FILETYPE= 7 CREATION DATE: 1-MAR-1990 11:08:20.10 UTAHGRAV.DOC DOCUMENTATION OF GRAVITY DATA FOR UTAH (a80) ASCII IN #/LINE 80 OUT #/LIN 80 IN/OUT 1 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 Principal Facts of Gravity Stations Used for Complete Bouguer Gravity Anomaly Map of Utah by Kenneth L. Cook Professor Emeritus Department of Geology and Geophysics, the University of Utah Viki Bankey U.S. Geological Survey Don R. Mabey Formerly Utah Geological and Mineral Survey Michael DePangher Formerly Department of Geology and Geophysics, the University of Utah Currently Consultant Data tape available from: EROS Data Center Data Services Officer Sioux Falls, South Dakota 57198 February 28, 1990 A cooperative project of the Utah Geological and Mineral Survey, the United States Geological Survey, and the Department of Geology and Geophysics, University of Utah. OUTLINE Abstract Background information Compilation of University of Utah data Merging and processing of data Preparation of map Editing of map Comparison of new map and data with old maps and data Acknowledgments References Description of magnetic tape Tape format Tape file header description APPENDICES Appendix A -- Key to designations of gravity stations used for the gravity map of Utah. FIGURES Figure 1 -- Columns and rows of USGS grids. ABSTRACT This report describes (1) the principal facts (observed gravity, elevation, latitude, longitude, terrain corrections, complete Bouguer anomaly, and free-air anomaly) of approximately 42,000 gravity stations and (2) these data interpolated to a 2.5-km square grid that were used to compile the complete Bouguer gravity anomaly map of the state of Utah (Cook and others, 1989). The project was a cooperative effort of (1) the Utah Geological and Mineral Survey (UGMS), (2) the United States Geological Survey (USGS), and (3) the Department of Geology and Geophysics, University of Utah. The gravity data were established by many individuals and organizations over a 30-year period. The 42,000 gravity stations comprise about 33,500 stations that were supplied by K.L. Cook from files of the University of Utah, and about 8,500 stations that were added by Viki Bankey from the files of the National Geophysical Data Center (of the National Oceanographic and Atmospheric Administration) and the USGS. The merging and processing of the data were done by Viki Bankey in the USGS Denver office. This report also describes in some detail the methods of compiling, processing, and reduction of the gravity data and also the editing of the preliminary worksheet copies of the gravity contour maps. These editing efforts were especially effective in eliminating as many "bad stations" as possible in the various data sets and thus providing a more accurate final set of data. Much of the gravity data is from the University of Utah files, and the sources of these data, especially from former students at the University and various petroleum companies, are acknowledged specifically herein. Also many different sources of financial support for the gravity research effort under the supervision of K.L. Cook at the University of Utah over a 30-year period are acknowledged specifically. The final data set was produced by Viki Bankey in the USGS Denver office. One file contains the principal facts of the gravity stations. A second file contains these data interpolated to a 2.5-km square grid. The 9-track magnetic tape containing the data was written at a density of 1600 bits per inch in ASCII format with a blocksize of 4000 bytes and a logical record size of 80 bytes. BACKGROUND INFORMATION The first published gravity map of Utah was prepared by K.L. Cook, J.R. Montgomery, J.T. Smith, and E.F. Gray and published by the Utah Geological and Mineral Survey (UGMS) in 1975 (Cook and others, 1975). This is a simple Bouguer gravity anomaly map at a scale of 1:1,000,000 based on approximately 27,000 gravity stations. In several areas of the state the data used to prepare this map were too sparse to adequately define the regional gravity anomalies, and the lack of terrain corrections limited the usefulness of the map in areas of high topographic relief. By 1981 digital terrain data that could be used to compute the terrain corrections necessary to prepare a complete Bouguer gravity anomaly map of Utah were available, and a geologic map of the state had been published at a 1:500,000 scale (Hintze, 1980). To produce a complete Bouguer gravity anomaly map of Utah at the scale of the geologic map a cooperative program between the University of Utah, the Utah Geological and Mineral Survey (UGMS), and the U.S. Geological Survey (USGS) was developed. K.L. Cook and D.R. Mabey, who was then with the USGS, developed preliminary plans for the map, and Donald T. McMillan, then Director of the UGMS, agreed that the UGMS would publish the map. General plans for the cooperative effort were agreed to in 1984 by Cook, Mabey, now representing the UGMS, and John DeNoyer and M. Dean Kleinkopf (USGS), and a cooperative agreement was signed in 1985 making the effort part of the Federal-State Cooperative Geologic Mapping (COGEOMAP) program. In addition, a memorandum of understanding between Cook and the UGMS was signed defining the responsibilities of K.L. Cook and the UGMS in compiling and publishing the gravity map. The objectives of the cooperative project were to compile and publish a complete Bouguer gravity anomaly map of Utah at a scale of 1:500,000 and make available to the public a digital data set of the principal facts of the gravity stations used to compile the map. This data set is to include the data from the University of Utah files that were not readily available to the public. The major responsibilities were: 1. Cook to provide gravity data from the University of Utah files in digital form. 2. The USGS to merge data from the University of Utah with other data available to the USGS and to terrain correct the data to produce a complete Bouguer gravity anomaly map. 3. Cook and Mabey to edit the gravity map and data set. 4. The USGS to revise the data set and map and prepare a "camera- ready" copy of the gravity part of the map and a digital data set on magnetic tape. 5. The UGMS to prepare the final version of the gravity map and publish it in the UGMS map series. 