High-resolution airborne magnetic and radiometric survey of the Republic Graben, Okanogan and Kettle metamorphic core complexes, Kootenay Arc and surrounding regions, Northeastern Washington

The Republic survey consists of high-resolution aeromagnetic and radiometric data designed to image the subsurface geology and structure of a large portion of northeastern Washington. These data are intended for rigorous modeling and interpretation of the geology and structure in this region and will be used to evaluate the potential for undiscovered resources and will contribute to USGS and Washington DNR-related mineral and geothermal resource assessments of the region. This release includes aeromagnetic and aeroradiometric data collected via low-altitude helicopter flown over northeastern Washington State, centered over the town of Republic, Washington. The data were acquired between September 26, 2022 and August 21, 2023 by Precision Geosurveys, Inc. of Langley, British Columbia and processed by EDCON-PRJ, Inc. of Lakewood, Colorado, contracted by the U.S. Geological Survey and funded through the Earth Mapping Resources Initiative (EarthMRI). The survey includes gridded data from target altitude of 80-100 meters above ground level, subject to aircraft climb and descent limitations. Primary transverse flight lines were flown in the east-west direction and spaced 200 meters apart. Tie lines were flown in the north-south direction and spaced 2000 meters apart. Additionally, the survey includes two transect lines flown down the Similkameen and Okanogan Valleys where local topography was too extreme to maintain an ideal drape surface. A total of 94,506 line kilometers of data were collected over an area of 16,885 square kilometers. Survey procedures are described in detail in the document “WA Republic Mag RAD D22 Project Report_report.pdf” available in this data release. The Republic aeromagnetic and aeroradiometric survey was collected over steep and highly variable terrain, thus the terrain clearance should be considered carefully when modeling and interpreting magnetic and radiometric data. This data release includes .csv file databases for the main survey and transect data collections, derivative magnetic and radiometric data in map view in .grd and .tiff file format, and shapefiles of the transect lines along the Similkameen and Okanogan Valleys.