SEISMOLOGY AND GEOLOGY ›› 2010, Vol. 32 ›› Issue (1): 51-58.DOI: 10.3969/j.issn.0253-4967.2010.01.005

• Brief Report • Previous Articles     Next Articles

THE ELECTRICAL CONDUCTIVITY STRUCTURE OF THE EASTERN TIBETAN PLATEAU AND ITS TECTONIC IMPLICATIONS

LIU Mei1,2, BAI Deng-hai1, XIAO Peng-fei1,2   

  1. 1. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
    2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
  • Received:2009-05-25 Revised:2010-02-22 Online:2010-03-19 Published:2010-05-22

青藏高原东部岩石圈电性结构特征及其构造意义

刘美1,2, 白登海1, 肖鹏飞1,2   

  1. 1. 中国科学院地质与地球物理研究所, 岩石圈演化国家重点实验室, 北京, 100029;
    2. 中国科学院研究生院, 北京, 100049
  • 作者简介:刘美,女,1983年生,2005年毕业于中国地质大学地球物理专业,现在中国科学院地质与地球物理研究所攻读硕士学位,主要从事地球电磁学研究,电话:010-82998352,E-mail:yuelianglm@yahoo.cn.
  • 基金资助:
    国家自然科学基金重点项目(40634025)资助

Abstract: A new MT study was conducted along the profile EHS3D-3(Xiachayu of Tibet-Qingshuihe of Qinghai)in 2007.The preferred 2-D model suggests that:1)the upper crust consists of separated resistive blocks;2)in mid-lower crust there is an extensive conductor beneath Lhasa block and Qiangtang terrain respectively due to aqueous fluids and/or partial melts and are inferred to as crustal flow channels at depth of Tiebtan Plateau;3)Yarlun-Zangbo and Bangonghu-Nujiang sutures are indicated by two conductive layers dipping to the north;4)Jinshajiang Fault might be a fracture belt of upper crust that was thinned and destructed by the upwelling of the hot/conductive body at depth.

Key words: magnetotelluric sounding, EHS3D, mid-lower conductor, flow channel, the eastern Tibetan Plateau

摘要: 主要介绍青藏高原东部下察隅—清水河(EHS3D-3)剖面的大地电磁(MT)探测结果。根据2007年沿该测线观测的MT数据,经过资料处理、分析和二维反演,得到了研究区岩石圈的电性结构。结果表明:沿剖面电阻率分布具有纵向成层,横向分区的特征;上地壳由不同大小的高阻体构成;拉萨地块和羌塘地体中下地壳分别存在一个大范围的低阻体,初步认为这2个低阻体由深部流体以及部分熔融所致,可能是高原东部环绕东构造结的2个物质流通道,同时也是高原南北两侧的2个主要剪切走滑带;雅鲁藏布缝合带和班公-怒江缝合带均表现为向北逐渐加深的相对低阻带,可能是俯冲板片表面低阻物质的反映;金沙江断裂深部表现为强烈的低阻体异常,但与该区其它缝合带的电性特征区别较大。

关键词: 大地电磁测深, EHS3D, 电性结构, 通道流, 青藏高原东部

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