Airborne measurement of the earth's magnetic field over all of North America provides gridded data describing the magnetic anomaly caused by variations in earth materials and structure.

Explains the process used to compile and analyze data from diverse magnetic surveys of an area to produce a consistent synoptic data set portraying the magnetic anomalies of the region.

Explanation of the Earth's magnetic field and how USGS measures it. Defines magnetic anomaly, induced and remanent magnetism in rocks, and describes magnetic anomaly maps.

Aeromagnetic flight-line measurements and gridded anomaly data

Geologic units, structural features, and aeromagnetic anomaly map of the area

Gridded data and maps for individual quadrangles and for the entire compilation

Aeromagnetic surveys of Washington state, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

New aeromagnetic point observation data with grids as well

Maps (no data) depicting aeromagnetic and Bouguer gravity anomaly in the study area. Report discusses rock sample density and magnetic properties, but data are buried in PDF tables.

Aeromagnetic data help provide the underpinnings of a hydrogeologic framework for Fort Irwin by locating inferred structural features or grain that influence groundwater flow. Magnetization boundaries defined by horizontal-gradient analyses coincide lo

A simplified geologic map, raw gravity and magnetic data, with derivative products including depth-to-source and rock densities, with limited interpretations of the underlying geology, structures, and mineral resources.

Aeromagnetic surveys of Arizona, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Arkansas and Louisiana, merged to form seamless grids across the states. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Colorado, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Georgia, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Missouri, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Montana, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Nebraska, Kansas, and Oklahoma, merged to form seamless grids across the states. Gravity anomaly data are provided as well.

Aeromagnetic surveys of New England, merged to form seamless grids across the state. Gravity anomaly data are provided as well. Data provided in a variety of formats.

Aeromagnetic surveys of New Jersey, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of New Mexico, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of North Dakota, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Preliminary data (grids and images) and maps for a new aeromagnetic survey

Aeromagnetic surveys of South Carolina, merged to form seamless grids across the state. Gravity anomaly data are provided as well. Data provided in a variety of formats.

Aeromagnetic surveys of South Dakota, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Utah, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Virginia, merged to form seamless grids across the state. Gravity anomaly data are provided as well. Data provided in a variety of formats.

Aeromagnetic surveys of Wisconsin, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Wyoming, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

The report contains digital data, primarily a layer of polygons linked to records summarizing previous interpretations of aeromagnetic anomalies. Data are presented in updated format for input to a GIS, standard graphics software, or map-plotting package.

Magnetic anomaly and radiometric data for this area, to understand the geological structure and processes controlling the presence and distribution of alkaline igneous rocks that may be enriched in rare earth elements. Data are provided in CSV, GeoTiff, and Geosoft XYZ (flight-line) formats, packaged using the compressed 7-zip format.

Aeroradiometric and aeromagnetic flight-line data from surveys flown at 400 feet with line spacing from 3 to 6 miles from 1974 through 1981.

Gridded and tabular magnetic data and gravity station observations. Maps depicting the data are included in the report.

Collection of historical gravity and aeromagnetic data in Afghanistan (1911 through 1967)

Gridded aeromagnetic and ground-based gravity station data

Aeromagnetic survey data giving the calculated magnetic anomaly. Data are provided in CSV format.

Analysis of geophysical data, inferring geologic structure of the study area

Aeromagnetic surveys of Idaho, merged to form seamless grids across the state. Data provided in a variety of formats.

Digital files and descriptions of airborne and ground collected magnetic data in Afghanistan

Intended to promote further understanding of the geology and structure in the central California Coast Ranges, includes downloadable gridded point database.

Gridded survey data with summary map images.

Flight-line data, flight-line and aeromagnetic anomaly map images

Grid data files along with maps in PDF and PostScript accompany this report

Gridded aeromagnetic anomaly data, along with aeromagnetic observations obtained during 2008.

Gridded data from aeromagnetic surveys

Flight-line data from the aeromagnetic survey

Basic aeromagnetic data and other airborne survey information for any region of Alaska. Flight-line point information, not grids.

