Filters: Tags: Bedrock geology (X)
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The Greenback Creek 7 ½’ Quadrangle is located on the west flank of the Sierra Ancha and directly northeast of Theodore Roosevelt Lake (Figure 1). The geology is dominated by sedimentary rocks of the middle Proterozoic Apache Group and the middle Proterozoic diabase that commonly intrudes it (e.g. Bergquist et al., 1981; Wrucke, 1989). Early to middle Proterozoic granitic rocks are exposed beneath the Apache Group, primarily along the southwestern edge of the bedrock exposures in the map area. Tertiary conglomerate and local sandstone are deposited on the bedrock and in the flanking Tonto Basin, and have been subjected to only minor faulting and tilting. Upper Cenozoic sedimentary units and geomorphic surfaces were...
Digital file containing a bedrock geology polygon coverage for British Columbia. Polygon coverage of geology compiled at 1:100,000 scale as part of the B.C. Ministry of Energy and Mines, BC Geological Survey Branch mineral potential project, 1994-1996. Original coding revised and rationalized in 2001-2002 by D.G. MacIntyre, updated and revised in 2002-2004 by N.W.D. Massey. Coverage generalized on lithostratigraphic map unit (MAPLABEL) designation. New mapping completed after 1996 is being added to this file on an ongoing basis. Bedrock Geology - This theme consists of a single layer of bedrock geology polygons. Polygons depict the nature of the bedrock geology based on a compilation of all geologic mapping done...
The Edwards and Trinity aquifers are major sources of water in south-central Texas and are both classified as major aquifers by the State of Texas. The population in Hays and Comal Counties is rapidly growing, increasing demands on the area's water resources. To help effectively manage the water resources in the area, refined maps and descriptions of the geologic structures and hydrostratigraphic units (HSUs) of the aquifers are needed. This digital map database presents the detailed 1:24,000-scale bedrock hydrostratigraphic map as well as names and descriptions of the geologic and hydrostratigraphic units of the Driftwood and Wimberley 7.5-minute quadrangles in Hays and Comal Counties, Tex. These digital data...
Categories: Data;
Types: Citation;
Tags: Balcones fault zone,
Blanco River,
Comal County,
Corbula bed,
Cretaceous,
U-Pb analyses were performed on igneous rocks from the Ray Mountains area of west-central Alaska. These new age analyses will allow us to better evaluate the geochronology of the granitic rocks that are the apparent source of the alluvial REE and tin resources. The plutonic samples have ages ranging from 98.0 +/- 0.9 Ma to 111.6 +/- 1.0 Ma. The sample location coordinates and analytical data tables associated with this report are available in digital format as comma-separated value (CSV) files.
This ArcView shapefile contains a polygon representation of the geology in the northern part of the (Montana) Powder River Basin. This theme was created specifically for the National Coal Resources Assessment in the Northern Rocky Mountains and Great Plains Region.
Categories: Data,
pre-SM502.8;
Types: Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Big Horn County,
Montana,
Northern Powder River Basin,
Powder River Basin,
Powder River Basin,
The New River Mesa Quadrangle is located along the northern fringe of the Phoenix metropolitan area. The quadrangle includes several high-standing mesas, and although the rugged terrain of the New River Mesa area is undeveloped, the area to the south is becoming increasingly urbanized and is undergoing rapid population growth. Geologic mapping was related to other previous and ongoing mapping projects of urban fringe areas located to the north and northeast of the Phoenix metropolitan area. A series of color 1 : 24,000-scale aerial photographs (dated 11-5-79 and 6-11-88) were obtained from the U. S. Department of Interior and the Tonto National Forest office in Phoenix, and these were used by the field geologists...
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. These data represent the extent of the lower Fort Union aquifer in the Powder River and Williston structural basins.
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. These data represent the extent of the Upper Hell Creek hydrogeologic unit in the Powder River and Williston structural basins.
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...
