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

Metadata also available as

Metadata:

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_lw - Digital raster grid of long-wavelength 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 to characterize local density variations primarily in the middle and upper crust. The raster grid, nrg_irg_lw, represents the long-wavelength data of the isostatic residual gravity (using a three-layer model). These data highlight anomalies primarily from sources residing in the lower middle crust, or shallow, broad sources that extend to substantial depths. This filter also de-emphasizes shallow, thin sources and noise due to measurement errors.
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 long-wavelength 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
Theme_Keyword: long wavelength
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:
Vertical_Positional_Accuracy_Report: The effect of the band-pass filtering has not been determined.
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:
This is the source for the original isostatic residual gravity anomaly data
Source_Information:
Source_Citation:
Citation_Information:
Originator: Phillips, J.D.
Publication_Date: 1997
Title: Potential-field geophysical software for the PC, version 2.2
Series_Information:
Series_Name: Open-File Report
Issue_Identification: 97-725
Publication_Information:
Publisher: U.S. Geological Survey
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 1997
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Phillips (1997)
Source_Contribution: Provided the algorithms used to filter the anomaly 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:
This is the source of the Airy-Heiskanen moded 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:
Source of the algorithms used in the upward continuation process
Process_Step:
Process_Description:
These data were extracted from the unpublished grid of isostatic residual gravity for the western United States (Hildenbrand and others, 2000). They were re-projected to the specifications of the study area and upward continued 5 km using USGS in-house developed software. Upward continuation was performed to enhance the regional aspects of the dataset. In-house software was used to convert from USGS grid format to ARC/INFO grid format. The isostatic residual field (nrg_irg) was calculated using an Airy-Heiskanen model (Simpson and others (1983). Upward continuation performed using the algorithms of Hildenbrand (1983).
Source_Used_Citation_Abbreviation: Hildenbrand and others, 2000
Source_Used_Citation_Abbreviation: Simpson and others (1983)
Source_Used_Citation_Abbreviation: Hildenbrand (1983)
Process_Date: 2003
Process_Step:
Process_Description:
The gridded isostatic residual gravity dataset (nrg_irg) was filtered to isolate prominent wavelengths in the dataset using USGS in-house developed software. This grid contains the long-wavelength data (assuming a three-layer model). In-house software was used to convert from USGS grid format to ARC/INFO grid format. Filtering was performed using the matched bandpass filtering algorithms of Phillips (1997)
Source_Used_Citation_Abbreviation: Phillips (1997)
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
Generated by mp version 2.8.6 on Thu Sep 29 09:23:30 2005