Filters: Tags: Plutonic Rocks (X)
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This data set maps and describes the geology of the San Bernardino Wash 7.5 minutequadrangle, Riverside County, southern California. The quadrangle, situated inJoshua Tree National Park in the eastern Transverse Ranges physiographic andstructural province, encompasses parts of the northwestern Eagle Mountains,east-central Pinto Basin, and eastern Pinto Mountains.The quadrangle is underlain by a basement terrane comprising metamorphosedProterozoic strata, Mesozoic plutonic rocks, and Jurassic and Mesozoic and (or)Cenozoic hypabyssal dikes. The basement terrane is capped by a widespread Tertiaryerosion surface preserved in remnants in the Pinto and Eagle Mountains and buriedbeneath Cenozoic deposits in Pinto Basin....
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.
A mineral resource assessment was performed by the U.S. Geological Survey (USGS) to assess the potential of undiscovered skarn-hosted tungsten resources in the Northern Rocky Mountain region of eastern Idaho and western Montana. This region has seen moderate tungsten trioxide (WO3) production in the past from a variety of mineralization styles including skarn, vein and replacement, and wolframite-quartz veins. The geology of the area is dominated by large plutons of Cretaceous to Tertiary age, emplaced into a belt of sedimentary rock ranging from Mesoproterozoic to Permian age, and affected by tectonism related to the Sevier and later Laramide orogenies. Known tungsten (W) skarn mineral sites are associated with...
Categories: Data;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service;
Tags: Ashton,
Bald Mountain,
Beaverhead County,
Bitterroot Range,
Boise County,
This U.S. Geological Survey (USGS) data release provides whole rock major, minor, and trace element geochemical data from the fluorine-rich Mount Emmons-Redwell porphyry molybdenum (Climax-type) deposit (Mt. Emmons-Redwell deposit), located approximately 5.6 km (3.5 mi) northwest of Crested Butte, Colorado. The Mt. Emmons-Redwell deposit partly underlies Redwell Basin on the northwest flank of Mount Emmons in the west-central region of the Colorado Mineral Belt. Mineralization of the Mt. Emmons-Redwell deposit occurs at depth as vein, veinlet, stockwork, and fracture-hosted Climax-type mineralization [308 Mt at 0.32% Mo (Galey, 1978; Guarnera and Anderson, 2007)], and is associated with the Mt. Emmons igneous complex....
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: <1GB,
Climax-type deposit,
Colorado,
Colorado Mineral Belt,
Crested Butte,
This data set contains boundaries and tags for major geologic units in Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. In addition to the polygons representing the areal extent of geologic units, it identifies major faults and continental glaciation in Alaska. The data depict the geology of the bedrock that lies at or near the land surface, but not the distribution of surficial materials such as soils, alluvium, and glacial deposits. This map complements the Generalized Geologic Map of the Conterminous United States by Reed and Bush. The data are generalized from a compilation prepared for use in the Geologic Map of North America, published as a paper map by the Geological Society of America and...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: AK,
Alaska,
Bedrock,
Faults,
Geologic History,
The Preliminary Interpretive Report 2004-3B, "Bedrock geologic map of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska," is the bedrock geologic map of an approximately 123-square-mile area in the central Livengood Quadrangle, Alaska.
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.
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 data set maps and describes the geology of the Fawnskin 7.5' quadrangle, San BernardinoCounty, California and contains original U.S. Geological Survey data generated by detailedfield observation and by interpretation of aerial photographs. The geologic map covers partof the northern San Bernardino Mountains. Bedrock units in the San Bernardino Mountains aredominated by large Cretaceous and Jurassic granitic bodies ranging in composition frommonzogranite to gabbro, and include lesser Triassic monzonite. These granitic rocks intrudehighly faulted and folded Late Proterozoic and Paleozoic formations representative of thosefound in the southern Great Basin. Low-angle thrust faults, many of them complexly folded,cut...
