REDOX systematics of hydrous mantle rocks and fluid-mediated redox budget and mass transfer with their progressive subduction

Aqueous fluids are a relevant driving force for mass transport and govern the geodynamic evolution of subduction zones and, ultimately, of planet Earth. Quantification of fluid-mediated chemical and redox budget cycling lags behind our petrologic and geodynamic understanding of subduction zone processes.

This project aims at quantifying the geochemistry and redox conditions of subducting hydrous mantle rocks, with focus on the antigorite dehydration reaction and beyond, working on natural samples from the central European Alps. We emphasize processes affecting redox budget and element transfer between reservoirs in the deep subduction context. Focus thereby is on the measurement of ferric/ferrous iron speciation for ferromagnesian silicate and oxide minerals, on the bulk composition of antigorite-dehydration fluid inclusion relics including S and halogen concentrations, and on the fate and speciation of carbon in meta-ophicarbonate. Together, these data shall help constraining the fluid mobility of elements relevant for potential redox budget transfer - or its fixation in product minerals of dehydration reactions - and, ultimately, will shed more light on fluid-mediated redox budget and element cycling associated with subduction zones.