A5060640956- Geochemistry and Geologic Mapping
- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Groundwater and Isotope Geochemistry
- Arsenic contamination and mitigation
- Heavy metals in environment
- Mine drainage and remediation techniques
- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Aeolian processes and effects
- Radioactive element chemistry and processing
- Groundwater flow and contamination studies
- Heavy Metal Exposure and Toxicity
- Paleontology and Stratigraphy of Fossils
- Atmospheric and Environmental Gas Dynamics
- Water Quality and Resources Studies
- Coal and Its By-products
- Geophysical and Geoelectrical Methods
- earthquake and tectonic studies
- Clay minerals and soil interactions
- Cryospheric studies and observations
- Atmospheric chemistry and aerosols
- Water Quality and Pollution Assessment
- Geological formations and processes
- Geological Studies and Exploration
United States Geological Survey
2014-2025
Denver Federal Center
2004-2019
Pacific Island Ecosystems Research Center
2009-2013
University of Oklahoma
2003
Oklahoma State University Oklahoma City
1993
Oklahoma State Department of Health
1993
United States Department of the Interior
1992
The critical role of rare earth elements (REEs), particularly heavy REEs (HREEs), in high-tech industries has created a surge demand that is quickly outstripping known global supply and triggered worldwide scramble to discover new sources. chemical analysis 23 sedimentary phosphate deposits (phosphorites) the United States demonstrates they are significantly enriched REEs. Leaching experiments using dilute H2SO4 HCl, extracted nearly 100% their total REE content show extraction from...
Research Article| August 01, 2014 Mapping Advanced Argillic Alteration at Cuprite, Nevada, Using Imaging Spectroscopy Gregg A. Swayze; Swayze 1U.S. Geological Survey, MS 964 Box 25046, Denver Federal Center, Denver, Colorado 80225 Corresponding author: e-mail, gswayze@usgs.gov Search for other works by this author on: GSW Google Scholar Roger N. Clark; Clark Alexander F.H. Goetz; Goetz 2University of Colorado, Department Sciences, Emeritas, Boulder, 80309 K. Eric Livo; Livo George Breit;...
Leachate from municipal landfills can create groundwater contaminant plumes that may last for decades to centuries. The fate of reactive contaminants in leachate-affected aquifers depends on the sustainability biogeochemical processes affecting transport. Temporal variations configuration redox zones downgradient Norman Landfill were studied more than a decade. leachate plume contained elevated concentrations nonvolatile dissolved organic carbon (NVDOC) (up 300 mg/L), methane (16 ammonium...
Cross crater is a 65 km impact crater, located in the Noachian highlands of Terra Sirenum region Mars (30°S, 158°W), which hosts aluminum phyllosilicate deposits first detected by Observatoire pour la Minéralogie, L'Eau, les Glaces et l'Activitié (OMEGA) imaging spectrometer on Express. Using high-resolution data from Reconnaissance Orbiter, we examine crater's basin-filling sedimentary deposits. Visible/shortwave infrared (VSWIR) spectra Compact Imaging Spectrometer for (CRISM) show...
First posted October 28, 2016 For additional information, contact: Center Director, USGS Central Mineral and Environmental Resources Science CenterBox 25046, Mail Stop 973 Denver, CO 80225http://minerals.usgs.gov/minerals/ This report draws on previous syntheses basic research studies of sedimentary exhalative (sedex) deposits to arrive at the defining criteria, both descriptive genetic, for sedex-type deposits. Studies tectonic, sedimentary, fluid evolution modern ancient basins have also...
Abstract Light‐absorbing particles in atmospheric dust deposited on snow cover (dust‐on‐snow, DOS) diminish albedo and accelerate the timing rate of melt. Identification these their effects is relevant to snow‐radiation modeling water‐resource management. Laboratory‐measured reflectance DOS samples from San Juan Mountains (USA) were compared with mass loading, particle sizes, iron mineralogy, carbonaceous matter type content, chemical compositions. Samples collected each spring for water...
Abstract Atmospheric particulate matter (PM) as light‐absorbing particles (LAPs) deposited to snow cover can result in early onset and rapid melting, challenging management of downstream water resources. We identified LAPs 38 samples (water years 2013–2016) from the mountainous Upper Colorado River basin by comparing among laboratory‐measured spectral reflectance, chemical, physical, magnetic properties. Dust sample averaged over wavelength range 0.35–2.50 μm, varied a factor 1.9 (range,...
Field and laboratory techniques were used to identify the biogeochemical factors affecting sulfate reduction in a shallow, unconsolidated alluvial aquifer contaminated with landfill leachate. Depth profiles of 35S-sulfate rates sediments positively correlated concentration dissolved sulfate. Manipulation samples revealed Michaelis−Menten-like relationship an apparent Km Vmax approximately 80 0.83 μM SO4-2·day-1, respectively. The core leachate plume was well below 20 coincided very low...
The National Water-Quality Assessment pilot project for the Central Oklahoma aquifer examined chemical and isotopic composition of ground water, abundances textures minerals in core samples, water levels hydraulic properties flow system to identify geochemical reactions occurring rates directions ground-water flow. underlies 3,000 square miles central consists Permian red beds, including parts Garber Sandstone, Wellington Formation, Chase, Council Grove, Admire Groups, Quaternary alluvium...