Satellite-Based Alteration Mapping for Beryllium Resource Delineation at Spor Mountain: A Scalable Framework for Critical Mineral Exploration

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Beryllium is designated a U.S. critical mineral due to its essential role in aerospace, defense, telecommunications, nuclear systems, and emerging electrification technologies. Spor Mountain, Utah, hosts the world's largest known bertrandite resource and represents a strategic domestic supply. However, direct spectral detection of bertrandite is limited by weak diagnostic absorption features and fine-grained intergrowth with silica and clay minerals. This study develops a satellite-based exploration framework that emphasizes alteration-proxy mapping to support critical mineral assessment and resource targeting. We integrate Sentinel-2, Landsat-8/9, and ASTER multispectral datasets with field-validation to characterize hydrothermal alteration assemblages genetically associated with bertrandite mineralization in Miocene topaz-bearing rhyolitic tuffs. Custom Sentinel-2 band ratios and composite indices were designed to enhance detection of Al-OH-rich clays (kaolinite-illite), silicification fronts, Fe-oxide alteration, and F-enriched lithologies. ASTER SWIR data further refine clay mineral discrimination in arid terrains where surface exposure is optimal. Structural interpretation from satellite imagery and SAR backscatter analysis constrains fracture-controlled fluid pathways linked to mineral emplacement. Regional-scale (>100 km²) mapping delineates alteration domains consistent with known mineralized trends and previously developed mine footprints. Results demonstrate that indirect spectral indicators, particularly alteration intensity and clay chemistry variation, provide robust proxies for beryllium-bearing systems where the ore mineral itself lacks strong spectral contrast. This work establishes a reproducible, satellite-based workflow for reconnaissance-to-target scale evaluation of bertrandite-hosted systems in peralkaline volcanic provinces. The approach supports domestic critical mineral supply assessments, reduces early-stage exploration risk, and provides…