Determination of redox conditions from the Fe oxidation state of epidote and lawsonite in subducted oceanic crust

The goal of this project is to evaluate redox conditions and trends in subducted oceanic crust by determining compositions of zoned, transition-metal-bearing minerals and evaluating the results as a function of P-T conditions. This study will track element budgets in metamorphic minerals, particularly those that are sources and sinks of Fe3+ by determining the Fe oxidation state with Fe K-edge Micro-XANES. It will extend the database on the role of Fe oxidation state in metamorphic reactions, which is a pre-requisite for developing thermodynamic models that will eventually allow tracing the evolution of redox conditions from the subducted oceanic crust to the mantle melts in subduction-related volcanism.