Mining-impacted sources of metal loading to an alpine stream based on a tracer-injection study, Clear Creek County, Colorado
David L. Fey, Laurie Wirt
2007, Reviews in Engineering Geology (17) 85-103
Base flow water in Leavenworth Creek, a tributary to South Clear Creek in Clear Creek County, Colorado, contains copper and zinc at levels toxic to aquatic life. The metals are predominantly derived from the historical Waldorf mine, and sources include an adit, a mine-waste dump, and mill-tailings deposits. Tracer-injection and...
Characterizing infiltration through a mine-waste dump using electrical geophysical and tracer-injection methods, Clear Creek County, Colorado
Robert R. McDougal, Laurie Wirt
2007, Reviews in Engineering Geology (17) 9-24
Infiltration of surface water through mine waste can be an important or even dominant source of contaminants in a watershed. The Waldorf mine site in Clear Creek County, Colorado, is typical of tens of thousands of small mines and prospects on public lands throughout the United States. In this study,...
Diets of swift foxes (Vulpes velox) in continuous and fragmented prairie in Northwestern Texas
J.F. Kamler, W.B. Ballard, M.C. Wallace, P. S. Gipson
2007, Southwestern Naturalist (52) 504-510
Distribution of the swift fox (Vulpes velox) has declined dramatically since the 1800s, and suggested causes of this decline are habitat fragmentation and transformation due to agricultural expansion. However, impacts of fragmentation and human-altered habitats on swift foxes still are not well understood. To better understand what effects these factors...
The distribution, occurrence and environmental effect of mercury in Chinese coals
Lingyun Zheng, Gaisheng Liu, C. L. Chou
2007, Science of the Total Environment (384) 374-383
Mercury (Hg) is a toxic, persistent, and globally distributed pollutant due to its characteristic properties such as low melting and boiling points, conversion between chemical forms and participation in biological cycles. During combustion mercury in coal is almost totally emitted to the atmosphere. With a huge amount of coal consumed,...
Investigation of the groundwater system at Masaya Caldera, Nicaragua, using transient electromagnetics and numerical simulation
R.E. MacNeil, W. E. Sanford, C.B. Connor, S.K. Sandberg, M. Diez
2007, Journal of Volcanology and Geothermal Research (166) 217-232
The distribution of groundwater beneath Masaya Volcano, in Nicaragua, and its surrounding caldera was characterized using the transient electromagnetic method (TEM). Multiple soundings were conducted at 30 sites. Models of the TEM data consistently indicate a resistive layer that is underlain by one or more conductive layers. These two layers...
Fate and groundwater impacts of produced water releases at OSPER "B" site, Osage County, Oklahoma
Yousif K. Kharaka, E. Kakouros, James J. Thordsen, Gil Ambats, Marvin M. Abbott
2007, Applied Geochemistry (22) 2164-2176
For the last 5 a, the authors have been investigating the transport, fate, natural attenuation and ecosystem impacts of inorganic and organic compounds in releases of produced water and associated hydrocarbons at the Osage-Skiatook Petroleum Environmental Research (OSPER) “A” and “B” sites,...
Scales of equilibrium and disequilibrium during cleavage formation in chlorite and biotite-grade phyllites, SE Vermont
C. K. McWilliams, R. P. Wintsch, Michael J. Kunk
2007, Journal of Metamorphic Geology (25) 895-913
Detailed electron microprobe analyses of phyllosilicates in crenulated phyllites from south-eastern Vermont show that grain-scale zoning is common, and sympathetic zoning in adjacent minerals is nearly universal. We interpret this to reflect a pressure-solution mechanism for cleavage development, where precipitation from a very small fluid reservoir fractionated that fluid. Multiple...
Probabilistic seismic demand analysis using advanced ground motion intensity measures
P. Tothong, N. Luco
2007, Earthquake Engineering and Structural Dynamics (36) 1837-1860
One of the objectives in performance-based earthquake engineering is to quantify the seismic reliability of a structure at a site. For that purpose, probabilistic seismic demand analysis (PSDA) is used as a tool to estimate the mean annual frequency of exceeding a specified value of a structural demand parameter (e.g....
