120-9 Mapping in Technicolor – A Multiphysics View of the Alabama Graphite Belt Through Two Earth MRI Airborne Geophysical Surveys

Abstract:

Demand for flake graphite has risen sharply in recent years as a critical component of modern high-capacity batteries and other industrial and military uses, but the US is currently 100% reliant on imported graphite.  To help evaluate potential domestic sources of graphite, the United States Geological Survey (USGS) conducted two airborne geophysical surveys over the Alabama graphite belt - a historically mined region of graphitic schists in the southern Appalachian Mountains - as part of the Earth Mapping Resources Initiative (Earth MRI).

The first survey, flown in 2023, collected electromagnetic data primarily over the graphite belt and surrounding areas. A subsequent 2024-2025 survey collected magnetic and radiometric data over a 450 km long region from the graphite belt to the Florida coast.  Electromagnetic methods are particularly effective at mapping graphite bearing rocks due to their ultra-low electrical resistivity, whereas magnetic and radiometric methods provide complementary information on crustal structures (kilometers deep) and near-surface (tens of centimeters) materials, respectively, with tighter line spacing and more continuous coverage.  Together, these data provide valuable subsurface structural and lithologic insights in an area where traditional geologic mapping is hindered by thick vegetation and soil cover.

Combining datasets has refined the extent of graphitic units and illuminated previously unresolved tectonic features within the Alabama graphite belt, traditionally defined by the graphitic members of the Higgins Ferry and Poe Bridge Mountain groups.  Integrated data analysis shows that extensive graphitic rocks likely also occur outside the traditionally defined graphite belt.  Magnetic and electromagnetic data suggest that low resistivity, moderately magnetic graphite-bearing rocks extend beneath Coastal Plain sediments, possibly as far as 25 km to the southwest.  Resistivity modeling shows low resistivities extending continuously beyond the northeastern Poe Bridge Mountain Group into the Wedowee Group to the southeast.  Previous mapping divides the Poe Bridge Mountain and Wedowee Groups in this area by a single fault, however, radiometric and magnetic data show no expression of the mapped fault in this area.  The combined datasets suggest a more complex boundary. 

Together, these new Earth MRI datasets provide a detailed, multiphysics view of the Alabama graphite belt and offer critical insights into its geologic framework, supporting future resource assessments in this strategically significant region.

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

doi: 10.1130/abs/2026AM-17765

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