120-6 More Than Pretty Colors: New Airborne Geophysical Data Reveal the Geophysical Framework of Critical Mineral Systems in the South-Central United States

Abstract:

The South-Central US hosts multiple critical mineral systems, however, understanding of their geological framework is hindered due to concealment beneath sediments, alluvium, and vegetation. Airborne magnetic data provide valuable information for mapping geologic structures at and below the surface, whereas radiometric data map near-surface radioelement (K, U, Th) concentrations that may indicate zones of alteration and serve as vectors towards mineralization. As part of the US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI) effort to modernize the Nation’s geologic and mineral resource mapping, eight high-resolution magnetic and radiometric surveys have been flown across the South-Central region since 2019, and two additional surveys are ongoing. The surveys were designed with state geological survey partners to target known critical mineral systems and areas of high critical mineral potential. More than tripling the resolution of legacy datasets, these surveys are flown along flight lines spaced 150 to 400 m apart at a nominal 80 to 100 m above ground level. Recently completed (2024-2025) and active Earth MRI airborne geophysical surveys in the South-Central US cover the Ozark Plateau and Upper Mississippi River Valley regions, where overlapping mineral systems have produced world-renowned mining districts. The high-resolution data offer new perspectives of the Paleozoic sedimentary section and the architecture of the mostly buried Precambrian crystalline basement. In Missouri and eastern Kansas, magnetic data show subsurface structures that likely facilitated formation of Mississippi-Valley type (MVT) Zn-Pb deposits in the Tri-State Mining District. The new data also reveal anomalies in other parts of the Eastern Granite Rhyolite terrane with similar characteristics to known critical-mineral bearing iron-oxide-apatite (IOA) and iron-oxide-copper-gold deposits in the Southeast Missouri Metallogenic Province. The Pea Ridge IOA-rare earth element (REE) deposit in Missouri was previously mined for magnetite and iron ore. At the surface, the highest Th values in the entire survey area occur over the exposed Pea Ridge mine tailings and are attributed to apatite and other Th-REE-bearing minerals. These examples highlight valuable geologic and mineral deposit insights derived from Earth MRI geophysical data, with additional use cases in studies of energy and water resources, natural hazards, and infrastructure and land-use planning.

Geological Society of America Abstracts with Programs. Vol. 58, No. 5, 2026

doi: 10.1130/abs/2026AM-20060

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