This report provides a digital version of the Geologic map of theStillwater Complex, Montana originally published by N. Page andW. Nokleberg (1974). Paper copies of the four geologic mapsheets from the original report were scanned and initiallyattributed by Optronics Specialty Company (Northridge, CA) andremitted to the U.S. Geological Survey for further attributionand publication of the geospatial digital files. The resultingdigital geologic dataset can be queried in a geographicinformation system (GIS) in many ways to produce a variety ofgeological maps.
A study conducted collected 57 surface rock samples from nine types of intrusive rock to reexamine the chemistry and metallic content of the major rock units of the Iron Hill complex
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 data set maps and describes the geology of thePorcupine Wash 7.5 minute quadrangle, Riverside County,southern California. The quadrangle, situated in JoshuaTree National Park in the eastern Transverse Rangesphysiographic and structural province, encompasses partsof the Hexie Mountains, Cottonwood Mountains, northernEagle Mountains, and south flank of Pinto Basin. It isunderlain by a basement terrane comprising Proterozoicmetamorphic rocks, Mesozoic plutonic rocks, and Mesozoicand Mesozoic or Cenozoic hypabyssal dikes. The basementterrane is capped by a widespread Tertiary erosionsurface preserved in remnants in the Eagle and CottonwoodMountains and buried beneath Cenozoic deposits in PintoBasin. Locally, Miocene...
This data set maps and describes the geology of the Pinto Mountain 7.5 minutequadrangle, Riverside County, southern California. The quadrangle, situated inJoshua Tree National Park in the eastern Transverse Ranges physiographic andstructural province, encompasses parts of the northeastern Hexie Mountains,central Pinto Mountains, and central Pinto Basin.The quadrangle is underlain by a basement terrane comprising Proterozoicmetamorphic rocks, Mesozoic plutonic rocks, and Mesozoic and Mesozoic and (or)Cenozoic hypabyssal dikes. The basement terrane is capped by a widespreadTertiary erosion surface preserved in remnants in the Hexie and Pinto Mountainsand buried beneath Cenozoic deposits in Pinto Basin. Locally, a...
The database for the Preliminary Geologic Map of the Cherry Hill Quadrangle, Dinwiddie, Sussex, and Greensville Counties, Virginia geographically straddles the Coastal Plain and Piedmont Provinces along the Tidewater Fall Line. Rocks of the eastern Piedmont Roanoke Rapids terrane crop out in the western part of the quadrangle and consist of greenschist- to amphibolite-facies Neoproterozoic felsic to intermediate metavolcanic rocks, some of which contain flattened quartz phenocrysts and are locally isoclinally folded; greenstone that is locally primary layered; and intrusive metadiorite and metagabbro, much of which has been altered to amphibolite. Most of these rocks are strongly foliated and jointed. Greenschist-facies...
This data release contains geochemical data from selected U.S. Geological Survey (USGS) projects from the 1960s-1980s that were previously unpublished as digital data. The objective of those projects was to describe the geology, determine petrologic and geochemical characteristics, or to evaluate the mineral resource potential of Federal Lands and adjacent study areas. These data comprise geochemical analyses from 36,498 samples--27,223 rock samples, 4,091 sediment samples, 2,351 soil samples, 330 heavy-mineral pan concentrate samples, 297 organic material samples, 58 mineral samples, 27 water samples, 11 miscellaneous samples, and 2,110 unspecified media samples. More than 78 percent of these samples were analyzed...
Categories: Data;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: "Geochemistry",
"Mineral Resources"],
Alaska,
California,
Colorado,
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...
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).
This report presents 40Ar/39Ar step-heating geochronology results for igneous and metamorphic rocks from the Alaska Division of Geological & Geophysical Surveys' (DGGS) Talkeetna Mountains C-4 Quadrangle and Adjoining Areas geologic mapping project. Hornblende-bearing gabbro returned a Late Triassic crystallization age consistent with regional results for Nikolai Greenstone-related magmatism. We determined Early Jurassic metamorphic ages for hornblende and sericite from two samples of upper greenschist to amphibolite grade metavolcanic rocks. Our results indicate that a granodiorite pluton intruding Wrangellia in the study area has a Middle Jurassic age consistent with the Talkeetna Arc, indicating that the Wrangellia...
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