Grids of total magnetic intensity for the park

Grids and map images for separate surveys and combined compilation

Magnetic anomaly expressed in grids with regular spacing derived from 85 separate surveys and provided in several different formats.

Grids and images depicting the data

Flight-line data, grids, and images derived from them

Flight-line data, grids, and images derived from them

Grids and flight-line data for three airborne geophysical surveys

Digital and analog archives comprising more than 1,000 surveys, covering approximately 8,000,000 line-km of data, flown at various flight heights and line spacings

Digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during a high-resolution aeromagnetic survey in southern Colorado and northern New Mexico during October, 2004

Two high-resolution aeromagnetic surveys in south-central Colorado compiled to assess the subsurface geologic framework of the San Luis basin for ground-water flow model construction, and to map concealed faults potentially related to geothermal resources

Flight-line aeromagnetic observations with gridded data derived from them.

Digital data, image files, and text files describing data formats and survey procedures for an aeromagnetic survey covering the southwestern portion of Taos County west of the Town of Taos, New Mexico, conducted in October, 2006

Aeromagnetic anomaly values digitized from older surveys

High resolution aeromagnetic survey used to infer the locations of igneous rock bodies in the area, which are provided in GIS data files

Maps and geospatial data for (a) geology; (b) tectonics; (c) isostatic gravity anomaly; (d) aeromagnetic anomaly; (e) depth to pre-Cenozoic basement.

Contains geologic, gravity anomaly, and aeromagnetic anomaly maps and the associated geologic and geophysical databases (ArcMap), as well as complete descriptions of the geologic map units and the structural relations in the mapped area.

U.S. Geological Survey Scientific Investigations Map 3412 is a series of products that consists of geophysical and geologic maps of Mountain Pass and vicinity, California. Maps A and B (red outline in above map image) are gravity and aeromagnetic maps, re

Grids, images, and flight-line paths for magnetic and resistivity surveys

Grids, line data, and imagery derived from them covering the small study area.

Data from a helicopter magnetic survey in this area to understand the nature of aquifers, the potential for geothermal energy resources, the likelihood of seismic hazards, and the geology of the northern Rio Grande rift. Data are provided in GXF grid and CSV formats.

Flight-line and gridded data, with description of methodology and interpretation

Aeromagnetic survey data from this area flown in 2016. This helicopter survey was flown at a flight-line spacing of 100 and 200 m, nominal elevation above ground of 70 m, for about 1,814 line-kilometers. Data are provided in GXF and shapefile formats.

Survey to map concealed faults that may be related to geothermal resources, such as hot springs; data given are surface locations of faults interpreted from the survey.

Aeromagnetic surveys of Illinois, Indiana, and Ohio, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of Iowa, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Aeromagnetic surveys of West Virginia, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Gridded data and images

Best available public-domain aeromagnetic and gravity data in the State of Michigan merged into composite grids. Magnetic data compiled from 25 separate magnetic surveys.

Previously created but unpublished map sheets were scanned, registered, and the contours were digitized. The point data released here were extracted from the digitized contour lines and include: latitude, longitude, and magnetic-field value (gamma). Data are provided in a fixed-field columnar text format.

Aeromagnetic surveys of Nevada, merged to form seamless grids across the state. Gravity anomaly data are provided as well. Data provided in a variety of formats.

Aeromagnetic surveys of Oregon, merged to form seamless grids across the state. Gravity anomaly data are provided as well.

Geologic map showing the structure and history of the basement rocks of Montana. Most of the state is covered by Phanerozoic bedrock units; the underlying basement structure must be inferred from magnetic anomaly data combined with geologic observations.

Principal basement structures formed during the Precambrian in the continental United States based on interpretation of regional aeromagnetic anomaly data of North America.

Map showing magnetic anomaly of California composed by merging and editing data from 123 distinct surveys conducted previously.

This map is intended to promote further understanding of the geology and structure in the region by serving as a basis for geophysical interpretations and by supporting geological mapping, water-resource investigations, and various topical studies.

Grid and flight-line data files provided by the geophysical survey contractors.

