Electrical Conductivity of Multiphase Garnet under High-Temperature and High-Pressure Conditions  

作　　者：Kui Han Xinzhuan Guo Hanyong Liu Fengbao Ji 

机构地区：[1]Ministry of Education,Key Laboratory of Earth Exploration and Information Techniques(Chengdu University of Technology),Chengdu,610059,China [2]Bayerisches Geoinstitute,University of Bayreuth,Bayreuth,D95447,Germany [3]CAS Key Laboratory of High-Temperature and High-Pressure Study of the Earth’Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,550081,China [4]State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing,210023,China [5]Tibet Museum of Natural Science,Lhasa,850000,China

出　　处：《Journal of Earth Science》2024年第6期1849-1859,共11页地球科学学刊（英文版）

基　　金：supported by the Natural Science Foundation of China(Nos.42304109 and 42230311);the CAS“Light of West China”program(No.Y9CR026)to Xinzhuan Guo;Chengdu University of Technology(Nos.10912-KYQD2020-08600 and 80000-2020ZF11409)to Kui Han。

摘　　要：Mineral mixing,a fundamental process during mantle convection,alters the chemical composition of mantle minerals.However,the impact of this process on the electrical conductivity of mineral assemblages remains poorly understood.We measured the electrical conductivity of three single-phase garnets and their corresponding mixtures at 1.5 GPa and varying temperatures using the impedance spectroscopy within frequency from 10^(-1)to 10^(6)Hz.The electrical conductivity of dehydrated garnets is primarily controlled by their iron content,exhibiting an activation energy about 1.0 eV,indicative of small polaron conduction.The garnet mixture displays lower electrical conductivities and higher activation energies compared to their single-phase counterparts.This discrepancy of conductivity can be half order of magnitude at high temperatures(>1073 K),suggesting formation of resistive grain boundaries during the mixing process.In the mantle transition zones,grain boundary conductivity could exert a limited impact on the bulk conductivity of the interface between the stagnant slab and ambient mantle.

关 键 词：ALMANDINE impedance spectroscopy interface conductivity anomalies GARNETS MINERALS 

分 类 号：P542.5[天文地球—构造地质学] P631.3[天文地球—地质学]