6. After the map was published, the USGS to release the magnetic tape containing the principal facts of the gravity data and provide copies of the tape to Cook, the UGMS, and the University of Utah. Viki Bankey became responsible for the USGS effort, and Michael DePangher assisted Cook in his effort. At the start of the compilation effort, the gravity data for Utah consisted of data from numerous surveys and compilations. These surveys and compilations involved a variety of data reduction and data storage procedures and often overlapped so that data from one station was duplicated in two or more compilations. Editing and merging the data was a complicated task. COMPILATION OF UNIVERSITY OF UTAH DATA Compilation work on the University of Utah gravity data was begun by Cook and students working under his supervision. Financial support for this work at the University of Utah was provided by grants-in-aid to the University of Utah from the organizations and individuals listed in the Acknowledgments. Also at this time Cook obtained written permission from the officials of various petroleum companies (also listed in the Acknowledgments) that had previously donated to him and/or the University of Utah gravity data in Utah (1) to use these data for the new gravity map of Utah and (2) to include the list of principal facts of these gravity stations with all the other stations used in making the gravity map, and to publish the list of principal facts of all of these stations after final publication of the map. A magnetic tape containing the principal facts of about 37,000 gravity stations in Utah compiled by K.L. Cook and John C. Groenewold was forwarded to the U.S. Geological Survey on September 24, 1985, for processing by the USGS. This list of stations comprised: 1) About 27,000 stations that were included on the simple Bouguer gravity anomaly map of the state of Utah (Cook and others, 1975). 2) About 10,000 additional new stations from various parts of Utah, obtained by the University of Utah. The 37,000 stations submitted to the USGS for processing had been assembled at the University of Utah over a 30-year period from many different separate data sets of gravity stations that had been established by many individuals and organizations. It was desirable to preserve, insofar as possible, the identity of each separate data set; and this was generally done by keeping the original station designations in the list of principal facts of the stations. It should be emphasized that each of the various data sets had been adjusted to the gravity base station network in Utah established in 1967 by the U. S. Army Map Service in a cooperative project with the Department of Geophysics, University of Utah (Cook and others, 1971). Before submitting the 37,000 stations to the USGS, and intermittently thereafter, the entire University of Utah data sets were carefully edited by K.L. Cook, Michael DePangher, and John C. Groenewold using the digital computer to compare the observed gravity values of the approximately 3,000 repeat stations within the University data sets. This study included (1) repeat stations within the same data sets for individual gravity surveys and (2) duplicate stations at the same location in different data sets for separate gravity surveys made at different times over a 30-year period. Using the digital computer, the principal facts of the gravity data for these repeat and duplicate stations were grouped together conveniently on computer printout listings for rapid comparison and analysis to detect errors and discrepancies between the various gravity surveys. Also, this information provided a measure of the accuracy of the gravity data for individual surveys and facilitated in making any necessary adjustments of the gravity data between different surveys. After adjustments of the gravity data between different surveys, a comparison of the observed gravity values of the repeat and duplicate stations showed that generally there was excellent consistency -- within 0.3 milliGal (i.e., within maximum tidal effect) --, which was gratifying. If the comparison showed a difference that exceeded 0.5 mGal, the bad station was generally discarded. However, in mountainous areas with difficulty of access and often poorer elevation control, stations with possible errors exceeding 0.5 mGal, and rarely exceeding 1.0 mGal, were retained. Accordingly, most of the stations are believed to be correct within 0.5 mGal in the valley areas and within 1.0 mGal in the mountainous areas. MERGING AND PROCESSING OF DATA The merging and processing of the gravity data were done by Viki Bankey in the USGS Denver Office. The 37,000 stations -- including the 3,000 repeat and duplicate stations -- provided by Cook were used as the basic data set and were supplemented by about 9,000 stations taken by Bankey from the files of the National Geophysical Data Center (of the National Oceanographic and Atmospheric Administration) and the USGS, collectively designated herein as "NOAA data". Thus, a total of about 46,000 stations (including repeat and duplicate stations) were used for the preliminary compilation for the entire state of Utah, for which the gravity data extended a distance of about 15 minutes of arc (approximately 25 km (15 miles)) beyond the Utah state border in all directions in order to reduce "edge effect" in the computer contouring. In merging the Cook and NOAA data sets, the Cook data set was given priority in the following manner: (1) To facilitate the gridding program (to be used later), only one gravity value was accepted by the computer for each station location, which was defined as lying within 0.15 minute of arc (about 250m (750 ft)) of the latitude and longitude of a given station. (2) Moreover, when accepting the principal facts of a station at a given station location, the computer would give priority to that station which appeared first in the listing, and reject the gravity values of all subsequent stations located within a radius of 0.15 minute of arc (about 250m (750 ft)) of the accepted station. (3) By this procedure, all repeat or duplicate stations from different data sets were rejected from the list that finally became the master list of principal facts of provisionally accepted stations to be used by Bankey for the preparation of the preliminary worksheet copies of machine-contoured gravity maps (see below). This procedure resulted as follows: in the Cook data listing of 37,000 stations, there were about 3,500 repeat and duplicate stations that were thus rejected; and similarly there were rejected about 500 repeat and duplicate stations of the 9,000 NOAA stations, so that the final gravity map comprises a total of about 33,500 Cook-data-set stations and about 8,500 NOAA-data-set stations, a total of about 42,000 stations. The observed gravity values for the 42,000 stations used to compile the map were first adjusted to conform to the International Gravity Standardization Net of 1971 (International Association of Geodesy, 1974) as follows: (1) By first accepting the observed gravity values of all 37,000 Cook stations (plus 9,000 NOAA stations), which had gravity data sets that were already adjusted to the gravity base station network in Utah established in 1967 (Cook and others, 1971). (2) And then adding algebraically the value of -13.74 milliGals to each of the accepted observed gravity values mentioned in item (1) above. Notes: (a) This change constitutes an adjustment incident to the "Potsdam datum correction" (Woollard, 1979, p. 1358-1364); but the datum correction value used by the USGS, now considered more reliable, is 1.0 mGal different from the value of 14.7 mGal proposed by Woollard. As a consequence, the numerical value of the observed gravity for any given station used for this map is 13.74 milliGals less than the previously published value of observed gravity given by Cook and others (1971) for the same station in the Utah