regional structural relations indicate that the CP thrust of Barnes and Poole (1968) actually comprises two separate, oppositely verging Mesozoic thrust systems: (1) the west-vergent CP thrust which is well exposed in the CP Hills and at Mine Mountain, and (2) the east-vergent Belted Range thrust located northwest of Yucca Flat. West-vergence of the CP thrust is indicated by large scale west-vergent recumbent folds in both its hangingwall and footwall and by the fact that the CP thrust ramps up section through hangingwall strata toward the northwest. Regional structural relations indicate that the CP thrust forms part of a narrow sigmoidal belt of west-vergent folding and thrusting traceable for over 180 km along strike. The Belted Range thrust represents earlier Mesozoic deformation that was probably related to the Last Chance thrust system in southeastern California, as suggested by earlier workers. A pre-Tertiary reconstruction of the Cordilleran fold and thrust belt in the region between the NTS and the Las Vegas Range bears a close resemblance to other regions of the Cordillera and has important implications for the development of hinterland-vergent deformation as well as for the probable magnitude of Tertiary extension north of Las Vegas Valley. Subsequent to Mesozoic deformation, the CP Hills were disrupted by at least two episodes of Tertiary extensional deformation: (1) an earlier episode represented by pre-middle Miocene low-angle normal faults, and (2) a later, post-11 Ma episode of high-angle normal faulting. Both episodes of extension were related to regional deformation, the latter of which has resulted in the present basin and range topography of the NTS region.

  13. Corneal topography matching by iterative registration.

    PubMed

    Wang, Junjie; Elsheikh, Ahmed; Davey, Pinakin G; Wang, Weizhuo; Bao, Fangjun; Mottershead, John E

    2014-11-01

    Videokeratography is used for the measurement of corneal topography in overlapping portions (or maps) which must later be joined together to form the overall topography of the cornea. The separate portions are measured from different viewpoints and therefore must be brought together by registration of measurement points in the regions of overlap. The central map is generally the most accurate, but all maps are measured with uncertainty that increases towards the periphery. It becomes the reference (or static) map, and the peripheral (or dynamic) maps must then be transformed by rotation and translation so that the overlapping portions are matched. The process known as registration, of determining the necessary transformation, is a well-understood procedure in image analysis and has been applied in several areas of science and engineering. In this article, direct search optimisation using the Nelder-Mead algorithm and several variants of the iterative closest/corresponding point routine are explained and applied to simulated and real clinical data. The measurement points on the static and dynamic maps are generally different so that it becomes necessary to interpolate, which is done using a truncated series of Zernike polynomials. The point-to-plane iterative closest/corresponding point variant has the advantage of releasing certain optimisation constraints that lead to persistent registration and alignment errors when other approaches are used. The point-to-plane iterative closest/corresponding point routine is found to be robust to measurement noise, insensitive to starting values of the transformation parameters and produces high-quality results when using real clinical data.

  14. An Assessment of Topography Measurements on Europa

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard; Hurford, T.; Foley, M.

    2006-09-01

    Many small patches of chaotic terrain on Europa appear to be bulged upward, giving qualitative impressions that chaos might represent "cryovolcanic" and/or convective upwelling. The same bulged appearance is explained by the oceanic melt-through model, as simply the topography expected after refreezing and buoyant equilibrium. Greenberg et al. suggested an observational test to discriminate between these models, based on whether the up-bulged chaos is higher than the typical tectonic terrain in the region (for up-welling) or only higher than its immediate moat-like surroundings (melt-through and refreezing). Several authors have taken up this challenge, presenting topographic maps to refute the melt-through model by showing high elevations for chaos. However, details on the methods (based on combinations of stereo images and photoclinometry) have been sketchy, and without quantitative analyses of precision. For example, near Tyre, topographic maps and profiles reportedly show elevated chaos areas. Yet the elevations differ between published results by much more than the purported 10m precision. Moreover, high-elevation portions of profiles that were labeled as chaos are actually tectonic terrain. Stereo actually shows that major chaos areas are lower than the tectonic terrain in the area. Also, variations in elevation within the tectonic terrain are so great that differences from chaotic terrain are in the noise. Moreover, our error-analyses for both stereo and photoclinometry indicate that uncertainties are greater than reported differences between elevations of chaotic and tectonic terrain. For example, stereo-based models may exaggerate the height of chaos by favoring rafts as tie features, and photoclinometry is sensitive to an uncertain photometric function and to sub-pixel slope variations. To paraphrase Mark Twain, reports of the death of the melt-through model have been greatly exaggerated. Any results based on topography should not be accepted until the

  15. Evolution of Neogene Dynamic Topography in Madagascar

    NASA Astrophysics Data System (ADS)

    Paul, J. D.; Roberts, G.; White, N. J.

