Shelf and open-ocean calcareous phytoplankton assemblages across the Paleocene-Eocene thermal maximum: Implications for global productivity gradients
S.J. Gibbs, T.J. Bralower, Paul R. Bown, J.C. Zachos, L.M. Bybell
2006, Geology (34) 233-236
Abrupt global warming and profound perturbation of the carbon cycle during the Paleocene-Eocene Thermal Maximum (PETM, ca. 55 Ma) have been linked to a massive release of carbon into the ocean-atmosphere system. Increased phytoplankton productivity has been invoked to cause subsequent CO2 drawdown, cooling, and environmental recovery. However, interpretations of...
Frictional strength heterogeneity and surface heat flow: Implications for the strength of the creeping San Andreas fault
M. A. d'Alessio, C.F. Williams, R. Burgmann
2006, Journal of Geophysical Research B: Solid Earth (111)
Heat flow measurements along much of the San Andreas fault (SAF) constrain the apparent coefficient of friction (??app) of the fault to <0.2, much lower than laboratory-derived friction values for most geologic materials. However, heat flow data are sparse near the creeping section of the SAF, a frictional "asperity" where...
Seismic attenuation structure of the Seattle Basin, Washington State from explosive-source refraction data
Q. Li, W.S.D. Wilcock, T. L. Pratt, C.M. Snelson, T.M. Brocher
2006, Bulletin of the Seismological Society of America (96) 553-571
We used waveform data from the 1999 SHIPS (Seismic Hazard Investigation of Puget Sound) seismic refraction experiment to constrain the attenuation structure of the Seattle basin, Washington State. We inverted the spectral amplitudes of compressional- and shear-wave arrivals for source spectra, site responses, and one- and two-dimensional Q-1 models at...
Model Parameter Estimation Experiment (MOPEX): An overview of science strategy and major results from the second and third workshops
Q. Duan, J. Schaake, V. Andreassian, S. Franks, G. Goteti, H.V. Gupta, Y.M. Gusev, F. Habets, A. Hall, L. Hay, T. Hogue, M. Huang, G. Leavesley, X. Liang, O.N. Nasonova, J. Noilhan, L. Oudin, S. Sorooshian, T. Wagener, E.F. Wood
2006, Conference Paper, Journal of Hydrology
The Model Parameter Estimation Experiment (MOPEX) is an international project aimed at developing enhanced techniques for the a priori estimation of parameters in hydrologic models and in land surface parameterization schemes of atmospheric models. The MOPEX science strategy involves three major steps: data preparation, a priori parameter estimation methodology development,...
Chemical evolution of Miocene wood: Example from the Belchatow brown coal deposit, central Poland
A. Drobniak, Maria Mastalerz
2006, International Journal of Coal Geology (66) 157-178
Miocene conifer wood samples from the Belchatow brown coal deposit in Poland were studied in order to discuss a range of chemical variations that occur as a result of biochemical coalification. Petrographic analysis, ultimate analysis, electron microprobe technique, and FTIR spectroscopy were used in this study. Our data show several...
Nonlinear inversion of potential-field data using a hybrid-encoding genetic algorithm
C. Chen, J. Xia, J. Liu, G. Feng
2006, Computers & Geosciences (32) 230-239
Using a genetic algorithm to solve an inverse problem of complex nonlinear geophysical equations is advantageous because it does not require computer gradients of models or "good" initial models. The multi-point search of a genetic algorithm makes it easier to find the globally optimal solution while avoiding falling into a...
Insular and migrant species, longevity records, and new species records on Guana Island, British Virgin Islands
C. W. Boal, F.C. Sibley, T.S. Estabrook, J. Lazell
2006, Wilson Journal of Ornithology (118) 218-224
We conducted mist netting each October from 1994 to 2004 on Guana Island, British Virgin Islands, and recorded bird sightings to develop a more complete inventory of the island's resident and migrant species. During our study, we recorded four new species for the British Virgin Islands: Magnolia Warbler (Dendroica magnolia;...
Recordings from the deepest borehole in the New Madrid Seismic Zone
Z. Wang, E.W. Woolery
2006, Seismological Research Letters (77) 148-153
The recordings at the deepest vertical strong-motion array (VSAS) from three small events, the 21 October 2004 Tiptonville, Tennessee, earthquake; the 10 February 2005 Arkansas earthquake; and the 2 June 2005 Ridgely, Tennessee, earthquake show some interesting wave-propagation phenomena through the soils: the S-wave is attenuated from 260 m to...
