nrg_irg - Digital raster grid of isostatic residual gravity anomalies for the Northern Rocky Mountains and adjacent areas, Idaho, Montana, Washington, Oregon, and Wyoming.

Metadata:

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

Identification_Information:

Citation:

Citation_Information:

Originator: Mankinen, E.A.

Originator: Hildenbrand, T.G.

Originator: Zientek, M.L.

Originator: Box, S.E.

Originator: Bookstrom, A.A.

Originator: Carlson, M.H.

Originator: Larsen, J.C.

Publication_Date: 2004

Title:

nrg_irg - Digital raster grid of isostatic residual gravity anomalies for the Northern Rocky Mountains and adjacent areas, Idaho, Montana, Washington, Oregon, and Wyoming.

Edition: version 1.0

Geospatial_Data_Presentation_Form: raster digital data

Series_Information:

Series_Name: Open-File Report

Issue_Identification: 1413

Publication_Information:

Publication_Place: Menlo Park, California

Publisher: U.S. Geological Survey

Online_Linkage: <http:/pubs.usgs.gov/of/2004/1413/>

Description:

Abstract:

Regional gravity surveys measure the attraction of gravity at the Earth’s surface. The magnitude of the gravity field at a single station, however, is influenced by a number of factors which must be predicted and compensated (e.g., mass, rotation and ellipsoidal shape of the Earth; elevation of the gravity station; attraction of nearby topography or bathymetric relief). By applying well-established corrections to all stations within a survey, gravity maps and their derivatives can be used tocharacterize local density variations primarily in the middle and upper crust. The raster grid, nrg_irg, represents the isostatic residual gravity anomaly for the study area. An isostatic regional field has been subtracted from the Bouguer anomaly to compensate for large-amplitude, long-wavelength anomalies caused by deep crustal and upper mantle density distributions related to topographic loads.

Purpose:

This raster grid was created to assist in developing regional digital earth science data and interpretations that can be used by Federal land managers in regional planning and special assessments such as road-less area withdrawals.

Supplemental_Information:

The isostatic residual gravity anomaly grid is provided in three formats; ESRI gird, Geosoft OASIS montaj format and binary format used by the USGS. This metadata file describes the processes used to create the ESRI grid and does not provide additional information about the Geosoft or USGS grids. The GeoSoft OASIS montaj format grid is available in the \GeoSoft folder at the top-level directory. The binary USGS format grid is available in the \USGS folder at the top-level directory.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2004

Currentness_Reference: publication date

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -118.553103

East_Bounding_Coordinate: -107.183007

North_Bounding_Coordinate: 49.204647

South_Bounding_Coordinate: 41.819054

Keywords:

Theme:

Theme_Keyword: geophysics

Theme_Keyword: gravity map

Theme_Keyword: isostatic residual gravity

Place:

Place_Keyword: Northern Rocky Mountains

Place_Keyword: Idaho

Place_Keyword: Montana

Place_Keyword: Washington

Place_Keyword: Oregon

Place_Keyword: Wyoming

Place_Keyword: USA

Access_Constraints: none

Use_Constraints: none

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Edward A. Mankinen

Contact_Organization: U.S. Geological Survey

Contact_Position: Geologist

Contact_Address:

Address: 345 Middlefield Rd, Mail Stop 937

City: Menlo Park

State_or_Province: CA

Postal_Code: 94025-3591

Contact_Voice_Telephone: (650) 329-4669

Contact_Facsimile_Telephone: (650) 329-4664

Contact_Electronic_Mail_Address: emank@usgs.gov

Native_Data_Set_Environment:

Microsoft Windows 2000 Version 5.1 (Build 2600) Service Pack 1; ESRI ArcGIS 8.3

Data_Quality_Information:

Attribute_Accuracy:

Logical_Consistency_Report: No duplicate features exist

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Accuracy is dependent upon the individual making the observation and the reliability of the station location, especially elevation. Dataset for the study area was developed over a number of years by many individuals and, thus, the quality may be highly variable. For regional surveys such as this, anomaly values generally are accurate to within 2 mGal (Simpson and Jachens, 1989).

Vertical_Positional_Accuracy:

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Hildenbrand, T.G.

Originator: Berger, B.

Originator: Jachens, R.C.

Originator: Ludington, S.

Publication_Date: 2000

Title:

Regional crustal structures and their relationship to the distribution of ore deposits in the western United States, based on magnetic and gravity data

Series_Information:

Series_Name: Economic Geology

Issue_Identification: v. 95

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2000

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Hildenbrand and others (2000)

Source_Contribution: Source of the isostatic residual gravity data

Source_Information:

Source_Citation:

Citation_Information:

Originator: Simpson, R.W.

