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Large effect of water on Fe–Mg interdiffusion in garnet | |
Baohua Zhang; Bowen Li; Chengcheng Zhao; Xiaozhi Yang | |
2019 | |
发表期刊 | Earth and Planetary Science Letters |
卷号 | 505页码:20-29 |
摘要 | The effect of water on the kinetics of Fe–Mg interdiffusion in garnet was investigated at 3 GPa and 1373–1673 K using diffusion couples of pyrope and almandine aggregates, over a wide range of water content (CH2O) from <7 up to ∼1260 wt. ppm. Diffusion profiles were measured by electron microprobe, and the obtained data were fitted by the Boltzmann–Matano equation. Our results show that Fe–Mg interdiffusion coefficient (DFe–Mg) is nearly independent of the composition of garnet over a wide range of Fe/Mg ratios (with XFe ranging from 0 to 1). The determined DFe–Mg can be described by the following Arrhenius relation: DFe–Mg (m2/s) = D0Cr H2O exp(−H/R T ), where log(D0) = −1.70 ± 0.50, r = 1.38 ± 0.06, and H = 310 ± 33 kJ/mol. The exponent r of 1.38 implies the incorporation mechanism of water is hydrogen associated with metal and partly silicon vacancies to form neutral point defect complexes. While at the same time, it also suggests a profound role of water in enhancing the Fe– Mg interdiffusion in garnet. With increasing water content from 100 to 1260 wt. ppm H2O, the Fe–Mg inter-diffusivity is enhanced by about two orders of magnitude, comparable to the effect of temperature increased by about 300 ◦C under dry condition. Such large effect of water on the kinetics of garnet is expected to have important implications for evaluating the closure temperature of available geospeedometry and geothermometry。 |
关键词 | Fe–mg Interdiffusion garnet water point Defects closure Temperature |
收录类别 | SCI |
语种 | 英语 |
文献类型 | 期刊论文 |
条目标识符 | http://ir.gyig.ac.cn/handle/42920512-1/10509 |
专题 | 地球内部物质高温高压实验室 |
作者单位 | 1.Key Laboratory for High-Temperature and High-Pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China 2.University of Chinese Academy of Sciences, Beijing 100049, China 3.Institute for Planetary Materials, Okayama University, Misasa, Tottori 682-0193, Japan 4.State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China |
推荐引用方式 GB/T 7714 | Baohua Zhang;Bowen Li;Chengcheng Zhao;Xiaozhi Yang. Large effect of water on Fe–Mg interdiffusion in garnet[J]. Earth and Planetary Science Letters,2019,505:20-29. |
APA | Baohua Zhang;Bowen Li;Chengcheng Zhao;Xiaozhi Yang.(2019).Large effect of water on Fe–Mg interdiffusion in garnet.Earth and Planetary Science Letters,505,20-29. |
MLA | Baohua Zhang;Bowen Li;Chengcheng Zhao;Xiaozhi Yang."Large effect of water on Fe–Mg interdiffusion in garnet".Earth and Planetary Science Letters 505(2019):20-29. |
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Large effect of wate(3304KB) | 期刊论文 | 作者接受稿 | 开放获取 | CC BY-NC-SA | 浏览 请求全文 |
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