The restricted gemuk group: A triassic to lower cretaceous succession in southwestern Alaska
Marti L. Miller, D. C. Bradley, T. K. Bundtzen, R. B. Blodgett, E.A. Pessagno Jr., R. D. Tucker, A. G. Harris
2007, Special Paper of the Geological Society of America 273-305
New data from an Upper Triassic to Lower Cretaceous deep marine succession-the herein reinstated and restricted Gemuk Group-provide a vital piece of the puzzle for unraveling southwestern Alaska's tectonic history. First defined by Cady et al. in 1955, the Gemuk Group soon became a regional catchall unit that ended up...
Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terrestrial cosmogenic nuclide, electron spin resonance, U-series and amino acid racemization methods
L.A. Owen, Jordon Bright, R.C. Finkel, M.K. Jaiswal, D. S. Kaufman, S. Mahan, U. Radtke, J.S. Schneider, W. Sharp, A.K. Singhvi, C.N. Warren
2007, Quaternary International (166) 87-110
A Late Quaternary spit-shoreline complex on the northern shore of Pleistocene Lake Mojave of southeastern California, USA was studied with the goal of comparing accelerator mass spectrometry (AMS) radiocarbon, luminescence, electron spin resonance (ESR), terrestrial cosmogenic radionuclide (TCN) surface exposure, amino acid racemization (AAR) and U-series dating methods. The pattern...
Invasive species and coal bed methane development in the Powder River Basin, Wyoming
E. Bergquist, P. Evangelista, T.J. Stohlgren, N. Alley
2007, Environmental Monitoring and Assessment (128) 381-394
One of the fastest growing areas of natural gas production is coal bed methane (CBM) due to the large monetary returns and increased demand for energy from consumers. The Powder River Basin, Wyoming is one of the most rapidly expanding areas of CBM development with projections of the establishment of...
Nature, diversity of deposit types and metallogenic relations of South China
K. Zaw, S. G. Peters, P. Cromie, C. Burrett, Z. Hou
2007, Ore Geology Reviews (31) 3-47
The South China Region is rich in mineral resources and has a wide diversity of deposit types. The region has undergone multiple tectonic and magmatic events and related metallogenic processes throughout the earth history. These tectonic and metallogenic processes were responsible for the formation of the diverse styles of base...
Dynamics of CFCs in northern temperate lakes and adjacent groundwater
John F. Walker, David A. Saad, Randall J. Hunt
2007, Water Resources Research (43)
Three dimictic lakes and one meromictic lake in and near the Trout Lake, Wisconsin, watershed were sampled to determine the variation of chlorofluorocarbon (CFC) concentrations within the lakes. The lakes were sampled during stratified conditions, during fall turnover, and during ice cover. The results demonstrate a considerable variation in CFC...
Return to the wild: Translocation as a tool in conservation of the desert tortoise (Gopherus agassizii)
K.J. Field, C.R. Tracy, P.A. Medica, R.W. Marlow, P.S. Corn
2007, Biological Conservation (136) 232-245
Translocation could be used as a tool in conservation of the threatened Mojave Desert Tortoise (Gopherus agassizii) by moving individuals from harm's way and into areas where they could contribute to conservation of the species. Numerous factors may affect the success of translocations, including the conditions experienced by tortoises in...
Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon
Pamela B. McLeod, Martine J. van den Heuvel-Greve, S. N. Luoma, R.G. Luthy
2007, Environmental Toxicology and Chemistry (26) 980-987
This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA). Test methods were developed for the use of clams to investigate the effects of...
Comparison of four approaches to a rock facies classification problem
M.K. Dubois, Geoffrey C. Bohling, S. Chakrabarti
2007, Computers & Geosciences (33) 599-617
In this study, seven classifiers based on four different approaches were tested in a rock facies classification problem: classical parametric methods using Bayes' rule, and non-parametric methods using fuzzy logic, k-nearest neighbor, and feed forward-back propagating artificial neural network. Determining the most effective classifier for geologic facies prediction in wells...
