Filters: Tags: 40Ar/39Ar (X)
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This dataset accompanies planned publication '40Ar/39Ar geochronology of hydrothermal activity related to orogenic gold mineralization in the Klamath Mountains, California, U.S.A.'. The Ar/Ar data are for samples that record the mineralization of the area. The geochronology provides time constraints for the mineralization studied in the manuscript. Samples were collected from the Klamath Mountains by Ryan Taylor (U.S. Geological Survey, Geophysics, and Geochemistry Science Center), who sent them to the USGS Denver Argon Geochronology Laboratory for Ar/Ar analysis.
This dataset accompanies publication 'Multiproxy Cretaceous-Paleogene boundary event stratigraphy: an Umbria-Marche basin-wide perspective'.
Categories: Data;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
GGGSC,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
This dataset accompanies publication 'A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system', in review in Geology, which analyzed eruptive products from the La Garita caldera.
This dataset accompanies publication: Minor, S.A., Caine, J.S., Ruleman, C.A., Fridrich, C.J., Chan, C.F., Brandt, T.R., Morgan,L.E., Cosca, M.A., and Grauch, V.J.S., in prep, Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado: U.S. Geological Survey Scientific Investigations Map (in revision), 2 plates, 27 ms. p, 1:24,000 scale.
Samples of vein-type magmatic-steam alunite were collected over several field seasons from five mines and prospects (L&N, Mt. Edna, Christmas, upper Mineral Products, and Close In) in the Alunite Ridge and Deer Trail Mountain area, Marysvale, Utah, as well as a sample from the Deer Trail mine workings from which sericite was separated. The magmatic-steam alunite and sericite were analyzed by the 40Ar/39Ar method to constrain the timing and duration of magmatic activity associated with the intrusion of two porphyry stocks beneath Alunite Ridge and Deer Trail Mountain. In addition, a sample of a highly altered rhyolitic quartz porphyry dike was collected from the upper Mineral Products mine, from which zircons were...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: "Mineral Resources"],
40Ar/39Ar,
Alunite Ridge,
Deer Trail Mountain,
Denver Argon Geochronology Laboratory,
The Alaska Division of Geological & Geophysical Surveys (DGGS), in partnership with the U.S. National Cooperative Geologic Mapping Program, mapped approximately 450 mi2 of the Talkeetna Mountains region of central Alaska at 1:50,000 scale over the course of six weeks in 2014. This area contains significant exposures of Late Triassic mafic volcanics and gabbro sills that have been the focus of region-wide exploration for the Strategic and Critical platinum-group elements (PGEs). The area also exposes numerous inactive and possibly active faults which project through the area of proposed hydropower development. The resulting geologic map offers an improved understanding of the geology, structural history, and mineral...
This geologic map and report depicts portions of the Livengood B-3, B-4, C-3, and C-4 quadrangles. The Livengood area is a historically productive placer mining area approximately 80 road miles north of Fairbanks, Alaska. This report 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. It expands and updates the Alaska Division of Geological & Geophysical Surveys (DGGS) Preliminary Interpretive Report (PIR) 2004-3 with the addition of new DGGS mapping and drillhole data from ITH, and integrates previously published DGGS surficial...
This dataset accompanies publication 'The influence of foreland structures on hinterland cooling: evaluating the drivers of exhumation in the eastern Bhutan Himalaya'. The Ar/Ar data provides time constraints for the cooling of rocks in the study area.
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
Bhutan,
GGGSC,
Geochemistry,
This dataset accompanies planned publication 'Lava-ice interactions at late Pleistocene trachyte-basaltic andesite fissure eruptions, Quetrupillán Volcanic Complex (39°30′ S, 71°43′ W), southern Chile', as well as planned future publications on this volcanic complex. The Ar/Ar data and the Pb, Sr, and Nd data are for basalt and trachyte lava flows at Quetrupillán volcano. The Ar geochronology and isotope geochemistry will aid in the understanding of the timing of eruptive activity and glacial damming of lava flows, and magma source compositions studied in the planned publications. Samples were collected from Quetrupillán volcano by Dave McGarvie (Univ. of Lancaster, UK) and Isla Simmons (Univ. of Edinburgh, UK),...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: 40Ar/39Ar,
Andes,
Argon Geochronology Laboratory,
Chile,
Geology, Geophysics, and Geochemistry Science Center,
40Ar/39Ar data from plutonic, dike, and alteration samples collected during geologic mapping of the eastern part of the Bonnifield mining district geologic map area in parts of Fairbanks A-1 and Fairbanks A-2 and Healy D-1 and Healy D-2 quadrangles yield results indicating the plutons, dikes, and a gold-bearing quartz vein in the Bonnifield Map area range from 85 to 95 m.y.
A quarry within the Cedar Mountain Formation in Mussentuchit Wash, Emery County, Utah, produced a fossil assemblage containing the remains of at least eight juvenile iguanodontid dinosaurs (Eolambia caroljonesa). The Cedar Mountain Formation lies stratigraphically between the Tithonian?Berriasian (Upper Jurassic) Brushy Basin Member of the Morrison Formation and the Cenomanian (Upper Cretaceous) Dakota Formation. Detailed stratigraphic, sedimentological, geochronological, palynological, and paleontological data have been collected along a measured section at the site of the Cifelli #2 Eolambia caroljonesa Quarry. These data provide a chronostratigraphic and a biostratigraphic framework for the Cedar Mountain Formation...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: 40Ar/39Ar,
Albian,
Angiospermae,
Biostratinomy,
Cedar Mountain Formation,
This dataset accompanies planned publication 'Genesis of early Neoproterozoic gold deposits, southwestern Amazon Craton, western Brazil'. The Ar/Ar data is for samples that record the mineralization of the area. The geochronology provides time constraints for the mineralization studied in the manuscript. Samples were collected from the Amazon Craton region, and collection was done by Rodrigo Prudente de Melo of the Univ. Federal de Goias, who sent them to the USGS Denver Argon Geochronology Laboratory for Ar/Ar analysis.
