1_README.TXT GRAVITY DATA OF NEVADA By D.A. Ponce 1997 U.S. Geological Survey 345 Middlefield Rd. MS 989 Menlo Park, CA 94025 E-mail: ponce@usgs.gov WWW site: http://wrgis.wr.usgs.gov/docs/gump/gump.html U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-42 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For sale by USGS Information Services Box 25286, Building 810 Denver Federal Center Denver, CO 80225 (888) ASK-USGS Library of Congress Cataloging-in-Publications Data Ponce, David A. Gravity data of Nevada [computer file] / by D.A. Ponce 1 computer laser optical disc : col. ; 4 3/4 in. -- (U.S. Geological Survey digital data series : DDS-42) Computer data. Title from disc label. Audience: Geoscientists 1. Gravity anomalies--Nevada--Measurement. 2. Gravity anomalies-- Southwestern States--Measurement. I. National Geophysical Data Center. II. Geological Survey (U.S.). III. Series: U.S. Geological Survey digital data series : DDS-42. QB337.5 <1997 00001> 526--DC12a 97-4516 CIP ISBN: 0-607-86636-5 CONTENTS ___________ Abstract Introduction Acknowledgments Disclaimer System Requirements Portable Document Format (PDF) File Related World Wide Web Sites Gravity Data Format and Reduction Selected References Appendix--List of Sources for Data from the National Geophysical Data Center ___________ ILLUSTRATIONS ________ Figure 1. Index map showing 1 x 2 degrees quadrangles 2. Gravity station location map 3. Topographic map 4. Complete Bouguer gravity map 5. Isostatic gravity map ___________ TABLES ________ Table 1. Data files on CD-ROM 2. Format of gravity data 3. Explanation of 4-digit accuracy code ABSTRACT Gravity data for the entire state of Nevada and adjacent parts of California, Utah, and Arizona are available on CD-ROM. About 80,000 gravity stations were compiled primarily from the National Geophysical Data Center and the U.S. Geological Survey. Gravity data were reduced to the Geodetic Reference System of 1967 and adjusted to the International Gravity Standardization Net 1971 gravity datum. Data were processed to complete Bouguer and isostatic gravity anomalies by applying standard gravity corrections including terrain corrections and isostatic corrections. A 1_README.TXT file describes the contents of the CD-ROM and includes a description of the data reduction process, selected principal fact references, and a list of sources for data from the National Geophysical Data Center. INTRODUCTION Gravity data for the entire state of Nevada and adjacent parts of California, Utah, and Arizona are available on Compact Disc-Read Only Memory (CD-ROM). Data are organized into 19 files, one for each of the 18 1 X 2 degree quadrangles (fig. 1) that cover Nevada as well as a single file containing all the data (table 1). About 80,000 gravity stations (fig. 2) have been compiled from various sources including the National Geophysical Data Center (National Geophysical Data Center, 1988), U.S. Geological Survey (USGS), Nevada Bureau of Mines and Geology, California Division of Mines and Geology, University of Nevada at Reno, Stanford University, Northwestern University, Colorado School of Mines, Los Alamos National Laboratory, and University of Texas at Dallas. Data were processed to complete Bouguer and isostatic gravity anomalies by applying standard gravity corrections including terrain corrections to a radial distance of 167 km and isostatic corrections based on an Airy-Heiskanen model of local compensation (Heiskanen and Moritz, 1967). ACKNOWLEDGMENTS I would especially like to thank Donald Plouff of the USGS for recent recompilations of several quadrangles in the northwestern part of Nevada and J.W. Erwin of the Nevada Bureau of Mines and Geology for access to various data sets throughout Nevada and for supporting a cooperative effort to release gravity data and maps for Nevada. Michael Diggles of the USGS developed the final CD-ROM architecture and produced the master. In addition, I acknowledge the contributions of numerous personnel from various organizations for acquiring or providing gravity data including: G.A. Abrams, R.V. Allen, T.V. Bare, R.G. Bates, D.L. Berger, H.R. Blank, Jr., A.J. Bol, R.E. Bracken, B.R. Buchanan, S.F. Carle, J.E. Carlson, R.H. Chapman, L.L. Chau, B.A. Chuchel, A.H. Cogbill, Jr., A. Conradi, Jr., C.E. Corry, R.A. Crewdson, F.E. Currey, D.A. Dansereau, K.J. Danti, D.A. Dinter, T.J. Durbin, R.K. Edquist, C.F. Erdman, G.R. Erickson, D.G. Evans, E.A. Frick, J.D. Garing, M.L. Gerdes, J.F. Gibbs, J.I. Gimlett, J.M. Glen, R.H. Godson, V.J.S. Grauch, R.N. Harris, J. Hasbrouck, D.L. Healey, D.C. Hobach, K.D. Holden, R.C. Jachens, P.E. Jansma, D.R. Jefferris, M.F. Kane, C.R. Karish, A.M. Katzenstien, H.E. Kaufmann, D.R. Kietzman, J.D. Kibler, K.S. Kirchoff- Stein, N.E. Kitchen, S.B. Kohrn, S.C. Kuehn, V.E. Langenheim, J.H. Laudon, J.S. Lewis, R.B. Livermore, D.R. Mabey, J. Mariano, D.K. Maurer, C.H. Miller, E.G. Miller, M.E. Milling, R.L. Morin, C.K. Moss, H.W. Oliver, D.L. Peterson, R.W. Plume, W.L. Rambo, D. Reidy, S.L. Robbins, C.W. Roberts, J.R Rosenbaum, H.F. Ryan, J.J. Rytuba, R.W. Saltus, C.H. Sandberg, D.H. Schaefer, H.L. Scheirer, K.M. Schmidt, E.D. Seals, L. Senior, D. Shiel, R.F. Sikora, E.H. Softky, J.B. Spielman, D.B. Snyder, S.L. Snyder, R.W. Tabor, J.M. Thomas, H.M. Van Buren, K. Velasco, S. Waddell, A. Wagini, R.R. Wahl, R. Ward, and C.W. Wilson. DISCLAIMER This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor the agency thereof nor any of their employees make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials. SYSTEM REQUIREMENTS The data and text on this CD-ROM require either a Macintosh or compatible computer or an IBM or compatible personal computer. The Macintosh should have a 68020 or higher processor (PowerPC recommended), 8 megabytes RAM (16 MB recommended), Apple System Software version 7.0 or later (7.1.2 or later recommended), and a 13-inch color monitor that can display 256 colors. The PC should have a 386 or higher processor (Pentium recommended), Microsoft Windows 3.1 or higher (Windows 95 or Windows NT recommended), 