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. This tabular data set represents the area of bedrock geology types in square meters compiled for every catchment of MRB_E2RF1 catchments for Major River Basins (MRBs, Crawford and others, 2006). The source data set is the "Geology of the Conterminous United States at 1:2,500,000 Scale--A Digital Representation of the 1974 P.B. King and H.M. Beikman Map" (Schuben and others, 1994). The MRB_E2RF1 catchments are based on a modified...
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...
Data from 391 boreholes (including coreholes) that penetrated buried pre-Cretaceous basement rocks that lie beneath Atlantic Coastal Plain sedimentary deposits in Georgia and South Carolina were compiled from non-proprietary, mostly published sources in order to support subsurface geologic mapping, geologic interpretation of geophysical data (aeromagnetic, gravity, seismic), topical studies as in geochronology, and applications ranging from mineral, energy, and water resources to earthquake hazards in the Charleston seismic zone. Most of the entries are based on previous literature. In a few cases where noted, drill cores or cuttings were examined for basic geologic observations. Boreholes into bedrock beneath the...
Categories: Data;
Types: Data,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Atlantic Coastal Plain,
Energy Resources,
Geophysics,
Georgia,
Hydrology,
In support of the proposed Susitna-Watana Hydroelectric Project, the Alaska Division of Geological & Geophysical Surveys (DGGS) developed a Geographic Information System (GIS)-based geologic compilation of published and unpublished maps for twelve, inch-to-mile (1:63,360-scale) quadrangles encompassing the proposed hydroelectric project footprint, including the anticipated reservoir and surrounding area. DGGS geologists reviewed and analyzed existing geologic mapping for quality and completeness, and the maps were converted for use in GIS. The conversion process included scanning and georeferencing the original hard-copy map documents, creating a geodatabase, digitizing the geologic data, assigning attributes, and...
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...
This data release presents 40Ar/39Ar step-heating geochronology results from rocks collected roughly 7 km southwest of Contact Point, Iliamna B-3 Quadrangle. Samples obtained from a felsic dike intruding the principal Bruin Bay fault plane near Contact Point produced biotite and plagioclase 40Ar/39Ar ages of 36.5 +/- 0.8 Ma and 31.5+/-0.7 Ma, respectively. The age dates inform stratigraphic, structural, and geochronologic studies along the western margin of lower Cook Inlet basin. The accompanying report also presents zircon U-Pb LA-ICP-MS geochronology results for dikes near Ursus Head.
These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. These data represent the extent of the Fox Hills aquifer in the Powder River and Williston structural basins.
Categories: pre-SM502.8;
Tags: Bedrock geology,
Canada,
Groundwater,
Groundwater availability,
NSDI,
The Texas Water Development Board classifies the karstic Edwards and Trinity aquifers as major sources of water in south-central Texas. To effectively manage the water resources in the area, detailed maps and descriptions of the geologic framework and hydrostratigraphic units of the aquifers outcropping in Hays County, Tex. are needed. In 2016 and 2018, the U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, mapped the geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within Hays County, Tex. at 1:24,000 scale. These digital data accompany Clark, A.K., Pedraza, D.E., and Morris, R.R., 2018, Geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers...
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Austin Group,
Balcones fault zone,
Barton Creek,
Blanco River,
Buda,
40Ar/39Ar analyses of igneous rocks from the Alaska Highway corridor between Delta Junction and the Canada border show a range of Cretaceous ages from about 68 Ma to about 112 Ma. The 25 samples fall into two broad age groups. The younger group ranges from about 68 Ma to 73 Ma; the older group ranges from a minimum age of about 84 Ma to about 103 Ma. One sample, a mafic dike, yielded an older age of about 112 Ma.
Mineral-resources personnel from the Alaska Division of Geological & Geophysical Surveys carried out a geological 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 geological mapping. Specifically, this work provides geologic context for geophysical surveys conducted in 2006. To represent a typical lithology, igneous or possible meta-igneous samples were collected and analyzed...
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