U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 2004-1413 Guide to Geophysical Data for the Northern Rocky Mountains and adjacent areas, Idaho, Montana, Washington, Oregon, and Wyoming by Mankinen, E.A., Hildenbrand, T.G., Zientek, M.L., Box, S.E., Bookstrom, A.B., Carlson, M.H., and Larsen, J.C. ------------------------------------------------------ This text document contains information describing the digital data accompanying this report. ------------------------ FILE ORGANIZATION Top level files: readme.txt - this file Top level directories: \Report - 34-page PDF document \ESRI - Information includes vector spatial databases as ESRI shapefiles (nrg_gravlin.shp, nrg_maxspot.shp, nrg_mxspt_iw.shp, nrm_maglin.shp, nrm_maxspot.shp, and nrm_mxspt_iw.shp) in zip archive (nr_shapefiles.zip); ArcInfo raster datasets (nrg_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) in zip archive (nr_grids.zip). To open and extract files from a ZIP archive, double-click on the archive listed in My Computer or Windows Explorer, click the Extract button and navigate to where the files will be stored. Use the ArcInfo COPY command or ArcCatalog to copy grids from one location to another. Windows Explorer should not be used to copy grids. Short explanation of each grid: nrg_bouguer - complete Bouguer gravity anomaly nrg_irg - isostatic residual gravity anomaly nrg_irg_1vd - first vertical derivative of isostatic residual gravity anomaly nrg_irg_inv - depth to pre-Cenozoic basin nrg_irg_iw - intermediate-wavelength isostatic residual gravity anomaly nrg_irg_lw - long-wavelength isostatic residual gravity anomaly nrg_irg_tr - terraced isostatic residual gravity anomaly nrm_aeromag - aeromagnetic anomaly nrm_magres - residual magnetic anomaly nrm_mpot - pseudogravity transformation of magnetic anomalies nrm_mpot_iw - intermediate-wavelength magnetic potential anomaly nrm_mpot_lw - long-wavelength magnetic potential anomaly nrm_mpot_tr - terraced magnetic potential anomaly Short explanation of each shapefile: nrg_gravlin.shp - interpreted major density boundaries nrg_maxspot.shp - horizontal gradients of the long- wavelength gravity anomalies and their maxima nrg_mxspt_iw.shp - horizontal gradients of the intermediate-wavelength gravity anomalies and their maxima nrm_maglin.shp - interpreted major magnetization boundaries nrm_maxspot.shp - horizontal gradients of the long- wavelength magnetic anomalies and their maxima nrm_mxspt_iw.shp - horizontal gradients of the intermediate-wavelength magnetic anomalies and their maxima \GeoSoft - Geosoft OASIS montaj format grids \USGS - in-house binary format grids used by the USGS \METADATA - FGDC compliant metadata files for each ESRI grid and shapefile in html format.