Evidence of hydrothermal fluid circulation driving elemental mass redistribution in an active fault zone

Abstract Important fault zone processes can be discerned from the characterization of fracture damage and chemical transformations associated with active seismic sources. To characterize 2010 M7.2?El Mayor-Cucapah rupture zone, continuous samples core 23 damaged rock were collected perpendicular to strike Borrego fault. Samples analyzed for clay mineralogy, bulk geochemistry, grain density which porosities volumetric strains derived. Prior forming, tonalitic protolith, containing chlorite, epidote, titanite, was subjected temperatures ?330–340?°C during deuteric alteration. Rocks within are partially pulverized contain abundant cataclastic seams. Porosity strain peak in zones 1.5?m–10.5?m core. Within these zones, losses Ca P mass, increases Mg Na along conservation Fe Si mass consistent oxidizing acidic conditions at