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This data release includes 40Ar/39Ar data from the U.S. Geological Survey for samples from the Gidami gold deposit in the Eastern Desert of Egypt. Rock samples were collected by Basem Zoheir--Benha University/University of Kiel. Potassium-bearing mineral grains were separated from the bulk sample and analyzed by argon geochronology at the U.S. Geological Survey Bascom ARgon Dating (BARD) Laboratory in Reston, Virginia. The data constrain the timing of gold mineralization in the Gidami gold deposit.
This U.S. Geological Survey (USGS) data release provides whole rock major, minor, and trace element geochemical data and zircon U-Pb geochronology and trace element concentrations for samples from pre-ignimbrite volcanoes within the San Juan locus of the mid-Cenozoic Southern Rocky Mountain volcanic field, Colorado. Samples were collected in order to constrain the evolution of the pre-ignimbrite magmatic system.
Categories: Data;
Tags: Colorado,
Geochemistry,
USGS Science Data Catalog (SDC),
United States,
geochemistry,
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,
The National Geologic Map Database (NGMDB) is a Congressionally mandated national archive of geoscience maps, reports, and stratigraphic information. The Geologic Mapping Act of 1992 and its Reauthorizations calls for the U.S. Geological Survey and the Association of American State Geologists (AASG) to cooperatively build this national archive, according to technical and scientific standards whose development is coordinated by the NGMDB. The NGMDB consists of a comprehensive set of publication citations, stratigraphic nomenclature, downloadable content in raster and vector formats, unpublished source information, and guidance on standards development. The NGMDB contains information on more than 110,000 maps and...
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
We report U-Pb zircon geochronology results for one metavolcanic and one metaplutonic rock sample from the Mount Hayes A-6 Quadrangle of central Alaska. These samples are representative of rock units assigned to the Clearwater terrane of Jones and others (1987), a sequence of greenschist-grade metavolcanic and metasedimentary rocks of poorly constrained age and tectonic origin. Our results indicate a crystallization age of 277.33 +/- 11.84 Ma for a felsic metavolcanic rock, and a 268.05 +/- 11.64 Ma crystallization age for a granitic metaplutonic unit intruding the former.
The 'UVX: Exploration, Water, Drilling and Correspondence' file is part of the A. F. Budge Mining Ltd. Mining collection. A. F. Budge Mining Ltd., a British company owned by Tony Budge, controlled properties across several western U. S. states and northern Mexico. The company was active in Arizona during the 1980s and into the early 1990s. The collection consists of economic geologic information including maps, logs, reports and records. A few properties make up most of the collection: Vulture, United Verde Extension and Korn Kob.
This data release presents zircon U-Pb LA-ICP-MS geochronology from igneous rocks exposed in a coastal exposure at Ursus Head, Iliamna C-2 Quadrangle. Sills and dikes exposed in a coastal exposure at Ursus Head are deformed within the Bruin Bay fault zone. Common dikes intruding late Triassic Kamishak Formation strata composing the hanging-wall of the Bruin Bay fault are cut by numerous small-scale, low-angle, bedding-parallel, and high angle contractional faults. Sample 09MAW006A collected from one of many dikes deformed in the fault zone produced a uni-modal distribution of zircon ages of with a weighted mean of 206.92 +/-0.96 (2 sigma, n=47) and an MSWD of 1.1. Sample 09BG020C collected from a sill of more mafic...
This data file presents 40Ar/39Ar step-heating geochronology results for a granite sample from the Livengood mining district. The Livengood area is a historically productive placer mining area approximately 80 road miles north of Fairbanks, Alaska. This data is a component of a geologic map and accompanying report that synthesizes recently collected and previously published agency and industry geologic data in a 1:50,000-scale comprehensive geologic map to build a better understanding of the geology and mineral-resource potential of the Livengood area.
The following report summarizes the dating results from Bradley Lake, Oregon. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and datingrelated calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.
Tables of U- and Th-isotopic data used to calculate uranium-series age estimates and initial 234U/238U activity ratios as well as 87Sr/86Sr, δ13C, and δ18O for samples of phreatic speleothems from Wind Cave National Park and U- and Sr-isotopic compositions of waters from the southern Black Hills of South Dakota, USA
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Black Hills,
Climatology,
Custer County,
Fall River County,
Geochemistry,
This dataset accompanies publication 'Elemental, isotopic, and geochronological variability in Mogollon-Datil Volcanic Province archaeological obsidian, Southwestern New Mexico: Solving issues of inter-source discrimination', published in Geoarchaeology (https://dx.doi.org/10.1002/gea.21672), which studied the ability of isotopic and argon geochronologic analyses to discriminate between archaeological obsidian sources in the Mogollon-Datil volcanic province.
