Filters: Tags: Uranium-lead analysis (X) > partyWithName: Christopher S Holm-Denoma (X)
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In 2016, with National Park Service support, several previously undated plutons were sampled in Glacier Bay National Park and Preserve along the west side of Glacier Bay for age determinations. Geochronologic analyses were conducted to determine the ages of the plutonic rocks in the Glacier Bay area. Five samples were collected by Frederic Wilson (USGS Alaska Science Center), from Dundas Bay and Geikie Inlet, and dated by laser ablation-inductively coupled plasma mass spectrometry U-Pb methods. The dates obtained ranged from approximately 112-118 Ma, indicating that these samples are younger than the Saint Elias plutonic suite (ca. 160 Ma-130Ma), which runs along the same trend as the sampled rocks to the south.
This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data from four samples collected from syn- and post-Columbia River Basalt Group strata. Samples were collected from within alluvial fan strata and gravel-mantled hillslopes. Sample 16MANC2-01 was collected from an excavation into rounded fluvial gravel deposits along the Manastash Ridge. The unit collected includes Cascadian derived volcanic clasts and is interpreted as an inset terrace of fluvial strata deposited on the Manastash Ridge. Sample 16MANC1-06 is a rhyodacitic boulder collected on a nearby exposure of gravel mantled hillslopes along Manastash Ridge. Sample 16MRF01 was collected...
Categories: Data;
Tags: Detrital Zircon,
GGGSC,
Geochronology,
Geology, Geophysics, and Geochemistry Science Center,
Kittitas Valley,
This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data to determine the ages of Challis igneous rocks in the Thunder Mountain volcanic field and dikes west of the volcanic field, especially in and near the Stibnite-Yellow Pine mining district, ID. These efforts were made to help understand the stratigraphy and lithologic characteristics of the Challis igneous rocks by determining their absolute ages.
Categories: Data;
Tags: Challis,
GGGSC,
Geochronology,
Geology, Geophysics, and Geochemistry Science Center,
Idaho,
This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data from four samples collected from fault-bounded bedrock units in northwestern Oregon. Samples were collected from a paleoseismic trench excavated across the Scoggins Valley strand of the Gales Creek Fault and nearby quarry. The trench is located on a ridge top saddle on the Scoggins Creek-Tualatin River divide, where it crosses a lidar scarp trending 300°, up to the east, with suggestion of dextral slip. Trench trends 060° across scarp, is 35 m long in bedrock. Loess, paleosols, and colluvium overlie bedrock. The trench exposes tuffaceous sediments of the Keasey Formation, which records...
Categories: Data;
Tags: Detrital Zircon,
GGGSC,
Gales Creek,
Geochronology,
Geology, Geophysics, and Geochemistry Science Center,
Zircon (ZrSiO4) and cassiterite (SnO2) samples were collected by the U.S. Geological Survey (USGS) from the Yazov Granite, Transbaikalia region, Eastern Siberia, Russia. Samples (in the form of mounted loose grains) were prepared and analyzed for direct age dating on a laser ablation inductively coupled plasma mass spectrometer (LA–ICPMS) system at the USGS in Denver, Colorado from February 2017 to June 2019. The data indicate that high tin concentrations in the Yazov Granite are caused by inheritance of older cassiterite crystals and may imply that these granites cannot be genetically related to primary tin ore deposits of the region. These results have broad implications in understanding how critical elements,...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: GGGSC,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
LA–ICPMS,
MRP,
From 2017-2019, framework metallogenic studies were completed in the eastern Yukon-Tanana upland in eastern Alaska. Numerous previously undated plutons known or suspected to contain components of porphyry, epithermal, and intrusion-related gold systems and associated deposit types were sampled for age and zircon trace element determinations between the Black Mountain area and the Yukon border, north of the Tanana River and south of the Yukon River. A collection of 54 samples were collected by Douglas Kreiner (USGS, Alaska Science Center). Zircon grains were separated from each sample. The samples were examined by U-Pb analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) in a USGS laboratory...
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