The Effect of Water on Fe‐Mg Interdiffusion Rates in Ringwoodite and Implications for the Electrical Conductivity in the Mantle Transition Zone | |
Baohua Zhang; Takashi Yoshino; Chengcheng Zhao | |
刊名 | Journal of Geophysical Research: Solid Earth |
2019 | |
页码 | 2510-2524 |
英文摘要 | We determined the kinetics of Fe‐Mg interdiffusion in ringwoodite aggregates as a function of water content (up to ~6,000 wt. ppm H2O) at 20 GPa and 1,373–1,673 K by the diffusion couple method. The dependence of Fe‐Mg interdiffusivity (DFe‐Mg) on Fe concentration was determined using the Boltzmann‐Matano method. The experimentally reported DFe‐Mg in ringwoodite within 0 ≤ XFe ≤ 0.1 could be fitted by the relation , where E* = (1 − XFe)EMg + XFeEFe (EMg = 140 ± 5 kJ/mol, EFe = 4 ± 2 kJ/mol), D0 = × 10−10 m2/s, n = −0.21 ± 0.10, r = 0.25 ± 0.03, and α = −24 ± 4. The water content exponent r of 0.25 suggests a nonnegligible role of water in enhancing Fe‐Mg interdiffusion in ringwoodite. The length scale over which the chemical heterogeneities are homogenized by Fe‐Mg interdiffusion in the mantle transition zone is estimated to be only a few hundred meters even assuming the whole Earth age. Comparison between the conductivities predicted from Fe‐Mg interdiffusion and those obtained from magnetotelluric surveys suggests that around 0.1 wt.% water can account for the high conductivity anomalies (~10−0.6–10−1 S/m) observed in the lower part of the mantle transition zone. |
语种 | 英语 |
内容类型 | 期刊论文 |
源URL | [http://ir.gyig.ac.cn/handle/42920512-1/10594] |
专题 | 地球化学研究所_地球内部物质高温高压实验室 |
作者单位 | 1.Institute for Planetary Materials, Okayama University, Tottori, Japan 2.Key Laboratory for High Temperature and High Pressure Study of the Earth's Interior, Institute of Geochemistry,Chinese Academy of Sciences, Guiyang, China |
推荐引用方式 GB/T 7714 | Baohua Zhang;Takashi Yoshino;Chengcheng Zhao. The Effect of Water on Fe‐Mg Interdiffusion Rates in Ringwoodite and Implications for the Electrical Conductivity in the Mantle Transition Zone[J]. Journal of Geophysical Research: Solid Earth,2019:2510-2524. |
APA | Baohua Zhang;Takashi Yoshino;Chengcheng Zhao.(2019).The Effect of Water on Fe‐Mg Interdiffusion Rates in Ringwoodite and Implications for the Electrical Conductivity in the Mantle Transition Zone.Journal of Geophysical Research: Solid Earth,2510-2524. |
MLA | Baohua Zhang;Takashi Yoshino;Chengcheng Zhao."The Effect of Water on Fe‐Mg Interdiffusion Rates in Ringwoodite and Implications for the Electrical Conductivity in the Mantle Transition Zone".Journal of Geophysical Research: Solid Earth (2019):2510-2524. |
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