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.

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.

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.

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.

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.

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

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

Gridded data from helicopter study of shallow geologic structures

The long-wavelength (50-2,500 km) content of the regional magnetic anomaly compilation was improved by utilizing a nearly homogeneous a nearly homogeneous set of NURE magnetic surveys flown from 1975 to 1981

New aeromagnetic point observation data with grids as well

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

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.

One DVD not available from the Alaska DGGS and not available from the USGS.

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.

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

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

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

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

Airborne geophysical data and a summary of the hydrologic application.

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.

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.

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 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 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.

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

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

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

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

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

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.

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

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.

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

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.

Mathematical modeling and analysis of aeromagnetic anomaly data (gridded data provide in another report).

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

Map and flight-line data, with documentation of the survey

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

Aeromagnetic flight-line measurements and gridded anomaly data

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

Gridded data from aeromagnetic surveys

Flight-line data from the aeromagnetic survey

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 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.

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.

Gridded data used to revise base of aquifer, with supporting elevation data.

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.

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.

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.

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

Measurements of in-situ magnetic properties of several map units to determined whether or not mapped lithologies were responsible for aeromagnetic anomalies observed in a previous high-resolution survey (data of Sweeney, 2000).

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 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

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

Aeromagnetic data collected during an airborne geophysical survey.

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

Diverse collection of previously published GIS datasets describing geological and geophysical characteristics of this area pertinent to the study of metallic mineral resources located there.

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.

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

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

Report with gravity station data in a spreadsheet

Field measurements: 548 gravity and 6484 magnetic anomaly locations, data in fixed-format text files.

Gravity station data and hand-held magnetometer measurements with analysis and description of methodology

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

Results of a detailed ground magnetic survey

Hand-held magnetometer and sample magnetic susceptibility measurements used to help interpret complex patterns in the magnetic anomaly of this area.

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.

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.

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.

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.

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.

Magnetic and gravity investigations were undertaken in Mono Lake to study regional crustal structures and to aid in understanding the geologic framework, in particular regarding potential geothermal resources and volcanic hazards throughout Mono Basin.

Database includes new helicopter aeromagnetic data, point locations of the local maximum horizontal gradient derived from the aeromagnetic data, and physical property data.

Magnetic susceptibility measurements with statistical analysis

In-place rock magnetic susceptibility measurements for 746 sites are reported in a database. These data, collected from 1991 through 2012, are intended to help improve geophysical modeling of the Earth’s crust in the Western United States.

Magnetotelluric sounding data collected in 2009 in this area to improve understanding of the hydrogeology of the Santa Fe Group and the nature of the sedimentary deposits comprising the principal groundwater aquifers of the Rio Grande rift.

Gridded data and images

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.

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.

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

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.

Report with excel tables showing principal facts (gravity observation data) and ground magnetic data.

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

Redigitized and corrected data from a previously published study

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

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

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

Describes electromagnetic sounding locations, data acquisition, calibration, and modeling; compares data to borehole data, correlating model results; and summarizes the applications and limitations of the TEM method. Examples of models are provided.

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.

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.

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.

Audio-magnetotelluric sounding data collected in 2017 in this area to understand geologic structure and lithologic variations.

Audiomagnetotelluric sounding data collected in 2018 in this area to understand subsurface geologic structure.

Audiomagnetotelluric station locations and data to characterize subsurface rock properties important for understanding surface water and groundwater quality issues, and also to improve knowledge of deep geologic structures that may have been conduits for hydrothermal fluids that formed mineral deposits.

Audiomagnetotelluric (AMT) sounding data collected in 2008 in this area in support of assessments of concealed mineral resources.

Seventy-seven major components of the North American continent were delineated at a general scale (1:5,000,000); including the general composition, geological environment, and types of primary metals endowments that can be expected in each domain.

Seventy-seven major components of the North American continent were delineated at a general scale (1:5,000,000); including the general composition, geological environment, and types of primary metals endowments that can be expected in each domain.

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

Reprocessed existing gravity data compiled from multiple sources, as well as newly collected gravity and ground magnetic data, and bulk densities and magnetic susceptibilities from outcrop, hand samples, and drill cores. Data are provided in CSV format.

