9506683 Tackley The PI will perform a numerical modeling study in global dynamics, with the aim of implementing a model of plate tectonics into numerical convection code, incorporating geochemical aspects into the code, studying the Earth's thermo-chemical evolution in the light of phase transitions, chemical differentiation and mixing, and plate tectonics, using a wide range of observations to constrain the model parameters. The PI will use large-scale 3-D numerical simulations on parallel supercomputers, analytical analyses, parameterized thermo-chemical history models, and interdisciplinary comparisons between results and observations. ***