Filters: Tags: igneous rocks (X)
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View north toward basalt dike (photograph EI10) in Hakatai Shale, Unkar Group, on north side of river mile 77.2, at beginning of Hance Rapids. Shinumo Sandstone forms cliff at upper edge of photograph.
Twenty-two igneous and metamorphic rock samples were collected in a 20-km-long swath centered on the Alaska Highway between Tetlin Junction, Alaska, and the Canada border. Igneous and metamorphic rock samples were submitted to the Apatite to Zircon, Inc. laboratory (A2Z), where zircon U-Pb age analysis, using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), was performed by Paul O'Sullivan. The 15 felsic plutonic rock samples and one gabbro sample yield Cretaceous zircon U-Pb weighted-mean ages ranging from 95.7 Ma to 106.2 Ma. Zircons from a metadiorite yield a Triassic weighted-mean age of about 241.9 Ma. Metamorphic zircons from two samples with felsic igneous protoliths yield Mississippian...
Cook Inlet has been recognized as the second-largest petroleum province in Alaska, second only to the North Slope. The south-central Tyonek Quadrangle is an area of significant geologic interest because it is the only location in Cook Inlet where the entire producing stratigraphy of the basin is exposed on the surface. Additionally, this area encompasses the structural boundary between the forearc basin and its sediment source rocks. To better understand the petroleum system and the geologic relationships between the exhumed arc intrusive rocks and adjacent Cenozoic stratigraphy of the Cook Inlet forearc basin, during the summer of 2010 the Alaska Division of Geological & Geophysical Surveys conducted a federally-funded...
Mineral Resources Section personnel from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a geologic field survey, including mapping and sampling, in the eastern part of the Bonnifield mining district in the Fairbanks A-1 and A-2 and the Healy D-1 and D-2 quadrangles, Alaska, from June 16 through July 18, 2008. The fieldwork provides basic information critical to building an understanding of Alaska's geology and is part of an integrated program of airborne geophysical surveys followed by geologic mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. Interpretation and synthesis of this data has been presented in professional and trade meetings....
Aerial view north towards Vulcans Throne volcano in distance on north side of river mile 179.3. View in foreground is north along Toroweap Fault in lower Prospect Canyon at faulted unnamed Pleistocene cinder cone and alluvium on east side of Prospect Canyon. Mount Trumbull (Pliocene basalt) on skyline, left side of photograph.
Aerial view north toward 900-foot-thick Cardenas Basalt of Unkar Group (black), that overlies Ochoa Point Member of Dox Formation, Unkar Group (red slope), overlain by Nankoweap Formation (purple strata), west side of Ochoa Point, 1 mile northwest of river mile 71.0.
Views northwest toward white Miocene tuff beds in the Gyp Hills, 2 miles east of Tassi Spring, north side of Tassi Wash.
Aerial view north toward 18-million-year (Ma) Peach Spring Tuff (brown) that overlies white Tertiary West Water Formation in upper Milkweed Canyon.
View of the west-facing wall inside 1,000-year-old Little Spring volcano, 2 miles south of Mount Trumbull.
Hundred and Fiftynine Mile Dike at top of Redwall Limestone (person for scale on dike), south of river mile 159.7.
View north toward basalt cascade down north wall of river, river mile 181.4.
View northwest and downriver toward basalt cascades over Esplanade Sandstone at north rim, Redwall Limestone (large gray cliff), undifferentiated Devonian and Cambrian strata below Redwall Limestone cliff to river, from river mile 184.3.
Aerial view north toward south side of Quaternary basalt neck and pyroclastic deposits of Yumtheska Vent West sample site, K-Ar age 0.780±0.15 thousand years (ka) (Wenrich and others, 1995).
Aerial view northwest toward basalt dikes (photograph EI06) on west side of Unkar Creek canyon in Solomon Temple Member of Dox Formation, Unkar Group, about 2 miles west of river mile 72.5.
The Reef Package is a sequence of coarse-grained cumulates that host the J-M Reef Pd-Pt deposit in the Stillwater Complex of Montana. The top of the Reef Package marks the top of economic-grade platinum-group element mineralization and is identified by a distinct change in rock fabric, from the coarse-grained rocks of the Reef Package to finer-grained cumulates in the hanging wall. This dataset tabulates whole-rock major, minor, and trace element geochemistry of rock samples collected from diamond drill holes that intersect the textural discontinuity at the top of the Reef Package from the underground working of the Stillwater Mine. The dataset also tabulates rock fabric data collected by electron backscatter diffraction...
Categories: Data;
Tags: Economic Geology,
Geochemistry,
Mineral Resources,
Montana,
USGS Science Data Catalog (SDC),
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,
The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (https://doi.org/10.5066/F7WH2N65) represents a seamless, spatial database of 48 State geologic maps that range from 1:50,000 to 1:1,000,000 scale. A national digital geologic map database is essential in interpreting other datasets that support numerous types of national-scale studies and assessments, such as those that provide geochemistry, remote sensing, or geophysical data. The SGMC is a compilation of the individual U.S. Geological Survey releases of the Preliminary Integrated Geologic Map Databases for the United States. The SGMC geodatabase also contains updated data for seven States and seven entirely new State geologic...
Categories: Data,
Data Release - Revised;
Types: ArcGIS REST Map Service,
ArcGIS Service Definition,
Downloadable,
Map Service;
Tags: Alabama,
Arizona,
Arkansas,
California,
Colorado,
Aerial view southeast toward west side of Separation hill of south Separation Canyon, Hualapai plateau; basalt flow over Tertiary Buck and Doe Conglomerate. K-Ar age is 19.03±0.44 million years (Ma) (Billingsley and others, 2006a).
View northwest toward basalt cascades over Esplanade Sandstone, Redwall Limestone (large gray cliff), Temple Butte Formation (lower left of photograph), north rim, north of river mile 184.3.
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