9419382 Lesher The program has as its goal to provide experimental constraints on the polybaric differentiation histories of North Atlantic magmas, and to evaluate geodynamic models of plume-initiated rifting of the Greenland-European continent. Two experimental studies will be conducted. First, the melting systematics of garnet lherzolite will be characterized at conditions inderred for the early Tertiary "Iceland" plume using the diamond aggregate technique to determine the compositions of low degree melt fractions for garnet lherzolite. Second, the partitioning of high field strength, rare earth, and transition group elements between basaltic liquids, clinopyroxene, and garnet will be measured up to 4.5 Gpa. The data obtained in this study are expected to have wider applications in the field of igneous petrology, geochemistry, and terrestrial and marine geology.