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Terrestrial Radioactivity and Gamma-ray Exposure in the United States and Canada: Gridded geographic images

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Robert P. Kucks

Publication_Date: 2005

Title:

Terrestrial Radioactivity and Gamma-ray Exposure in the United States and Canada: Gridded geographic images

Online_Linkage:

<http://mrdata.usgs.gov/cgi-bin/mapserv?map=radiometric.map&request=getcapabilities&service=WMS&version=1.1.1>&

Larger_Work_Citation:

Citation_Information:

Originator: Duval, Joseph S.

Originator: Carson, John M.

Originator: Holman, Peter B.

Originator: Darnley, Arthur G.

Publication_Date: 2005

Title:

Terrestrial radioactivity and gamma-ray exposure in the United States and Canada

Series_Information:

Series_Name: U.S. Geological Survey Open-File Report

Issue_Identification: 2005-1413

Online_Linkage: <http://pubs.usgs.gov/of/2005/1413/>

Description:

Abstract:

Aerial gamma-ray surveys measure the gamma-ray flux produced by the radioactive decay of the naturally occurring elements K-40, U-238, and Th-232 in the top few centimeters of rock or soil. If the gamma-ray system is properly calibrated the data can be expressed in terms of the estimated concentrations of the radioactive elements. A ternary color-composite image was generated by commercial software Geosoft Oasismontaj to map the combination of all three elements.

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.

Supplemental_Information:

Digital Data Series DDS-9 (CD-ROM) contains gridded radiometric geophysical data images that were created for the Decade of North American Geology (DNAG) but only available for the U.S.

Purpose:

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.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1999

Ending_Date: 2005

Currentness_Reference: all available NURE data for the U.S. has been processed

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -168.0

East_Bounding_Coordinate: -53.0

North_Bounding_Coordinate: 71.33

South_Bounding_Coordinate: 25.0

Access_Constraints: None

Use_Constraints: None

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Robert P. Kucks

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: mailing address

Address:

Box 25046, MS 964
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225-0046

Country: USA

Contact_Voice_Telephone: (303) 236-1405

Contact_Electronic_Mail_Address: rkucks@usgs.gov

Data_Set_Credit:

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

Native_Data_Set_Environment:

The NURE data were originaly stored in ASCII format on 9-track magnetic tapes. They are currently available on the report DVD as Geosoft Oasismontaj databases (.gdb) but can be converted to ASCII form.

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: ternary, gamma-ray, radiometric

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Categories

Theme_Keyword: geoscientificInformation

Place:

Place_Keyword_Thesaurus: none

Place_Keyword: United States, Canada

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

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.

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value:

0.1 percent potassium; 0.1 ppm uranium and thorium

Attribute_Accuracy_Explanation:

The potassium concentration data are usually expressed in units of percent potassium (percent K). The uranium and thorium concentration data are usually expressed in units of parts per million equivalent (ppm).

Logical_Consistency_Report:

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.

Completeness_Report:

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.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The accuracy was dependent on the flight specifications and tolerances of the Department of Energy during their surveying.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: 100

Horizontal_Positional_Accuracy_Explanation: Dependent on flight positioning recovery used by NURE project

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The accuracy was dependent on the flight specifications and tolerances of the Department of Energy during their surveying.

Quantitative_Vertical_Positional_Accuracy_Assessment:

Vertical_Positional_Accuracy_Value: 100

Vertical_Positional_Accuracy_Explanation: Dependent on flight positioning recovery used by NURE project

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Duval, Joseph S.

Originator: Darnley, Arthur G. (editor)

Originator: Garrett, Robert G. (editor)

Publication_Date: 1990

Title:

Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States

Series_Information:

Series_Name: Journal of Geochemical Exploration

Type_of_Source_Media:

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1975

Ending_Date: 1983

Source_Currentness_Reference: original data collection period for the NURE program

Source_Citation_Abbreviation: Duval, Darnley, and Garrett 1990

Source_Contribution: Material re-processed to obtain the present grids

Source_Information:

Source_Citation:

Citation_Information:

Originator: Duval, Joseph S.

