Electrical conductivity of albite-(quartz)-water and albite-water-NaCl systems and its implication to the high conductivity anomalies in the continental crust
Electrical conductivity of albite-(quartz)-water and albite-water-NaCl systems and its implication to the high conductivity anomalies in the continental crust
复制标题
钠长石-（石英）-水和钠长石-水-NaCl体系的电导率及其对大陆地壳高电导率异常的意义
DOI：
10.1016/j.epsl.2014.12.021
复制
发表时间：
2015-02-15
影响因子：
5.3
通讯作者：
Shimojuku, Akira
中科院分区：
文献类型：
--
作者：
Guo, Xinzhuan;Yoshino, Takashi;Shimojuku, Akira
用阻抗谱测量了钠长石-水、钠长石-石英-水和钠长石-水-氯化钠体系在1 Gpa和400-1000K温度范围内的电导率。钠长石-石英-水体系的电导率与温度的关系不能用Arrhenian公式表示，而在含卤水体系中的电导率与温度的关系符合Arrhenian定律，表现出很小的温度依赖性。钠长石-石英-水体系的电导率在1000-800K之间随温度降低而降低，在800-550K附近进一步冷却后迅速增加。基于热力学标定，钠长石-石英-水体系的体电导率与水中溶解的H+、OH-、Na+、AlO2-和HSiO3-的总浓度随温度的变化一致。体积电导率与含水流体分数之间存在较小的负相关关系。钠长石水-氯化钠样品的电导率高于钠长石(石英)水样品的电导率，表现出以下特点：(1)电导率对温度的依赖性较小；(2)电导率随流体含量和盐度的增加而增大。结果表明，陆壳中常见的10(-1)S/m的高电导率异常可以用流体含量低至0.014的钠长石和石英在650K以下的温度下的存在来解释。在地温高于650K的情况下，10(-1)S/m的观测值可以用含盐量为1vol%的含卤钠长石来解释，如果盐度与海水相似。(C)2014爱思唯尔B.V.保留所有权利。
The electrical conductivities of albite-water, albite-quartz-water and albite-water-NaCl systems have been measured in terms of impedance spectroscopy at 1 GPa and 400-1000 K. The relationship between electrical conductivity and temperature in the albite-(quartz)-water system cannot be expressed by the Arrhenian formula, whereas that in the brine-bearing system follow the Arrhenian law showing small temperature dependence. The electrical conductivity of the albite-(quartz)-water samples decreased with decreasing temperature from 1000 to 800 K, then increased rapidly upon further cooling from 800 to around 550 K. The bulk conductivities of the albite-(quartz)-water system are consistent with variation of the total concentration of the dissolved electric charge carriers of H+, OH-, Na+, AlO2- and HSiO3- in aqueous fluid with temperature based on the thermal dynamic calibration. There is a small negative dependence of bulk conductivity on aqueous fluid fraction. Electrical conductivity of the albite-water-NaCl samples is higher than that of the albite-(quartz)-water samples, which shows the following features: (1) small dependence of conductivity on the temperature; (2) increase of electrical conductivity with the fluid fraction and the salinity. Our results suggest that the high conductivity anomalies of 10(-1) S/m typically observed in the continental crust can be explained by the presence of albite and quartz with fluid fraction as low as 0.014 at temperatures lower than 650 K. In the case that the geotherm is higher than 650 K, the observed value of 10(-1) S/m can be explained by the brine-bearing albite with a fluid fraction of 1 vol% if the salinity is similar to the seawater. (C) 2014 Elsevier B.V. All rights reserved.