Grid and flight-line data files provided to USGS by contract geophysical surveyors

Gridded data for aeromagnetic surveys with contractors' reports describing the data collection

Aeromagnetic surveys of Texas, merged to form seamless grids across the state. Gravity anomaly data are provided as well. Data provided in a variety of formats.

Interpretation of aeromagnetic data, with geologic structure, to infer thickness and estimate capacity of an aquifer.

Grids and flight-line data for the surveys of this area

New gravity and magnetic compilations and elevation-bathymetry models compiled for the Lake Superior region, providing continuous sets of observations for geologic interpretations spanning political boundaries such as US States and the US-Canada border where bedrock geology is largely concealed beneath glacial deposits and surface water. Data are provide in GeoTiff, GXF, and CSV (for gravity station data) formats.

Gridded data from helicopter study of shallow geologic structures

Maps showing aeromagnetic survey results, locations of gravity station data, and discussions of processing within the report

The USGS had an aerial survey flown over parts of Cameron, Hidalgo, and Willacy Counties in Texas. The aerial survey included measurements of the earth's magnetic field and of the radioactivity of the surface rocks and soils.

This report presents the results of analyses and interpretation of aerial gamma-ray, Landsat TM, geologic, and digital elevation data of the Big Bend area in Texas.

Maps, grids, and flight-line databases of a detailed aerial survey and maps and grids of satellite data

Study to estimate the 3-D distribution of permafrost, to evaluate the effectiveness of these methods at mapping permafrost geometry, and to better define the physical properties of the subsurface in discontinuous permafrost areas.

Airborne electromagnetic and magnetic survey data were collected in 2017 along 347 line kilometers. Includes processed AEM and magnetic data and inverted resistivity depth sections. Data are provided in CSV format.

Airborne electromagnetic and magnetic survey data were collected during 2016 along 300 line kilometers in this area, flown at a nominal flight height of 30 m above terrain along widely spaced reconnaissance lines. Includes raw and processed AEM data, laterally-constrained inverted resistivity depth sections along all flight lines, and unprocessed and processed magnetic data. Data are provided in CSV format.

Airborne electromagnetic (AEM) and magnetic survey data along 1,637 line-km at a nominal flight height of 30m above terrain (averaging 53m), with nominal line spacing 1 km or 4 km. Data provided are minimally processed AEM and magnetic measurements, fully processed AEM data were used to develop an included resistivity model.

Airborne electromagnetic (AEM) and magnetic survey data, a total of 3065 line-kilometers, collected during October 2001 with line spacing 400m and nominal altitude of 30m. Includes raw and processed AEM data and magnetic data, in CSV format.

Airborne electromagnetic and magnetic survey data were collected during 2019 along 1,467 line-kilometers in this area. The survey was flown at a mean flight height of 140 meters (m) above terrain and line spacings ranging from 150 m to 600 m. Data are provided in CSV and shapefile formats.

Airborne electromagnetic (AEM) and magnetic survey data collected in 2015 along 769 line-kilometers including raw and processed AEM and magnetic data, processed AEM resistivity-depth inversions. Data are provided in CSV format.

Airborne electromagnetic and magnetic survey data were collected in 2014 in this area. The survey was flown at a nominal flight height of 30 m above terrain, line spacing of 200 m with a smaller area at 100 m. Includes raw and processed AEM data and spatially-constrained inverted resistivity depth sections, and unprocessed and processed magnetic data that has been drift corrected, leveled, and draped to terrain. Data are provided in CSV format.

Airborne electromagnetic and magnetic survey data in 2012 along 556 line-kilometers over this volcano flown at a nominal flight height of 30 meters (m) above terrain with a nominal spacing of 250 m. Data are provided in CSV and GeoTiff formats.

Airborne electromagnetic and magnetic survey data collected during 2021 over 3,170 line kilometers with nominal flight height of 30 - 40 m above terrain and nominal line spacing of 0.5 miles. Data are provided in Geosoft database, Geosoft grid, GeoTiff, Geosoft map, and netCDF formats.