gravity base station network. (b) The effect of this new datum correction and the new 1967 gravity formula (see below) is discussed in the section "Comparison of new map and data with old map and data". The adjusted observed gravity values were then reduced to the simple Bouguer gravity anomaly values using the 1967 gravity formula (International Association of Geodesy, 1971) at a reduction density of 2.67 g/cm3. Standard USGS reduction equations and related expansions are explained in Cordell and others (1982). Computer-calculated terrain corrections, assuming a rock density of 2.67 g/cm3, were made radially from each station to a distance of 167 km (100 miles) using the method of Plouff (1977). The two separate terrain-correction values--one for the inner zones and one for the outer zones--were added to give the total terrain-correction value for each station. The total terrain-correction value was then added algebraically to the simple Bouguer gravity anomaly value to give the complete Bouguer gravity anomaly value for each station. PREPARATION OF MAP The map was prepared on a Lambert Conformal Conic projection based on standard parallels 33 degrees and 45 degrees and with a central meridian longitude of 111.2500 degrees W and a base latitude of 36.7500 degrees N. The irregularly spaced complete Bouguer gravity anomaly values were gridded at a 2.5-km spacing using a computer program by Webring (1981) based on minimum curvature (Briggs, 1974). The gridded data were contoured at a 5-milliGal interval using a program by Godson and Webring (1982), with contour smoothing using splines under tension. Minor corrections to the computer contouring were made by hand. The contour map originally extended beyond the state boundary about 15 minutes of arc (about 25 km (15 miles)) in all directions to reduce "edge effect" in the computer contouring, and was trimmed by hand to ensure accuracy at the map edges. The inferred dashed contours (drawn by hand) in the two following areas are to be considered approximate only because the contours were taken (and adjusted) from former gravity maps of known high quality for which the principal facts of the gravity stations are no longer available: 1. Ogden Valley area -- contours were taken (and adjusted) largely from Stewart (1970). No principal facts were available. 2. Rozel Point area (at northeastern margin of Great Salt Lake) -- contours were taken (and adjusted) (1) partly from Cook and others (1966) and (2) partly from the 1951 gravity map of the area made available to K.L. Cook by the Utah Southern Oil Company, for which no principal facts were available. 3. In the area of Bear Lake, few gravity data were available and the computer-generated contours have been adjusted based on known geology; and the inferred contours are dashed. EDITING OF MAP The map was edited by K.L. Cook and D.R. Mabey with the assistance of M. DePangher. To facilitate editing of the map, preliminary worksheet copies of the machine-contoured gravity maps -- in the form of 1 degree x 2 degree quadrangle maps at a scale of 1:250,000 (and contour interval of 2 mGal and a grid-interval of 1.5 km) of the entire state of Utah -- were prepared by Viki Bankey. A total of 14 different quadrangle maps for Utah were thus prepared. The process of recognizing and eliminating the "bad stations" was accomplished by recognizing large, erroneous, "bulls-eye" one-station anomalies on the preliminary machine-contoured worksheet gravity maps and omitting them from the data sets. Also, in many areas, by consulting geologic and/or topographic maps, many bad stations were eliminated so that the gravity contours would conform better with the known geologic and/or topographic features -- as, for example, Basin and Range faults. Many of the eliminated stations were at unreasonable locations indicating errors in either the latitude or longitude. Note: The total number of bad stations rejected in the editing process were too few to alter materially the above-discussed statistics of the stations rejected because they were repeat or duplicate stations. Later, a second set of preliminary worksheet copies of similar maps at a scale of 1:250,000 and contour interval of 2 mGal and grid interval of 2.0 km were prepared and edited to detect and eliminate bad stations not previously recognized. Next, various versions of the complete Bouguer gravity anomaly map of the entire state at a scale of 1:500,000 and 5-mGal contour interval were prepared. The map with a 2.5-km grid interval is preferred, and was used as a worksheet map for editing the "final model copy". Finally, a camera-ready copy was prepared on scribecoat, under the supervision of Bankey, by the National Mapping Division of the USGS in Denver; and this copy was transmitted to the UGMS office in Salt Lake City for final preparation for publication (Cook and others, 1989). COMPARISON OF NEW MAP AND DATA WITH OLD MAPS AND DATA For those people and organizations using the new gravity map and data, and especially those who may wish to merge their own gravity data in Utah with the data included in the principal facts of gravity data listed on the new magnetic tape (see below), it will be helpful to discuss here a comparison between the new gravity map and data with the old gravity maps and data. To compare the new gravity map and data with old gravity maps and data, some of the basic principles of the reduction of gravity data need to be considered. In this discussion, "old gravity maps and data" will refer especially to the former maps of parts of Utah compiled by Cook and students and gravity data used for these former maps. For the old gravity maps and data, the reduction of the gravity data used (1) the theoretical gravity at mean sea level based on the 1930 International gravity formula and (2) a combined total elevation correction factor taken as +0.06 mGal/ft (which is the "rounded" value (from 0.05999 mGal/ft (0.19683 mGal/m)) that includes a free-air correction of 0.09406 mGal/ft (0.30861 mGal/m) and a Bouguer correction of -0.03407 mGal/ft (0.11178 mGal/m) for an assumed rock density of 2.67 g/cm3 and a universal constant of gravitation value of 0.6667 x 10-07 cgs units. For the new gravity map and data, the present USGS method of reduction of the gravity data, as explained in detail by Cordell and others (1982), uses: (1) the theoretical gravity at mean sea level based on the new 1967 gravity formula (as discussed earlier); (2) a separate computation for the free-air correction, which varies with latitude; (3) a separate computation for the Bouguer correction (-0.1119 mGal/m); and (4) in addition, a "Earth's curvature correction" term, which is a modification of the Bouguer slab approximation. The "datum correction" used by Bankey is -13.74 mGal. It should be noted that -- as pointed out by Woollard (1979, p. 1364-1365) -- the datum correction is the same sign as the difference in theoretical sea level gravity used in the old (1930) International gravity formula and the new (1967) gravity formula (used for the new gravity map), which varies from - 17.15 mGal at the equator to -3.58 