Impedance spectroscopy analysis on electrical properties of serpentine at high pressure and high temperature  

作　　者：朱茂旭 谢鸿森 郭捷 许祖鸣 白武明 

机构地区：[1]Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China [2]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100101, China

出　　处：《Science China Earth Sciences》2001年第4期336-345,共10页中国科学（地球科学英文版）

基　　金：This work was jointly supported by the National Natural Science Foundation of China (Grant Nos.49672099, 49904005) and Open Laboratory of High Temperature and High Pressure Geodynamics, Chinese Academy of Sciences. We are indebted to Dr. Zhou Wenge for

摘　　要：The electrical conductivity of serpentine is measured and the microscopic conductance mechanisms are investigated with impedance spectroscopy at 2.5–4.0 GPa and 220–780°C. The results show that the electrical conductivity is strongly dependent on the frequencies used, and that only arc I, which reflects grain interior conductance, occurs and dominates the whole conductance processes over 12-105Hz at high pressure before dehydration. The arc II, which indicates the grain boundary process, begins to occur at the initial stage of dehydration. After dehydration, due to the presence of highly conductive networks of free water, the electrical conductivity is not dependent on frequencies any longer and the total electrical conductivity is dominated by process of ionic conductance of free water in interconnected networks. Dehydration of serpentine enhances pronouncedly the total electrical conductivity, through which highly conductive layers (HCL) may be formed in the earth’s interior.The electrical conductivity of serpentine is measured and the microscopic conductance mechanisms are investigated with impedance spectroscopy at 2.5-4.0 GPa and 220-780℃. The results show that the electrical conductivity is strongly dependent on the frequencies used, and that only arcⅠ, which reflects grain interior conductance, occurs and dominates the whole conductance processes over 12-105 Hz at high pressure before dehydration. The arcⅡ, which indicates the grain boundary process, begins to occur at the initial stage of dehydration. After dehydration, due to the presence of highly conductive networks of free water, the electrical conductivity is not depen-dent on frequencies any longer and the total electrical conductivity is dominated by process of ionic conductance of free water in interconnected networks. Dehydration of serpentine enhances pro-nouncedly the total electrical conductivity, through which highly conductive layers (HCL) may be formed in the earth's interior.

关 键 词：electrical conductivity grain interior conductance free water DEHYDRATION simulated experiments 

分 类 号：P575[天文地球—矿物学]