Self-diffusion of oxygen and silicon in MgSiO3 perovskite

We present results of simultaneous measurements of self-diffusion of oxygen and silicon in magnesium silicate perovskite. Oxygen diffusion is similar to 2 orders of magnitude faster than Si self-diffusion and Fe-Mg interdiffusion in perovskite, with D(0) = 9.16 x 10(-4) (+0.16/-9.2 X 10(-6)) m(2)/s and Q = 501 +/- 80 kJ/mol at 25 GPa. Despite this high 0 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. (C) 2008 Elsevier B.V. All rights reserved.