Investigation of the differentiation of mantle lithosphere and asthenosphere and growth of continental and oceanic crust requires a thorough understanding of mineral, melt and fluid phase relationships and physical properties from ambient to high-pressure-temperature conditions, often beyond experimental capability. Beyond what we can learn directly from seismological techniques or from deep materials transported to the Earth's surface, we rely heavily on a combination of theory-based extrapolation of material properties and computational simulation of geomaterial properties at deep Earth conditions. To help achieve these ends, my research has dealt with the thermodynamics and transport properties of some high-PT geosilicate systems. In particular, (1) a new thermodynamic model has been developed for mineral solubility in aqueous (H2O-rich) fluids at pressures up to 5 GPa (e.g.

mantle metasomatism and partial melting in subduction zones) based on Generalized Born theory using a simple model that relates mineral solubility to the dielectric constant of supercritical H2O, (2) results for the Equation of State, structure and transport properties from 0--30 GPa and 2000--5500 K for liquid CaMgSi2O6, an important component of the mantle based on Molecular Dynamics simulations are presented, (3) phase-equilibria based simulation results representing the behavior of a set mafic magma types in response to contamination by mafic to silicic and pelitic country rock via Energy-Constrained Assimilation-Fractional Crystallization (EC-AFC) processes, and (4) Ten new 40Ar/39Ar eruption ages for the western Aeolian Islands, southern Italy are presented and utilized to constrain the late Quaternary insular uplift history, demonstrating that all seven islands in this archipelago except Alicudi have experienced a similar uplift rate since c.

125 ka during periods of volcanic quiescence, while uplift/subsidence rates vary dramatically during periods of volcanic activity on the islands of Alicudi and Filicudi.