Filters: Tags: Metamorphic Rocks (X)
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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 bedrock geologic map was produced by using airborne magnetic and electromagnetic surveys, data and notes from several months of fieldwork, geochemical data, and laboratory investigations. These maps are the result of new field investigations in the Eagle A-1 Quadrangle by DGGS in 1999, 2000, and 2001. Field investigations are part of a three-year mapping program to provide geologic ground truth for airborne geophysical surveys flown by DGGS in the Fortymile mining district during 1998.
This geologic map was produced by merging a bedrock geologic map and a surficial geologic map of the Eagle A-1 Quadrangle. Surficial geologic units were determined by a combination of air photo interpretation and site-specific field investigations. Bedrock geologic units were determined by using a combination of airborne magnetic and electromagnetic surveys, several months of fieldwork, geochemical data, and laboratory investigations. These maps are the result of new field investigations by DGGS in 1999 and 2001.
This map shows the subcrop pattern of the Mesozoic rock units present at the top Mesozoic unconformity (also commonly referred to as the base Tertiary unconformity) in Cook Inlet basin, Alaska. The subcrop is projected onto the top Mesozoic unconformity depth surface of Cook Inlet basin, Alaska, published by Shellenbaum and others (2010). Publicly available geologic and geophysical data from multiple sources were collected, interpreted, and integrated into the subcrop map. Formation picks at the top Mesozoic unconformity were determined for 109 wells. Mesozoic horizons from two regional marine two-dimensional (2-D) seismic datasets (approximately 3,300 miles) were interpreted. Eight map units were established for...
View downriver toward a Precambrian “island” of schist (photographs WM06, WM08, WM09) during the Cambrian sea encroachment, right bank of river mile 212.5.
View northwest and downriver toward schist and granite upstream of Burnt Spring Canyon, upper right edge of photograph, Lower Granite Gorge, river mile 257.7.
View southeast and upriver toward Vishnu Schist near river mile 111.2 from east side of Hakatai Canyon near old cable crossing, south of and above river mile 11.3.
View northwest and downriver along granite and gneiss walls of Lower Granite Gorge, river mile 236.8.
Aerial view east toward schist and granite in Diamond Creek canyon.
View northwest and downriver toward white pegmatite intrusion into black Vishnu Schist, south side of river mile 106.0.
Aerial view southwest from above Phantom Ranch (lower right of photograph), toward Kaibab Suspension Bridge, just upstream of Bright Angel Creek delta, river mile 88.1. Granite and pegmatite dikes in black Vishnu Schist.
View north toward north side of river mile 105.2 from lower Ruby Canyon (photographs EM30, EM31) toward pegmatite and granite intrusions into Vishnu Schist.
Aerial view north toward unnamed canyon just west of Vishnu Creek canyon (lower right), about a half mile north of river mile 81.8. Vishnu Schist is dark rock below lowest flat strata of Tapeats Sandstone, lower center of photograph.
The geochemical data included here were generated as part of the Earth Mapping Resources Initiative (Earth MRI), which was developed by the U.S. Geological Survey (USGS) in response to a Federal directive calling on various Federal agencies to address potential vulnerabilities in the Nation’s supply of critical mineral resources. Earth MRI is a partnership between the USGS, State Geological Surveys, and industry coordinating with other federal agencies to accomplish the mission. The primary purpose of this initiative is to identify potentially mineralized areas containing critical minerals by gathering new basic geologic data about the United States and its territories and to make these data publicly available through...
Categories: Data,
Data Release - Revised;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service,
Shapefile;
Tags: Alabama,
Alaska,
Alaska Division of Geological & Geophysical Surveys,
Arizona,
Arizona Geological Survey,
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...
The geologic map database of the Great Smoky Mountains National Park region of Tennessee and North Carolina is a result from studies from 1993 to 2003 as part of a cooperative investigation by the U.S. Geological Survey with the National Park Service (NPS). This work resulted in a 1:100,000-scale geologic map derived from mapping that was conducted at scales of 1:24,000 and 1:62,500. The geologic data are intended to support cooperative investigations with the NPS, the development of a new soil map by the Natural Resources Conservation Service, and the All Taxa Biodiversity Inventory. In response to a request by the NPS, we mapped previously unstudied areas, revised the geology where problems existed, and developed...
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...
This U.S. Geological Survey (USGS) data release provides whole rock isotope geochemistry, zircon hafnium isotope geochemistry, feldspar mineral chemistry, and zircon, monazite, and xenotime geochronology for a paragneiss sampled from a drill core from North Dakota. The sample was collected from the 9-11R E-M Larson well in order to constrain the depositional age, provenance, metamorphic history, and geochemical character of basement terranes.
Categories: Data;
Tags: Geochemistry,
North Dakota,
USGS Science Data Catalog (SDC),
geochemistry,
geochronology,
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...
WM32. View west toward Great Unconformity between Precambrian granite and Cambrian Tapeats Sandstone
View west toward Great Unconformity between Precambrian granite and Cambrian Tapeats Sandstone, just downstream of Quartermaster Canyon, west side of river mile 260.9. Bighorn sheep for scale.
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