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Gamma-ray, Magnetic, and Topographic Data for the Colorado Front Range

Metadata:

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

Identification_Information:

Citation:

Citation_Information:

Originator: Duval, Joseph S.

Originator: Reed, John C.

Originator: Zietz, Isadore

Publication_Date: 2000

Title:

Gamma-ray, Magnetic, and Topographic Data for the Colorado Front Range

Geospatial_Data_Presentation_Form: raster digital data

Series_Information:

Series_Name: USGS Open-File Report

Issue_Identification: 2000-331

Publication_Information:

Publication_Place: Reston, Virginia

Publisher: U.S. Geological Survey

Description:

Abstract:

The grid files presented here are in ASCII format that uses the definitions of the grid exchange format (GXF). The files can be viewed using a suitable word processing program. The different grids are:

Kfrco.gxf    potassium concentrations in the rocks and soils
Ufrco.gxf    uranium concentrations in the rocks and soils
Thfrco.gxf   thorium concentrations in the rocks and soils
Magfrco.gxf  residual magnetic field
Terrfrco.gxf digital elevations

The data used to create the potassium (K), uranium (U), thorium (Th), and magnetic (Mag) grids were obtained as part of the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy (USDOE). The NURE Program included aerial surveys that collected gamma-ray and magnetic data. The aerial surveys were flown at a nominal altitude of 122 meters above the ground. The aerial survey flightlines were generally flown east- west with north-south tielines. For the data covering the mountains of the Colorado Front Range, the flightline spacing is 1 mile (1600 meters) for the east-west lines and about 8 miles (12.8 km) for the north-south tielines. For the data covering the plains to the east of the mountains, the flightline spacing is 3 miles (4800 m) for the east-west lines and about 16 miles (25.6 km) for the north-south tielines. In the mountains, helicopters were used with a detector volume of 2000 cubic inches (32.8 liters) of thallium doped sodium iodide (NaI(Tl)). Over the plains, fixed-wing aircraft were used with about 3300 cubic inches (54 liters) of NaI(Tl) detector. The magnetometers used were proton-precession magnetometers with base stations used to make diurnal corrections. The USDOE contracted with private contractors to conduct the aerial surveys and the contractors were responsible for all aspects of calibration and data processing.
The data used to create the grid of digital elevations were derived from the U.S. Geological Survey (USGS) 1:250,000 topographic quadrangle maps. The topographic maps were digitized at intervals of three arc-seconds and were then averaged to intervals of 15 seconds. The resulting 15-second data were used to calculate the grid presented here.
The units of the grid data are:

Potassium     percent K
Uranium       parts per million (ppm) eU
Thorium       ppm eTh
Magnetic      nano Teslas
Elevation     meters

Purpose:

These data were originally obtained to aid in the estimate of uranium resources in the United States.

Status:

Progress: In Work

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -106

East_Bounding_Coordinate: -105

North_Bounding_Coordinate: 36

South_Bounding_Coordinate: 32

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: Geophysical Data

Place:

Place_Keyword_Thesaurus: Geographic Names Information System

Place_Keyword: Colorado

Access_Constraints: None

Use_Constraints: None

Time_Period_of_Content:

Currentness_Reference: publication date

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 1978

Ending_Date: 1979

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

The absolute accuracy of the concentrations of potassium, uranium, and thorium are estimated to be on the order of 20-30 percent. The accuracy of the magnetic data is about 2 nT. Because of the manner in which the elevation data have been averaged, the values should only be used in a qualitative manner.

Completeness_Report:

All of the available flightline data were used. Because of differences in the calibrations of the data sets, scaling adjustments were made to correct scaling differences. The following publication provides detailed information on the corrections made:
Duval, J.S. and Riggle, F.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, Release 2, 3 CD-ROMs.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

The position of the aircraft during the aerial surveys was constantly monitored.

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: 100

Horizontal_Positional_Accuracy_Explanation: meters, estimated

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The position of the aircraft during the aerial surveys was constantly monitored.

Quantitative_Vertical_Positional_Accuracy_Assessment:

Vertical_Positional_Accuracy_Value: 100

Vertical_Positional_Accuracy_Explanation: meters, estimated

Logical_Consistency_Report:

The concentration data are based upon calibrations done using the airport calibration pads in Grand Junction, Colorado and the dynamic test strip at Lake Mead, Nevada.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Geometrics, Inc.

Publication_Date: 1979

Title:

Aerial gamma ray and magnetic survey; Rock Springs, Rawlins, and Cheyenne quadrangles, Wyoming and the Greeley Quadrangle, Colorado

Geospatial_Data_Presentation_Form: document

Series_Information:

Series_Name: Open-File Report

Issue_Identification: GJBX-17-79

Publication_Information:

Publication_Place: Grand Junction, CO

Publisher: U.S. Department of Energy

Other_Citation_Details: 5 volumes

Online_Linkage: None

Type_of_Source_Media: paper

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19780101

Beginning_Time: Unknown

Ending_Date: 19791231

Ending_Time: Unknown

Source_Currentness_Reference: publication date

Source_Contribution:

These publications describe the aerial surveys, how they were flown, and data processing steps.