Originator: Jachens, R.C.

Originator: Blakely, R.J.

Publication_Date: 1983

Title:

Airyroot: a FORTRAN program for calculating the gravitational attraction of an Airy isostatic root out to 166.7 km

Series_Information:

Series_Name: Open-File Report

Issue_Identification: 83-883

Publication_Information:

Publisher: U.S. Geological Survey

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1983

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Simpson and others (1983)

Source_Contribution:

source of the Airy-Heiskanen model used to calculate the isostatic residual field

Source_Information:

Source_Citation:

Citation_Information:

Originator: Hildenbrand, T.G.

Publication_Date: 1983

Title:

FFTFIL: A filtering program based on two-dimensional Fourier analysis

Series_Information:

Series_Name: Open-File Report

Issue_Identification: 83-237

Publication_Information:

Publisher: U.S. Geological Survey

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1983

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Hildenbrand (1983)

Source_Contribution: Provided the algorithms used in the upward continuation process

Process_Step:

Process_Description:

The gravity data obtained from NIMA were gridded at a spacing of 1 km using the minimum curvature algorithm of Webring (1981). The standard geophysical grids were converted to Arc grids using an ARC/INFO Macro subroutine created in-house.

Source_Used_Citation_Abbreviation: NIMA

Source_Used_Citation_Abbreviation: Webring (1981)

Process_Date: 2003

Process_Step:

Process_Description:

The gridded isostatic residual gravity dataset was re-projected in Albers equal-area projection and clipped to the extent of the study area.

Source_Used_Citation_Abbreviation: NIMA

Process_Date: 2003

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 802

Column_Count: 831

Vertical_Count: 1

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Albers Conical Equal Area

Albers_Conical_Equal_Area:

Standard_Parallel: 44.000000

Standard_Parallel: 48.000000

Longitude_of_Central_Meridian: -114.000000

Latitude_of_Projection_Origin: 41.000000

False_Easting: 0.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: row and column

Coordinate_Representation:

Abscissa_Resolution: 1000.000000

Ordinate_Resolution: 1000.000000

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1927

Ellipsoid_Name: Clarke 1866

Semi-major_Axis: 6378206.400000

Denominator_of_Flattening_Ratio: 294.978698

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey Information Services

Contact_Address:

Address_Type: mailing address

Address: P.O. Box 25286

City: Denver

State_or_Province: CO

Postal_Code: 80225

Country: USA

Contact_Voice_Telephone: (888) ASK-USGS

Contact_Voice_Telephone: (888) 275-8747

Contact_Electronic_Mail_Address: infoservices@usgs.gov

Resource_Description: Downloadable data for USGS Open-File Report 2004-1413

Distribution_Liability:

The U.S. Geological Survey (USGS) provides these geographic data "as is". The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty. In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by USGS.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: ZIP

Format_Version_Number: 9.0

Format_Specification: WINZIP® 9.0

Format_Information_Content:

ZIP archive for thirteen ArcInfo® grids: nr_bouguer, nrg_irg, nrg_irg_1vd, nrg_irg_inv, nrg_irg_iw, nrg_irg_lw, nrg_irg_tr, nrm_aeromag, nrm_magres, nrm_mpot, nrm_mpot_iw, nrm_mpot_lw, and nrm_mpot_tr.

File_Decompression_Technique:

To open a ZIP archive, double-click on the archive listed in My Computer or Windows Explorer, drag and drop the archive onto WINZIP®, or use the standard Open dialogue box.

Transfer_Size: 26 (MB)

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://pubs.usgs.gov/of/2004/1413>

Fees: No fee for downloadable data and report

Technical_Prerequisites:

User must have geographic information system (GIS) software capable of reading ESRI ArcInfo® file formats.

Metadata_Reference_Information:

Metadata_Date: 20050929

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Jeremy C. Larsen

Contact_Organization:

Information Systems Support (under contract to the U.S. Geological Survey)

Contact_Position: contractor

Contact_Address:

Address_Type: mailing and physical address

Address: 904 W. Riverside Ave, Room 202

City: Spokane

State_or_Province: WA

Postal_Code: 99201

Contact_Voice_Telephone: (509) 368-3118

Contact_Electronic_Mail_Address: jlarsen@usgs.gov

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time

Metadata_Extensions:

Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>

Profile_Name: ESRI Metadata Profile