Categories: Data;
Types: Citation;
Tags: 40Ar/39Ar,
CMERSC,
Central Minerals and Environmental Resources Science Center,
MRP,
Mogollon Mountains,
This dataset accompanies planned publication 'Detrital record of the Late Oligocene – Early Miocene mafic volcanic arc in the Southern Patagonian Andes (~51°S) from single-clast geochronology and trace element geochemistry'. The Ar/Ar data is for samples that record the detrital sedimentary record of the basin. The geochronology provides time constraints for the sedimentation studied in the manuscript. Samples were collected from the Magallanes-Austral Basin, and collection was supervised by Julie Fosdick, who sent them to the USGS for Ar/Ar analysis.
This dataset accompanies publication '40Ar/39Ar geochronology and petrogenesis of the Table Mountain Shoshonites, Golden, CO', to be published in Rocky Mountain Geology, which analyzed lava flows on North and South Table Mountain in Golden, CO, for argon geochronology and geochemistry.
Categories: Data;
Tags: 40Ar/39Ar,
Cretaceous,
Eocene,
GGGSC,
Geology, Geophysics, and Geochemistry Science Center,
The Geochronology Repository is an active collection of radiometric ages generated by the Montana Bureau of Mines and Geology (MBMG). The geochronology data are organized in a public facing database with attributes describing field location, geologic context, geochronology method, and laboratory of analysis. Hand samples, thin sections, heavy mineral separates, and grain mounts of processed samples are stored in the MBMG Geologic Materials Repository. The collection is available to the public.
This collection consists of geological samples associated with the research of USGS Scientist Emeritus Michael J. Kunk. The collection contains rock samples stemming from Kunk’s earth science research in North America on geochronology, geochemistry, landscape evolution, volcanology, mineralogy, and structural geology. This collection contains four pallets of geological samples and materials.
This U.S. Geological Survey (USGS) data release includes whole rock geochemical and isotopic data, and uranium-lead isotopic data collected by both Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Sensitive High Resolution Ion Microprobe-Reverse Geometry (SHRIMP-RG) methods for rocks in Colorado, Wyoming, Utah, and New Mexico.
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Colorado,
Geochemistry,
National Cooperative Mapping Program,
New Mexico,
USGS Science Data Catalog (SDC),
This DGGS Raw Data File presents 40Ar/39Ar age dating results for selected igneous rocks encountered in the Styx River area of the western Alaska Range. Crystallization ages on biotite and hornblende from plutonic rocks range from about ~60 to ~63 Ma, while a sericite alteration age in plutonic rocks altered by a dike swarm also is around ~63 Ma. Sericite alteration associated with a copper-molybdenum porphyry ranges from ~10 to ~11 Ma. Analyses were performed by the University of Alaska Fairbanks Geochronology Laboratory, and results were reported by Paul Layer and Jeff Benowitz. This data release includes the following products: a summary of sample collection methods, the laboratory report, analytical data tables...
This report presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) Wrangellia Mineral Assessment project, part of a multi-year effort focusing on improving the publicly available geoscientific information for the western Wrangellia terrane. The samples described in this report were selected and analyzed to improve our understanding of the geology and structural history of the Wrangellia Mineral Assessment project area. A metagabbro rock sample returned a Late Triassic crystallization age consistent with regional ages for Nikolai Greenstone-related magmatism; however, the two amphibole separates ages do not overlap,...
This publication contains previously unpublished geochemical analyses or re-analyses of lavas, magmatic inclusions, and a few gabbroic cumulate inclusions from Alaska volcanoes (Akutan, Augustine, Buzzard Creek, Dana, Douglas, Fourpeaked, Frosty, Great Sitkin, Iliamna, Kaguyak, Kiska, Okmok, Prindle Cone, Recheshnoi, Redoubt, Spurr, Ukinrek Maars, Vsevidof, Westdahl, Wrangell) collected by the authors and others over the past 35 years. It provides substantial data sets for three volcanoes (Vsevidof, Westdahl, and Douglas) for which little or no published data exist. All analyses were made by the GeoAnalytical laboratory at Washington State University in Pullman, WA. The ICP/MS data have been reduced using the 2006...
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