8 megabytes RAM (16 MB recommended), and a VGA color monitor that can display 256 colors. This CD-ROM was produced in accordance with the ISO 9660 and Macintosh HFS standards. All ASCII and PDF files can be accessed from PC, Macintosh, and Unix platforms, the display software packages provided are designed for use under a PC Windows-based or Macintosh system, as appropriate. PORTABLE DOCUMENT FORMAT (PDF) FILE In addition to the ASCII text (1_README.TXT) and data files (in the DATA directory), This disc contains Portable Document Format (PDF) files for viewing and searching documents. The ACROBAT directory contains installers for Adobe Acrobat Reader 3.0 for both Windows (PC directory) and Macintosh (MAC directory, INST_R30 installer). For Windows, a 16- bit version (RS16E30.EXE installer) is provided for Windows 3.1 and a 32-bit version (RS32E30.EXE installer) is provided for Windows NT and Windows 95. The Windows installers are self-extracting archives that open in the directory you specify. Once opened, run the Setup program to proceed. You can use the installers provided on this disc or download the latest version of Adobe Acrobat Reader free via the Internet from the Adobe homepage on the World Wide Web at http://www.adobe.com/ In order to view PDF files you will need a reader that can translate PDF files. This CD-ROM contains a full-text index (INDEX.PDX) that is for use in searching the .PDF files for words or sets of words using the search tool in Acrobat Reader. Within the DDS_42.PDF file, links (highlighted text) are provided that allow you to jump to another part of document, change views, or display figures. Links to the World Wide Web will access the user's connection to the Internet and browser software if available. The CD-ROM also contains a full-text index (INDEX.PDX and associated subdirectory) that can be used to search for words or phrases using the search tool supplied with Acrobat Reader described above. If your version of Acrobat Reader has a "File" "Preferences" "General..." check box for "Open Cross-Document Links In Same Window," deselect it; this will keep the main document open when you view another PDF file. RELATED WORLD WIDE WEB SITES Western Region Geophysics-http://wrgis.wr.usgs.gov/docs/gump/gump.html U.S. Geological Survey-http://www.usgs.gov National Geophysical Data Center-http://www.ngdc.noaa.gov Nevada Bureau of Mines and Geology-http://www.nbmg.unr.edu State of Nevada-http://www.state.nv.us GRAVITY DATA FORMAT AND REDUCTION Principal facts of gravity data are contained in the DATA directory. The data files are listed in table 1 and are in the ASCII format described in table 2. Accuracy codes, if available, which describe location and observed gravity accuracies, are listed in table 3. Gravity data were reduced using the Geodetic Reference System of 1967 (International Union of Geodesy and Geophysics, 1971) and adjusted to the International Gravity Standardization Net 1971 (IGSN 71) gravity datum (Morelli, 1974). Observed gravity values were ultimately tied to an IGSN 71 network of base stations throughout Nevada described by Jablonski (1974). Gravity data were reduced to complete Bouguer and isostatic anomalies using a reduction density of 2.67 g/cm^3. Gravity stations were processed by applying standard corrections to the data that include: a field reading to gravity unit conversion, which converts readings in arbitrary units to milligals by using manufacturer's factors and a calibration constant determined by repeated measurements over established calibration loops; an earth-tide correction, which removes the effect of the tidal attraction of the sun and moon; the instrument drift correction, which accounts for nonelastic changes in the instrument's spring and temperature effects; a free-air correction, which accounts for the different elevation of each station; a Bouguer correction, which accounts for the attraction of rock material between the station and sea-level; a latitude correction, which takes into account the variation of the Earth's gravity at sea-level with latitude; the curvature correction, which corrects for the Earth's curvature; a terrain correction, which removes the effect of topography to a radial distance of 167 km; and an isostatic correction, which removes long-wavelength variations in the gravity field and is based on a model of isostatic compensation. Terrain corrections nearest the station, inner-zone terrain corrections, were calculated using the Hayford-Bowie system (Swick, 1942), the Hammer (1939) system, or by using a digital elevation model and a computer procedure. Terrain corrections farther away from the station, outer- zone terrain corrections, were recomputed for all data using a digital elevation model (fig. 3) and a computer procedure by Godson and Plouff (1988). The extent of the inner-zone terrain correction varies from source to source and, if available, a one-letter code is used to denote its extent (table 1). In general, for USGS data, terrain corrections consist of a three part process: a field terrain correction to a radial distance of 68 or 175 m, a manually estimated inner-zone correction to a radii of 2.29 or 8.95 km, and an outer-zone correction to a radius of 167 km using a computer procedure adapted from Godson and Plouff (1988). A terrain corrected, complete Bouguer gravity map of Nevada is shown in figure 4. Isostatic corrections were removed from the Bouguer gravity field using a method by Jachens and Roberts (1981). The isostatic model is based on an Airy-Heiskanen model for local isostatic compensation of topographic loads with an assumed sea-level crustal thickness of 25 km, a crustal density of 2.67 g/cm-3, and a density contrast across the base of the crust of 0.4 g/cm-3. A discussion of the isostatic correction and its significance was given by Simpson and others (1986). An isostatic gravity map of the state of Nevada is shown in figure 5. Table 1. List of gravity data files in the DATA directory ________________________________________________________________________ File