Changes in physical properties of rocks during serpentinization and implications for natural hydrogen exploration

Serpentinization, transforms the physical properties of ultramafic rocks, with significant implications for natural hydrogen exploration. This study compiles and analyzes over 1,000 samples from diverse geological settings to elucidate relationships between rock properties—such as density, seismic velocities, elastic moduli, porosity, and magnetic susceptibility—and the degree of serpentinization. Our findings reveal systematic trends, including marked reductions in density and seismic velocities, and increases in porosity and magnetic susceptibility, which can serve as measurable proxies for identifying hydrogen-rich source rocks. By establishing robust empirical and cross-property relationships, we offer predictive rock physics tools to enhance geophysical exploration and reduce interpretation uncertainties in hydrogen exploration. Furthermore, this work uses differential effective medium models to capture rock property changes during serpentinization, laying the groundwork for further rock physics modeling. These insights not only improve the understanding of subsurface hydrogen systems but also pave the way for innovative exploration strategies in the growing field of natural hydrogen exploration.