mGal at the poles. However, in the conversion of Bouguer anomalies from the old to the new system, the datum correction is applied with regard to sign as a negative quantity and the latitude correction with sign reversed as a positive quantity. Accordingly it can be reasoned, by using Table 1 of Woollard (1979, p.1353), that for a gravity station at latitude 38 degrees (for example) and at sea level (where the free-air, Bouguer, and Earth's curvature corrections may be assumed zero), the Bouguer gravity anomaly value, using the new (1967) system and the datum correction of -13.74 mGal used by the USGS, is 1.74 mGal less algebraically than the corresponding Bouguer gravity anomaly value obtained in the old (1930) system. (This value is obtained by algebraically adding the value of -13.74 mGal (datum correction used by Bankey) and +12.00 mGal (taken from the "difference" column, for latitude 38 degrees, in Woollard's above-mentioned Table 1). Obviously, this value changes slightly with latitude (about 0.23 mGal per degree of latitude at 38 degrees latitude; see Table 1 of Woollard). By making an actual comparison between the complete Bouguer gravity anomaly values obtained from the new (1967) and old (1930) systems, one can demonstrate that the above analysis is correct for both the new gravity map of Utah and the new principal facts of gravity stations as contained in the listing on the magnetic tape. In particular, a comparison was made in selected areas and for selected stations in the region between latitude 38 degrees and 39 degrees on the complete Bouguer gravity anomaly map of the Richfield 1-degree x 2-degree quadrangle (Cook and others, 1981), and compared with the corresponding areas and stations on the new gravity map of Utah. The comparison shows that, at these latitudes, the complete Bouguer gravity anomaly values obtained from the new (1967) system are about 4 mGal less algebraically than the corresponding complete Bouguer gravity anomaly values obtained from the old (1930) system. The apparent discrepancy between (1) the approximately 4-mGal difference for actual stations in the Richfield quadrangle at latitudes of about 38 degrees and at elevations of 5,000 feet to 9,500 feet and (2) the 1.74-mGal difference for a station at sea level at latitude 38 degrees can be explained by the differences in the method of data reduction between the old (1930) system used by Cook and students and the new (1967) system used by the USGS. In particular, different formulas were used in the two systems for (1) free-air corrections and (2) Bouguer corrections; and the Earth's curvature correction term was used in the new (1967) system only. To summarize, it should be emphasized that the complete Bouguer gravity anomaly values on the new gravity map of Utah and listed in the principal facts of gravity stations in the magnetic tape (see below) -- which were obtained using the present USGS method of data reduction with the new (1967) system -- are algebraically less by several milliGals (the exact value depending on latitude and station elevation) than the complete Bouguer gravity anomaly values given for the corresponding stations on gravity maps and gravity data published and/or open filed by Cook and students using their above-discussed method of data reduction with the old (1930) system. Note: In making a comparison of maps, it should be noted that the new gravity map of Utah was computer-contoured using the gravity data interpolated to a 2.5-km square grid. Therefore the location of contour lines on this map may be slightly shifted from the more exact location of the corresponding contour lines on a map that had instead been contoured by hand using the exact complete Bouguer gravity anomaly values at the irregularly spaced stations. However, the difference between (1) the computer-generated contours and (2) contours that might otherwise be derived by hand-contouring the complete Bouguer gravity anomaly values of irregularly spaced stations is too small to change the above conclusion: namely, that the contoured Bouguer gravity anomaly values on the new map are algebraically less by several milliGals than the corresponding contoured-by-hand or computer- contoured Bouguer gravity anomaly values at the same station using the old (1930) system, as discussed above. Finally, in making a comparison of old and new gravity data and maps, the accuracy of the terrain corrections is very important. It should be emphasized that the terrain data and terrain-correction program used by the USGS in computing the complete Bouguer anomaly values for the new map differ from those used to prepare gravity maps in Utah before 1989. In areas of high local topographic relief the difference in terrain corrections and the complete Bouguer gravity anomaly values based on different sets of terrain data and different computation methods may be several milliGals. Terrain corrections computed for the new map are more accurate than those computed for most earlier maps. The new terrain corrections may be either larger or smaller but because they are likely to be more complete they will most commonly be larger than the earlier values. Increasing the terrain correction algebraically increases the complete Bouguer gravity anomaly value. Therefore, because this effect manifests itself in an opposite sense algebraically from that discussed above, comparisons of new and old gravity data in areas of very high local topographic relief should be made with caution. ACKNOWLEDGMENTS The following petroleum companies donated gravity data to K.L. Cook and/or the University of Utah and have given written permission (1) to use these data for the new gravity map of Utah and (2) to include the list of principal facts of these gravity stations with all the other stations used in making this map, and to eventually publish the list of principal facts of all these stations after final publication of the map: Amoco Production Company * Atlantic Richfield Company * Chevron Oil Company (now Chevron USA, Inc.) * Gulf Research and Development Company * Humble Oil and Refining Company (now Exxon, U.S.A.) * Utah Southern Oil Company (contour map). Since June 1984, the following organizations and individuals have provided one or more grants-in-aid to the University of Utah to support gravity research under the supervision of K.L. Cook that included the compilation, reduction, and editing of gravity data used for this map: Amoco Production Company * Cecil H. Green The Green Foundation Conoco Inc. * Chevron U.S.A., Inc. * Exxon, U.S.A. * Merrill S. Ginsburg * Mobil Oil Corporation * Phillips Petroleum Company * Tenneco Oil Exploration and Production Company * Union Oil Company of California * During the 30-year period prior to June 1984, financial support for the original measurements and compilations of the gravity data by the University of Utah was giving by many of the organizations and individuals previously listed (and indicated with an asterisk) and, in addition, the following: National Science Foundation; U.S. Geological Survey; Department of Energy (Division of Geothermal Energy); Utah