name Quadrangle Number of Range in lat Range in long stations (degrees) (degrees) ________________________________________________________________________ CALIENTE.ISO Caliente 4,786 37 - 38 114 - 116 DV.ISO Death Valley 12,037 36 - 37 116 - 118 ELKO.ISO Elko 2,121 40 - 41 114 - 116 ELY.ISO Ely 2,821 39 - 40 114 - 116 GOLD.ISO Goldfield 15,527 37 - 38 116 - 118 KINGMAN.ISO Kingman 3,161 35 - 36 114 - 116 LASVEGAS.ISO Las Vegas 4,318 36 - 37 114 - 116 LOVELOCK.ISO Lovelock 1,743 40 - 41 118 - 120 LUND.ISO Lund 8,454 38 - 39 114 - 116 MARIPOSA.ISO Mariposa 2,804 37 - 38 116 - 118 MCD.ISO McDermitt 1,991 41 - 42 116 - 118 MILLETT.ISO Millett 3,460 39 - 40 116 - 118 RENO.ISO Reno 2,198 39 - 40 118 - 120 TONOPAH.ISO Tonopah 4,275 38 - 39 116 - 118 VYA.ISO Vya 1,574 41 - 42 118 - 120 WALKER.ISO Walker Lake 3,701 38 - 39 118 - 120 WELLS.ISO Wells 1,661 41 - 42 114 - 116 WIN.ISO Winnemucca 2,654 40 - 41 116 - 118 NEVADA.ISO --- 79,286 35 - 42 114 - 120 ________________________________________________________________________ Table 2. Format of gravity data [ft, feet; g/cc, grams/cubic-centimeter; mGal, milligal] ______________________________________________________________________ Column FORTRAN Description format ______________________________________________________________________ 1-8 A8 Station name 10-11 F2.0 Latitude, in degrees 12-15 F4.2 Latitude, in minutes to 0.01 minute 17-19 F3.0 Longitude, in degrees 20-23 F4.2 Longitude, in minutes to 0.01 minute 24-29 F6.1 Elevation, in ft to 0.1 ft 30-36 F7.2 Observed gravity, in mGal to 0.01 mGal, without leading 9 37-40 A4 Four character accuracy code 41-46 F6.2 Free-air anomaly, in mGal to 0.01 mGal 47-52 F6.2 Simple Bouguer anomaly, in mGal to 0.01 mGal 53-57 F5.2 Inner-zone terrain correction, in mGal to 0.01 mGal 58-62 F5.2 Total terrain correction, in mGal to 0.01 mGal 63 A1 Terrain correction code denoting extent of inner-zone terrain correction and system, upper case denotes Hayford-Bowie system of zones, lower case denotes Hammer system of zones. Z, computer calculated from 0.0-0.59 km 64-69 F6.2 Complete Bouguer anomaly reduced for a density of 2.67 g/cc, in mGal to 0.01 mGal 70-75 F6.2 Isostatic gravity anomaly reduced for a density of 2.67 g/cc, in mGal to 0.01 mGal ______________________________________________________________________ Table 3. Explanation of 4-digit accuracy code [alt, altimetry; blk, black; brn, brown; elev., elevation; NGS, National Geodetic Survey; NMD, National Mapping Division; PG, photogrammetry; USGS, U.S. Geological Survey; VABM, vertical angle bench mark] ____________________________________________________________________ General elevation and location code--First digit Code Explanation Code Explanation ____________________________________________________________________ A Altimetry, good control P On or near surveyed mark B On USGS or NGS level-line bench mark Q River gradient interpolation C Contour line interpolation R Lake elev. by leveling D Destroyed or not found reference mark S Sea level elev. E Near non-USGS level-line bench mark T Photogrammetry by USGS NMD F Map elev., blk or field checked U Unknown elev. source G Map elev., brn or not field checked V On vertical angle bench mark H Near vertical angle bench mark W Map elev., blue I Other special source X On or near boundary marker K Photogrammetry by other than USGS NMD Y Altimetry, poor control N Near USGS or NGS level-line bench mark Z Special source M On non-USGS level-line bench mark ____________________________________________________________________ Approximate Elevation gravity Elevation code--Second digit accuracy effect (ft) (mGal) ____________________________________________________________________ 1 On bench mark 0.2 0.01 2 Near bench mark 0.3 0.02 3 Transit or good alidade survey 1.0 0.06 4 VABM or black map elev. 2.0 0.12 5 Blk elev. on old map or good PG 4.0 0.24 6 Brn elev. or good PG on 20-ft contour map 10 0.6 7 Brn elev. on 80-ft contour map or good alt 20 1.2 8 Contour interpolation on 80-ft contour map 40 2.4 9 Contour interp. on 200-ft contour map, poor alt 80 4.8 ____________________________________________________________________ Approx. Latitude code--Third digit Latitude Distance gravity (based at lat 37) accuracy accuracy effect (min) (ft) (mGal) ____________________________________________________________________ 1 Triangulation or special survey data 0.007 42 0.01 2 Location known to 0.04 in on 1:24,000 map 0.014 84 0.02 3 0.10 in, 1:24,000 or 0.04 in, 1:62,500 map 0.035 210 0.05 4 0.21 in, 1:24,000 or 0.08 in, 1:62,500 map 0.07 420 0.1 5 0.42 in, 1:24,000 or 0.16 in, 1:62,500 map 0.14 840 0.2 6 0.40 in, 1:62,500 or 0.1 in, 1:250,000 map 0.35 2,100 0.5 7 0.80 in, 1:62,500 or 0.2 in, 1:250,000 map 0.7 4,200 1.0 8 1.60 in, 1:62,500 or 0.4 in, 1:250,000 map 1.4 8,400 2.0 9 4.00 in, 1:62,500 or 1.0 in, 1:250,000 map 3.5 21,000 5.0 ____________________________________________________________________ Approximate Observed gravity code--Fourth digit gravity effect (mGal) ____________________________________________________________________ 1 Local survey with special gravity meter 0.01 2 Multiple observations with LaCoste and Romberg meter 0.02 3 Average LaCoste and Romberg or multiple Worden meter 0.05 4 LaCoste and Romberg observation with small vibrations or average Worden meter 0.1 5 Data from loop with closure error this large 0.2 6 Data from loop with closure error this large 0.5 7 Data from loop with closure error this large 1 8 Data from loop with closure error this large 2 9 Data from loop with closure error this large 4 ____________________________________________________________________ SELECTED REFERENCES Bol, A.J., Snyder, D.B., Healey, D.L., and Saltus, R.W., 1983, Principal facts, accuracies, sources, and base station descriptions for 3672 gravity stations in the Lund and Tonopah 1 X 2 degree quadrangles, Nevada: available from National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22152, PB83-202-671, 86 p. Bracken, R.E., and Kane, M.F., 1983, Principal facts for gravity stations in the Nevada