The goal of this project is to understand the effects of high pressure on grain-growth in fine-grained olivine and B-phase aggregates and on dislocation recovery in olivine by the static annealing at high temperatures using the multiple anvil high pressure apparatus. This study will yield the first data set on the kinetics of grain-growth and dislocation recovery at very high pressure under well-controlled chemical environments. The results have important applications in a wide range of geological problems, including the evaluation of annealing effects in paleopiezometers, the evaluation of the effects of transformation superplasticity, and the creep mechanisms and the mechanisms of dynamic recrystallization in these minerals.