Geological and Mineral Survey; American Smelting and Refining Company; Bear Creek Mining Company; Continental Oil Company; H.V.W. Donohoo; Kennecott Copper Corporation; Marathon Oil Company; Phelps Dodge Corporation; Shell Oil Corporation; Texaco Inc.; The Anaconda Company; and various entities of the University of Utah, namely the Computer Center, the Department of Geology and Geophysics, the Engineering Experiment Station, the Uniform School Fund, and the University Research Fund. The support was largely in the form of fellowships or grants-in-aid to students and/or faculty of the University of Utah. Beginning October 1, 1985, additional support for the UGMS and USGS was provided by including the compilation and publication of the new gravity map of Utah as one of the facets of the new Federal-State Cooperative Geologic Mapping (COGEOMAP) program between the state of Utah and the federal government (Oviatt and Davis, 1987; Mabey, 1987; Reinhardt and Miller, 1987). A listing of principal students involved in the gravity surveys, too numerous to acknowledge individually on the published map, is included on the magnetic tape of the principal facts of the gravity data (see Appendix A below). John C. Groenewold (during 1984-1985), former graduate student at the University of Utah, ably assisted K.L. Cook in the preliminary compilation, reduction, and editing of the University of Utah gravity data used for this gravity map. Encouragement for this project has been given especially by Donald T. McMillan and Genevieve Atwood, Directors of the UGMS; John Denoyer and M. Dean Kleinkopf, USGS; William P. Nash, Robert B. Smith, and Frank H. Brown, University of Utah. REFERENCES Bankey, Viki, 1985, Description of magnetic tape containing Idaho state gravity anomaly data: U.S. Geological Survey unpublished report; U.S. Dept. of Interior, EROS Data Center, 5p. Bankey, Viki, Webring, Michael, Mabey, D.R., Kleinkopf, M.D., and Bennett, Earl, 1985, A Bouguer gravity map of Idaho: U.S. Geological Survey MF- 1773, scale 1:500,00. Briggs, I. C., 1974, Machine contouring using minimum curvature: Geophysics, v. 39, no. 1, p. 39-48. Cook, K.L., Adhidjaja, J.I., and Gabbert, S.C., 1981, Complete Bouguer gravity anomaly and generalized geology map of Richfield 1-degree x 2- degree quadrangle, Utah: Utah Geological and Mineral Survey Map 59; scale 1:250,000; contour interval 2 mGal. Cook, K.L., Bankey, Viki, Mabey, D.R., and DePangher, Michael, 1989, Complete Bouguer gravity anomaly map of Utah: Utah Geological and Mineral Survey Map No. 122, scale 1:500,000, contour interval 5 milliGals. Cook, K. L., Berg, J. W., Jr., Johnson, W. W., and Novotny, R. T., 1966, Some Cenozoic structural basins in the Great Salt Lake area, Utah, indicated by regional gravity data: in Guidebook to the Geology of Utah, No. 20, Wm. Lee Stokes, Editor, Utah Geological Society, Salt Lake City, 1966, p. 57-75. Cook, K. L., Montgomery, J. R., Smith, J. T., and Gray, E. F., 1975, Simple Bouguer gravity anomaly map of Utah: Utah Geological and Mineral Survey Map 37, scale 1:1,000,000, contour interval 5 milliGals. Cook, K. L., Nilsen, T. H., and Lambert, J. F., 1971, Gravity base station network in Utah--1967: Utah Geological and Mineralogical Survey Bulletin 92, 57 p. Cordell, Lindrith, Keller, G. R., and Hildenbrand, T. G., 1982, Bouguer gravity map of the Rio Grande Rift, Colorado, New Mexico, and Texas: U. S. Geological Survey Geophysical Investigations Series, Map GP-949, scale 1:1,000,000. Defense Mapping Agency, 1974, World Relative Gravity Reference Network, North America, Part 2: St. Louis, Missouri, Aerospace Center, DMAAC Reference Publication 25, with supplement updating gravity values to the International Gravity Standardization Net 1971, 1635 p. Godson, R. H., and Webring, M. W., 1982, CONTOUR: A modification of G. I. Evendon's general purpose contouring program: U. S. Geological Survey Open-File Report 82-797, 73 p. Hintze, L.F., 1980, Geologic Map of Utah: Utah Geological and Mineral Survey; scale 1:500,000. International Association of Geodesy, 1971, Geodetic Reference System, 1967: International Association of Geodesy Special Publication No. 3, 116 p. International Association of Geodesy, 1974, The international Gravity Standardization Net 1971: International Association of Geodesy Special Publication No. 4, 194 p. Mabey, D. R., 1987, COGEOMAP--Update on geophysical maps: Utah Geological and Mineral Survey, Survey Notes, Summer/Fall 1987, p. 7. Oviatt, C. G., and Davis, F. D., 1987, COGEOMAP: Utah Geological and Mineral Survey, Survey Notes, Summer/Fall 1987, p. 2-7. Plouff, Donald, 1977, Preliminary documentation for a FORTRAN program to compute gravity terrain corrections based on topography digitized on a geographic grid: U. S. Geological Survey Open-File Report 77-535, 43 p. Reinhardt, Juergen, and Miller, D. M., 1987, COGEOMAP: A new era in cooperative geologic mapping: U. S. Geological Survey Circular 1003, 12 p. Stewart, S. W., 1958, Gravity survey of Ogden Valley in the Wasatch Mountains, north-central Utah: American Geophysical Union Transactions, v. 39, p. 1151-1157. Webring, M. W., 1981, MINC: A gridding program based on minimum curvature: U. S. Geological Survey Open-File Report 81-1224, 41 p. Woollard, G. P., 1979, The new gravity system--changes in international gravity base values and anomaly values: Geophysics, v. 44, no. 8, p. 1352-1366. DESCRIPTION OF MAGNETIC TAPE A magnetic tape containing the principal facts (observed gravity, elevation, latitude, longitude, terrain corrections, complete Bouguer anomaly, and free air anomaly) of the finally accepted 41,960 gravity stations, as well as the 2.5-km gridded data, used in making the gravity map of Utah was prepared by Viki Bankey. The number of gravity stations listed on this tape differs from the total number of gravity stations (approximately 46,000) stated in the "Discussion" on the published gravity map of Utah (Cook and others, 1989) because the latter figure included repeat and duplicate stations. The tape is available from EROS Data Center, Data Services Officer, Sioux Falls, South Dakota 57198. The listing of the principal facts of the gravity stations includes the sources of the original data which have been arranged to preserve, insofar as possible, the groupings of the individual gravity data sets of the various individuals and organizations that have made the field measurements. In particular, the various individuals and organizations may be identified by the letter or number designations of the individual gravity stations (see Appendix A), for which the original coding has been preserved when practical. It should be noted specifically that the principal students involved in the University of Utah gravity surveys, who were too numerous to acknowledge individually on the published map, are identified in the listing in Appendix A. The two following sections, which give the detailed descriptions of (1) the tape format and (2) the tape file header, are taken from an unpublished USGS report by Bankey (1985), which she prepared to describe the magnetic tape containing the gravity