Diffuse flow hydrothermal manganese mineralization along the active Mariana and southern Izu-Bonin arc system, western Pacific
J.R. Hein, M. S. Schulz, R.E. Dunham, R. J. Stern, S.H. Bloomer
2008, Journal of Geophysical Research B: Solid Earth (113)
Abundant ferromanganese oxides were collected along 1200 km of the active Izu-Bonin-Mariana arc system. Chemical compositions and mineralogy show that samples were collected from two deposit types: Fe-Mn crusts of mixed hydrogenetic/hydrothermal origin and hydrothermal Mn oxide deposits; this paper addresses only the second type. Mn oxides cement volcaniclastic and...
ALLTEM UXO detection and discrimination
T.H. Asch, D.L. Wright, C.W. Moulton, T.P. Irons, M.N. Nabighian
2008, Conference Paper, SEG Technical Program Expanded Abstracts
ALLTEM is a multi-axis electromagnetic induction system designed for unexploded ordnance (UXO) applications. It uses a continuous triangle-wave excitation and provides good late-time signal-to-noise ratio (SNR) especially for ferrous targets. Multi-axis transmitter (Tx) and receiver (Rx) systems such as ALLTEM provide a richer data set from which to invert for...
Brazilian analog for ancient marine environments on Mars
N.T. Bridges, S.J. Hook, B.J. Thomson, J.K. Crowley, Filho C.R. de Souza, J.B. Macambira, Pereira Silva de Lima Silva, G.
2008, Eos, Transactions, American Geophysical Union (89) 329-330
[No abstract available]...
Peri-equatorial paleolatitudes for Jurassic radiolarian cherts of Greece
I.W. Aiello, J.T. Hagstrum, G. Principi
2008, Tectonophysics (448) 33-48
Radiolarian-rich sediments dominated pelagic deposition over large portions of the Tethys Ocean during middle to late Jurassic time as shown by extensive bedded chert sequences found in both continental margin and ophiolite units of the Mediterranean region. Which paleoceanographic mechanisms and paleotectonic setting favored radiolarian deposition during the Jurassic, and...
Ice-walled-lake plains: Implications for the origin of hummocky glacial topography in middle North America
L. Clayton, J.W. Attig, N.R. Ham, M.D. Johnson, C.E. Jennings, K.M. Syverson
2008, Geomorphology (97) 237-248
Ice-walled-lake plains are prominent in many areas of hummocky-till topography left behind as the Laurentide Ice Sheet melted from middle North America. The formation of the hummocky-till topography has been explained by: (1) erosion by subglacial floods; (2) squeezing of subglacial till up into holes in stagnant glacial ice; or...
Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith
J.G. Moore, T. W. Sisson
2008, Geosphere (4) 387-400
Study of four K-feldspar megacrystic granitic plutons and related dikes in the Sierra Nevada composite batholith indicates that the megacrysts are phenocrysts that grew in contact with granitic melt. Growth to megacrystic sizes was due to repeated replenishment of the magma bodies by fresh granitic melt that maintained temperatures above...
Downflow limestone beds for treatment of net-acidic, oxic, iron-laden drainage from a flooded Anthracite Mine, Pennsylvania, USA: 1. Field evaluation
C.A. Cravotta III, S.J. Ward
2008, Mine Water and the Environment (27) 67-85
Passive-treatment systems that route acidic mine drainage (AMD) through crushed limestone and/or organic-rich substrates have been used to remove the acidity and metals from various AMD sources, with a wide range of effects. This study evaluates treatment of net-acidic, oxic, iron-laden AMD with limestone alone, and with organic-rich compost layered...
Relationship of floodplain ichnocoenoses to paleopedology, paleohydrology, and paleoclimate in the Willwood Formation, Wyoming, during the Paleocene-Eocene Thermal Maximum
J.J. Smith, S.T. Hasiotis, M. J. Kraus, D.T. Woody
2008, Palaios (23) 683-699
Vertical changes in distribution, abundance, and ichnodiversity of ichnocoenoses in alluvial deposits of the Willwood Formation suggest significantly drier moisture regimes in the Bighorn Basin, Wyoming, during the Paleocene-Eocene Thermal Maximum (PETM), a transient period of global warming. The Willwood Formation at Polecat Bench contains an abundant assemblage of ichnofossils,...
