NOT YOUR MOTHER′S DATA: NEW HIGH-RESOLUTION AIRBORNE MAGNETIC AND RADIOMETRIC DATA PROVIDE INSIGHTS INTO THE GEOPHYSICAL FRAMEWORK OF THE UNITED STATES SOUTHERN MIDCONTINENT

Understanding of the geologic framework hosting the wealth of mineral resources across the US southern Midcontinent is obscured due to thick vegetation and surficial sedimentary cover. Airborne geophysical data provide an effective and complementary approach to traditional ground-based geologic mapping. Since 2014, the US Geological Survey (USGS) has completed nine high-resolution airborne magnetic and radiometric surveys throughout the southern Midcontinent and a tenth is currently active. These surveys are largely supported by the USGS Earth Mapping Resources Initiative with supplemental funding from the USGS National Cooperative Geologic Mapping Program. The new surveys improve the resolution of legacy airborne data by more than double and were collected using modern survey methods and designs with flight-line spacings of 200 to 400 m apart and mean flight heights of 115 to 170 m above terrain. Data from individual surveys are or will be made publicly available but are presented here as a single merged grid showing continuous magnetic coverage across parts of Arkansas, Missouri, Illinois, Indiana, Kentucky, and Tennessee. Designed to improve our understanding of the geophysical framework of the southern Midcontinent and to facilitate geologic mapping efforts, the high-resolution data provide novel insights into lithologic and structural features of the region by enhancing internal details of buried and exposed igneous bodies and subtle magnetic features within sedimentary units. The new airborne magnetic and radiometric data cover a variety of recognized mineral systems including critical mineral-bearing focus areas like the southeast Missouri iron metallogenic province, the Arkansas alkaline province, and several sedimentary-hosted lead-zinc Mississippi Valley-type deposits and districts. The surveys also cover significant geologic features such as the Reelfoot rift, the New Madrid and Wabash Valley seismic zones, and the southern edge of the Illinois basin. In addition to mineral and energy resource applications, these data can be used to inform a broad range of research areas, including water resources and groundwater pathways, infrastructure and land-use planning, and potential natural hazard risks.