anomaly data used for the gravity map of Idaho (Bankey and others, 1985). Tape Format The 9-track magnetic tape was written at a density of 1600 BPI and contains files of data records in an unlabelled ASCII format. Block size is 4000 bytes and logical record size is 80 bytes. The first 10 lines of each file contains descriptive information about the files. Data records begin on line 11. Tape file header and data description The FORTRAN format identifier describing each record is given in brackets following the entry description. Line 1: type of file stored on tape (1=grid, 2-6=binary, 7-8=ASCII) [a9,i5] creation date [a66] Line 2: name of file written to tape [a80] Line 3: description of the file [a80] Line 4: FORTRAN format of data in record [a80] Line 5: "grid", "binary", or "ascii" [a6]; no. of characters produced by the FORTRAN format (binary or ascii) or number of values per line (grid) [a10,i5]; no. of words (32 bit, 4 byte) per disk file record (binary or grid) or no. of characters per record (ascii) [a10,i5]; tape records per file line [a10,i5] Line 6: For grid files only; grid identification [a56]; program that created grid [a8]; central meridian of grid [f8.3]; base latitude of grid [f8.3]. Line 7: For grid files only; no. of columns in grid [i5]; no. of rows in grid [i5]; no of values per grid position [i4]; projection (4=Lambert Conformal Conic) [i2]; position of first column in km (x0) [e16.8]; equal spacing interval of columns (dx) [e16.8]; position of first row in km (y0) [e16.8]; equal spacing interval of rows (dy) [e16.8]. Lines 8-10: Descriptive text Line 11: Gravity data record begins here. Following is the header record and first 10 data lines of file 1: FILETYPE= 2 CREATION DATE: 12-FEB-1990 10:38:54.47 UTAH88FIN.POS USGS GRAVITY DATA FILE (2a4,2f10.4,2f9.3,f10.3,2f7.2,f10.3) BINARY IN #/LINE 80 OUT #/LIN 10 IN/OUT 1 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 USGS TAPE FILE HEADER ...... DATA BEGINS AT RECORD #11 SW256 113.8257 41.0230 -4.950 -148.980 4200.000 0.21 0.30 -139.508 SW257 113.8067 41.0230 -2.940 -146.860 4200.000 0.24 0.38 -137.500 SW367 113.8430 40.9972 16.040 -133.740 4397.000 0.84 0.67 -139.352 SW150 113.6480 41.1708 -2.700 -147.420 4200.000 0.02 -0.20 -124.008 GSL3 112.2517 40.7615 -42.350 -185.640 4172.000 0.02 0.27 -197.688 bc001 109.1602 40.2900 -34.600 -214.560 5251.000 0.13 0.45 -333.492 bc002 109.1407 40.2867 -30.220 -211.550 5289.000 0.02 0.48 -332.977 bc003 109.1178 40.3113 -20.560 -208.880 5509.000 0.13 0.91 -341.797 bc004 109.1128 40.3290 -18.250 -212.540 5700.000 0.06 1.54 -355.859 bc005 109.0965 40.3413 -5.820 -214.360 6130.000 0.13 1.91 -382.748 Following is a description and FORTRAN format of each record for each of the 41,960 gravity stations of file 1: station ID A8 longitude (decimal degrees, west lon) F10.4 latitude (decimal degrees) F10.4 free-air anomaly in mGal F9.3 complete Bouguer anomaly (2.67 g/cm3) in Mgal F9.3 elevation (feet) F10.3 terrain correction (0-.895 km) in mGal F7.2 terrain correction (.895 - 166.7 km) in mGal F7.2 observed gravity (1971 datum) minus 980,000.000 mGal F10.3 Following is the header record and first 5 data lines of file 2: FILETYPE= 1 CREATION DATE: 12-FEB-1990 10:29:32.59 UTAH88FIN.GRD USGS STANDARD GRID FILE OF UTAH GRAVITY (5E16.8) GRID IN #/LINE 5 OUT #/LIN 197 IN/OUT 40 Complete Bouguer Gravity Anomaly Map of Utah min-curv -111.25 36.75 196 245 1 0 -0.26662039E+03 0.25000000E+01 0.00000000E+00 0.25000000E+01 THE TWO LINES ABOVE CONTAIN GRID SPECIFICATIONS. LINE 1: GRID ID (a56), CREATION PROGRAM (a8), C MERID, BASE LAT LINE 2: #COL, #ROW, #VAL, PROJ, X ORIG., DEL X, Y ORIG., DEL Y 0.00000000E+00 -0.14064244E+03 -0.14079659E+03 -0.14184879E+03 -0.14286613E+03 -0.14432541E+03 -0.14606606E+03 -0.14753131E+03 -0.14792339E+03 -0.14627486E+03 -0.14134193E+03 -0.13403368E+03 -0.12656284E+03 -0.12182195E+03 -0.12008015E+03 -0.12085061E+03 -0.12296484E+03 -0.12555009E+03 -0.12776535E+03 -0.12956944E+03 -0.13127844E+03 -0.13313017E+03 -0.13535600E+03 -0.13827325E+03 -0.14220195E+03 Following is a description and FORTRAN format of the data contained in the second file on the tape containing the gridded data. A row is defined as a series of data positions that extend from west to east along a common north coordinate. The first value in each row contains a "0", which indicates an evenly spaced grid. The first row is the southernmost (see fig. 1). Dvals (dummy values) are used to indicate areas of no data and have a value of 0.1000E+31. Line 1-10: Header record Line 11 Complete Bouguer values (mGal) 5E16.8 and after row 1, column 1-end row 2, column 1-end, etc. where line 11 contains the first 5 elements of row 1; line 12 contains the second 5 elements of row 1, and so on, until all elements in the grid are exhausted. NORTH columns---> ^ . . . . . ... (numbers=rows) W | . . . . . ... (letters=columns) E r 4a 4b 4c 4d 4e ... S o 3a 3b 3c 3d 3e ... T w 2a 2b 2c 2d 2e ... s 1a 1b 1c 1d 1e ... SOUTH Figure 1--Columns and rows of USGS grids Appendix A -- Key to Designations of Gravity Stations Used for the Gravity Map of Utah (Last updated on February 12, 1990) The original designations of the gravity stations used for the gravity map of Utah have been preserved in so far as possible, in order that the original sets of gravity data can be identified if desired. Generally each of the different gravity surveys has been coded by either (1) a letter designation or (2) a code-number designation. In the following lists, the letter or code-number designation is given, together with other pertinent information, when available, such as party chief or investigators, source of gravity data, date of survey, and area of survey. Letter Designations A Robert T. Novotny; 1957-58; Antelope Island area. AA Eckhard Kuennemann; 1978; northern Escalante Desert area. AJ Jopie I. Adhidjaja; 1979; Mount Dutton area. AM Amoco Production Company; pre-1972; northeastern Utah. B William W. Johnson; 1957-58; east central Tooele County. bc Bankey and Kulik, USGS OFR89-115, southwestern Wyoming, north- eastern Utah, and northwestern Colorado. BK Robert W. Case; 1976; Sevier Lake area, Millard County. BL Joseph W. Berg, Jr., and Loren H. Rausher; 1958; boat work on margin of Great Salt Lake. BW William M. Dolan and William W. Johnson; 1957; Brigham City, Utah, to Weston, Idaho, area. C Amoco Production Company; pre-1972; northeastern Utah. CA University of Utah Gravity Class; 1963; western Millard County. caser Joesting, Case, and Plouff, USGS, 1963, Moab/Needles area. cases Joesting, Case, and Plouff, USGS, 1963, La Sal Mountains. ccb Dick Blank, USGS, 1986, Cedar City ccs " " " " " " CK William G. Calkins; 1970; Desert Mountain area, central Juab County. CRF Randy Keller, University of Texas at El Paso, 1984, Brigham City. CV Robert C. Gray; 1965; Cache Valley. CVG University of Utah Gravity Class; 1964; northern Cache Valley. CW Howard S. Fishman; 1971; western half of Salina 1-degree x 2-degree quadrangle and easternmost Richfield 1-degree x 2-degree quadrangle. D William W. Johnson; 1957; Clive to Wildcat Mountain area. D William W. Johnson and Mark