Teachers doing science: An authentic geology research experience for teachers
D. Hemler, T. Repine
2006, Journal of Geoscience Education (54) 93-102
Fairmont State University (FSU) and the West Virginia Geological and Economic Survey (WVGES) provided a small pilot group of West Virginia science teachers with a professional development session designed to mimic experiences obtained by geology majors during a typical summer field camp. Called GEOTECH, the program served as a research...
Unusual Holocene and late Pleistocene carbonate sedimentation in Bear Lake, Utah and Idaho, USA
W. Dean, J. Rosenbaum, G. Skipp, S. Colman, R. Forester, A. Liu, K. Simmons, J. Bischoff
2006, Sedimentary Geology (185) 93-112
Bear Lake (Utah-Idaho, USA) has been producing large quantities of carbonate minerals of varying mineralogy for the past 17,000 years. The history of sedimentation in Bear Lake is documented through the study of isotopic ratios of oxygen, carbon, and strontium, percent organic carbon, percent CaCO3, X-ray diffraction mineralogy, HCl-leach inorganic...
Gas slug ascent through changes in conduit diameter: Laboratory insights into a volcano-seismic source process in low-viscosity magmas
M.R. James, S.J. Lane, B. A. Chouet
2006, Journal of Geophysical Research B: Solid Earth (111)
Seismic signals generated during the flow and degassing of low-viscosity magmas include long-period (LP) and very-long-period (VLP) events, whose sources are often attributed to dynamic fluid processes within the conduit. We present the results of laboratory experiments designed to investigate whether the passage of a gas slug through regions of...
Morphometric discrimination of early life stage Lampetra tridentata and L richardsoni (Petromyzonidae) from the Columbia river basin
M.H. Meeuwig, J.M. Bayer, R.A. Reiche
2006, Journal of Morphology (267) 623-633
The effectiveness of morphometric and meristic characteristics for taxonomic discrimination of Lampetra tridentata and L. richardsoni (Petromyzonidae) during embryological, prolarval, and early larval stages (i.e., age class 1) were examined. Mean chorion diameter increased with time from fertilization to hatch and was significantly greater for L. tridentata than for L....
Quantitative estimation of minimum offset for multichannel surface-wave survey with actively exciting source
Y. Xu, J. Xia, R. D. Miller
2006, Journal of Applied Geophysics (59) 117-125
Multichannel analysis of surface waves is a developing method widely used in shallow subsurface investigations. The field procedures and related parameters are very important for successful applications. Among these parameters, the source-receiver offset range is seldom discussed in theory and normally determined by empirical or semi-quantitative methods in current practice....
Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California
S. Gao, S. Goldberg, M.J. Herbel, A.T. Chalmers, R. Fujii, K.K. Tanji
2006, Chemical Geology (228) 33-43
Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes...
Holocene history of drift ice in the northern North Atlantic: Evidence for different spatial and temporal modes
M. Moros, John T. Andrews, D. D. Eberl, E. Jansen
2006, Paleoceanography (21)
We present new high-resolution proxy data for the Holocene history of drift ice off Iceland based on the mineralogy of the <2-mm sediment fraction using quantitative X-ray diffraction. These new data, bolstered by a comparison with published proxy records, point to a long-term increasing trend in drift ice input into...
The role of environmental gradients in non-native plant invasion into burnt areas of Yosemite National Park, California
R. Klinger, E.C. Underwood, P.E. Moore
2006, Diversity and Distributions (12) 139-156
Fire is known to facilitate the invasion of many non-native plant species, but how invasion into burnt areas varies along environmental gradients is not well-understood. We used two pre-existing data sets to analyse patterns of invasion by non-native plant species into burnt areas along gradients of topography, soil and vegetation...
New maps, new information: Coral reefs of the Florida keys
B. H. Lidz, C. D. Reich, R.L. Peterson, E.A. Shinn
2006, Journal of Coastal Research (22) 260-282
A highly detailed digitized map depicts 22 benthic habitats in 3140.5 km2 of the Florida Keys National Marine Sanctuary. Dominant are a seagrass/lime-mud zone (map area 27.5%) throughout Hawk Channel and seagrass/carbonate-sand (18.7%) and bare carbonate-sand (17.3%) zones on the outer shelf and in The Quicksands. A lime-mud/seagrass-covered muddy carbonate-sand...