    2012-12-01

    Madagascar is located on the fringes of the African superswell. Its position and the existence of a +30 mGal long wavelength free-air gravity anomaly suggest that its present-day topography is maintained by convective circulation of the sub-lithospheric mantle. Residual depth anomalies of oceanic crust encompassing the island imply that Madagascar straddles a dynamic topographic gradient. In June-July 2012, we examined geologic evidence for Neogene uplift around the Malagasy coastline. Uplifted coral reef deposits, fossil beach rock, and terraces demonstrate that the northern and southern coasts are probably being uplifted at a rate of ~0.2 mm/yr. Rates of uplift clearly vary around the coastline. Inland, extensive peneplains occur at elevations of 1 - 2 km. These peneplains are underlain by 10 - 20 m thick laterite deposits, and there is abundant evidence for rapid erosion (e.g. lavaka). Basaltic volcanism also occurred during Neogene times. These field observations can be combined with an analysis of drainage networks to determine the spatial and temporal pattern of convectively driven uplift. ~100 longitudinal river profiles were extracted from a digital elevation model of Madagascar. An inverse model is then used to minimize the misfit between observed and calculated river profiles as a function of uplift rate history. During inversion, the residual misfit decreases from ~20 to ~4. Our results suggest that youthful and rapid uplift of 1-2 km occurred at rates of 0.2-0.4 mm/yr during the last ˜15 Myr. The algorithm resolves distinct phases of uplift which generate localized swells of high topography and relief (e.g. the Hauts Plateaux). Our field observations and modeling indicate that the evolution of drainage networks may contain useful information about mantle convective processes.

  16. Episodic growth of topography in eastern Tibet

    NASA Astrophysics Data System (ADS)

    Kirby, E.; Furlong, K.; Wang, E.; Shi, X.; van Soest, M.; Xu, G.; Kamp, P.; Hodges, K.

    2012-04-01

    High topography associated with the eastern portions of the Tibetan Plateau is thought to have developed as eastward flow of deep crust from beneath central Tibet drove crustal thickening and attendant surface uplift along the periphery of the plateau. The onset of rapid Late Miocene exhumation (ca. 10-15 Ma) in deep canyons of eastern Tibet is inferred to herald surface uplift which enabled rapid fluvial incision and the development of high topographic relief. Although consistent with geophysical data, this model struggles to explain the timing and amount of Cenozoic shortening adjacent to the Sichuan Basin. Here we report cooling histories of rocks currently exposed along a ~3 km vertical section adjacent to the Sichuan Basin derived from multiple low-temperature thermochronologic systems including apatite and zircon fission-track and (U-Th)/He. Our results reveal that this margin of the plateau was subject to slow, steady exhumation during early Cenozoic time, requiring that limited topographic relief (<1000m) was present prior to initial collision of India and Asia. Moreover, thermal models of exhumation-driven cooling demonstrate that subsequent exhumation of >10 km occurred in two temporally-distinct episodes, during Oligocene (~30-25 Ma) and Late Miocene (~10-15 Ma) time, separated by a hiatus of at least 10 Ma. These results challenge the notion that the plateau in eastern Tibet developed as a singular consequence of lower crustal flow. Rather, our findings require a punctuated history of mountain building that potentially reconciles conflicting models for relative roles of upper crustal shortening and lower crustal flow in the development of topography adjacent to the Sichuan Basin.

  17. Absorber topography dependence of phase edge effects

    NASA Astrophysics Data System (ADS)

    Shanker, Aamod; Sczyrba, Martin; Connolly, Brid; Waller, Laura; Neureuther, Andy

    2015-10-01

    Mask topography contributes to phase at the wafer plane, even for OMOG binary masks currently in use at the 22nm node in deep UV (193nm) lithography. Here, numerical experiments with rigorous FDTD simulation are used to study the impact of mask 3D effects on aerial imaging, by varying the height of the absorber stack and its sidewall angle. Using a thin mask boundary layer model to fit to rigorous simulations it is seen that increasing the absorber thickness, and hence the phase through the middle of a feature (bulk phase) monotonically changes the wafer-plane phase. Absorber height also influences best focus, revealed by an up/down shift in the Bossung plot (linewidth vs. defocus). Bossung plot tilt, however, responsible for process window variability at the wafer, is insensitive to changes in the absorber height (and hence also the bulk phase). It is seen to depend instead on EM edge diffraction from the thick mask edge (edge phase), but stays constant for variations in mask thickness within a 10% range. Both bulk phase and edge phase are also independent of sidewall angle fluctuation, which is seen to linearly affect the CD at the wafer, but does not alter wafer phase or the defocus process window. Notably, as mask topography varies, the effect of edge phase can be replicated by a thin mask model with 8nm wide boundary layers, irrespective of absorber height or sidewall angle. The conclusions are validated with measurements on phase shifting masks having different topographic parameters, confirming the strong dependence of phase variations at the wafer on bulk phase of the mask absorber.

