Electrical Conductivity of Clinopyroxene-NaCl-H2O System at High Temperatures and Pressures: Implications for High-Conductivity Anomalies in the Deep Crust and Subduction Zone
Electrical Conductivity of Clinopyroxene-NaCl-H2O System at High Temperatures and Pressures: Implications for High-Conductivity Anomalies in the Deep Crust and Subduction Zone
复制标题
高温高压下单斜辉石-NaCl-H2O体系的电导率：对地壳深部和俯冲带高电导率异常的影响
DOI：
10.1029/2019jb019093
复制
发表时间：
2020
影响因子：
3.9
通讯作者：
Wang Mengqi
中科院分区：
文献类型：
--
作者：
Sun Wenqing;Dai Lidong;Li Heping;Hu Haiying;Jiang Jianjun;Wang Mengqi
在673-973 K和1 GPa下，测量了单斜辉石（Cpx）-NaCl-H2O体系在不同盐度（5，10，15，20，25 wt%）和流体体积分数（5，10，15，20，25 vol%）下的电导率。为了与Cpx-NaCl-H2O系统的电性能进行比较，在相同的温度和压力下研究了干燥Cpx、含水Cpx和Cpx-H2O系统的电导率。实验结果表明：（1）所有样品的电导率与温度和Cpx的关系符合Arrhenius关系，其活化焓随盐度的增加而降低（盐水中NaCl的质量分数）和流体分数（Cpx-NaCl-H2O系统中生理盐水的体积分数）;（2）在固定流体体积分数为10%时，Cpx-NaCl-H2O体系的电导率随盐度的增加而略有增加，含5和25wt%盐水的体系电导率之间的差距约为1个数量级;（3）在5wt%的固定盐度下，Cpx-NaCl-H2O体系的电导率（25体积%）盐水流体比具有5体积%盐水流体的系统高大约1.5个数量级。青藏高原南部、大别造山带、格伦维尔省和新西兰中部的异常高电导率可能是由单斜辉石与具有相应盐度和流体组分的相互连通的含盐流体引起的。
Electrical conductivities of the clinopyroxene (Cpx)‐NaCl‐H2O system with various salinities (5, 10, 15, 20, 25 wt%) and fluid fractions (5, 10, 15, 20, 25 vol%) were measured at 1 GPa and 673–973 K. For comparison with electrical properties of the Cpx‐NaCl‐H2O system, the conductivities of dry Cpx, hydrous Cpx, and a Cpx‐H2O system were researched at the same temperature and pressure. The experimental results included (1) the electrical conductivities of all samples that were associated with Cpx and the temperatures conform to the Arrhenius relationship that is used to fit the activation enthalpy, which decreased with increasing salinity (mass fraction of NaCl in saline fluids) and fluid fraction (volume fraction of saline fluids in the Cpx‐NaCl‐H2O system); (2) at a fixed fluid fraction of 10 vol%, the conductivities of the Cpx‐NaCl‐H2O system increased slightly with an increase in salinity, and the gap between the conductivities of the systems with 5 and 25 wt% saline fluids was approximately 1 order of magnitude; (3) at a fixed salinity of 5 wt%, the conductivity of the Cpx‐NaCl‐H2O system with 25 vol% saline fluids was approximately 1.5 orders of magnitude higher than that of the system with 5 vol% saline fluids. Furthermore, it was proposed that the unusually high conductivities of southern Tibetan Plateau, Dabie Orogen, Grenville province and central New Zealand can be caused by clinopyroxene with interconnected saline fluids with corresponding salinities and fluid fractions.