portion of the Kingman 1 X 2 degree quadrangle: available from National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22152, PB84-103-084. Chapman. R.H., 1979, Principal facts and accuracies for 857 gravity stations on the Death Valley 1 X 2 degree quadrangle, California and Nevada: California Division of Mines and Geology Open-File Report 77-9, 42 p. Erwin, J.W., 1982, Principal facts for a set of regional gravity data for the Wells 1 X 2 degree sheet, Nevada: Nevada Bureau of Mines and Geology Open-File Report 82-2. Erwin, J.W., 1982, Principal facts for a set of regional gravity data for the Millett 1 X 2 degree sheet, Nevada: Nevada Bureau of Mines and Geology Open-File Report 82-3. Godson, R.H., and Plouff, Donald, 1988, BOUGUER version 1.0, a microcomputer gravity-terrain-correction program: U.S. Geological Survey Open-File Report 88-644-A, Documentation, 22 p.; 88-644-B, Tables, 61 p.; 88-644-C, 5 1/4-inch diskette. Hammer, Sigmund, 1939, Terrain corrections for gravimeter stations: Geophysics, v. 4, p.184-194. Harris, R.N., Ponce, D.A., Healey, D.L., and Oliver, H.W., 1989, Principal facts for about 16,000 gravity stations in the Nevada Test Site and vicinity: U.S. Geological Survey Open-File Report 89-682-A, Principal facts documentation, 78 p.; 89-682-B, Gravity data listing on paper, 286 p.; and 89-682-C, Gravity data on diskette, 2 3.5-in diskettes. Healey, D.L., 1970, Gravity surveys in the California portion of the Kingman quadrangle: U.S. Geological Survey Open-File Report 70-158, 20 p. Healey, D.L., Wahl, R.R., and Currey, F.E., 1981, Principal facts, accuracies, sources, and base station descriptions for gravity stations in the Nevada part of the Goldfield and Mariposa 1 x 2 degree sheets: U.S. Geological Survey Open-File Report USGS-474-311, 12 p. Heiskanen, W.A., and Moritz, H., Physical Geodesy: New York, W.H. Freeman, 364 p. International Association of Geodesy, 1971, Geodetic Reference System 1967: International Association of Geodesy Special Publication no. 3, 116 p. Jablonski, H. M., 1974, World relative gravity reference network North America, Parts 1 and 2: U.S. Defense Mapping Agency Aerospace Center Reference Publication no. 25, originally published 1970, revised 1974, with supplement of IGSN 71 gravity datum values, 1261 p. Jachens, R.C., and Roberts, C.W., 1981, Documentation of a FORTRAN program, 'isocomp', for computing isostatic residual gravity: U.S. Geological Open-File Report 81-574, 26 p. Morelli, Carlo (Ed.), 1974, The International Gravity Standardization Net, 1971: International Association of Geodesy Special Publication no. 4, 194 p. National Geophysical Data Center, 1988, U.S. Department of Defense gravity files: available from National Geophysical Data Center, National Oceanic and Atmospheric Administration, Mail Code E/Gcx2, 325 Broadway, Boulder, CO 80303. Plouff, Donald, 1982, Gravity observations in the Walker Lake 1 X 2 degree quadrangle, California-Nevada: U.S. Geological survey Open-File Report 82-405, 105 p. Plouff, Donald, 1990, Principal facts for gravity data compiled for the Conterminous United States Mineral Appraisal Program, Tonopah 1- by 2- degree quadrangle: U.S. Geological Survey Open-File Report 90-457-A, text, 22 p.; 90-457-B, tables, 61 p.; 90-457-C, 3.5-in diskette. Plouff, Donald, 1994, Principal facts and field data for gravity data in and adjacent to the Reno 1 X 2 degree quadrangle, Nevada and California: U.S. Geological Survey Open-File Report 94-006-A, text, 16 p.; 94-006-B, 3.5-in diskette. Plouff, Donald, 1996, Principal facts and field observations for gravity data in and adjacent to the Bureau of Land Management's Winnemucca District and Surprise Resource Area, northwest Nevada and northeast California: U.S. Geological Survey Open-File Report 96-290-A, text, 26 p.; 96-290-B, 3.5-in diskette. Ponce, D.A., 1992, Principal facts for about 2,800 gravity stations on the Ely 1 x 2 degree quadrangle, Nevada and Utah: U.S. Geological Survey Open-File Report 92-431, 43 p., diskette. Ponce, D.A., 1996, Bouguer gravity map of Nevada, Elko sheet: Nevada Bureau of Mines and Geology Map 107, scale 1:250,000. Reidy, D., Kane, M.F., Healey, D.L., Peterson, D.L., and Kaufmann, H.E., 1978, Principal facts for a set regional gravity data for the Las Vegas 10 by 20 sheet, Nevada: U.S. Geological Survey Open-File Report 78-1012, 36 p. Robbins, S.L., Oliver, H.W., and Huber, D.F., 1975, Principal facts, accuracies, sources, base station descriptions, and plots for 1931 gravity stations on the Mariposa and part of the Goldfield 10 by 20 quadrangles, California and Nevada: available from National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22152, PB-241-469, 79 p. Saltus, R.W., 1988, Gravity data for the State of Nevada on magnetic tape: U.S. Geological Survey Open-File Report 88-433, 20 p.; 9-track magnetic tape available from User Services Unit, EROS Data Center, Sioux Falls, South Dakota 57198. Sikora, R.F., 1991, Principal facts for 133 gravity stations, with color maps of Bouguer and isostatic residual gravity anomalies on the Winnemucca 1 X 2 degree quadrangle, Nevada: U.S. Geological Survey Open- File Report 91-256-A, documentation, 40 p., 91-256-B diskette. Simpson, R.W., Jachens, R.C., and Blakely, R.J., 1986, A new isostatic residual gravity map of the conterminous United States with a discussion on the significance of isostatic residual gravity anomalies: Journal of Geophysical Research, v. 91, no. B8, p. 8,348-8,372. Snyder, D.B., Tang, R.W., Oliver, H.W., and Morin, R.L., 1982, Principal facts, accuracies, sources, base station descriptions and plots for 2,255 new and revised gravity stations in the western half of the Caliente 1 X 2 degree quadrangle, Nevada and Utah: available from National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22152, PB81-179-780, 101 p. Swick, C.A., 1942, Pendulum gravity measurements and isostatic reductions: U.S. Coast and Geodetic Survey Special Publication 232, 82 p. APPENDIX--LIST OF SOURCES FOR DATA FROM THE NATIONAL GEOPHYSICAL DATA CENTER A list of gravity sources from data obtained from the National Geophysical Data Center for Nevada and adjacent parts of California, Utah, and Arizona is shown below. Their data and source list are available from the National Geophysical Data Center, National Oceanic and Atmospheric Administration, Mail Code E/GCX2, 325 Broadway, Boulder, Colorado 80303, USA. These data are from the Department of Defense- Defense Mapping Agency gravity files and their source codes are contained in the first four digits of the gravity station name (table 2). 