Zhang Bao-Hua, Guo Xuan, Yoshino Takashi, Xia Qun-Ke
Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China.
CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
Natl Sci Rev. 2021 Apr 12;8(11):nwab064. doi: 10.1093/nsr/nwab064. eCollection 2021 Nov.
Magmatic liquids, including silicate and carbonate melts, are principal agents of mass and heat transfer in the Earth and terrestrial planets, and they play a crucial role in various geodynamic processes and in Earth's evolution. Electrical conductivity data of these melts elucidate the cause of electrical anomalies in Earth's interior and shed light on the melt structure. With the improvement in high-pressure experimental techniques and theoretical simulations, major progress has been made on this front in the past several decades. This review aims to summarize recent advances in experimental and theoretical studies on the electrical conductivity of silicate and carbonate melts of different compositions and volatile contents under high temperature and pressure. The electrical conductivity of silicate melts depends strongly on temperature, pressure, water content and the ratio of non-bridging oxygens to tetrahedral cations (NBO/T). By contrast, the electrical conductivity of carbonate melts exhibits a weak dependence on temperature and pressure due to their fully depolymerized structure. The electrical conductivity of carbonate melts is higher than that of silicate melts by at least two orders of magnitude. Water can increase electrical conductivity significantly and reduce the activation energy of silicate melts. Conversely, this effect is weak for carbonate melts. In addition, the replacement of alkali-earth elements (Ca or Mg) with alkali elements causes a significant decrease in the electrical conductivity of carbonate melts. A distinct compensation trend is revealed for the electrical conductivity of silicate and carbonate melts under anhydrous and hydrous conditions. Several important applications of laboratory-based melt conductivity are introduced in order to understand the origin of high-conductivity anomalies in the Earth's mantle. Perspectives for future studies are also provided.
岩浆液体，包括硅酸盐熔体和碳酸盐熔体，是地球及类地行星中质量和热量传输的主要媒介，它们在各种地球动力学过程及地球演化中发挥着关键作用。这些熔体的电导率数据有助于阐明地球内部电异常的成因，并揭示熔体结构。随着高压实验技术和理论模拟的改进，在过去几十年里这方面已取得重大进展。本综述旨在总结近年来关于不同成分和挥发物含量的硅酸盐熔体及碳酸盐熔体在高温高压下电导率的实验和理论研究进展。硅酸盐熔体的电导率强烈依赖于温度、压力、含水量以及非桥氧与四面体阳离子的比例（NBO/T）。相比之下，碳酸盐熔体的电导率因其完全解聚的结构而对温度和压力的依赖性较弱。碳酸盐熔体的电导率比硅酸盐熔体的电导率至少高两个数量级。水可显著提高电导率并降低硅酸盐熔体的活化能。相反，这种效应在碳酸盐熔体中较弱。此外，用碱金属取代碱土元素（Ca或Mg）会导致碳酸盐熔体的电导率显著降低。在无水和含水条件下，硅酸盐熔体和碳酸盐熔体的电导率呈现出明显的补偿趋势。为了理解地球地幔中高电导率异常的起源，介绍了基于实验室熔体电导率的几个重要应用。还提供了未来研究的展望。
