Si and O self-diffusion in hydrous forsterite and iron-bearing olivine from the perspective of defect chemistry |
| |
Authors: | Hongzhan Fei Tomoo Katsura |
| |
Institution: | 1.Institute for Study of the Earth’s Interior,Okayama University,Misasa,Japan;2.Bayerisches Geoinstitut,University of Bayreuth,Bayreuth,Germany |
| |
Abstract: | We discuss the experimental results of silicon and oxygen self-diffusion coefficients in forsterite and iron-bearing olivine from the perspective of defect chemistry. Silicon diffusion is dominated by VO ··-associated VSi″″, whereas oxygen diffusion is dominated by hopping of VO ·· under anhydrous conditions, and by (OH)O · under hydrous conditions. By considering the charge neutrality condition of (OH)O ·] = 2VMe″] in hydrous forsterite and iron-bearing olivine, we get D Si ∝ (\(C_{{{\text{H}}_{2} {\text{O}}}}\))1/3 and D O ∝ (\(C_{{{\text{H}}_{2} {\text{O}}}}\))0, which explains the experimental results of water effects on oxygen and silicon self-diffusion rates (Fei et al. in Nature 498:213–215, 2013; J Geophys Res 119:7598–7606, 2014). The \(C_{{{\text{H}}_{2} {\text{O}}}}\) dependence of creep rate in the Earth’s mantle should be close to that given by Si and O self-diffusion coefficients obtained under water unsaturated conditions. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|