Diffusion of hydrogen in (Mg,Fe)(2)SiO4 and high pressure polymorphs refined by the cB Omega model

作者：Zhang Baohua^*

来源：Journal of Asian Earth Sciences, 2012, 54-55: 9-17.

DOI：10.1016/j.jseaes.2012.02.017

• Olivine
• Wadsleyite
• Ringwoodite
• Hydrogen diffusion
• cB Omega model
• Point defect

Diffusion of hydrogen in (Mg,Fe)(2)SiO4 polymorphs is critical for understanding and quantifying kinetic processes in Earth%26apos;s interior. Here, we suggest an approach to reproduce the diffusion coefficient of hydrogen in (Mg,Fe)(2)SiO4 polymorphs as a function of temperature in terms of the bulk elastic and expansivity data. In particular, anisotropy of hydrogen diffusivity in olivine and forsterite was reproduced. On the other hand, the pressure dependence of hydrogen diffusion in (Mg,Fe)(2)SiO4 polymorphs is performed in this study. Our results show the refined diffusivities derived from the cB Omega model agree well with the experimental data if the relevant uncertainties are considered. Furthermore, the cB Omega model is also found to give a reasonable estimation of the activation enthalpy for hydrogen diffusion in (Mg,Fe)(2)SiO4 polymorphs.

• 出版日期2012-8-2