Originator: Jones, William J.

Originator: Riggle, Frederick R.

Originator: Pitkin, James A.

Publication_Date: 1990

Title: Potassium and thorium maps of the conterminous United States

Geospatial_Data_Presentation_Form: map

Series_Information:

Series_Name: U.S. Geological Survey Open-File Report

Issue_Identification: 90-338

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1975

Ending_Date: 1983

Source_Currentness_Reference: original data collection period for the NURE program

Source_Citation_Abbreviation: OFR 90-338

Source_Contribution: Material re-processed to obtain the present grids

Source_Information:

Source_Citation:

Citation_Information:

Originator: Phillips, Jeffrey D.

Originator: Duval, Joseph S.

Originator: Ambroziak, Russell A.

Title:

National geophysical data grids; gamma-ray, gravity, magnetic, and topographic data for the conterminous United States

Publication_Date: 1993

Series_Information:

Series_Name: U.S. Geological Survey Digital Data Series

Issue_Identification: DDS-9

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1975

Ending_Date: 1983

Source_Currentness_Reference: original data collection period for the NURE program

Source_Citation_Abbreviation: DDS-9

Source_Contribution: Material re-processed to obtain the present grids

Source_Information:

Source_Citation:

Citation_Information:

Originator: Duval, Joseph S.

Publication_Date: 1995

Title:

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

Edition: 1

Series_Information:

Series_Name: U.S. Geological Survey Digital Data Series

Issue_Identification: DDS-31

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1975

Ending_Date: 1983

Source_Currentness_Reference: original data collection period for the NURE program

Source_Citation_Abbreviation: DDS-31 Release 1

Source_Contribution: Material re-processed to obtain the present grids

Source_Information:

Source_Citation:

Citation_Information:

Originator: Duval, Joseph S.

Originator: Riggle, Frederic E.

Publication_Date: 1999

Title:

Profiles of gamma-ray and magnetic data from aerial surveys over the conterminous United States

Edition: 2

Geospatial_Data_Presentation_Form:

Series_Information:

Series_Name: U.S. Geological Survey Digital Data Series

Issue_Identification: DDS-31

Type_of_Source_Media: CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1975

Ending_Date: 1983

Source_Currentness_Reference: original data collection period for the NURE program

Source_Citation_Abbreviation: DDS-31 Release 2

Source_Contribution: Material re-processed to obtain the present grids

Process_Step:

Process_Description:

The gamma-ray data were extracted from the NURE files and Canadian data sets; then projected, gridded, and displayed in a ternary form using the commercial software package Geosoft Oasis Montaj. Three elemental grids were calculated, one each for K, U, and Th, and a fourth that is the composite of each of these, referred to here as CCM.

Process_Date: 2005

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Robert P. Kucks

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address:

Box 25046, MS 964
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225-0046

Country: USA

Address_Type: mailing address

Contact_Electronic_Mail_Address: rkucks@usgs.gov

Contact_Voice_Telephone: (303)236-1405

Process_Step:

Process_Description:

The gamma-ray absorbed dose was calculated using the equation

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.

Process_Date: 2005

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Robert P. Kucks

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address:

Box 25046, MS 964
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225-0046

Country: USA

Address_Type: mailing address

Contact_Electronic_Mail_Address: rkucks@usgs.gov

Contact_Voice_Telephone: (303)236-1405

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: pixel

Row_Count: 2371

Column_Count: 5823

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.02

Longitude_Resolution: 0.02

Geographic_Coordinate_Units: Decimal degrees

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.0

Denominator_of_Flattening_Ratio: 298.257222101

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: CCM grid cell

Entity_Type_Definition:

Gamma-ray flux produced by the radioactive decay of naturally occuring elements expressed in concentrations of radioactive elements

Attribute:

Attribute_Label: potassium percentage, uranium and thorium ppm

Attribute_Definition:

expressed in units of percent potassium (percent K) and equivalent concentration of uranium and thorium in ppm (ppm eU & ppm eTh)

Attribute_Definition_Source: Duval, Darnley, and Garrett 1990

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0

Range_Domain_Maximum: 100.0

Attribute_Units_of_Measure: percent of element

Attribute_Measurement_Resolution: 0.1

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)

Enumerated_Domain_Value_Definition:

Cells lacking color (white) represent areas of no data in image.

