This proposal for the third and fourth year of an intended six-year project, will determine the trace element and isotopic systematics (Sr, Nd, Pb) of minerals and whole-rocks from contiguous layers in the Horman Peridotite. These data are being integrated with new and previous whole-rock and mineral major element analyses. Interpretations of the comprehensive data generated in this collaborative U.S.-Japan effort will enable the PIs to understand the processes that created compositional variations and layering within the Horoman Peridotite. As a result, they expect to significantly improve the understanding of melt formation, migration and segregation in the upper mantle. In addition, this peridotite is in an arc tectonic setting, and it may be an example of how oceanic asthenosphere is modified by subduction processes. Therefore, the results of this research may contribute to an understanding of the arc volcanism that results from plate convergence.
