Filters: Tags: radiometric dating (X)
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This data release codifies and attributes explanatory factors that could potentially impact groundwater quality at 142 groundwater sites (wells or developed springs) used for domestic water supply and 310 groundwater sites used for public water supply in the northern Sierra Nevada foothills. Water quality from domestic groundwater sites was assessed as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) program in 2015-2017. Domestic groundwater sites from two of the U.S. Geological Survey’s Priority Basin Project Shallow Aquifer Assessment study units are attributed here: The Yuba-Bear Watersheds (YBW) study unit (sampled in 2015-2016) and the American-Cosumnes-Mokelumne...
Fine-grained sediment was collected from the banks of Napa River, Sonoma Creek, and tributaries in March 2018 and from shallow nearshore areas of the northern reach of San Francisco Bay in April 2018. Bulk sediment was dated using activities of short-lived cosmogenic radionuclides (beryllium-7, cesium-137, and lead-210). Contents of potentially toxic metals and source-rock-indicative elements, including rare earth elements, were quantified in the fine fraction of sediment (particles less than 0.063 mm diameter). Ratios of stable carbon-13/carbon-12 isotopes and total carbon to total nitrogen were determined in sedimentary organic matter.
Categories: Data;
Tags: Bedrock geochemistry,
CMHRP,
Carquinez Straight,
Coastal and Marine Hazards and Resources Program,
Environmental Health,
These 40Ar/39Ar thermochronologic data for white mica and K-feldspar from alteration zones around lode veins are for the study of the Butte mining district, U.S.A. Results of the study are described and interpreted in Lund and others (2018). These data are shared to meet open data requirements.
This dataset includes tables of U- and Th-isotopic data used to calculate uranium-series age estimates (230Th/U method) and initial 234U/238U activity ratios for samples of tufa mounds formed by groundwater seepage. In addition, data include 87Sr/86Sr and 234U/238U values determined for spring discharge and streamflow collected from sites in the vicinity of Buffalo National River.
Categories: Data;
Tags: Arkansas,
Boone County,
Buffalo National River,
Carroll County,
Geochemistry,
Sample Analyses: Four samples of silica sinter from Giant and Castle Geysers composed of opal-A or opal-A/C were analyzed for U-Th isotopes at USGS laboratories in Denver, CO (https://www.usgs.gov/centers/gecsc/science/denver-radiogenic-isotope-lab?qt-science_center_objects=0#qt-science_center_objects). Small fragments, weighing approximately 10 g, were cut and polished to enable microsampling using carbide dental burrs. Sub-samples consisted of small pits or trenches that cut across microfabric elements and integrate material weighing 0.082–0.109 g. Resulting powders were digested using concentrated hydrofluoric acid (HF) after spiking with known amounts of a mixed 229Th-233U-236U tracer solution. After evaporation,...
Categories: Data;
Tags: Geysers,
Upper Geyser Basin,
Yellowstone National Park,
Yellowstone National Park,
radiometric dating,
Sample Collection: Field work was conducted in November 2018 in the Upper Geyser Basin. Three sinter samples were collected from Castle Geyser and one sinter sample was collected from Solitary Geyser. At Castle Geyser, an effort was made to identify stable surfaces associated with the oldest exposed stratigraphic levels of sinter deposition, in order to target material emplaced during early stages of hydrothermal activity in the basin. At Solitary Geyser, material was collected from an exposure on the upper surface of a sinter deposit. All four sinter sample locations were selected to coincide with collection sites for material dated by radiocarbon methods, to enable a cross-comparison of results. Sinter was collected...
Categories: Data;
Tags: Upper Geyser Basin,
Yellowstone National Park,
Yellowstone National Park,
beryllium,
geyser,
This data release includes field observations and laboratory data for two trenches excavated across the Lost River fault zone, Idaho, in September 2019. The field sites include the Sheep Creek site (44.282541 degrees N, 113.941193 degrees W) on the southernmost Warm Springs section and the Arentson Gulch site (44.247816 degrees N, 113.918554 degrees W) on the northernmost Thousand Springs section. Field observations include descriptions of stratigraphic units exposed in the trenches; laboratory data include 41 radiocarbon ages and 4 infrared stimulated luminescence ages.
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Arentson Gulch,
Seismology,
Soil Sciences,
Stratigraphy,
USGS Science Data Catalog (SDC),
Sediment cores were collected from three sites within the Plum Island Ecosystems Long-Term Ecological Research (PIE-LTER) domain in Massachusetts to obtain estimates of long-term marsh decomposition and evaluate shifts in the composition and reactivity of sediment organic carbon in disturbed marsh environments. Paired sediment cores were collected from three sites on the marsh platform and from three ponds; these cores were about 100 and 50 centimeters in length, respectively. The marsh sites had similar elevations, at about 1.41 to 1.51 meters relative to the North American Vertical Datum of 1988, and similar salt marsh grass communities, dominated by Spartina patens, S. alterniflora, and Distichlis spicata. Permanently...
These datasets provide the measurements and analytical data used to describe the evolution of Neogene faulting near Blythe, California. The data include structural measurements and results from Ar-Ar and U-Pb geochronology that address the research questions of the associated publication. Structural measurement datasets provide fault surface kinematic measurements and tabulations of structural data used in the manuscript stereoplots. Argon datasets include analytical data from Ar-Ar geochronology. U-Pb datasets include analytical data from calcite samples synkinematic with fault movement. Shear estimate datasets include estimations of fault slip magnitude in the Blythe region. These datasets are associated with...
These data are for a geochronologic study of emplacement ages for plutons of the Cretaceous Idaho batholith and detrital zircon ages for metasedimentary rocks, west-central Idaho. Zircon from six samples of discrete plutons across a regional transect were dated by sensitive high resolution ion microprobe (SHRIMP). SHRIMP U-Pb ages of igneous rocks connect the igneous activity to structural history, crustal depths, and origins of epigenetic gold-silver-antimony-tungsten±mercury mineral deposits. Zircon from four samples of metasedimentary rocks in the southern part of the central Idaho mineral province were dated—three by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) methods and one by SHRIMP...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: "Mineral Resources"],
"Structural Geology",
Detrital Zircon,
GGGSC,
Geochronology,
This data release provides radiocarbon measurements from a core obtained off San Francisquito Creek in South San Francisco Bay.
Categories: Data;
Tags: CMHRP,
Coastal and Marine Hazards and Resources Program,
Hooks Point,
PCMSC,
Pacific Coastal and Marine Science Center,
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