Detailed_Description:

Entity_Type:

Entity_Type_Label: K grid cell

Entity_Type_Definition:

Gamma-ray flux produced by the radioactive decay of naturally occuring elements, expressed in concentrations of radioactive elements

Attribute:

Attribute_Label: potassium percentage

Attribute_Definition: expressed in units of percent potassium (percent K)

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0

Range_Domain_Maximum: 4.0

Attribute_Units_of_Measure: percent K

Attribute_Measurement_Resolution: 0.1

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)

Enumerated_Domain_Value_Definition:

Cells lacking color (white) represent areas of no data in image.

Detailed_Description:

Entity_Type:

Entity_Type_Label: Th grid cell

Entity_Type_Definition:

Gamma-ray flux produced by the radioactive decay of naturally occuring elements, expressed in concentrations of radioactive elements

Attribute:

Attribute_Label: thorium concentration

Attribute_Definition:

expressed in units of parts per million equivalent thorium (ppm eTh)

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0

Range_Domain_Maximum: 24.0

Attribute_Units_of_Measure: ppm eTh

Attribute_Measurement_Resolution: 0.1

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)

Enumerated_Domain_Value_Definition:

Cells lacking color (white) represent areas of no data in image.

Detailed_Description:

Entity_Type:

Entity_Type_Label: U grid cell

Entity_Type_Definition:

Gamma-ray flux produced by the radioactive decay of naturally occuring elements, expressed in concentrations of radioactive elements

Attribute:

Attribute_Label: uranium concentration

Attribute_Definition:

expressed in units of parts per million equivalent uranium (ppm eU)

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0

Range_Domain_Maximum: 6.0

Attribute_Units_of_Measure: ppm eU

Attribute_Measurement_Resolution: 0.1

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)

Enumerated_Domain_Value_Definition:

Cells lacking color (white) represent areas of no data in image.

Detailed_Description:

Entity_Type:

Entity_Type_Label: exp grid cell

Entity_Type_Definition:

Gamma-ray flux produced by the radioactive decay of naturally occuring elements, expressed in concentrations absorbed doses

Attribute:

Attribute_Label: nanoGrays per hour

Attribute_Definition: gamma-ray absorbed dose rate

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0

Range_Domain_Maximum: 125.0

Attribute_Units_of_Measure: nanoGrays per hour

Attribute_Measurement_Resolution: 1

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: (no value)

Enumerated_Domain_Value_Definition:

Cells lacking color (white) represent areas of no data in image.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: USGS Map Distribution

Contact_Address:

Address_Type: mailing address

Address:

Box 25286, Building 810
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225

Country: USA

Contact_Voice_Telephone: (888)ASK-USGS

Resource_Description: U.S. Geological Survey Open-File Report 2005-1413

Distribution_Liability:

The USGS has made every effort to verify the veracity of this information, but is not liable for any inaccuracies.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: Geotiff

Format_Specification: Arc-Info image format

Format_Information_Content: pixel

File_Decompression_Technique: none

Transfer_Size: 40.5

Format_Version_Date: 2005

Digital_Form:

Digital_Transfer_Information:

Format_Name: OGC WMS

Format_Version_Number: 1.1.1

Format_Information_Content: Uranium, Thorium, Potassium, and color composite grids

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

<http://mrdata.usgs.gov/cgi-bin/mapserv?map=radiometric.map&request=getcapabilities&service=WMS&version=1.1.1>&

Fees: none

Metadata_Reference_Information:

Metadata_Date: 20091118

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Robert P. Kucks

Contact_Organization: U.S. Geological Survey

Contact_Electronic_Mail_Address: rkucks@usgs.gov

Contact_Address:

Address_Type: mailing address

Address:

Box 25046, MS 964
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225

Country: USA

Contact_Voice_Telephone: (303)236-1405

Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998