432 R. M. PERRY PRINCIPAL FACTS OF GRAVITY STATIONS, EDWARDS AIR FORCE BASE AREA AIR FORCE GEOPHYSICS LABORATORY (AFGL) Survey Year 1960 483 G. A. THOMPSON GRAVITY MEASUREMENTS BETWEEN HAZEL AND AUSTIN, NEVADA, A STUDY OF BASIN-RANGE STRUCTURE STANFORD UNIVERSITY Survey Year 1954 764 W. E. BONINI IDAHO, WYOMING, MONTANA, WASHINGTON AND OREGON GRAVITY ANOMALIES IDAHO BUREAU OF MINES AND GEOLOGY Survey Year 1959 933 GRAVITY OBSERVATIONS IN CLARK COUNTY, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1959 1083 NATIONAL GRAVIMETER BASE NETWORK NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA) Date Unknown 2078 G. P. WOOLLARD TRIP SS, ROCKIES UNKNOWN Date Unknown 2113 GRAVITY SURVEY, EDWARDS AIR FORCE BASE AREA AIR FORCE GEOPHYSICS LABORATORY (AFGL) Survey Year 1963 2149 CRUSTAL STUDIES, LINE SEVEN, EUREKA - FALLON NEVADA PROFILE U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1963 2179 GRAVITY REDUCTIONS, NEVADA BASIN AND RANGE PROJECT GROUP 1 - NEVADA U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 2207 GRAVITY DATA, OWENS VALLEY, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1957 2231 D. R. MABEY GRAVITY DATA IN DEATH VALLEY, CALIFORNIA PB-210 683 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1955 2235 GRAVITY DATA, CARSON SINK, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 2293 GRAVITY DATA IN SIERRA NEVADA, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1961 2381 GRAVITY DATA, CHANNEL ISLANDS, CALIFORNIA AND OTHER U.S. DATA NAVOCEANO DMAH/TC Survey Year 1963 2388 GRAVITY DATA, INDIAN WELLS REGION, CALIFORNIA NAVOCEANO Survey Year 1963 2493 NEVADA TEST SITE GRAVITY SURVEY, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1963 2515 R. G. BATES GRAVITY OBSERVATIONS IN PAHRUMP, MESQUITE AND IVANPAH VALLEYS, CALIFORNIA AND NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1965 2516 D. R. MABEY PRINCIPAL FACTS OF GRAVITY STATIONS IN THE WESTERN MOJAVE DESERT, CALIFORNIA PB-206 674 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1954 2531 OREGON STATE GRAVITY DATA OREGON STATE UNIVERSITY Survey Year 1965 2649 J. I. GIMLETT THE GRAVIMETRIC METHOD APPLIED TO BASIN EXPLORATION, EXEMPLIFIED BY A STUDY OF WARM SPRINGS VALLEY, WASHOE COUNTY, NEVADA STANFORD UNIVERSITY Survey Year 1965 2660 GRAVITY DATA IN EUREKA VALLEY, CALIFORNIA AND GOLDFIELD, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1965 2665 R. H. CHAPMAN CALIFORNIA GRAVITY BASE STATION NETWORK CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1965 2695 GRAVITY DATA, NORTHERN NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1958 2696 GRAVITY DATA, BULL RUN, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1958 2702 GRAND CANYON GRAVITY SURVEY, ARIZONA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1965 2713 T. R. LAFEHR GRAVITY SURVEY IN SOUTHERN CASCADE RANGE, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1965 2716 R. C. FAREWELL GRAVITY DATA IN MADERA COUNTY, CALIFORNIA PART XXXI-REVISED U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1961 2733 NATIONAL GRAVITY BASE NET AND EXCENTERS DMAHTC/GSS Survey Year 1967 2773 GRAVITY DATA IN ALTURAS, CALIFORNIA AREA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1967 2774 GRAVITY DATA IN FRESNO, CALIFORNIA AREA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1966 2777 GRAVITY DATA IN MARIPOSA, CALIFORNIA AREA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1966 2853 GRAVITY DATA FOR THE KINGMAN AND TRONA MAP SHEETS, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1960 3046 J. W. ERWIN GRAVITY DATA FOR THE BATTLE MOUNTAIN AREA, NEVADA UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1967 3047 J. W. ERWIN GRAVITY DATA FOR THE TONAPAH AREA, NEVADA UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1967 3048 J. W. ERWIN GRAVITY DATA FOR THE YERINGTON AREA, NEVADA UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1967 3113 PRINCIPAL FACTS FOR GRAVITY STATIONS, BAKERSFIELD, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) DMAH/TC Survey Year 1968 3136 S. L. ROBBINS GRAVITY DATA IN CALIFORNIA, FRESNO AMS SHEET U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1970 3182 W. F. HANNA GRAVITY DATA IN BAKERSFIELD AMS SHEET, PART XII, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1969 3236 S. L. ROBBINS GRAVITY DATA FOR THE MARIPOSA AMS SHEET, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1969 3238 S. L. ROBBINS GRAVITY DATA IN THE MARIPOSA, SACRAMENTA AND WALKER LAKE AMS SHEETS, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1969 3260 W. L. RAMBO GRAVITY DATA IN CHICO RENO, SACRAMENTO AND WALKER LAKE AMS SHEETS, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1969 3277 ARIZONA REGIONAL GRAVITY SURVEY AND BASE NETWORK DMAH/TC Survey Year 1969 3358 J. R. MONTGOMERY GRAVITY DATA IN UTAH UNIVERSITY OF UTAH Survey Year 1970 3373 S. L. ROBBINS GRAVITY DATA IN WALKER LAKE AMS SHEET, PART 23, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1970 3377 H. W. OLIVER PRINCIPAL FACTS AND PLOTS FOR GRAVITY STATIONS IN SOUTHERN SIERRA NEVADA AND VICINITY, CALIFORNIA PB-231 185/AS U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1970 3379 ARIZONA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1970 3382 CALIFORNIA GRAVITY FOR ALTURAS AMS SHEET CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1970 3383 GRAVITY DATA FOR DEATH VALLEY AMS SHEET IN CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1970 3385 GRAVITY DATA FOR TRONA AMS SHEET IN CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1970 3391 S. L. ROBBINS