Mineral Resources On-Line Spatial Data
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During the period 1975-83, the U.S. Department of Energy carried out the National Uranium Resource Evaluation (NURE) Program, which included aerial gamma-ray surveys of most of the United States. These data were reprocessed to generate this product.
Kucks, Robert P. , 2005, Terrestrial Radioactivity and Gamma-ray Exposure in the United States and Canada: Gridded geographic images:.This is part of the following larger work.
Duval, Joseph S., Carson, John M., Holman, Peter B., and Darnley, Arthur G., 2005, Terrestrial radioactivity and gamma-ray exposure in the United States and Canada: U.S. Geological Survey Open-File Report 2005-1413.Online Links:
This is a Raster data set. It contains the following raster data types:
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.02. Longitudes are given to the nearest 0.02. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.0.
The flattening of the ellipsoid used is 1/298.257222101.
Value | Definition |
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(no value) | Cells lacking color (white) represent areas of no data in image. |
Range of values | |
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Minimum: | 0.0 |
Maximum: | 100.0 |
Units: | percent of element |
Resolution: | 0.1 |
Value | Definition |
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(no value) | Cells lacking color (white) represent areas of no data in image. |
Range of values | |
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Minimum: | 0.0 |
Maximum: | 4.0 |
Units: | percent K |
Resolution: | 0.1 |
Value | Definition |
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(no value) | Cells lacking color (white) represent areas of no data in image. |
Range of values | |
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Minimum: | 0.0 |
Maximum: | 24.0 |
Units: | ppm eTh |
Resolution: | 0.1 |
Value | Definition |
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(no value) | Cells lacking color (white) represent areas of no data in image. |
Range of values | |
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Minimum: | 0.0 |
Maximum: | 6.0 |
Units: | ppm eU |
Resolution: | 0.1 |
Value | Definition |
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(no value) | Cells lacking color (white) represent areas of no data in image. |
Range of values | |
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Minimum: | 0.0 |
Maximum: | 125.0 |
Units: | nanoGrays per hour |
Resolution: | 1 |
The U.S Geological Survey reprocessed the aerial gamma-ray (NURE) data to produce maps showing surface concentrations of potassium, uranium, and thorium for the conterminous United States. These maps have been released as USGS Open-File Reports. Some of the reprocessed data have also been released in profile form. The Canadian Geological Survey data were processed by the Radiation Geophysics Section of the CGS. See Open-File Report 2005-1413 for further references.USGS employees: Duval, Riggle, and Snyder Canadian GS employees: Carson, Holman, and Darnley
(303) 236-1405 (voice)
rkucks@usgs.gov
Because uranium, thorium, and potassium concentration data are useful in geologic studies and because the NURE data are the only nationwide database on the natural radiation environment, the U.S. Geological Survey reprocessed the aerial gamma-ray data to produce maps showing surface concentrations of potassium, uranium, and thorium for the conterminous United States.
Duval, Joseph S., Darnley, Arthur G. (editor), and Garrett, Robert G. (editor), 1990, Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States: Journal of Geochemical Exploration.
Duval, Joseph S., Jones, William J., Riggle, Frederick R., and Pitkin, James A., 1990, Potassium and thorium maps of the conterminous United States: U.S. Geological Survey Open-File Report 90-338.
Phillips, Jeffrey D., Duval, Joseph S., and Ambroziak, Russell A., 1993, National geophysical data grids; gamma-ray, gravity, magnetic, and topographic data for the conterminous United States: U.S. Geological Survey Digital Data Series DDS-9.
Duval, Joseph S., 1995, Profiles of gamma-ray and magnetic data for aerial surveys over parts of the Western United States from longitude 108 to 126 degrees W. and from latitude 34 to 49 degrees N: U.S. Geological Survey Digital Data Series DDS-31.
Duval, Joseph S., and Riggle, Frederic E., 1999, Profiles of gamma-ray and magnetic data from aerial surveys over the conterminous United States: U.S. Geological Survey Digital Data Series DDS-31.
Person who carried out this activity:
(303)236-1405 (voice)
rkucks@usgs.gov
D = 13.2 K + 5.48 eU + 2.72 eTh
where K is the concentration of potassium in units of percent K, eU is the concentration of uranium in ppm, eTh is the concentration of thorium in ppm, and D is the absorbed dose in nanoGrays per hour (nGy/hr). This equation is based upon the equation published by Grasty (see OF Report). The grid of the gamma-ray absorbed dose was calculated using the grids of potassium, uranium, and thorium concentrations. That grid was then displayed in image form using the commercial software package Geosoft Oasismontaj.
Person who carried out this activity:
(303)236-1405 (voice)
rkucks@usgs.gov
make these surveys were calibrated, many of the earlier surveys were done without calibration and conversion to the concentrations of the radioactive elements. Detailed examinations of the digital data available on magnetic tape also showed that many of the "calibrated" surveys do not match the data from other "calibrated" surveys of adjacent areas. For these reasons, the data must be corrected to obtain a consistent data base for the conterminous United States. If the gamma-ray system is properly calibrated the data can be expressed in terms of the estimated concentrations of the radioactive elements.
The accuracy was dependent on the flight specifications and tolerances of the Department of Energy during their surveying.
The accuracy was dependent on the flight specifications and tolerances of the Department of Energy during their surveying.
Data coverage extends thoroughly across the conterminous US. Significant gaps exist in the coverage of Alaska, especially the area south of the North Slope but north of the Brooks Range, and the Aleutian islands. Central Canada is covered as are most of the Atlantic provinces and eastern Ontario. Large gaps exist in Quebec, the western provinces, and both northern and southwestern Ontario.
Although many of the airborne gamma-ray systems used to make these surveys were calibrated, many of the earlier surveys were done without calibration and conversion to the concentrations of the radioactive elements. Detailed examinations of the digital data available on magnetic tape also showed that many of the "calibrated" surveys do not match the data from other "calibrated" surveys of adjacent areas. For these reasons, the data must be corrected to obtain a consistent data base for the conterminous United States.
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(888)ASK-USGS (voice)
U.S. Geological Survey Open-File Report 2005-1413
The USGS has made every effort to verify the veracity of this information, but is not liable for any inaccuracies.
Data format: | pixel in format Geotiff Arc-Info image format Size: 40.5 |
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(303)236-1405 (voice)
rkucks@usgs.gov