Filters: Tags: lake sediment (X)
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The geochemical data included here were generated as part of a Technical Assistance Agreement between the U.S. Geological Survey (USGS) and Rio Tinto Exploration based in Salt Lake City, Utah. Beginning in November of 2015, we began a project to reanalyze up to 60,000 archived sample splits originally collected as part of the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) project from selected areas in Arizona, California, Idaho, Montana, Nevada, New Mexico, and Utah. A small amount (approximately 0.25 g) of sieved <75 micron sample material was retrieved from the USGS National Geochemical Sample Archive for geochemical analysis. These samples were analyzed...
Categories: Data,
Data Release - Revised;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Arizona,
California,
Hydrogeochemistry and Stream Sediment Reconnaissance,
Idaho,
Montana,
The current state of permafrost in Alaska and meaningful expectations for its future evolution are informed by long-term perspectives on previous permafrost degradation. Thermokarst processes in permafrost landscapes often lead to widespread lake formation and the spatial and temporal evolution of thermokarst lake landscapes reflects the combined effects of climate, ground conditions, vegetation, and fire. This study provides detailed analyses of thermokarst lake sediments of Holocene age from the southern loess uplands of the Yukon Flats; including bathymetry and sediment core analyses across a water depth transect. The sediment core results, dated by radiocarbon and 210Pb, indicate the onset of finely laminated...
Selected archived sample splits collected as part of the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program, were reanalyzed by the U.S. Geological Survey (USGS) as part of a NURE-HSSR Reanalysis project (Smith and others, 2018). A small amount (approximately 0.25 grams [g]) of sieved less than 75-micron sample material was retrieved from the USGS National Geochemical Sample Archive for geochemical analysis. These samples were analyzed for 51 elements under a Technical Assistance Agreement with a third party by ALS Global laboratories using their ultra-trace four-acid-digestion dual-mode inductively coupled plasma-optical emission spectrometry/mass spectrometry...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Alaska,
DOE,
Economic Geology,
GGGSC,
Geochemistry,
Methodological considerations on the determination of benthic methyl-mercury (CH3Hg) production potentials were investigated on lake sediment, using 197Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and γ-irradiation. Flash freezing showed similar CH3Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with γ-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated 197Hg(II) carry-over...
Categories: Publication;
Types: Citation;
Tags: 197Hg tracer,
Lake sediment,
Mercury,
Mercury methyla
Seasonal trends of benthic methylmercury (methyl-Hg) production were examined in both littoral and open water sites of three lakes (Escondido, Moreno, and Morenito) in the North Andean Patagonia region of Argentina. Potentials of methyl-Hg production were measured by amending sediment samples with inorganic 197Hg(II), incubating for either 24 and 32 h at room temperature, and subsequently assaying the radiolabelled organomercury produced. Seasonal variations of benthic methyl-Hg production were studied but no significant correlation was observed. Lake littoral sites exhibited up to two fold higher methyl-Hg production potentials in most cases. Sediment from lakes Moreno and Morenito generally exhibited much lower...
During recent decades, lake levels in the Yukon Flats region of interior Alaska have fluctuated dramatically. However, prior to recorded observations, no data are available to indicate if similar or more extreme variations occurred during past centuries and millennia. This study explores the history of Yukon Flats lake origins and lake levels for the past approximately 5,500 years from sediment analyses guided by previous work on permafrost extent, thermokarst, and modern isotope hydrology. Sediments dated by 210Pb and AMS radiocarbon indicate stable chronologies following initial lake initiation. Subsequent lithology is autochthonous, and oxygen isotope ratios of endogenic carbonate reflect lake level change at...
Categories: Data;
Tags: Alaska,
Holocene,
Land Use Change,
USGS Science Data Catalog (SDC),
Yukon Flats,
These datasets provide information about the physical properties, total sediment chemistry, and batch experiment chemistry (to evaluate element mobility) of sediment cores from the Farmington Lake reservoir in Farmington, NM. The sediment cores were collected in November 2019.
The National Uranium Resource Evaluation (NURE) program was initiated by the Atomic Energy Commission (now the Department of Energy; DOE) in 1973 with a primary goal of identifying uranium resources in the United States. The Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program was one of nine components of NURE. Planned systematic sampling of stream sediments, soils, groundwater, and surface water over the entire United States began in 1975 under the responsibility of four DOE national laboratories: Lawrence Livermore Laboratory (LLL), Los Alamos Scientific Laboratory (LASL), Oak Ridge Gaseous Diffusion Plant (ORGDP), and Savannah River Laboratory (SRL). Each DOE laboratory developed its own sample...
Categories: Collection,
Data;
Tags: Arizona,
California,
Collection,
Hydrogeochemistry and Stream Sediment Reconnaissance,
Idaho,
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