120-7 Airborne Geophysical Surveying of the USGS Earth Mapping Resources Initiative

Abstract:

The U.S. Geological Survey's (USGS) Earth Mapping Resources Initiative (Earth MRI) represents a strategic, multi-phase effort to modernize the available data to study the Nation's geologic framework in support of domestic critical mineral resource assessments.  Here we discuss a high-resolution airborne geophysical data collection campaign that was started in 2019 as part of this effort and is now well underway, covering areas identified as containing or with potential to contain critical minerals.  The USGS list of critical minerals includes rare earth elements, lithium, cobalt, nickel, and other commodities essential to modern technology and national security supply chains. 

Airborne geophysical data collection under Earth MRI currently utilizes three primary methodologies: (1) high-resolution aeromagnetic surveys, which can delineate subsurface lithologic and structural controls on mineralization; (2) airborne gamma-ray spectrometry, which provides near-surface radioelement distributions (Potassium, Uranium, and Thorium) useful for surficial geologic mapping and identification of lithologies associated with critical mineral deposits; and (3) airborne electromagnetic surveys, which characterize the electrical conductivity structure of the upper few hundred meters and map surficial cover thickness, lithologies, structure, hydrologic features, and in some cases conductive ore-bearing horizons such as those associated with graphite.  Surveys are designed in coordination with state geological surveys and prioritized using a data-gap analysis overlain with critical mineral deposit-type models.

To date, Earth MRI airborne geophysical data collection covers over 75,000 square miles across geologically diverse mineral systems of the United States. All acquired data are processed to modern standards, rigorously quality-controlled, and released publicly through ScienceBase (www.sciencebase.gov), ensuring broad accessibility for governmental, academic, and industry users.  Integration of Earth MRI airborne data with geologic mapping, geochemical sampling, hyperspectral, and topographic lidar products provides a powerful, multi-layer framework for understanding critical mineral systems at various scales.  The large volume of newly acquired geophysical data also presents an opportunity for the USGS to potentially create and refine regional and national-scale compilations.  Earth MRI's airborne geophysics component exemplifies the role of foundational public-sector geoscience underpinning prospectivity studies, informing land-use and resource management decisions, and strengthening domestic mineral supply chains for a 21st-century economy.  Beyond furthering the understanding of the Nation’s mineral resources, these data are valuable for understanding energy and water resources; hazards (e.g., landslides, earthquakes); mine waste; abandoned wells; and other natural and anthropogenic features.

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

doi: 10.1130/abs/2026AM-15439

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