GRAVITY DATA IN CHICO, SACRAMENTO AND SUSANVILLE AMS SHEETS, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1970 3450 ARIZONA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1971 3463 ARIZONA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1971 3502 PEMBERTON TRIP AD, SERIES PI, 938 UNIVERSITY OF WISCONSIN Survey Year 1954 3503 G. P. WOOLLARD TRIP AE, SERIES B PRINCETON UNIVERSITY Survey Year 1939 3507 J. MACK R. M. IVERSON TRIP AI, SERIES M UNIVERSITY OF WISCONSIN Survey Year 1955 3516 F. PRESS TRIP AS, SERIES FP UNIVERSITY OF WISCONSIN Date Unknown 3575 J. C. ROSE TRIP TT, SERIES F UNIVERSITY OF WISCONSIN Survey Year 1949 3578 W. E. BLACK TRIP TW, SERIES F UNIVERSITY OF WISCONSIN Survey Year 1950 3598 N. A. OSTENSO TRIP ZZ, SERIES NI UNIVERSITY OF WISCONSIN Survey Year 1953 3667 S. L. ROBBINS GRAVITY DATA IN SUSANVILLE AMS SHEET, PART 30, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1971 3682 OREGON STATE GRAVITY BASE NETWORK DMAH/TC Survey Year 1971 3683 ARIZONA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1971 3754 M. F. KANE J. E. CARLSON GRAVITY OBSERVATIONS AND BOUGUER VALUES FOR CLARK COUNTY, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1971 3816 NEVADA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1972 3817 NEVADA GRAVITY BASE SURVEY DMAH/TC Survey Year 1972 3871 OREGON STATE REGIONAL GRAVITY ANOMALY SURVEY REPORT NUMBER 56D DMAH/TC Date Unknown 3872 NEVADA REGIONAL GRAVITY SURVEY 79-B DMAH/TC Survey Year 1972 3891 GRAVITY DATA, WINNEMUCCA SHEET UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1972 3915 NEVADA REGIONAL GRAVITY SURVEY DMAH/TC Survey Year 1973 3973 IDAHO REGIONAL SURVEY 94-B DMAH/TC Survey Year 1973 4078 R. H. CHAPMAN C. BISHOP SOURCE DATA FOR BOUGUER ANOMALY MAP OF CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1964 4099 GRAVITY DATA IN THE UNITED STATES, NORTH - SOUTH PROFILES DMAH/TC HAWAII INSTITUTE OF GEOPHYSICS (HIG) Survey Year 1967 4548 A. H. COGBILL GRAVITY DATA IN MINERAL COUNTY, NEVADA NORTHWESTERN UNIVERSITY Survey Year 1974 4603 S. L. ROBBINS AND OTHERS GRAVITY DATA ON THE MARIPOSA AND GOLDFIELD QUADRANGLES CALIFORNIA AND NEVADA PB-241 469/AS U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1975 4604 S. L. ROBBINS GRAVITY FOR THE FRESNO QUADRANGLE, CALIFORNIA PB-241 577/AS U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1975 4673 AMS RIDGECREST QUADRANGLE, CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Survey Year 1975 4674 AMS COSO PEAK, MATURANGO PEAK, AND HAIWEE RESERVOIR QUADRANGLES CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4675 AMS LAMONT, ONYX, CROSS MOUNTAIN, AND HAIWEE RESERVOIR QUADRANGLES IN CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4676 AMS LITTLE LAKE QUADRANGLE, CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4677 AMS INYOKERN QUADRANGLE, CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4678 AMS SEARLES LAKE, TRONA, SALTDALE, RANDSBURG, AND MOUNT SPRINGS CANYON QUADRANGLES, CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4735 R. H. CHAPMAN GRAVITY DATA, ALTURAS AREA OF CALIFORNIA (TERRAIN CORRECTED) CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 4756 W. F. HANNA R. SIKORA GRAVITY DATA IN THE BAKERSFIELD 1 X 2 DEGREE QUADRANGLE CALIFORNIA PB-238 122/AS U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1973 4771 S. L. ROBBINS AND OTHERS PRINCIPAL FACTS FOR GRAVITY STATIONS ON THE MARIPOSA AND PART OF THE GOLDFIELD 1 X 2 DEGREE QUADRANGLES CALIFORNIA AND NEVADA PB-241 469/AS U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1974 4781 PRINCIPAL FACTS FOR GRAVITY STATIONS ON THE WALKER LAKE 1 X 2 DEGREE QUADRANGLE, CALIFORNIA AND NEVADA PB-251 249/AS U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 4787 PRINCIPAL GRAVITY FACTS FOR CHARLES SHELDON ANTELOPE RANGE NEVADA AND OREGON OPEN-FILE REPORT 76-0601 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4788 PRINCIPAL GRAVITY FACTS FOR MCDERMITT, NEVADA OPEN-FILE REPORT 77-0536 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4832 D. L. PETERSON PRINCIPAL FACTS FOR GRAVITY STATIONS IN STEAMBOAT HILLS AND WABUSKA, NEVADA OPEN-FILE REPORT 75-0443 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1975 4834 D. L. PETERSON D. A. DANSEREAU PRINCIPAL FACTS FOR GRAVITY STATIONS IN GERLACH AND SAN EMIDIO KNOWN GEOTHERMAL RESOURCES AREAS (KGRA), NEVADA OPEN-FILE REPORT 75-0668 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4835 D. L. HEALEY PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE WESTERN PART OF THE GOLDFIELD 2 DEGREE SHEET, NEVADA OPEN-FILE REPORT 76-0057 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4836 D. L. HEALEY PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE NEVADA PORTION OF THE MARIPOSA 2 DEGREE SHEET OPEN-FILE REPORT 76-0058 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4837 D. L. HEALEY PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE WESTERN PART OF THE TONOPAH 2 DEGREE SHEET, NEVADA OPEN-FILE REPORT 76-0059 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4838 D. L. HEALEY PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE NEVADA PORTION OF THE WALKER LAKE 2 DEGREE SHEET OPEN-FILE REPORT 76-0060 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4839 D. L. PETERSON D. A. DANSEREAU PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE ELKO HOT SPRINGS KNOWN GEOTHERMAL RESOURCE AREA (KGRA), NEVADA OPEN-FILE REPORT 76-0151 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4852 GRAVITY DATA, DRY LAKE, NEVADA DMAHTC/GSS Date Unknown 4869 D. L. PETERSON D. B. HOOVER PRINCIPAL FACTS FOR A GRAVITY SURVEY OF BALTAZOR KNOWN GEOTHERMAL RESOURCE AREA, NEVADA, OPEN-FILE REPORT 77-0067-C U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4877 RALSTON VALLEY GRAVITY DATA DMAHTC/GSS Date Unknown 4932 C. W. WILSON D. L. PETERSON PRINCIPAL FACTS FOR GRAVITY STATIONS IN CLAYTON VALLEY, NEVADA OPEN-FILE REPORT 77-0256 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 4933 D. L. PETERSON J. H. HASSEMER PRINCIPAL FACTS FOR A GRAVITY SURVEY OF PINTO HOT SPRINGS KNOWN GEOTHERMAL RESOURCE