GEOLOGIC ANALYSES TO GUIDE FIELD SURVEYS OF POTENTIAL HYDROGEN EMISSIONS ASSOCIATED WITH CHROMITE DEPOSITS IN OPHIOLITE COMPLEXES IN CALIFORNIA

This study develops geological analyses to identify candidate locations for hydrogen emissions in California's ophiolite complexes, focusing on chromite deposits. Recent research suggests a connection between hydrogen (H2) emissions and chromite deposits that may indicate the potential for past or current serpentinization processes in ultramafic rocks. Podiform chromite deposits are associated with ultramafic rocks throughout California, particularly on the eastern slopes of the Sierra Nevada Mountains and the California Coast Range. We identified a subset of recorded chromite mines in Tuolumne County that lie on or close to mapped faults that could enable transport of hydrogen from subsurface stores or from active serpentinization. Fault locations were determined using satellite and lidar data. The candidate sites will be surveyed for soil hydrogen concentrations at a depth of 1 meter for statistical assessment of possible subsurface hydrogen outgassing. This study aims to enhance our understanding of geologic sites associated with natural hydrogen emissions and their potential as a clean energy resource.