Magnetic data collected as part of a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties, are provided as digital flight-line and grid files. Magnetic surveys measure subtle variations in the Earth’s magnetic field and are sensitive to differences in the magnetic properties of rocks from ground level to many kilometers below. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a magnetometer mounted in a stinger extending from the nose of the aircraft. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief, but higher clearances, as much as 200–500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.

This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a magnetometer mounted in a stinger extending from the nose of the aircraft and a gamma-ray spectrometer stowed onboard. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief to maximize detection of gamma-rays, but higher clearances, as much as 200-500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.

This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a magnetometer mounted in a stinger extending from the nose of the aircraft and a gamma-ray spectrometer stowed onboard. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief to maximize detection of gamma-rays, but higher clearances, as much as 200-500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.

This data release provides digital flight line data for a high-resolution airborne magnetic survey over parts of Montana in the vicinity of the Boulder Batholith. The airborne survey was jointly funded by the Earth Mapping Resources Initiative and Kennecott Exploration Company. The survey was designed to meet complementary needs related to 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 were collected from a helicopter flown at a nominal terrain clearance of 100 meters (m) above topography along E-W flight lines spaced at 200 m intervals. Tie lines were flown in an N-S direction every 2000 m. Data were collected by Sander Geophysics Limited (SGL), and Dewberry Engineers, Inc. under contract with the USGS using a helicopter with a magnetometer mounted in a stinger. The survey operated out of the Butte, Montana, airport from June of 2022 to August of 2022. Files that are available in this child item include flight line data for the magnetic survey, grids, and a geotiff of the gridded total-field anomalies.

This data release provides digital flight line data for a high-resolution airborne magnetic survey over parts of Montana in the vicinity of the Boulder Batholith. The airborne survey was jointly funded by the Earth Mapping Resources Initiative and Kennecott Exploration Company. The survey was designed to meet complementary needs related to 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 were collected from a helicopter flown at a nominal terrain clearance of 100 meters (m) above topography along E-W flight lines spaced at 200 m intervals. Tie lines were flown in an N-S direction every 2000 m. Data were collected by Sander Geophysics Limited (SGL), and Dewberry Engineers, Inc. under contract with the USGS using a helicopter with a magnetometer mounted in a stinger. The survey operated out of the Butte, Montana, airport from June of 2022 to August of 2022. Files that are available in this child item include flight line data for the magnetic survey, grids, and a geotiff of the gridded total-field anomalies.

This data release provides digital flight line data for a high-resolution airborne magnetic survey over parts of Montana in the vicinity of the Boulder Batholith. The airborne survey was jointly funded by the Earth Mapping Resources Initiative and Kennecott Exploration Company. The survey was designed to meet complementary needs related to 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 were collected from a helicopter flown at a nominal terrain clearance of 100 meters (m) above topography along E-W flight lines spaced at 200 m intervals. Tie lines were flown in an N-S direction every 2000 m. Data were collected by Sander Geophysics Limited (SGL), and Dewberry Engineers, Inc. under contract with the USGS using a helicopter with a magnetometer mounted in a stinger. The survey operated out of the Butte, Montana, airport from June of 2022 to August of 2022. Files that are available in this child item include flight line data for the magnetic survey, grids, and a geotiff of the gridded total-field anomalies.

Radiometric data collected as part of a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties, are provided as digital flight-line and grid files. Radiometric (or gamma-ray) surveys measure naturally occurring low-level radiation and are sensitive to the presence of rocks near the surface that are enriched in uranium, thorium, or potassium. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a gamma-ray spectrometer stowed onboard. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief to maximize detection of gamma-rays, but higher clearances, as much as 200–500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.

Radiometric data collected as part of a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties, are provided as digital flight-line and grid files. Radiometric (or gamma-ray) surveys measure naturally occurring low-level radiation and are sensitive to the presence of rocks near the surface that are enriched in uranium, thorium, or potassium. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2021 using a helicopter equipped with a gamma-ray spectrometer stowed onboard. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with east-west lines spaced 150 meters apart and north-south lines spaced 1,000 meters apart. A terrain clearance of 80 meters above ground could be realized in areas of low relief to maximize detection of gamma-rays, but higher clearances, as much as 200–500 meters, were required over rugged terrain and populated areas for safety reasons. A total of 17,032 kilometers were flown along the lines, covering a 2,200 square-kilometer irregular area. SGL performed extensive data processing after completion of flying and delivered the final data and report in February 2022.

This data release provides digital flight line data for a high-resolution airborne magnetic survey over parts of Montana in the vicinity of the Boulder Batholith. The airborne survey was funded by the Earth Mapping Resources Initiative and was designed to meet complementary needs related to geologic mapping and characterization of mineral resource potential. A total of 45,634 line-km of magnetic data were acquired over an irregular-shaped area of 8,272 km^2. Data were collected from a helicopter flown at a nominal terrain clearance of 100 m above topography along E-W flight lines spaced at 200 m intervals. Tie lines were flown in an N-S direction every 2000 m. Data were collected by Sander Geophysics Limited and Dewberry Engineers, Inc. under contract with the USGS using a helicopter with a magnetometer mounted in a stinger. The survey operated out of the Butte, Montana, airport from July of 2023 to October of 2023. Files that are available in this publication include flight line data for the magnetic survey, a data dictionary, and geoTIFFs of the gridded results.

Magnetic data collected as part of a high-resolution airborne magnetic and radiometric survey over the southwest portion of the Colorado Mineral Belt in southwestern Colorado are provided as digital flight-line and grid files. Magnetic surveys measure subtle variations in the Earth’s magnetic field and are sensitive to differences in the magnetic properties of rocks from ground level to many kilometers below. Data for this survey were acquired by NV5 Geospatial, Inc. and is sub-contractors Precision GeoSurveys, Inc. and EDCON-PRJ, Inc under contract with the USGS. The survey was flown by helicopter in September and October of 2023. Magnetic data were measured from a magnetometer mounted in a stinger extending from the nose of the aircraft. The helicopter pilots followed pre-planned flight paths in a grid-like pattern, with north-south lines spaced 200 meters apart and east-west lines spaced 1,000 meters apart. Lines were flown 100 meters above ground as much as possible to resolve details of the magnetic field. This clearance could be realized in areas of low relief but higher clearances, as much as 200-500 meters, were required over rugged terrain and populated areas for safety reasons. Areas with restricted airspace, such as Wilderness Areas, were avoided. A total of 28,472 linear kilometers of data were collected along the lines, covering a 4,719 square-kilometer irregular area. EDCON-PRJ performed extensive data processing after completion of flying and delivered the final data and report in April 2024.