9706214 Grove This project will carry out a series of coordinated experimental, field and theoretical studies aimed at understanding the processes, conditions of formation and chemical evolution of subduction zone magmas. Experimental melting studies of peridotite and peridotite-analog bulk compositions at 1 to 3 GPa will investigate the effects of variable amounts of H2O (up to 8 wt. %) on the melting of the mantle wedge above the subduction zones. Experiments performed under crustal pressure (100 to 800 MPa) and H2O-saturated conditions on basaltic andesites, andesites and andesite-analog compositions will provide information on model fractional crystallization of subduction zone magams. Field studies in the Southern Cascade Range, U.S.A. to investigate spatially and temporally related lava flows will provide input fo rthe mantle melting and fractional crystallization studies. Modeling studies will reproduce the physical conditions of melt generation in the mantle wedge. The primary objective of this work is to understand factors that control the development of subduction-related magmatism globally.
