黑云斜长片麻岩电导率研究  

ELECTRICAL CONDUCTIVITY OF BIOTITE-PLAGIOCLASE GNEISS AT HIGH TEMPERATURE AND HIGH PRESSURE

作　　者：郭颖星[1,2,3] 王多君[2,3] 李丹阳[2,3] 陈小斌[4] 

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国科学院计算地球动力学重点实验室,北京100049 [3]中国科学院大学地球科学学院,北京100049 [4]中国地震局地质研究所,北京100029

出　　处：《地震地质》2014年第3期907-917,共11页Seismology and Geology

基　　金：中国科学院;国家外国专家局创新团队国际合作伙伴计划(KZZD-EW-TZ19);中国地震局地质研究所基本科研业务专项(IGCEA1005);国家自然科学基金(41074063);中国科学院知识创新工程重要方向项目(KZCX2-YW-QN608)共同资助

摘　　要：在压力为1.0GPa、温度为400～1 073K条件下,用交流阻抗谱法研究了采自山东泰山的黑云斜长片麻岩平行及垂直面理方向的电导率.在实验温度范围内,黑云斜长片麻岩实验样品电导率的对数值为-6.0～0.5S/m,满足Arrhenius方程.电导率在平行面理方向比垂直面理方向高出约1个数量级.平行面理方向样品电导率分别在第3轮升、降温过程中的881～1 040K之间出现1个明显的电导率突变过程,这可能与黑云母的脱水有关.在低温段,垂直及平行面理方向样品的活化焓分别为0.43和0.49eV,在高温段则分别为3.40和1.53eV.将该实验电导率结果与华东地区大地电磁结果进行对比发现,在中下地壳范围内,该实验结果部分位于大地电磁结果范围内,说明黑云斜长片麻岩可能是组成这一地区中下地壳的候选岩石之一.The electrical conductivity of biotite-plagioclase gneiss was investigated at pressure of 1GPa and temperatures from 400 to 1073K by impedance spectroscopy within a frequency range of 10-1 to 106Hz.The electrical conductivity of the samples increases with increasing temperature,which can be described approximately as the Arrhenius equation.The logarithm of electrical conductivity varies from-6 to-0.5S/m at the range of 400 to 1073K.The measurement results reveal that the conductivities of samples with different orientations differ by an order of magnitude at the same temperature.The electrical conductivity parallel to foliation shows abrupt change in the temperature range of 881 ～ 1040K in the third heating and cooling cycle,which may be associated with the dehydration of biotite.The calculated activation enthalpies are 0.49eV （parallel to foliation）and 0.43eV （perpendicular to foliation）for low temperatures and 1.53eV （parallel）and 3.40eV （perpendicular） for high temperatures,respectively.The experiment results are compared with the magnetotelluric observations of the middle and lower crust in East China,our model is consistent with the electrical conductivity structures derived from geophysical observations.Our results indicate that the biotite-plagioclase gneiss may be one of the candidate rocks in this region.

关 键 词：高温高压 电导率 黑云斜长片麻岩 

分 类 号：P313[天文地球—固体地球物理学]