This dataset accompanies planned publication 'Conditions, mechanisms, and timing of high-grade metamorphism and ductile deformation of the southern segment of the Central Anatolian Ophiolite'. The Ar/Ar data are for samples that record the metamorphic deformation of the ophiolite. The geochronology provides time constraints for the deformation studied in the manuscript. Samples were collected from the Central Anatolian Ophiolite by Molly Radwany and Donna Whitney, who sent them to the USGS for Ar/Ar analysis.
This dataset accompanies planned publication 'Timing of Hydrothermal Alteration and Au-Sb-W Mineralization, Stibnite-Yellow Pine District, Idaho'. The Ar/Ar data is for samples that record the mineralization of the area. The geochronology provides time constraints for the mineralization studied in the manuscript. Samples were collected from the Yellow Pine region, and collection was done by numerous USGS scientists, who sent them to the USGS Denver Argon Geochronology Laboratory for Ar/Ar analysis.
Categories: Data;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
GGGSC,
Geochemistry,
Geology, Geophysics, and Geochemistry Science Center,
This map is the result of field investigations by DGGS in 1997 and 1998. This geologic map and report supersede the previously released Public Data File 99-24B, Preliminary interpretive bedrock geologic map of the Healy A-6 Quadrangle, southcentral Alaska. The current map has been updated to include mapping of areas adjacent to the Healy A-6 Quadrangle, newly interpreted bedrock units based on newly acquired analytical, paleontologic, and Ar40/Ar39 data. Ages for the rock units were modified. Field investigations were part of a two-year mapping program to provide geologic ground truth for airborne geophysical surveys flown by DGGS in the Chulitna region of southcentral Alaska during 1996.
40Ar/39Ar data from plutonic and volcanic samples collected during preliminary mapping of the Tyonek D-6 and parts of Tyonek D-5, D-7 and C-6 quadrangles yield results indicating three discrete igneous events at about 55, 60 and 68 Ma. Igneous clasts from a boulder conglomerate retain Early Cretaceous ages.
This data release includes 40Ar/39Ar data from the U.S. Geological Survey for samples from the Santa Cruz Basin, Arizona. Mineral samples were collected by Kenzie Turner and William Page from the upper Santa Cruz Basin, Arizona. Potassium-bearing mineral grains were separated from the bulk sample and analyzed by argon geochronology at the U.S. Geological Survey Argon Geochronology Laboratory in Denver, Colorado. The data provide age constraints on units in the relevant geologic mapping area.
Categories: Data,
Data Release - Revised;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: 40Ar/39Ar,
Argon Geochronology Laboratory,
Arizona,
GGGSC,
Geochemistry,
This Alaska Division of Geological & Geophysical Surveys (DGGS) Raw Data File presents 40Ar/39Ar age dating results for a volcanic whole-rock sample, selected minerals from various metamorphic rocks and igneous dikes, and white mica from both metamorphic- and hydrothermal-mineralization-related veins encountered on the southern Seward Peninsula, as well as select minerals from one plutonic rock from Cape Denbeigh, eastern Norton Sound, Alaska. Cooling ages on glaucophane, barroisite, amphibole, paragonite, and biotite from metamorphic rocks range from 84 Ma to 209 Ma. The cooling age of white mica in a possible fault zone is 144 Ma. Cooling ages on late-stage metamorphic minerals (winchite and white mica) from veins...
The deposits of Eocene Lake Gosiute that constitute the Green River Formation of Wyoming contain numerous tuff beds that represent isochronous, correlatable stratigraphic markers. Tuff beds selected for 40Ar/39Ar analysis occur within laminated mudstone, are matrix supported, and lack evidence of reworking. These tuffs contain 2%?15% euhedral phenocrysts of quartz, plagioclase, sanidine, biotite, and minor amphibole, pyroxene, and zircon, encased in a matrix of altered glassy ash. Air abrasion and handpicking under refractive- index oils were required to obtain clean, unaltered phenocrysts of sanidine. 40Ar/39Ar age determinations from single-crystal and <1 mg multigrain aliquots of sanidine and biotite allowed...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: 40Ar/39Ar,
Early Eocene Climate Optimum,
Geological Society of America Bulletin,
Green River Formation,
Wasatchian-Bridgerian,
40Ar/39Ar data from seven plutonic samples and one metamorphic sample collected during mineral assessment studies in 1991 show that various rock units in the Selawik Hills plutonic complex were emplaced in the order syenite/monzonite (nonfoliated, 106.6 ± 0.8 Ma; foliated, 101.7 ± 0.7 Ma; both on hornblende), followed by nepheline syenite (103.7 ± 0.8 Ma on hornblende) and then quartz monzonite (100.4 ± 3.7 Ma on biotite). 40Ar/39Ar data from Granite Mountain hornblendes yielded ages slightly older, but overlapping, those from Selawik Hills. In this suite, the silica-undersaturated phase appears to be younger (105.7 ±0.8 Ma) than the silica-saturated phase(s) (106.8 ± 0.8 Ma and 107.1 ± 0.8 Ma).
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