Airborne magnetic and radiometric survey, Boulder Batholith region, Montana, 2022

This data release provides digital flight line data for a high-resolution airborne magnetic and radiometric 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 km. 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 and a fully calibrated gamma-ray spectrometer. The survey operated out of the Butte, Montana, airport from June of 2022 to August of 2022. Files that are available in this publication include flight line data for the magnetic survey, flight line data for the radiometric survey and a report describing the survey parameters, field operations, quality control and data reduction procedures. A zip file is provided that contains the contractor's deliverable products that includes Geosoft databases and grids for the magnetic and radiometric survey and the report describing the survey and data reduction.

Version History
First release:  July, 2023
Version 2:  April, 2024

Version 2
This project was jointly funded by the US Geological Survey Earth Mapping Resources Initiative and Kennecott Exploration Company. The original data release (July, 2023) consisted of USGS-funded data only. Data that were added to the data release on April, 2024, which consisted of aeromagnetic and radiometric data, were funded by Kennecott Exploration Company and was withheld from the original release as proprietary data. This revision includes all data acquired as part of the survey.

Changes from previous version:
1) Added aeromagnetic and radiometric data funded by Kennecott Exploration Company.
2) Updated metadata to reflect the extent of the full data release.
3) Updated spatial reference .shp files to reflect the extent of the full data release.
4) Updated contractor report and deliverables to reflect the extent of the full data release.
5) Updated geotiffs to reflect the extent of the full data release.