Thermal history of the unsaturated zone at Yucca Mountain, Nevada, USA
J. F. Whelan, L.A. Neymark, R.J. Moscati, B.D. Marshall, E. Roedder
2008, Applied Geochemistry (23) 1041-1075
Secondary calcite, silica and minor amounts of fluorite deposited in fractures and cavities record the chemistry, temperatures, and timing of past fluid movement in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a high-level radioactive waste repository. The distribution and geochemistry of these deposits are consistent with...
Guidelines for landslide susceptibility, hazard and risk zoning for land use planning
R. Fell, J. Corominas, C. Bonnard, L. Cascini, E. Leroi, W. Z. Savage
2008, Engineering Geology (102) 85-98
[No abstract available]...
Effects of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in zebrafish: General and reproductive toxicity
S. Mukhi, R. Patino
2008, Chemosphere (72) 726-732
Mixed-sex populations of young adult zebrafish (???2-month-old) were exposed to measured RDX concentrations of 0, 1 or 9.6 ppm for up to 12 weeks followed by a 15-day rearing period in untreated water. RDX caused high mortality at 9.6 ppm, with most deaths occurring within the first 8 weeks of...
The use of groundwater age as a calibration target
Leonard F. Konikow, G.Z. Hornberger, L.D. Putnam, A.M. Shapiro, B.A. Zinn
2008, Conference Paper, IAHS-AISH Publication
Groundwater age (or residence time), as estimated on the basis of concentrations of one or more environmental tracers, can provide a useful and independent calibration target for groundwater models. However, concentrations of environmental tracers are affected by the complexities and mixing inherent in groundwater flow through heterogeneous media, especially in...
Estimation of bedrock depth using the horizontal‐to‐vertical (H/V) ambient‐noise seismic method
John W. Lane Jr., Eric A. White, Gregory V. Steele, James C. Cannia
2008, Conference Paper, Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008
Estimating sediment thickness and the geometry of the bedrock surface is a key component of many hydrogeologic studies. The horizontal‐to‐vertical (H/V) ambient‐noise seismic method is a novel, non‐invasive technique that can be used to rapidly estimate the depth to bedrock. The H/V method uses a single, broad‐band three‐component seismometer to...
Is Rangeland Health Relevant to Mongolia?
Bolormaa Damdinsuren, J. E. Herrick, David A. Pyke, K. M. Havstad
2008, Rangelands (30) 25-29
DOI: 10.2111/1551-501X(2008)30[25:IRHRTM]2.0.CO;2...
Morelia spilota spilota (Diamond python). Reproduction
M. L. Brien, C. H. Brien, R.N. Reed
2008, Herpetological Review (39) 355-355
No abstract available. ...
Characterizing submarine ground‐water discharge using fiber‐optic distributed temperature sensing and marine electrical resistivity
Rory Henderson, Frederick D. Day-Lewis, John W. Lane Jr., Charles F. Harvey, Lanbo Liu
2008, Conference Paper, Symposium on the Application of Geophysics to Engineering and Environmental Problems 2008
Submarine ground‐water discharge (SGD) contributes important solute fluxes to coastal waters. Pollutants are transported to coastal ecosystems by SGD at spatially and temporally variable rates. New approaches are needed to characterize the effects of storm‐event, tidal, and seasonal forcing on SGD. Here, we evaluate the utility of two geophysical methods‐fiber‐optic...
