No effect of water on oxygen self-diffusion rate in forsterite

Abstract

We systematically measured oxygen self-diffusion coefficients (DO) in forsterite along b crystallographic axis at a pressure of 8 GPa and temperatures of 1600-1800 K, over a wide range of water content (CH2O) from 1 up to ~800 weight ppm. The experimental results suggest that DOα(CH2O)0.05±0.06 ≈ (CH2O)0. Thus, water has no significant effect on oxygen self-diffusion rate in forsterite. Since the CH2O dependence of silicon self-diffusion rate is also very small, the effect of water on olivine rheology is not significant by assuming the diffusion controlled creep mechanism.