Source_Citation_Abbreviation: USDOE, GJBX-17-79

Source_Information:

Source_Citation:

Citation_Information:

Originator: Geometrics, Inc.

Publication_Date: 1979

Title:

Aerial gamma ray and magnetic survey; Rockies/Laramie Range Project; Denver and Pueblo quadrangles, Colorado

Geospatial_Data_Presentation_Form: document

Series_Information:

Series_Name: Open-File Report

Issue_Identification: GJBX-49-79

Publication_Information:

Publication_Place: Grand Junction, CO

Publisher: U.S. Department of Energy

Other_Citation_Details: 4 volumes

Online_Linkage: None

Type_of_Source_Media: paper

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 19780101

Beginning_Time: Unknown

Ending_Date: 19791231

Ending_Time: Unknown

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: USDOE, GJBX-49-79

Source_Contribution:

This report describes the aerial survey, how it was flown, and data processing steps.

Process_Step:

Process_Description:

The flightline data were read from tape and were converted to grids using USGS gridding programs.

Source_Used_Citation_Abbreviation: USDOE, GJBX-17-79 and GJBX-49-79

Process_Date: 1997

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Joseph S. Duval

Contact_Organization: U.S. Geological Survey

Contact_Position: Geophysicist

Contact_Address:

Address_Type: mailing address

Address:

12201 Sunrise Valley Drive
Mail Stop 954

City: Reston

State_or_Province: VA

Postal_Code: 20192

Country: USA

Contact_Voice_Telephone: (703) 648-6106

Contact_Facsimile_Telephone: (703) 648-6383

Contact_Electronic_Mail_Address: jduval@usgs.gov

Contact_Instructions: email preferred

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Transverse Mercator

Transverse_Mercator:

Scale_Factor_at_Central_Meridian: 0.9996

Longitude_of_Central_Meridian: -105

Latitude_of_Projection_Origin: 0

False_Easting: 0

False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: Row and Column

Coordinate_Representation:

Abscissa_Resolution: 0.635

Ordinate_Resolution: 0.635

Planar_Distance_Units: kilometers

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1927

Ellipsoid_Name: Clarke 1866

Semi-major_Axis: 6378.2064

Denominator_of_Flattening_Ratio: 294.98

Spatial_Data_Organization_Information:

Indirect_Spatial_Reference: The data are located strictly by the coordinates.

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 539

Column_Count: 181

Vertical_Count: 1

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: USGS ESIC-Open-File Report Sales

Contact_Address:

Address_Type: mailing address

Address:

Mail Stop 517
U.S. Geological Survey
Box 25286, Building 810
Denver Federal Center

City: Denver

State_or_Province: CO

Postal_Code: 80225-0286

Country: USA

Contact_Voice_Telephone: (303) 202-4210

Contact_Facsimile_Telephone: (303) 236-4031

Resource_Description: USGS Open-File Report 2000-331

Distribution_Liability:

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: GXF

Format_Version_Number: 1.0

Format_Information_Content: Colorado Front Range Potassium

Transfer_Size: 850 kilobytes

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://geo-nsdi.er.usgs.gov/metadata/open-file/00-331/kfrco.gxf>

Digital_Form:

Digital_Transfer_Information:

Format_Name: GXF

Format_Version_Number: 1.0

Format_Information_Content: Colorado Front Range Thorium

Transfer_Size: 850 kilobytes

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

<http://geo-nsdi.er.usgs.gov/metadata/open-file/00-331/thfrco.gxf>

Digital_Form:

Digital_Transfer_Information:

Format_Name: GXF

Format_Version_Number: 1.0

Format_Information_Content: Colorado Front Range Uranium

Transfer_Size: 850 kilobytes

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://geo-nsdi.er.usgs.gov/metadata/open-file/00-331/ufrco.gxf>

Digital_Form:

Digital_Transfer_Information:

Format_Name: GXF

Format_Version_Number: 1.0

Format_Information_Content: Colorado Front Range magnetic anomaly

Transfer_Size: 850 kilobytes

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

<http://geo-nsdi.er.usgs.gov/metadata/open-file/00-331/magfrco.gxf>

Digital_Form:

Digital_Transfer_Information:

Format_Name: GXF

Format_Version_Number: 1.0

Format_Information_Content: Colorado Front Range Elevation

Transfer_Size: 850 kilobytes

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name:

<http://geo-nsdi.er.usgs.gov/metadata/open-file/00-331/terrfrco.gxf>

Fees: none

Metadata_Reference_Information:

Metadata_Date: 20071119

Metadata_Review_Date: 20000606

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Peter N. Schweitzer

Contact_Organization: U.S. Geological Survey

Contact_Position: Geophysicist

Contact_Address:

Address_Type: mailing address

Address:

12201 Sunrise Valley Drive
Mail Stop 954

City: Reston

State_or_Province: VA

Postal_Code: 20192

Country: USA

Contact_Voice_Telephone: (703) 648-6533

Contact_Facsimile_Telephone: (703) 648-6252

Contact_Electronic_Mail_Address: pschweitzer@usgs.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time with time differential factor

Metadata_Access_Constraints: None

Metadata_Use_Constraints: None