Diffusion in Fe-Mg olivine at elevated temperatures

In the process of deformation of a solid at low strain rates, the rate of atomic migration in the crystal lattice is a critical factor. Experiments designed to measure the diffusion coefficient of Fe in olivine were unsuccessful. It is theoretically shown that at temperatures greater than one-half of the melting temperature the diffusion coefficient of Mg in olivine silicate is an exponential function of temperature and pressure. [formula omitted] The results also indicate that at T > .5Tm and at nonhydrostatic stresses