AREA, NEVADA, OPEN-FILE REPORT 77-0067-B U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 4935 D. L. PETERSON H. E. KAUFMANN PRINCIPAL FACTS FOR A GRAVITY SURVEY OF SALT WELLS BASIN, CHURCHILL COUNTY, NEVADA, OPEN-FILE REPORT 77-0067-D U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 4936 D. L. HEALEY F. E. CURREY PRINCIPAL FACTS FOR GRAVITY STATIONS IN CENTRAL NEVADA, NYE, ESMERALDA, LANDER, EUREKA AND WHITE PINE COUNTIES, NEVADA OPEN-FILE REPORT 77-0510 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 4943 GRAVITY DATA - SACRAMENTO, CALIFORNIA DMAHTC/GSS Survey Year 1978 4944 GRAVITY DATA - MOHAVE, CALIFORNIA DMAHTC/GSS Survey Year 1978 4960 S. L. ROBBINS H. W. OLIVER R. F. SIKORA W. L. RAMBO C. W. ROBERTS PRINCIPAL FACTS FOR GRAVITY IN THE CHICO QUADRANGLE CALIFORNIA PB-276 770 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 4965 W. F. ISHERWOOD D. PLOUFF PRINCIPAL FACTS FOR GRAVITY OBSERVATIONS IN THE COSO HOT SPRINGS AREA, CALIFORNIA, OPEN-FILE REPORT 78-0298 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 4999 A. H. COGBILL REGIONAL GRAVITY SURVEY OF WESTERN NEVADA NORTHWESTERN UNIVERSITY Survey Year 1976 5018 D. L. PETERSON H. E. KAUFMANN PRINCIPAL FACTS FOR A GRAVITY SURVEY OF THE DOUBLE HOT SPRINGS KNOWN GEOTHERMAL RESOURCE AREA, HUMBOLDT COUNTY, NEVADA OPEN-FILE REPORT 78-0107-A U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 5019 D. L. PETERSON H. E. KAUFMANN GRAVITY SURVEY OF GERLACH EXTENSION KNOWN GEOTHERMAL RESOURCE AREA, PERSHING COUNTY, NEVADA OPEN-FILE REPORT 78-0107-B U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 5020 D. L. PETERSON H. E. KAUFMANN PRINCIPAL FACTS FOR A GRAVITY SURVEY OF THE FLY RANCH EXTENSION KNOWN GEOTHERMAL RESOURCE AREA, PERSHING COUNTY, NEVADA OPEN-FILE REPORT 78-0107-C U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1977 5037 ARIZONA AND NEVADA GRAVITY DATA DMAHTC/GSS Survey Year 1979 5057 W. F. HANNA MT. PINOS GRAVITY CALIBRATION LOOP, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1968 5068 J. W. ERWIN MILLETT, NEVADA GRAVITY SURVEY UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1978 5069 J. W. ERWIN RENO, NEVADA GRAVITY SURVEY UNIVERSITY OF NEVADA, MACKAY SCHOOL OF MINES Survey Year 1978 5116 GRAVITY DATA, NEVADA DMAHTC/GSS Survey Year 1968 5130 GRAVITY DATA FOR NEVADA DMAHTC/GSS Survey Year 1969 5144 GRAVITY DATA FOR THE STATE OF NEVADA DMAHTC/GSS Survey Year 1971 5163 NEVADA REGIONAL GRAVITY SURVEY DMAHTC/GSS Survey Year 1972 5171 NEVADA REGIONAL GRAVITY SURVEY DMAHTC/GSS Survey Year 1972 5237 S. H. BIEHLER GRAVITY STATIONS IN SOUTHERN CALIFORNIA UNIVERSITY OF CALIFORNIA Date Unknown 5241 D. REIDY M. F. KANE D. L. HEALEY D. L. PETERSON H. E. KAUFMANN PRINCIPAL FACTS FOR A SET OF REGIONAL GRAVITY DATA FOR THE LAS VEGAS 1 X 2 DEGREE SHEET, NEVADA OPEN-FILE REPORT 78-1012 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1978 5258 C. E. CORRY GRAVITY DATA IN NEVADA * 2716 ETC. CLIMAX MOLYBDENUM Date Unknown 5271 GRAVITY DATA FOR GARDEN/COAL, HAMLIN, SNAKE EAST, WHITE RIVER AND WHIRLWIND VALLEYS, NEVADA DMAHTC/GSS Survey Year 1979 5280 CALIFORNIA LAND GRAVITY SURVEY 2626 NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA) Date Unknown 5503 R. A. CREWDSON GEOPHYSICAL STUDIES IN THE BLACK ROCK DESERT GEOTHERMAL PROSPECT, NEVADA COLORADO SCHOOL OF MINES Survey Year 1976 5651 R. T. GREEN K. L. COOK PRINCIPAL FACTS OF GRAVITY STATIONS FOR THE SOUTHWESTERN PART OF THE SOUTHERN UTAH GEOTHERMAL BELT, WASHINGTON COUNTY, UTAH UNIVERSITY OF UTAH U. S. DEPARTMENT OF ENERGY Survey Year 1980 5675 GRAVITY DATA IN NEVADA AND CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1980 5704 GRAVITY DATA IN THE VALLEYS OF UTAH AND NEVADA DMAHTC/GSS Survey Year 1980 5786 GRAVITY DATA IN THE VALLEYS OF UTAH AND NEVADA DMAHTC/GSS Survey Year 1980 5788 D. H. SCHAEFER D. K. MAURER PRINCIPAL FACTS FOR GRAVITY STATIONS IN LEMMON VALLEY, WASHOE COUNTY, NEVADA OPEN-FILE REPORT 80-0071 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1979 5829 REGIONAL GRAVITY DATA IN NEVADA DMAHTC/GSS Survey Year 1980 5840 D. SNYDER GRAVITY DATA IN THE TONOPAH, NEVADA 1 X 2 DEGREE QUADRANGLE U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1980 5845 GRAVITY SURVEY IN RAILROAD VALLEY, NEVADA DMAHTC/GSS Survey Year 1981 5869 D. H. SCHAEFER D. K. MAUER PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE WESTERN ARM OF THE BLACK ROCK DESERT, NEVADA OPEN-FILE REPORT 80-0577 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1979 5870 GRAVITY DATA IN THE KOBEN AND LITTLE SMOKEY VALLEYS, NEVADA DMAHTC/GSS Survey Year 1981 5871 GRAVITY DATA IN THE LITTLE SMOKEY AND ANTELOPE VALLEYS, NEVADA DMAHTC/GSS Survey Year 1981 5874 D. L. HEALEY R. R. WAHL F. E. CURREY COMPLETE BOUGUER GRAVITY MAP OF THE TONOPAH 1 X 2 DEGREE QUADRANGLE, NEVADA * 4936 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1980 5893 GRAVITY DATA IN THE NEVADA VALLEYS OF: STONE CABIN, LONG, BUTTE, PENOYER, COAL, GARDEN, AND REVEILLE DMAHTC/GSS Survey Year 1981 5907 GRAVITY DATA IN MONITOR VALLEY AND GRANTS RANGE VALLEY DMAHTC/GSS Survey Year 1981 5918 GRAVITY DATA IN THE SOUTHWESTERN UNITED STATES AND MEXICO UNIVERSITY OF ARIZONA Date Unknown 5962 D. H. SCHAFER BASIN AND RANGE GRAVITY DATA IN NEVADA U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 5966 D. B. SNYDER H. W. OLIVER PRELIMINARY RESULTS OF GRAVITY INVESTIGATIONS OF THE CALICO HILLS, NEVADA TEST SITE, NYE COUNTY, NEVADA OPEN-FILE REPORT 81-0101 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1979 6050 D. A. PONCE PRELIMINARY GRAVITY INVESTIGATIONS OF THE WAHMONIE SITE, NEVADA TEST SITE, NYE COUNTY, NEVADA OPEN-FILE REPORT 81-0522 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1981 6126 J. W. ERWIN GRAVITY DATA FOR THE WELLS ONE BY TWO DEGREE AREA IN NEVADA NEVADA BUREAU OF MINES AND GEOLOGY Survey Year 1979 6136 GRAVITY DATA IN MESQUITE VALLEY AND SURROUNDING AREAS, NEVADA MASSACHUSETTS INSTITUTE OF TECHNOLOGY (MIT) Date Unknown 6199 FINAL WSMC AREA GRAVITY DATA SET * 5948, 5949, 5952, 5953, 5957, 5961, 5987, 5994, 5997, 6017, 6034, 6045, 6046, 6058, 6097, 