气候变化领域集成服务门户(CCPortal): Electrical Conductivity in Texturally Equilibrated Fluid-Bearing Forsterite Aggregates at 800°C and 1 GPa: Implications for the High Electrical Conductivity Anomalies in Mantle Wedges

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DOI	10.1029/2020JB021343
	Electrical Conductivity in Texturally Equilibrated Fluid-Bearing Forsterite Aggregates at 800°C and 1 GPa: Implications for the High Electrical Conductivity Anomalies in Mantle Wedges
	Huang Y.; Guo H.; Nakatani T.; Uesugi K.; Nakamura M.; Keppler H.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Aqueous fluids are one of the principal agents of chemical transport in Earth´s interior. The precise determination of fluid fractions is essential to understand bulk physical properties, such as rheology and permeability, and the geophysical state of the mantle. Laboratory-based electrical conductivity measurements are an effective method for estimating the fluid distribution and fraction in a fluid-bearing rock. In this study, the electrical conductivity of texturally equilibrated fluid-bearing forsterite aggregates was measured for the first time with various fluid fractions at a constant salinity of 5.0 wt.% NaCl at 1 GPa and 800°C. We found that the electrical conductivity nonlinearly increases with increasing fluid fraction, and the data can be well reproduced by the modified Archie's law. The three-dimensional (3-D) microstructure of the interstitial pores visualized by the high-resolution synchrotron X-ray computed micro-tomography (CT) shows a change in fluid distribution from isolated pockets at a fluid fraction of 0.51 vol.% to interconnected networks at fluid fractions of 2.14 vol.% and above due to grain anisotropy and grain size differences, accounting for the nonlinear increase in electrical conductivity. The rapid increase in conductivity indicates that there is a threshold fluid fraction between 0.51 and 2.14 vol.% for forming interconnected fluid networks, which is consistent with the 3-D images. Our results provide direct evidence that the presence of >1.0 vol.% aqueous fluid with 5.0 wt.% NaCl is required to explain the high conductivity anomalies above 0.01 S/m detected in deep fore-arc mantle wedges. © 2021. The Authors.
英文关键词	Brine-bearing forsterite aggregates; electrical conductivity; mantle wedge; subduction zones; textural equilibrium; X-ray CT
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187202
作者单位	Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Miyagi, Japan; Bayerisches Geoinstitut, University of Bayreuth, Bayreuth, Germany; Spring-8, Japan Synchrotron Radiation Research Institute (JASRI), Hyogo, Japan; Geological Survey of Japan, Tsukuba, Ibaraki, Japan
推荐引用方式 GB/T 7714	Huang Y.,Guo H.,Nakatani T.,et al. Electrical Conductivity in Texturally Equilibrated Fluid-Bearing Forsterite Aggregates at 800°C and 1 GPa: Implications for the High Electrical Conductivity Anomalies in Mantle Wedges[J],2021,126(4).
APA	Huang Y.,Guo H.,Nakatani T.,Uesugi K.,Nakamura M.,&Keppler H..(2021).Electrical Conductivity in Texturally Equilibrated Fluid-Bearing Forsterite Aggregates at 800°C and 1 GPa: Implications for the High Electrical Conductivity Anomalies in Mantle Wedges.Journal of Geophysical Research: Solid Earth,126(4).
MLA	Huang Y.,et al."Electrical Conductivity in Texturally Equilibrated Fluid-Bearing Forsterite Aggregates at 800°C and 1 GPa: Implications for the High Electrical Conductivity Anomalies in Mantle Wedges".Journal of Geophysical Research: Solid Earth 126.4(2021).