A project for monitoring trends in burn severity
Jeffery C. Eidenshink, Brian Schwind, Ken Brewer, Zhu-Liang Zhu, Brad Quayle, Stephen M. Howard
2007, Fire Ecology (3) 3-21
Jeff Eidenshink, Brian Schwind, Ken Brewer, Zhi-Liang Zhu, Brad Quayle, and Elected officials and leaders of environmental agencies need information about the effects of large wildfires in order to set policy and make management decisions. Recently, the Wildland Fire Leadership Council (WFLC), which implements and coordinates the National Fire Plan...
ADCP measurements of gravity currents in the Chicago River, Illinois
C.M. Garcia, K. Oberg, M.H. Garcia
2007, Journal of Hydraulic Engineering (133) 1356-1366
A unique set of observations of stratified flow phenomena in the Chicago River was made using an upward-looking acoustic Doppler current profiler (ADCP) during the period November 20, 2003 to February 1, 2004. Water density differences between the Chicago River and its North Branch (NB) seem to be responsible for...
Seismic hazard and risk assessment in the intraplate environment: The New Madrid seismic zone of the central United States
Z. Wang
2007, Special Paper of the Geological Society of America 363-374
Although the causes of large intraplate earthquakes are still not fully understood, they pose certain hazard and risk to societies. Estimating hazard and risk in these regions is difficult because of lack of earthquake records. The New Madrid seismic zone is one such region where large and rare intraplate earthquakes...
Exhumation and continental strike-slip fault systems: Introduction
S. M. Roeske, A.B. Till, D.A. Foster, J.C. Sample
2007, Geological Society of America Special Papers vii-x
Metamorphic rocks adjacent to and within strike-slip faultsystems occur in a wide range of tectonic settings. Detailed studies show that for a number of these locales a significant part of the exhumation occurred during strike-slip fault motion, but the specific processes involved are often cryptic. Although some sites share characteristic...
Seabirds as indicators of marine ecosystems: Introduction: A modern role for seabirds as indicators
John F. Piatt, William J. Sydeman, Francis Wiese
2007, Marine Ecology Progress Series (352) 199-204
A key requirement for implementing ecosystem-based management is to obtain timely information on significant fluctuations in the ecosystem (Botsford et al. 1997). However, obtaining all necessary information about physical and biological changes at appropriate temporal and spatial scales is a daunting task. Intuitively, one might assume that physical data are more...
Growth rate differences between resident native brook trout and non-native brown trout
S.M. Carlson, A.P. Hendry, B. H. Letcher
2007, Journal of Fish Biology (71) 1430-1447
Between species and across season variation in growth was examined by tagging and recapturing individual brook trout Salvelinus fontinalis and brown trout Salmo trutta across seasons in a small stream (West Brook, Massachusetts, U.S.A.). Detailed information on body size and growth are presented to (1) test whether the two species...
Total petroleum system assessment of undiscovered resources in the giant Barnett Shale continuous (unconventional) gas accumulation, Fort Worth Basin, Texas
R. M. Pollastro
2007, American Association of Petroleum Geologists Bulletin (91) 551-578
Undiscovered natural gas having potential for additions to reserves in the Mississippian Barnett Shale of the Fort Worth Basin, north-central Texas, was assessed using the total petroleum system assessment unit concept and a cell-based methodology for continuous-type (Unconventional) resources. The Barnett-Paleozoic total petroleum system is defined in the Bend arch-Fort...
Prey resources before spawning influence gonadal investment of female, but not male, white crappie
D.B. Bunnell, S.E. Thomas, R.A. Stein
2007, Journal of Fish Biology (70) 1838-1854
In this study, an outdoor pool experiment was used to evaluate the effect of prey resources during 4 months before spawning on the gonadal investments of male and female white crappie Pomoxis annularis, a popular freshwater sportfish that exhibits erratic recruitment. Fish were assigned one of three feeding treatments: starved, fed...
Increased groundwater to stream discharge from permafrost thawing in the Yukon River basin: Potential impacts on lateral export of carbon and nitrogen
Michelle Ann Walvoord, Robert G. Striegl
2007, Geophysical Research Letters (34)
Arctic and subarctic watersheds are undergoing climate warming, permafrost thawing, and thermokarst formation resulting in quantitative shifts in surface water - groundwater interaction at the basin scale. Groundwater currently comprises almost one fourth of Yukon River water discharged to the Bering Sea and contributes 5-10% of the dissolved organic carbon...
