高温高压菱镁矿电导率实验研究  

An experimental study on the electrical conductivity of magnesite under high temperature and high pressure

作　　者：亓玉青 胡海英[1] 代立东[1] 孙文清[1] 王梦琦 景称心 胡仔明 QI Yu-qing;HU Hai-ying;DAI Li-dong;SUN Wen-qing;WANG Meng-qi;JING Chen-xin;HU Zi-ming(Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球化学研究所地球内部物质高温高压重点实验室,贵州贵阳550081 [2]中国科学院大学,北京100049

出　　处：《矿物学报》2022年第1期14-20,共7页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(编号:41772042,41774099,42072055);中国科学院“西部之光”A类项目。

摘　　要：在俯冲带中,菱镁矿相比于其他碳酸盐矿物会在更高的温度压力环境下稳定存在,常被认为是地球深部碳循环的主要载体,其电学性质的研究对俯冲带及地球深部的电性结构具有重要的意义。本文在YJ-3000t高温高压设备上利用Solartron-1260阻抗/增益-相位分析仪,在1~3 GPa和773~1173 K条件下,对天然菱镁矿的电导率进行了原位测量。实验结果表明,在实验条件下,天然菱镁矿的电导率在10;~10;S/m范围内,菱镁矿的电导率对温度有很强的依赖性,随着温度的升高,电导率增大,电导率与压力的关系呈正相关,随着压力的升高而增强。结合前人的研究成果及样品电导率随温度、压力的效应和活化能,可推断天然菱镁矿导电机制为大极化子导电。Magnesite, relative to other carbonate minerals, can be stable at higher temperature and pressure conditions in the subduction zone, hence it is regarded as the main carrier of carbon cycle in the deep interior of the earth. Its electrical properties are of great significance for understanding the electrical structures of the subduction zone and the deep interior of the earth. In this study, the electrical conductivities of natural magnesite samples, which were in the YJ-3000 t multi-anvil apparatus under the conditions of 1~3 GPa and 773~1173 K, have been measured in-situ by using the Solartron-1260 impedance/gainphase analyzer. The results show that the conductivities of natural magnesite samples under experimental conditions vary from 10;S/m to 10;S/m, and they are increased with the increase of temperature and pressure. The dependency of electrical conductivity of magnetite on temperature is much stronger than that on pressure.Combined with the previous research results and the temperature and pressure effect and activation energy influence characteristics of electrical conductivities(Arrhenius parameters) of magnesite samples in this study, it is proposed that the dominant conduction mechanism of magnesite at high temperature and high pressure is the large polaron conduction.

关 键 词：菱镁矿 电导率 高温高压 导电机制 

分 类 号：P319.2[天文地球—固体地球物理学]