  18. The topography of chaos terrain on Europa

    NASA Astrophysics Data System (ADS)

    Patterson, G.; Prockter, L. M.; Schenk, P.

    2010-12-01

    Chaos terrain and lenticulae are commonly observed surface features unique to the Galilean satellite Europa. Chaos terrain occurs as discrete regions of the satellite’s surface 10s to 100s of km in size that are disrupted into isolated plates surrounded by hummocky matrix material. Lenticulae occur as positive- or negative-relief domes km to 10s of km in diameter that can disrupt the original surface in a manner similar to chaos terrain. Evidence suggests that they each form via an endogenic process involving the interaction of a mobile substrate with the brittle surface and it has been proposed that ice shell thinning or surface yielding coupled with brine production represents the most plausible mechanism for the formation of these features. These similarities in morphology and formation mechanism indicate they may represent a continuum process. We explore whether larger chaos terrain represent the coalescence of smaller lenticulae by examining topography within chaos to determine whether it contains domes on length scales similar to lenticulae. Schenk and Pappalardo (2004) alluded to the presence of several prominent domes within Conamara Chaos and we have previously shown that at least 4 and as many as 9 domes with length scales similar to lenticulae are present within and along the margins of the feature. This was accomplished by using Fourier analysis to decompose the topographic signature of Conamara Chaos and the surrounding terrain into discrete wavelength components. A low-pass filter was then used to strip away shorter wavelength components of the topography associated with the region and determine if longer wavelength features were present within the terrain. Here we present new work identifying the presence, size, and distribution of domes within the boundaries of other chaos terrains across the surface of Europa and discuss implications for chaos formation.

  19. Hydrology of the Black Hills area, South Dakota

    USGS Publications Warehouse

    Driscoll, Daniel G.; Carter, Janet; Williamson, Joyce; Putnam, Larry

    2002-01-01

    The Black Hills Hydrology Study was initiated in 1990 to assess the quantity, quality, and distribution of surface water and ground water in the Black Hills area of South Dakota. This report summarizes the hydrology of the Black Hills area and the results of this long-term study.The Black Hills area of South Dakota and Wyoming is an important recharge area for several regional, bedrock aquifer systems and various local aquifers; thus, the study focused on describing the hydrologic significance of selected bedrock aquifers. The major aquifers in the Black Hills area are the Deadwood, Madison, Minnelusa, Minnekahta, and Inyan Kara aquifers. The highest priority was placed on the Madison and Minnelusa aquifers, which are used extensively and heavily influence the surface-water resources of the area.Within this report, the hydrogeologic framework of the area, including climate, geology, ground water, and surface water, is discussed. Hydrologic processes and characteristics for ground water and surface water are presented. For ground water, water-level trends and comparisons and water-quality characteristics are presented. For surface water, streamflow characteristics, responses to precipitation, annual yields and yield efficiencies, and water-quality characteristics are presented. Hydrologic budgets are presented for ground water, surface water, and the combined ground-water/surface-water system. A summary of study findings regarding the complex flow systems within the Madison and Minnelusa aquifers also is presented.

  20. Volcanically-Triggered Rainfall and the Effect on Volcanological Hazards at Soufriere Hills, Montserrat

    NASA Astrophysics Data System (ADS)

    Poulidis, Alexandros-Panagiotis; Renfrew, Ian; Matthews, Adrian

    2014-05-01

    Atmospheric flow simulations over and around the Soufriere Hills volcano in the island of Montserrat in the Caribbean are studied, through a series of numerical model experiments, in order to link interactions between the volcano and the atmosphere. A heated surface is added on the top of the mountain, in order to simulate the dome of an active volcano that is not undergoing an eruption. A series of simulations with different atmospheric conditions and control parameters for the volcano will be presented. Simulations are made using the Weather Research and Forecasting (WRF) model, with a high resolution digital elevation map of Montserrat. Simulations with an idealised topography have also been examined, in order for the results to have general applicability to similar-sized volcanoes located in the Tropics. The model was initialised with soundings from representative days of qualitatively different atmospheric conditions from the rainy season. The heated volcanic dome changes the orographic flow response significantly, depending upon the atmospheric conditions and the magnitude of the dome surface temperature anomaly. The flow regime and qualitative characteristic features, such orographic clouds and rainfall patterns, can all change significantly. For example, the orographic rainfall over the volcano can be significantly enhanced with increased dome temperatures. The implications of these changes on the eruptive behaviour of the volcano and resulting secondary volcanic hazards, such as lahars, will be discussed.