O. Halverson; 1959; Clive to Wildcat Mountain area. D___A Daniel L. Carrier; 1977-78; Black Rock Desert area. DC Daniel L. Carrier; 1977-78; Black Rock Desert area. DC__A Daniel L. Carrier; 1977-78; Black Rock Desert area. DD Deborah A. Davis; 1981; Goshen Valley area. DG University of Utah Gravity Class; 1964; western Millard County. DM Don R. Mabey; 1980; Jet Ranger helicopter stations in the Richfield 1-degree x 2-degree quadrangle. DS Donald C. Selk; 1975; Heber City area and Jericho area. DZ Donald A. Zimbeck; 1964-65; northeastern Utah. E Chevron Oil Company (now Chevron U.S.A. Inc.); pre-1972; northeastern and southeastern Utah. EH Elwood Hardman; 1963-64; Iron and Washington counties. F Richard C. Fox; 1979; Jordan Valley area. F1,F2 University of Utah Gravity Class; 1973; Fumerole Butte, Keg (McDowell) Mountains, and Desert Mountain in Juab and Millard counties. FB Timothy B. Smith; 1973; Fumerole Butte area. FX Richard C. Fox; 1979; Jordan Valley area. G Ralph C. Holmer; 1954; western Colorado. G Robert C. Gray; 1964; long east-west profiles in southern Utah from Cedar City to Blanding. G Robert P. Brown (U.S.A.F. Geodetic Survey Squadron); 1968; Gunnison area of the Sevier River Valley. GSL U. S. Government, Army Map Service; 1968; Great Salt Lake bottom gravity meter survey. GU Gulf Research and Development Company; pre-1972; northeastern and southeastern Utah. H William W. Johnson; 1958; Heber Valley area. HE University of Utah Gravity Class; 1963; west of Sevier Lake, Millard County. HF Howard S. Fishman; 1970-71; western half of Salina 1-degree x 2-degree quadrangle and easternmost Richfield 1-degree x 2-degree quadrangle. I64 University of Utah Gravity Class; 1964; northern Cache Valley. IB Itthachai Thangsuphanich; 1975; west of Minersville. IT Itthachai Thangsuphanich; 1975; southern part of Mineral Range, eastern Beaver County. IW University of Utah Gravity Class; 1964; west of Sevier Lake, Millard County. J J. Burlin Johnson; 1955-56; central Tooele and central Juab counties. JA Jopie I. Adhidjaja and Stephen C. Gabbert; 1979; eastern flank of the Cricket Mountains. JC James A. Carter; 1977; Mineral Mountains. JG John C. Groenewold and Kenneth L. Cook; 1979; Hansel and Pocatello valleys. JR Jerry R. Montgomery; 1970; central Utah, east and southeast of Utah Lake. JS James T. Smith; 1972; east-west profile in Sevier and Emery counties. K National Oceanographic and Atmospheric Administration (N.O.A.A.); northeastern and southeastern Utah. L Daniel Lum; 1956-57; northern Wasatch Front and eastern margin of Great Salt Lake. L University of Utah Gravity Class; 1958; northern Wasatch Front and eastern margin of Great Salt Lake. LU Donald C. Selk; 1974; Lund area. LY Laura F. Serpa; 1978; Black Rock Desert area. M Mark O. Halverson; 1959; northwestern Utah and south central Idaho. M Don L. Peterson (U.S. Geological Survey); Milford area. MB Myron G. Best; 1956; southwestern and northeastern margins of Great Salt Lake. MBE Don R. Mabey (U.S. Geological Survey); Oquirrh Mountains area. MH Mark E. Halliday; 1977; four 15-minute quadrangles-- Sevier, Monroe, Delano Peak, and Marysvale. MK Mohamed M. M. Khattab; 1967; northwestern Utah and southern Idaho. MM Philip M. Mudgett; 1962; south central Millard and central Beaver counties. MS Meiiji Resource Consultants; 1980; Utah Valley and Goshen Valley areas. N Chevron Oil Company (now Chevron U.S.A. Inc.) and Atlantic Richfield Company; pre-1972; southeastern Utah. NGS Joesting, Case, and Plouff, 1963; Escalante area. P William W. Johnson and Lee Johnson; 1957; Promontory Range and Bear Lake areas. P William W. Johnson and Mark O. Halverson; 1959-60; Cache County and northern Rich County. P S. Parker Gay, Jr. (Applied Geophysics); 1978; southern Jordan Valley (Utah State Prison area). PG S. Parker Gay, Jr. (Applied Geophysics); 1978; southern Jordan Valley (Utah State Prison area). Q Robert P. Quitzau; 1960-61; Rich and Morgan counties. RB Robert P. Brown; 1968; Sanpete and Sevier valleys and adjacent areas in Sanpete, Sevier, Millard, and Juab counties. RC Robert S. Crosson; 1963; western Juab and Millard counties. RD Robert C. Gray and Donald A. Zimbeck; 1964; north-south profile through Price. RF Richard C. Fox; 1965; central Garfield and central Kane counties. RG Ronald T. Green; 1979; southwestern corner of Utah. RR William W. Johnson; 1957-58; Western Pacific railroad tracks south of Great Salt Lake. RS Richard J. Sontag; 1963; Beaver area. RS Robert F. Sawyer; 1976; Thermo Hot Springs area in south central Beaver County. RV Don L. Peterson (U.S. Geological Survey); 1968; Rhodes Valley (Kamas area). S Joseph W. Berg, Jr., and William M. Dolan; 1957; Snowville area, including part of Idaho and northwestern and north central Box Elder County. S William W. Johnson and Mark O. Halverson; 1959; Snowville area, including part of Idaho and northwestern and north central Box Elder County. SF Jerry R. Montgomery; 1970; Salt flats on the southern part of the Great Salt Lake Desert, including profiles. SFLH Jerry R. Montgomery; 1970; Salt flats along the old Lincoln Highway from Deep Creek Mountains to Dugway in the southern part of the Great Salt Lake Desert. SG Stephen C. Gabbert; 1978; Pine Valley area. SI William W. Johnson; 1957; Snowville area including part of Idaho. SI William W. Johnson and Mark O. Halverson; 1959; Snowville area including part of Idaho near Portage and Clarkston. SI William W. Johnson, Jesse C. Stepp, and Kenneth L. Cook; 1960; Snow- ville area including part of Idaho near Hansel Valley. SKUL James L. Baer and Alvin K. Benson; 1987; Skull Valley - Ripple Valley, Tooele County SL Joseph W. Berg, Jr., and William M. Dolan; 1957; northern and northwestern margins of the Great Salt Lake. SR Donald C. Selk; 1974; San Rafael Swell area. SR Joseph W. Berg, Jr., and William W. Johnson; 1957; Southern Pacific Railroad causeway across the Great Salt Lake. SR Richard J. Sontag; 1963; Beaver area. su Anne E. McCafferty and John Cady, 1987, southeastern Utah wilderness areas, Kane and Garfield counties; USGS OFR87-200. SW Joseph W. Berg, Jr., and William M. Dolan; 1957; Stansbury-Wendover area. SW Kenneth L. Cook, William W. Johnson, Loren H. Rausher, Mark Halverson, and James Morgan; 1958; Great Salt Lake Desert area; Wendover area; Newfoundland Mountains area; Pilot Valley area; Lucin area; Donner-Reid Pass. SW Jesse C. Stepp; 1960; Stansbury-Wendover area. T Edward Thiel; 1955-56; Uinta Mountains and adjacent area to the west. TA James I. Tanis; 1960-62; east-west profiles across Utah. TC Terry J. Crebs; 1974-75; northern Mineral Range, eastern Beaver County. TP Joseph W. Berg, Jr., and Harry D. Narans, Jr.; 1957; Timpie profile. U A.C.I.C data; Utah. UI Robert C. Gray and Donald A. Zimbeck; 1964; western Uinta Moun- tains. UM Stephen R. Gray; 1966-67; four profiles in southwestern Utah. UU Jerry R. Montgomery; 1969; Fish Springs Range area. W Kenneth L. Cook and Joseph W. Berg, Jr.; 1961, 1972; Wasatch Front area. WB William D. Brumbaugh; 1977; Black Rock Desert, Cove Fort, and northern Mineral Range in southeastern Millard and northeastern Beaver counties. WI William F. Isherwood; 1964, 1967; eastern Millard County. WP Win Pe; 1978-79; Escalante Desert and vicinity, Iron and Washington counties. WU Jerry R. Montgomery; 1969; western Utah. X U.S. Geological Survey; Central Colorado Plateau, southeastern Utah. YW Yun F. Wang; 1967; Gilson Mountains area, eastern Juab County. YY Richard J. Sontag; 1963; eastern half of Richfield 1-degree x 2-degree quadrangle. Code-Number Designations 1-__ University of Utah Gravity Class; 1971; Juab Valley. 