Airborne electromagnetic and magnetic survey data collected during April and May 2019 along 1,467 line-kilometers in this area. Data are provided in netCDF format.

Airborne electromagnetic (AEM) and magnetic survey data to support groundwater salinity mapping and hydrogeologic framework development. Data are provided in CSV format.

Data from a helicopter-borne electromagnetic and magnetic survey flown over this area area in 2000. Nominal elevation of the sensor was 60 meters. Survey coverage comprises 1,914 line kilometers. Data are provided in CSV format.

Airborne electromagnetic (AEM) and magnetic survey data in this area to aid groundwater studies. Includes inverted resistivity model. Data are provided in CSV, plotted sections provided in PDF.

Airborne electromagnetic and magnetic survey data were collected during 2016 along 4,212 line-kilometers over this area. The survey was flown with a nominal line spacing of 450 meters or less, and mean flight height about 48 m providing depth of investigation about 500m. Data are provided in CSV format, flight lines in shapefile format.

Releases airborne survey data, resistivity cross-sections and depth slices derived from data inversion. Resulting resistivity models confirm geologic framework, constrain hydrostratigraphy and depth to basement, and reveal fault and fold distribution.

Airborne electromagnetic (AEM) and magnetic survey data were collected in 2016 along 4,212 line-kilometers over this area as part of a study of the subsurface geologic structure and geothermal and groundwater resources of Yellowstone National Park. Data are provided in CSV format.

Airborne electromagnetic, magnetic, and radiometric data were acquired along 27,204 line-kilometers over this area. Data are provided in netCDF format.

Airborne electromagnetic, magnetic, and radiometric data were acquired in 2018-2019 along 16,816 line-kilometers flown at a nominal sensor flight height of 30 m above terrain with 6- to 12-kilometer spaced east-west flight lines to understand subsurface geologic structure and inform hydrologic models. Data are provided in CSV and GXF grid formats. Flight lines are provided in shapefile format.

Airborne electromagnetic, magnetic, and radiometric data were acquired from 2019 to 2020 along 24,030 line-kilometers over the Mississippi Alluvial Plain. Survey was flown at a nominal height of 120 m above terrain with 6-kilometer spaced east-west flight lines. Data are provided in ASEG-GDF2 format.

Airborne electromagnetic, magnetic, and radiometric data were acquired in 2018 along 2,364 line-kilometers in this area at anominal sensor flight height of 30 m above terrain with 250 to 1,000-meter spaced flight lines. Data are provided in GXF grid, CSV, and GeoTiff formats.

Airborne electromagnetic, magnetic, and radiometric data collected in 2017 over 1,984 line-kilometers in this area. Data include inverted resistivity and IP models as well. Data are provided in CSV format.

Compilation of airborne geophysical surveys (magnetic, radiometric, and electromagnetic) with links, for each survey to the data, metadata, and preview images. Includes a measure of quality indicating which surveys are likely most useful for investigations of subsurface mineral deposits. Data are provided in Esri file geodatabase, shapefile, and CSV formats.

Airborne surveys measuring the earth's magnetic field, resistivity or other electomagnetic properties, or gamma ray emission over parts of North America.

Three contractor reports and data files for an airborne electromagnetic survey describing data aquisition and processing. Processed geophysical data were inverted to produce resistivity depth sections along flight lines. Results are described herein.

Gravity, magnetic, and radiometric data obtained in airborne surveys conducted in 2012 with a flight line spacing of 200m and nominal height above ground 125m. Data are provided in GXF grid, GeoTiff, and CSV formats.

Airborne geophysical surveys were conducted in this area in 2015 with a nominal survey height above ground of 200 meters and flight line spacing 250 meters. Includes magnetic and radiometric (gamma spectrometry) data from those surveys. Data are provided in Geotiff and CSV formats.

Digital flight line data for a high-resolution horizontal magnetic gradient and radiometric survey over this area. Data are provided in netCDF, GeoTiff, and CSV formats,

Digital flight-line aeromagnetic and aeroradiometric survey data over of the southeast Mojave Desert, parts of California and Nevada. Data files are provided in CSV as well as Geosoft binary database and grid exchange format (GXF).

Digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey of this area. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area.

Digital flight line data for a high-resolution magnetic and radiometric survey over an area of northwest Arkansas. Data files in CSV format, with GeoTiff as well.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey over this area to support geologic mapping and characterization of mineral resource potential. A total of 34,041-line km of magnetic and radiometric data were acquired over an irregular-shaped area of 6178 km2. Data are provided in CSV, netCDF, and GeoTIFF formats.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey over Charleston, South Carolina and the surrounding region. Data packages in CSV format, TIFF images provided as well.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey with goals of better understanding placer deposits containing critical mineral resources titanium, zirconium, and rare earth elements and of imaging the crystalline basement partly buried beneath Atlantic Coastal Plain sediments. Data are provided in CSV (magnetic) and netCDF (radiometric) formats as well as GeoTIFF images.

Digital flight line data for a high resolution magnetic and radiometric survey over this area. Data are provided in CSV format.

Digital flight line data for a high resolution horizontal magnetic gradient and radiometric survey over this area. Flight line spacing was 300 m, mean terrain clearance was 140 m. Includes flight line data for the magnetic gradient survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. Data are provided in CSV format, flight lines are provided in shapefile format.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey over this area to better understanding volcanogenic massive sulfide mineral deposits, sediment hosted manganese deposits, and their surrounding geologic framework. Data are provided in CSV and GeoTiff formats.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey of this area. A total of 40,139-line km of magnetic and radiometric data were acquired over an irregular-shaped area of 9140 sq km. Data are provided in CSV, GeoTIFF, and Geosoft formats.

Digital flight line data for a high-resolution horizontal magnetic gradient and radiometric survey over an area of southeast Missouri and western Illinois. Data are provided in CSV and GeoTiff formats.

Digital flight line data for a high-resolution magnetic and radiometric survey over an area of southeast Illinois, western Kentucky, and southern Indiana. Data are provided in CSV and GeoTiff formats.

Digital flight line data for a high-resolution airborne magnetic and radiometric survey over this area. Data are provided in CSV and GeoTIFF formats.

High-resolution, high-sensitivity aeromagnetic data to assess the area for anomalies and magnetic features pertaining to the local geology. Flight lines were spaced 0.25 miles (400 meters) apart in an east-west alignment. Data are provided in CSV and GeoTIFF formats.

Digital flight line data for a high-resolution magnetic survey with line spacing 150 meters and nominal terrain clearance 80 meters over most of the study area. Data are provided as Geosoft databases and grids. Data over two small areas (less than 1 sq km combined) were redacted because those areas include multiple tracts of Native American lands.

Digital flight line data from a high-resolution magnetic survey over this area. The survey was flown in 2008 by Aeroquest under contract to Kennecott Eagle Minerals Company using a fixed-wing aircraft with a magnetometer mounted in a tail stinger. The USGS has obtained this 66,074 line km subset of the survey dataset for public release. Data are provided in Geosoft database and CSV formats.

Airborne magnetic survey data collected from this area to better understand the lithology and structure of exposed and concealed Precambrian rocks in support of mineral resource investigations. Results are provided in Geosoft database, grid exchange format, GeoTiff, and CSV.

Airborne magnetic survey data collected from this area to understand Precambrian rocks concealed under Paleozoic sedimentary rocks in northeast Iowa. Data are provided in GXF grid and CSV formats. Flight lines are provided in shapefile format.

Includes a wide variety of geological and geophysical data: geologic, aeromagnetic, and gravity maps with SLAR, DEM, TM, and NDVI imagery.

Regional grid files and 3D voxel models were used to study crustal architecture. Includes grid files consist of surface grids used in the inversions, and calculated geophysical data grids produced by the inversions. Data are provided in GOCAD voxel and GXF grid formats.

Aeromagnetic data collected during an airborne geophysical survey.

GIS data for geologic units and structural features, with aeromagnetic and gravity maps in PDF

Geological, geophysical, geochemical, or lidar data acquisition projects funded by the Earth Mapping Resource Initiative (Earth MRI) pertaining to the study of critical mineral resources in the US.

