9303967 Wyllie This research project is concerned with the origin of the intrusive and extrusive siliceous magmas characteristic of compressive plate boundaries. The processes involved in the flux of materials, vapors and magmas from subducted oceanic crust, through the overlying mantle wedge, and into the continental crust will be examined by means of dehydration- melting experiments. Projects of particular interest include the dehydration melting of amphibolite and biotite- amphibole gneisses in the 10-20 kb range, phase relationships and melting products from basalt-calcite at 10 kb, and determinination of the H2O-undersaturated liquidus surface of monzodiorite as a means to address the origin of mantle-derived LILE-enriched Archean monzodiorites.