My primary research interest centers around the chemical and physical processes involved in magmatic differentiation. My work utilizes a wide range of techniques and approaches including geologic field mapping, petrologic and geochemical analysis (major and minor element geochemistry, electron micro-probe) and fluid dynamic modeling. Over the years I have had students conduct research in several areas including the Aleutian Islands, the Cascade Mountains of western Oregon and northern California, the Basin and Range province of the western U.S., and the mid-ocean ridge East Pacific Rise. These studies, largely funded by the National Science Foundation, have considered such diverse topics as the role of subducted crust in the high pressure formation of island arc basalt, the relative roles lower crustal melting, magma mixing and fractional crystallization in the formation of calc-alkaline andesitic magma, the growth and temporal evolution of low-pressure magma chambers beneath subduction-related volcanoes and, finally, the physical mechanisms of low-pressure fractional crystallization in both mid-ocean ridge and subduction zone settings. Most recently, my work has centered around: (1) the role of vapor (H2O) exsolution on the dynamics of magma ascent, crystallization and differentiation of magma; and (2) geochemical modeling of Rare-Earth Element (REE)-SiO2 systematics as a potential means of discriminating between a fractional crystallization and crustal (amphibolite) melting origin for intra-oceanic silicic magmas.
A second area of interest is one-atmosphere experimental petrology.
