Filters: Tags: Plutonic Rocks (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 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 dataset is intended to provide seamless, integrated geologic mapping of the U.S. Intermountain West region as a contribution to The National Geologic Map supported by the National Cooperative Geologic Mapping Program of the U.S. Geological Survey. Surficial and bedrock geology are included in this data release as independent datasets at a variable resolution from 1:50,000 to 1:250,000 scale. No original interpretations are presented in this dataset; rather, all interpretive data are assimilated from referenceable publications. Derivative polygon features created for this dataset demonstrate the distribution of SIGMa-GeMS Geologic Provinces derived from the distribution of map units. Initial contributions to...
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,
The geology of an area of 660 square miles mostly in the northeastern corner of Tennessee and small adjacent areas in Virginia and North Carolina is the subject of this report. The region lies principally in the Unaka province, with extensions northwestward into the Appalachian Valley and southwestward into the Blue Ridge province. The report combines results of surveys made between 1941 and 1953 by the U. S. Geological Survey, the Tennessee Division of Geology, and the Tennessee Valley Authority, and is published in cooperation with the Tennessee Division of Geology. Northeasternmost Tennessee is a region of widespread mineralization and was formerly important for mineral production. Iron, manganese, and bauxite...
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 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,
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 geologic database is a digitized version of the original 1:24,000-scale analog geologic map titled "Geologic map of the Vidal, California, and Parker SW, California-Arizona quadrangles", published by the U.S. Geological Survey (USGS) in 1980. The map area straddles the Arizona-California border, and is located approximately 9.0 km (5.6 mi) west-southwest of Parker, CA, immediately south of the unincorporated communities of Vidal and Vidal Junction, CA. The map area includes the northern Riverside Mountains, which contain a prominent suite of Permian, Mesozoic, and potentially Precambrian metamorphic and metasedimentary rocks. These rocks predominantly consist of gneisses, schists, limestones, and dolomites,...
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 is a preliminary map and geodatabase of the coseismic surface rupture and other coseismic features generated from the August 9, 2020, Mw 5.1 earthquake near Sparta, North Carolina. Geologic mapping facilitated by analysis of post-earthquake quality level 0 to 1 lidar, document the coseismic surface rupture, named the Little River fault, and other coseismic features. The Little River fault is traced for approximately 4 kilometers and cuts the regional Paleozoic fabric (mean foliation, 063°/57°), and the dominant strike of joint sets are 0°–10°, 130°–150° and 320°–340°. Individual fault strands occur in an en echelon pattern within an approximately 10-meter-wide zone. Trenches across the Little River...
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...
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 geologic database is a digitized version of the 1:24,000-scale original analog geologic map titled "Geologic map of the Parker NW, Parker, and parts of the Whipple Mountains SW and Whipple Wash quadrangles, California and Arizona", published by the U.S. Geological Survey (USGS) in 1980. The map area straddles the Arizona-California border and includes the community of Parker, AZ, and the southeastern part of the Whipple Mountains, where the prominent Whipple Mountains Detachment Fault separates lower plate Cretaceous and older gneisses from upper plate crystalline, volcanic, and sedimentary rocks. The Whipple Mountains are surrounded by numerous Neogene sedimentary units that record the arrival and subsequent...
Regional geologic investigations show that all the metamorphosed crystalline rocks underlying the Greenville 1 degree x 2 degree quadrangle are allochthonous. Seismic-reflection studies, the COCORP line (Cook and others, 1979), and the U.S. Geological Survey (USGS) seismic lines (Harris and Bayer, 1979; Harris and others, 1981) present seismic profiles across different parts of the southern Appalachians. Recent geophysical studies for the now discontinued Appalachian Ultradeep Core Hole (ADCOH) project were concentrated in the Greenville quadrangle (Hatcher and others, 1988). The ADCOH seismic-reflection profiles tie in with the COCORP profile of Cook and others (1979), providing a three-dimensional view of the...
The Blue Ridge belt in northwestern North Carolina and northeastern Tennessee is composed chiefly of 1,000-million to 1,100-million-year-old metamorphic and plutonic rocks that have been thrust many miles northwestward across unmetamorphosed Cambrian(?) and Cambrian sedimentary rocks of the Unaka belt. The Blue Ridge thrust sheet is rooted on the southeast along the Brevard zone, a zone of strike-slip faulting along which metamorphic and plutonic rocks of the Inner Piedmont belt are juxtaposed with rocks of the Blue Ridge. Near the southeastern edge of the Blue Ridge belt, the Blue Ridge thrust sheet is breached by erosion, and the rocks beneath are exposed in the Grandfather Mountain window, which is 45 miles long...
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).
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