6133, 6138, 6145, 6150, 6168 DMAHTC/GSS Survey Year 1982 6206 HIG GRAVITY DATA COVERING THE UNITED STATES NATIONAL GEODETIC SURVEY HAWAII INSTITUTE OF GEOPHYSICS (HIG) Date Unknown 6235 FINAL WSMC AREA GRAVITY DATA SET, CALIFORNIA - CONTRACTOR DATA * 6190,6198 DMAHTC/GSS STRATA SEARCH, INCORPORATED Survey Year 1982 6266 GRAVITY DATA IN THE VICINITY OF LUND, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1982 6267 GRAVITY DATA IN THE VICINITY OF TONOPAH, CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1982 6405 P. E. JANSMA D. B. SNYDER D. A. PONCE PRINCIPAL FACTS OF GRAVITY STATIONS WITH GRAVITY AND MAGNETIC PROFILES FROM THE SOUTHWEST NEVADA TEST SITE, NYE COUNTY, NEVADA AS OF JANUARY, 1982 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1982 6410 D. B. SNYDER C. W. ROBERTS R. W. SALTUS R. F. SIKORA PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE STATE OF CALIFORNIA U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 6586 D. A. PONCE W. F. HANNA PRELIMINARY APPRAISAL OF GRAVITY AND MAGNETIC DATA AT SYNCLINE RIDGE, WESTERN YUCCA FLAT, NEVADA TEST SITE, NYE COUNTY, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1982 6590 A. J. BOL D. B. SNYDER D. L. HEALEY R. W. SALTUS PRINCIPAL FACTS, ACCURACIES, SOURCES, AND BASE STATION DESCRIPTIONS FOR 3672 GRAVITY STATIONS IN THE LUND AND TONOPAH 1 X 2 DEGREE QUADRANGLES, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1981 6614 D. PLOUFF GRAVITY OBSERVATIONS IN THE WALKER LAKE 1 X 2 DEGREE QUADRANGLE CALIFORNIA AND NEVADA OPEN-FILE REPORT 82-0405 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1982 6625 R. K. EDQUIST NEVADA, BALTAZOR HOT SPRINGS AND PAINTED HILLS U. S. DEPARTMENT OF ENERGY Survey Year 1981 6663 D. T. TREXLER B. A. KOENIG T. FLYNN J. L. BRUCE ASSESSMENT OF THE GEOTHERMAL RESOURCES OF CARSON-EAGLE VALLEYS AND BIG SMOKY VALLEY, NEVADA NEVADA BUREAU OF MINES AND GEOLOGY Survey Year 1980 6669 R. G. CHAPMAN GRAVITY DATA IN CALIFORNIA CALIFORNIA DIVISION OF MINES AND GEOLOGY (CDMG) Date Unknown 6711 C. L. CARLISLE THE SUBSURFACE STRUCTURE OF THE IVANPAH VALLEY, CALIFORNIA AS DETERMINED BY GEOPHYSICAL MEASUREMENTS UNIVERSITY OF CALIFORNIA, SANTA BARBARA Survey Year 1981 6756 D. A. PONCE S. B. KOHRN R. W. SALTUS J. B. SPIELMAN B. A. CHUCHEL PRELIMINARY PRINCIPAL FACTS FOR GRAVITY STATIONS ON THE ELY 1 X 2 DEGREE QUADRANGLE, NEVADA OPEN-FILE REPORT 84-0387 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1984 6759 D. H. SCHAEFER J. M. THOMAS B. G. DUFFRIN PRINCIPAL FACTS FOR GRAVITY STATIONS IN DIXIE, FAIRVIEW, AND STINGAREE VALLEYS, CHURCHILL AND PERSHING COUNTIES, NEVADA OPEN-FILE REPORT 84-0586 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1981 6948 C. K. MOSS G. A. ABRAMS PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE OSGOOD MOUNTAINS HUMBOLDT COUNTY, NEVADA OPEN-FILE REPORT 84-0835 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1984 6976 B. G. DUFFRIN D. L. BERGER D. H. SCHAEFER PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE HUMBOLDT HOUSE GEOTHERMAL AREA, PERSHING COUNTY, NEVADA OPEN-FILE REPORT 85-0162 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1981 7151 SOUTHERN CALIFORNIA GRAVITY SURVEY U. S. GEOLOGICAL SURVEY (USGS) Date Unknown 7239 A. M. KATZENSTIEN K. J. DANTI EVALUATION OF GEOTHERMAL POTENTIAL OF THE NAVAL AIR WEAPONS TRAINING COMPLEX, FALLON, NEVADA NAVAL WEAPONS CENTER Survey Year 1980 7358 A. WAGINI PRINCIPAL FACTS, ACCURACIES, AND SOURCES FOR 1951 GRAVITY STATIONS ON THE WINNEMUCCA 1 X 2 DEGREE QUADRANGLE, NEVADA U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1985 7567 D. H. SCHAEFER B. G. DUFFRIN R. W. PLUME PRINCIPAL FACTS FOR GRAVITY STATIONS IN PARADISE AND STAGECOACH VALLEYS, HUMBOLDT AND LYON COUNTIES, NEVADA (PARADISE VALLEY DATA ONLY) OPEN-FILE REPORT 85-0694 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1983 7568 D. H. SCHAEFFER B. G. DUFFRIN R. W. PLUME PRINCIPAL FACTS FOR GRAVITY STATIONS IN PARADISE AND STAGECOACH VALLEYS, HUMBOLDT AND LYON COUNTIES, NEVADA (STAGECOACH VALLEY DATA ONLY) OPEN-FILE REPORT 85-0694 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1983 7632 R. W. SALTUS R. N. HARRIS PRINCIPAL FACTS FOR 125 GRAVITY STATIONS IN AND AROUND THE GOSHUTE MOUNTAINS-TOANO RANGE, ELKO COUNTY, NEVADA OPEN-FILE REPORT 86-0153 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1985 7633 R. L. MORIN PRINCIPAL FACTS FOR 106 GRAVITY STATIONS IN/AROUND RESTING SPRING, NOPAH AND KINSTON RANGES, CASTLE PEAK, CINDER CONES, AND FT. PIUTE BLM WILDERNESS STUDY AREAS,SE CALIFORNIA, OPEN-FILE REPORT 86-0260 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1985 7773 ARIZONA GRAVITY DATA BASE, LAND DATA IN ARIZONA, NEW MEXICO AND MEXICO UNIVERSITY OF ARIZONA Survey Year 1985 7838 J. M. GLEN J. S. LEWIS D. A. PONCE GRAVITY OBSERVATIONS ALONG A PASSCAL SEISMIC LINE IN WEST-CENTRAL NEVADA OPEN-FILE REPORT 87-0403 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1986 7863 R. N. HARRIS J. M. GLEN PRINCIPAL FACTS FOR 163 GRAVITY STATIONS IN THE CHERRY CREEK RANGE AND VICINITY, ELKO AND WHITE PINE COUNTIES, NEVADA OPEN-FILE REPORT 86-0559 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1986 7864 D. L. PETERSON C. W. WILSON PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE BRUNEAU-GRANDVIEW AREA OWYHEE AND ELMORE COUNTIES, IDAHO AND ELKO COUNTY, NEVADA OPEN-FILE REPORT 76-0233 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 7902 P. A. BECK GEOLOGIC AND GRAVITY STUDIES OF THE STRUCTURES OF THE NORTHERN BULLFROG HILLS, NYE COUNTY, NEVADA CALIFORNIA STATE UNIVERSITY Survey Year 1976 7942 R. R. WAHL D. L. PETERSON PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE CARSON SINK REGION NEVADA OPEN-FILE REPORT 76-0344 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1976 8206 D. A. PONCE H. W. OLIVER CHARLESTON PEAK GRAVITY CALIBRATION LOOP, NEVADA OPEN-FILE REPORT 81-0985 U. S. GEOLOGICAL SURVEY (USGS) Survey Year 1980 8391 J. W. BERG W. M. DOLAN GRAVITY DATA IN STANSBURY - WENDOVER AREA, UTAH UNIVERSITY OF UTAH Survey Year 1957 8395 GRAVITY DATA IN UTAH UNIVERSITY OF UTAH Survey Year 1987 21