2-__ University of Utah Gravity Class; 1972; Mona area of Juab Valley. 2-1.E Robert F. Sawyer; 1976; Thermo Hot Springs area, Beaver County. 2-1.W Robert F. Sawyer; 1976; Thermo Hot Springs area, Beaver County. 8___ Robert P. Brown; 1968; central Utah -- in the Gunnison area of the Sevier River valley. 9___ University of Utah Gravity Class; 1968; Gunnison area of the Sevier River valley in U.S. Geological Survey 7.5-minute quadrangles Redmound, Redmound Canyon, Aurora, and Sigurd. 41 University of Utah Gravity Class; 1974; northern part of Milford Valley. 51 Robert F. Sawyer; 1976; Thermo Hot Springs area, Beaver County. 61 University of Utah Gravity Class; 1961; Skull Valley area. 65A University of Utah Gravity Class; 1965; along the border between Beaver and Iron counties. 65B University of Utah Gravity Class; 1965; along the border between Beaver and Iron counties. 66C University of Utah Gravity Class; 1966; Lincoln Highway profile near Gold Hill. 69 University of Utah Gravity Class; 1969; the Fish Springs Range area in west central Juab County. 72 University of Utah Gravity Class; 1972; Keg (McDowell) Mountains area, Juab County. 74 University of Utah Gravity Class; 1974; Milford and Thermo Hot Springs areas in Beaver County. 75 University of Utah Gravity Class; 1975; Thermo Hot Springs area in Beaver County. 76 University of Utah Gravity Class; 1976; Monroe Hot Springs area of Sevier Valley. 77 University of Utah Gravity Class; 1977; Fillmore area, Millard County. 78 University of Utah Gravity Class; 1978; Profiles along 21st South street, Big Cottonwood Canyon, and Little Cottonwood Canyon. 80 University of Utah Gravity Class; 1980; Whirlwind Valley and nor- thern Sevier Lake areas, Millard County. 81 University of Utah Gravity Class; 1981; Whirlwind Valley area, Millard County. 4-digit designations for NOAA data (assigned by Defense Mapping Agency). This list includes references if 15 or more stations from the original data set is included in the data for the state of Utah and vicinity. The Utah data set of 41,960 stations has preserved the original 15-minute boundary and so includes data from adjoining states. NOTE: some of the data sets below do not have unique identifiers for each gravity station: for example, all of the data from set 6203 are labelled "6203 1". References below have been furnished by the Defense Mapping Agency, and are in chronological order. 764 W. E. BONINI IDAHO, WYOMING, MONTANA, WASHINGTON AND OREGON GRAVITY ANOMALIES IDAHO BUREAU OF MINES AND GEOLOGY 1959 2179 GRAVITY REDUCTIONS, NEVADA BASIN AND RANGE PROJECT GROUP 1 USGS 2506 ARIZONA GRAVITY SURVEY DEFENSE MAPPING AGENCY TOPOGRAPHIC CENTER (DMATC) 2695 GRAVITY DATA, NORTHERN NEVADA USGS 1958 2702 GRAND CANYON GRAVITY SURVEY USGS 1965 3097 GRAVITY DATA IN ARIZONA UNIVERSITY OF ARIZONA 1967 3399 D. L. PETERSON GRAVITY DATA, MALAD VALLEY, IDAHO USGS 1970 3401 D. L. PETERSON GRAVITY DATA CACHE VALLEY IN UTAH AND IDAHO USGS 1970 3506, 3507, 3575, 3598 UNIVERSITY OF WISCONSIN 1949, 1953, 1955 3603 GRAVITY DATA FROM THE CURLEW VALLEY, UTAH AND IDAHO USGS 1964 3604 GRAVITY DATA FROM THE LOWER MALAD VALLEY, UTAH SURVEY USGS 1964 3925 GRAVITY DATA IN IDAHO, MONTANA, AND WYOMING USGS 1972 3932, 3948 UTAH REGIONAL GRAVITY SURVEY DEFENCE MAPPING AGENCY TOPOGRAPHIC CENTER 1973 4059 TRIP GB, SERIES AS, GRAVITY STATIONS IN UTAH, COLORADO, NORTH DAKOTA AND SOUTH DAKOTA HAWAII INSTITUTE OF GEOPHYSICS/ATLANTIC RICHFIELD COMPANY 4060 TRIP GB. SERIES AV, GRAVITY STATIONS IN WYOMING HAWAII INSTITUTE OF GEOPHYSICS/ATLANTIC RICHFIELD COMPANY 1949 4099 GRAVITY DATA IN THE UNITED STATES, NORTH - SOUTH PROFILES DEFENSE MAPPING AGENCY/HAWAII INSTITUTE OF GEOPHYSICS 1967 4346 GRAVITY SURVEY IN THE NORTHERN UTAH AREA USGS 1971 4597 C. E. CORRY GRAVITY DATA IN THE ABAJO MOUNTAINS IN UTAH TEXAS A + M UNIVERSITY 1974 4598 C. E. CORRY GRAVITY DATA IN THE HENRY MOUNTAINS OF UTAH TEXAS A + M UNIVERSITY 1974 4846 C. J. HARR D. R. MABEY GRAVITY SURVEY OF POCATELLO VALLEY IN IDAHO AND UTAH USGS 1976 4870 D. L. PETERSON PRINCIPAL FACTS FOR A GRAVITY SURVEY OF BATTLE CREEK - SQUAW HOT SPRINGS AND VICINITY, NORTHERN CACHE VALLEY, IDAHO USGS 1976 5118 UTAH REGIONAL GRAVITY SURVEY DEFENSE MAPPING AGENCY 1971 5130 GRAVITY DATA FOR NEVADA DEFENSE MAPPING AGENCY 1969 5131 GRAVITY DATA FOR UTAH DEFENSE MAPPING AGENCY 1969 5144 GRAVITY DATA FOR THE STATE OF NEVADA DEFENSE MAPPING AGENCY 1971 5161 GRAVITY DATA FOR THE STATE OF UTAH DEFENSE MAPPING AGENCY 1971 5163 NEVADA REGIONAL GRAVITY SURVEY DEFENSE MAPPING AGENCY 1972 5165, 5173 UTAH REGIONAL GRAVITY SURVEY DEFENSE MAPPING AGENCY, 1971,1972 5177 IDAHO REGIONAL GRAVITY SURVEY DEFENSE MAPPING AGENCY 1972 5268 C. W. WILSON D. R. MABEY PRINCIPAL FACTS FOR GRAVITY STATIONS IN THE SOUTHERN RAFT RIVER AREA, CASSIA COUNTY, IDAHO, USGS OFR73-165 5271 GRAVITY DATA FOR GARDEN/COAL, HAMLIN, SNAKE EAST, WHITE RIVER AND WHIRLWIND VALLEYS, NEVADA DEFENSE MAPPING AGENCY 1979 5293 W. D. BRUMBAUGH K. L. COOK GRAVITY SURVEY OF THE COVE FORT - SULPHURDALE KGRA AND THE NORTH MINERAL MOUNTAINS AREA, MILLARD AND BEAVER COUNTIES, UTAH UNIVERSITY OF UTAH 1976 5294 J. A. CARTER K. L. COOK I. THANGSUPHANICH REGIONAL GRAVITY AND AEROMAGNETIC SURVEYS OF THE MINERAL MOUNTAINS AND VICINITY, MILLARD AND BEAVER COUNTIES, UTAH, AND THE REGIONAL GRAVITY SURVEY OF SOUTHERN MINERAL MOUNTAINS UNIVERSITY OF UTAH 1976 5473 D. L. PETERSON PRINCIPAL FACTS FOR GRAVITY STATIONS IN PARTS OF BEAVER, IRON, AND MILLARD COUNTIES, SOUTHWESTERN UTAH USGS 1973 5573 UTAH REGIONAL GRAVITY DATA DEFENSE MAPPING AGENCY 1980 5650 L. F. SERPA K. L. COOK DETAILED GRAVITY AND AEROMAGNETIC SURVEYS IN THE BLACK ROCK DESERT AREA, UTAH UNIVERSITY OF UTAH/DEPARTMENT OF ENERGY 1980 5653 R. BERUFF GRAVITY SURVEY IN UTAH DEFENSE MAPPING AGENCY 1980 5675 GRAVITY DATA IN NEVADA AND CALIFORNIA USGS 1980 5704, 5786 GRAVITY DATA IN THE VALLEYS OF UTAH AND NEVADA DEFENSE MAPPING AGENCY 1980 5829 REGIONAL GRAVITY DATA IN NEVADA DEFENSE MAPPING AGENCY 1980 5878 DECLASSIFIED SOURCES IN MONTANA, WYOMING, NORTH/SOUTH DAKOTA,FROM: 2313,3403,3700,3972,4306,4311,4637,5091,5100,5110,5112,5113,5115, 5135,5138,5139,5160,5164,5178,5181,5182,5183,5185,5186,5188,5195. DEFENSE MAPPING AGENCY 1963 5918 GRAVITY DATA IN THE SOUTHWESTERN UNITED STATES AND MEXICO UNIVERSITY OF ARIZONA 6126 J. W. ERWIN GRAVITY DATA FOR THE WELLS ONE BY TWO DEGREE AREA IN NEVADA NEVADA BUREAU OF MINES AND GEOLOGY 1979 6203 C. AIKEN GRAVITY DATA IN COLORADO NATIONAL GEODETIC SURVEY/UNIVERSITY OF TEXAS AT DALLAS 6206 HAWAII INSTITUTE OF GEOPHYSICS GRAVITY DATA COVERING THE U.S. NATIONAL GEODETIC SURVEY 6299 M. L. ZOBACK JUAB VALLEY GRAVITY SURVEY USGS 1982