Interpreting the spatio-temporal patterns of sea turtle strandings: Going with the flow
K.M. Hart, P. Mooreside, L.B. Crowder
2006, Biological Conservation (129) 283-290
Knowledge of the spatial and temporal distribution of specific mortality sources is crucial for management of species that are vulnerable to human interactions. Beachcast carcasses represent an unknown fraction of at-sea mortalities. While a variety of physical (e.g., water temperature) and biological (e.g., decomposition) factors as well as the distribution...
Uranyl adsorption and surface speciation at the imogolite-water interface: Self-consistent spectroscopic and surface complexation models
Y. Arai, M. McBeath, J.R. Bargar, J. Joye, J.A. Davis
2006, Geochimica et Cosmochimica Acta (70) 2492-2509
Macro- and molecular-scale knowledge of uranyl (U(VI)) partitioning reactions with soil/sediment mineral components is important in predicting U(VI) transport processes in the vadose zone and aquifers. In this study, U(VI) reactivity and surface speciation on a poorly crystalline aluminosilicate mineral, synthetic imogolite, were...
Predicting water-surface fluctuation of continental lakes: A RS and GIS based approach in Central Mexico
M.E. Mendoza, G. Bocco, M. Bravo, Granados E. Lopez, W. R. Osterkamp
2006, Water Resources Management (20) 291-311
Changes in the water-surface area occupied by the Cuitzeo Lake, Mexico, during the 1974-2001 period are analysed in this study. The research is based on remote sensing and geographic information techniques, as well as statistical analysis. High-resolution satellite image data were used to analyse the 1974-2000 period, and very low-resolution...
Estimating crustal heterogeneity from double-difference tomography
J.-L. Got, V. Monteiller, J. Virieux, P. Okubo
2006, Pure and Applied Geophysics (163) 405-430
Seismic velocity parameters in limited, but heterogeneous volumes can be inferred using a double-difference tomographic algorithm, but to obtain meaningful results accuracy must be maintained at every step of the computation. MONTEILLER et al. (2005) have devised a double-difference tomographic algorithm that takes full advantage of the accuracy of cross-spectral...
Evaluation of kinetic uncertainty in numerical models of petroleum generation
K. E. Peters, C.C. Walters, P.J. Mankiewicz
2006, American Association of Petroleum Geologists Bulletin (90) 387-403
Oil-prone marine petroleum source rocks contain type I or type II kerogen having Rock-Eval pyrolysis hydrogen indices greater than 600 or 300-600 mg hydrocarbon/g total organic carbon (HI, mg HC/g TOC), respectively. Samples from 29 marine source rocks worldwide that contain mainly type II kerogen (HI = 230-786 mg HC/g...
Spirit rover localization and topographic mapping at the landing site of Gusev crater, Mars
Rongxing Li, Brent A. Archinal, Raymond E. Arvidson, Jim Bell, Phillip R. Christensen, Larry S. Crumpler, David J. Des Marais, Kaichang Di, Tom Duxbury, Matthew P. Golombek, John Grant, Ronald Greeley, Joe Guinn, Aaron H. Johnson, Randolph L. Kirk, Mark Maimone, Larry H. Matthies, Michael Malin, Timothy Parker, Michael H. Sims, Shane D. Thompson, Steven W. Squyres, Laurence A. Soderblom
2006, Journal of Geophysical Research E: Planets (111)
By sol 440, the Spirit rover has traversed a distance of 3.76 km (actual distance traveled instead of odometry). Localization of the lander and the rover along the traverse has been successfully performed at the Gusev crater landing site. We localized the lander in the Gusev crater using two-way Doppler...
Studying toxicity
A. Elkus, L. LeBlanc, C. Kim, R. Van Beneden, G. Mayer
2006, International Water Power and Dam Construction (58) 30-32
With funding from the George Mitchell Center for the Environment at the University of Maine, a team of scientists used a simple laboratory-based sediment resuspension design, and two well-established aquatic toxicology models, fathead minnows (Pimephales promelas) and zebrafish (Danio rerio), to evaluate if resuspension of Penobscot river sediment significantly elevates...
Research article: Watershed management councils and scientific models: Using diffusion literature to explain adoption
M.D. King, N. Burkardt, B. T. Clark
2006, Environmental Practice (8) 125-134
Recent literature on the diffusion of innovations concentrates either specifically on public adoption of policy, where social or environmental conditions are the dependent variables for adoption, or on private adoption of an innovation, where emphasis is placed on the characteristics of the innovation itself. This article uses both the policy...