A regional profile on the Utah-Nevada State line reveals a deeply penetrating, broad electrical conductor suggesting the southwestern limit of intact Archean crust is farther north than previously reported with implications for future mineral exploration.

Nevada is one of the Earth's premier gold producing regions, accounting for approximately 64 percent of the U.S and nine percent of the world total. The impact of these mines on nearby local economies and on our national balance of payments is profound, a

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.

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

Surveys originally carried out by Soviet geophysicists from 1972 through 1974 were digitized. Georeferencing was problematic as were some of the measured characteristics; we explain what we did and how we have understood these data.

Geologic units, structural features, magnetic and gravity anomaly contours and radiometric ages of this area

Geologic units and faults from USGS Open File Report 98-38, concerning assessment of the mineral resources of Puerto Rico

This metal ore deposit formed over a period of time in which its tectonic setting was changing, consequently it shows a range of characteristics typical of several different types of deposits. Rock geochemistry data are provided in tabular form.

Geologic map with faults, along with additional scientific information needed for mineral resource assessment (geochemical analyses, mineral occurrences, geologic terranes, and estimated undiscovered resources)

To help understand the hydrogeologic controls in the basin and how they affect surface and groundwater interactions with nearby mine workings, electrical resistivity profile, self–potential, and magnetic measurement data are provided herein.

Existing and new gravity station data and magnetometer measurements used to infer geologic structure of this area

Geophysical interpretation of the southern Española basin for the purpose of understanding the hydrogeologic framework including shallow faults, igneous units, and basement rocks

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

Gravity map and data used to infer details of the geologic structure of the area. Surveys were conducted during or prior to 1975.

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

A collection of geoscientific data for this area, provided in the mid-1990s using file formats in common use at that time, which are now obsolete. Much of the data is now available in formats more convenient to users of the 2020s at mrdata.usgs.gov.

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

Major assessment of the environmental effects of historical mining in the Animas River watershed with GIS data files, tables, and plates.

Magnetotelluric soundings collected in 2019 to help inform depth-dependent fault zone geometry, fluid content and porosity in this part of the fault zone. Data are provided in MTH5 format.

The purpose of this report is to release one north-south and two east-west regional magnetotelluric sounding profiles collected where drillhole data are sparse. No interpretation of the data is included.

Magnetotelluric stations collected from 2015-2019 across parts of Minnesota, Wisconsin and the Upper Peninsula of Michigan to support regional investigations into the geologic and tectonic framework of the area and to support mineral resource investigations.

Magnetotelluric station data collected from 2016-2019 across parts of Missouri, Arkansas, Tennessee, Illinois, and Kentucky to support regional investigations into the geologic and tectonic framework of the area and mineral resource and geologic hazard investigations.

Magnetotelluric sounding data collected in July 2018 in the Silverton Caldera complex, Colorado, in the Southern Rocky Mountain Volcanic Field to understand the geologic structure of this area.

Magnetotelluric station locations and data intended to help to characterize subsurface rock properties important for understanding surface water and groundwater quality issues, and also to improve knowledge of deep geologic structures that may have been conduits for hydrothermal fluids that formed mineral deposits.

Magnetotelluric (MT) sounding data collected in 2003 along a north-south profile in this area to learn whether major mining districts in the Northern Nevada Gold Province are underlain by rocks of the Archean Wyoming craton, which are known to contain orogenic gold deposits, or by accreted rocks of the Paleoproterozoic Mojave province.

Magnetotelluric sounding data collected in 2006 in this area to improve understanding of the hydrogeology of the Santa Fe Group and the nature of the sedimentary deposits comprising the principal groundwater aquifers of the Rio Grande rift.

Magnetotelluric sounding data collected in 2003 along a north-south profile west of Wendover, Nevada, to understand the rocks underlying mineral deposits in this area.

Magnetotelluric sounding data collected in 2008 in this area to help USGS understand concealed mineral resources.

National-scale geologic, geophysical, and mineral resource raster and vector data covering the United States, Canada, and Australia. Data are provided in shapefile, CSV, Excel, and GeoTIFF formats.

Rock density and magnetic susceptibility measurements of samples drawn from this area. Data are provided in CSV format.

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