Self-diffusion of oxygen and silicon in MgSiO3 perovskite

Abstract

We present results of simultaneous measurements of self-diffusion of oxygen and silicon in magnesium silicate perovskite. Oxygen diffusion is ~2 orders of magnitude faster than Si self-diffusion and Fe–Mg interdiffusion in perovskite, with D0=9.16×10−4 (+0.16/−9.2×10−6) m2/s and Q=501±80 kJ/mol at 25 GPa. Despite this high O diffusivity, however, the electrical conductivity of the lower mantle will be dominated by electronic conduction and the present-day core is likely to be out of redox equilibrium with the mantle.