<h1>Introduction</h1>The San Juan-Silverton caldera complex located near Silverton, Colorado, in the Southern Rocky Mountains volcanic field is an ideal natural laboratory for furthering the understanding of shallow-to-deep volcanic-related mineral system

Uninterpreted geophysical measurements and geochemical and mineralogical analytical data from samples collected during the summer field seasons from 2007 to 2010. Data are available in a single Geographic Information System (GIS) database.

Report describing detailed interpretation of geophysical survey data to draw inferences about subsurface geologic features and likely consequences for the hydrogeologic system.

Gravity and aeromagnetic data analysis described in a report, with a few physical property analyses

Data from more than 660 gravity stations, 100 line-km of truck-towed magnetometer traverses, and 260 physical-property sites in this area.

Gravity station data and physical property measurements used to infer subsurface geologic structure

A set of geophysical maps with anomalies that are labeled and keyed to tables containing information on each anomaly and its source.

Maps of aeromagnetic data and a table of gravity station data now available for download

Report with generalized interpretation and Excel tables of gravity and physical property data including an explanations of their formats.

Aerial, truck-towed, and hand-held magnetometer measurements, gravity station data, and sample density and magnetic susceptibility measures

Mathematical analysis of gravity and aeromagnetic data, with basic and derived grids and vector data and maps.

The objective of the survey was to improve the understanding of the relationship between surface water and groundwater systems critical to developing management programs for water resources.

Flight line data, grids, and inversions for these surveys are intended to help understand shallow groundwater and develop groundwater resource plans for the aquifer.

Electrical resistivity depicted in georeferenced grids and maps, representing different approximate depths of investigation for each area. The range of subsurface investigation is comparable to the depth of shallow aquifers.

The objective of the contracted survey was to improve the understanding of the relation between surface water and groundwater systems critical to developing groundwater models used in management programs for water resources.

High resolution magnetic and gravity gradient data were collected in this area centered on the Pea Ridge iron oxide-apatite rare-earth element deposit. Flight lines spacing was 400 m, nominal flight height above terrain was 80 m. Includes flight line data for the gravity gradiometry survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. Data are provided in CSV format.

Survey parameters, data acquisition and processing procedures, and products of a 1999 airborne geophysical survey of this area. Data provided in GXF format and binary formats.

Detailed airborne gravity gradiometry, magnetic, and radiometric survey data for this area flown with flight-line spacing of 100 and 200 m, nominal flight-line elevation above ground of 70 m, for about 1,814 line-kilometers. Data are provided in CSV and Geosoft database (.gdb) format. Gravity and hillshade are in GXF grids.

Using geophysical and remote-sensing data, previously unrecognized targets of potential mineralization were identified; this report shows those targets along with the evidence for their potential.

Mathematical modeling, coupled with new observations of magnetic susceptibility, yield better estimates of the underground configuration of granite plutons.

Flight line data for an airborne magnetic survey with nominal sensor height of 60m above terrain, flight-line data for a gravity gradiometry survey, with a report containing instrument and procedure details. Data are provided in CSV format.

Flight line data from airborne surveys conducted in 2017, provided in comma-separated values (csv format). Three areas were flown along a draped surface with a nominal survey height above ground of 120 meters. The flight line spacing for these areas was 200 to 400 m for Area 123, in southwestern Oklahoma; 1000 m for Area 4, in northwestern Oklahoma, and 800 m for Area 5, in north-central Oklahoma.

Results of mathematical modeling of gravity and magnetic anomaly data to infer the geologic structure of the area

Multi-chapter report combining geologic, geochemical, geophysical, and mining activity data. Downloadable data for coal resource information only.

Magnetic and gravity anomaly and structure contour data

A planned partnership between the USGS, the Association of American State Geologists, and other Federal, State, and private organizations to collect scientific information useful for finding and exploiting critical mineral resources in the US.

Geophysical modeling used to study mineral deposit geometry. Includes 227 new gravity stations.