Levee evaluation using MASW: Preliminary findings from the Citrus Lakefront Levee, New Orleans, Louisiana
John W. Lane Jr., Julian M. Ivanov, Frederick D. Day-Lewis, Drew Clemens, Robert Patev, Richard D. Miller
2008, Conference Paper
The utility of the multi‐channel analysis of surface waves (MASW) seismic method for non‐invasive assessment of earthen levees was evaluated for a section of the Citrus Lakefront Levee, New Orleans, Louisiana. This test was conducted after the New Orleans' area levee system had been stressed by Hurricane Katrina in 2005....
The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results
J.R. Schaefer, W. E. Scott, William C. Evans, J. Jorgenson, R. G. McGimsey, B. Wang
2008, Geochemistry, Geophysics, Geosystems (9)
A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated...
Development of a model to assess ground-water availability in California's Central Valley
Claudia C. Faunt, Randall T. Hanson, Kenneth Belitz
2008, Water Resources Impact (10) 27-30
No abstract available....
Application of MODFLOW’s farm process to California’s Central Valley
Claudia C. Faunt, Randall T. Hanson, Wolfgang Schmid, Kenneth Belitz
2008, Conference Paper, California Central Valley Groundwater Modeling Workshop, Proceedings
Historically, California’s Central Valley has been one of the most productive agricultural regions in the world. The Central Valley also is rapidly becoming an important area for California’s expanding urban population. During 1980–2007, the population nearly doubled in the Central Valley, increasing the competition for water. Because of the importance...
Ground-based thermography of fluvial systems at low and high discharge reveals potential complex thermal heterogeneity driven by flow variation and bioroughness
M.B. Cardenas, J. W. Harvey, A.I. Packman, D.T. Scott
2008, Hydrological Processes (22) 980-986
Temperature is a primary physical and biogeochemical variable in aquatic systems. Field‐based measurement of temperature at discrete sampling points has revealed temperature variability in fluvial systems, but traditional techniques do not readily allow for synoptic sampling schemes that can address temperature‐related questions with broad, yet detailed,...
A gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: I. Laboratory development
K.M. Campbell, R. Root, P. A. O’Day, J. G. Hering
2008, Environmental Science & Technology (42) 497-503
A gel probe equilibrium sampler has been developed to study arsenic (As) geochemistry and sorption behavior in sediment porewater. The gels consist of a hydrated polyacrylamide polymer, which has a 92% water content. Two types of gels were used in this study. Undoped (clear) gels were used to measure concentrations...
Fluctuating Arctic Sea ice thickness changes estimated by an in situ learned and empirically forced neural network model
G. I. Belchansky, David C. Douglas, Nikita G. Platonov
2008, Journal of Climate (21) 716-729
Sea ice thickness (SIT) is a key parameter of scientific interest because understanding the natural spatiotemporal variability of ice thickness is critical for improving global climate models. In this paper, changes in Arctic SIT during 1982-2003 are examined using a neural network (NN) algorithm trained with in situ submarine ice...
In situ Raman spectroscopic investigation of the structure of subduction-zone fluids
Kenji Mibe, I.-M. Chou, William A. Bassett
2008, Journal of Geophysical Research B: Solid Earth (113)
In situ Raman spectra of synthetic subduction-zone fluids (KAlSi3O8-H2O system) were measured to 900?? and 2.3 GPa using a hydrothermal diamond-anvil cell. The structures of aqueous fluid and hydrous melt become closer when conditions approach the second critical endpoint. Almost no three-dimensional network was observed in the supercritical fluid above...
Monitoring lingering oil from the Exxon Valdez spill on Gulf of Alaska armored beaches and mussel beds sixteen years post-spill
G.V. Irvine, D.H. Mann, J.W. Short
2008, Report, TOXLINE
Final Rept. ; Prepared in Cooperation With Alaska Univ., Fairbanks. Inst. of Arctic Biology. Sponsored By National Marine Fisheries Service, Juneau, Ak. AlaskaFisheries Science Center. ; Stranded Exxon Valdez Oil Has Persisted for 16 Years At Boulder-Armored Beach Sites Along National Park Coastlines Bordering the Gulf of Alaska. These Sites Are Up to...
