Quantifying Geochemical Exchange at the Slab-Wedge Interface in the Higashi-Akaishi Peridotite Japan

Quantifying Geochemical Exchange at the Slab-Wedge Interface in the Higashi-Akaishi Peridotite Japan Quantifying Geochemical Exchange at the Slab-Wedge Interface in the Higashi-Akaishi Peridotite, Japan" Quantifying the chemical reactions that result from the recycling of tectonic plates in the presence of H2O-bearing volatiles at subduction zones is fundamental to understanding the differentiation history of our planet, and its unique evolution among the terrestrial planets in our solar system. Despite wide acceptance that slab-derived fluids trigger mantle melting beneath arc volcanoes, many questions remain about the specifics of chemical transfer via fluids and/or melts from the subducting slab to the locations of magma genesis in the mantle wedge. Specific questions include: 1) are hydrous minerals, specifically chlorite, formed at the base of the mantle wedge a key player in the formation of arc magmas as hypothesized by high-pressure experiments and studies of boron isotope fractionation?, 2) how do melts of subducted sediment react with mantle wedge to form arc magmas?, and 3) what is the oxidation state of the mantle and near solidus arc magmas at the base of the mantle wedge? We propose in-situ analyses of the major and trace element, Fe3+/FeT, and boron isotopic composition of rare peridotite and eclogite minerals from the Higashi-akaishi ultramafic complex, Japan that represent residues and trapped melts exhumed from the base of the mantle wedge to resolve these questions and quantify chemical reactions near the slab-wedge interface. These data will also be used to constrain starting compositions for high-pressure experiments on sediment melt-mantle wedge reactions where in-situ chemical and isotopic analyses alone are insufficient to resolve the outstanding questions.