MINERAL/MATRIX PARTITION-COEFFICIENTS FOR ORTHO-PYROXENE, PLAGIOCLASE, AND OLIVINE IN BASALTIC TO ANDESITIC SYSTEMS - A COMBINED ANALYTICAL AND EXPERIMENTAL-STUDY

Mineral/matrix partition coefficients have been determined for a large suite of elements including Li, Be, Ti, V, Cr, Mo, Rb, Sr, Y, Zr, Nb, Cs, Ba, REEs, Ta, Pb, Th, and U for olivine, orthopyroxene, and plagioclase from a suite of calc-alkaline volcanics from Mt. Adams, Washington. The partition coefficients were determined via a combination of ICP-MS bulk analyses and IPMA microanalyses. The IPMA data were used to correct the larger ICP-MS data set for matrix contamination effects. Crystallization temperatures and the extent of equilibration between crystalline phases and host matrices were evaluated via 0.1 MPa phase equilibrium experiments. The result is a comprehensive set of partition coefficients, determined simultaneously on the same samples, which may be applied to studies of the petrogenesis of anhydrous calc-alkaline magmas.