青藏高原西缘壳幔电性结构与断裂构造: 札达-泉水湖剖面大地电磁探测提供的依据

金胜; 叶高峰; 魏文博; 邓明; 景建恩

青藏高原西缘壳幔电性结构与断裂构造: 札达-泉水湖剖面大地电磁探测提供的依据

金胜^{1, 2,},
叶高峰^{1, 2},
魏文博^{1, 2},
邓明^{1, 2},
景建恩^{1, 2}

1.
地质过程与矿产资源国家重点实验室和地下信息探测技术与仪器教育部重点实验室, 北京 100083
2.
中国地质大学地球物理与信息技术学院, 北京 100083

基金项目:

国家自然科学基金项目 4040406

北京市重点学科“地球探测与信息技术” XK104910598

详细信息

作者简介:
金胜(1970-), 男, 副教授, 主要从事地球物理电法勘探的教学与研究工作.E-mail: jinsheng@cugb.edu.cn

中图分类号: P631.3
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出版历程
- 收稿日期: 2007-04-12
- 刊出日期: 2007-07-25

The Electrical Structure and Fault Feature of Crust and Mantle of Western Tibet Plateau: Based on Results of Magnetotelluric Survey along Profile Zhada-Quanshuihu

JIN Sheng^{1, 2
,},
YE Gao-feng^{1, 2},
WEI Wen-bo^{1, 2},
DENG Ming^{1, 2},
JING Jian-en^{1, 2}

1.
State Key Laboratory of Geological Processes and Mineral Resources; Geo-detection Laboratory of the Ministry of Education, Beijing 100083, China
2.
School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China

摘要

摘要: 青藏高原西缘札达至泉水湖剖面大地电磁探测结果表明, 研究区被雅江缝合带、班公-怒江缝合带划分为3个构造区域, 由南至北分别为喜玛拉雅地体、冈底斯地体和羌塘地体.研究区内普遍存在中下地壳高导层, 高导层的顶面埋深起伏较大, 冈底斯内的高导层埋深大, 羌塘和喜玛拉雅地体内的高导层埋深较浅.在班公-怒江缝合带南侧高导层埋深最大, 班公-怒江缝合带南北两侧高导层埋深存在一个约20km的错动.冈底斯地体内的地壳高导层呈北倾形态, 南羌塘的地壳具有双高导层.沿剖面的上地壳存在多组规模不等、产状不同的电性梯度带或畸变带, 反映了沿剖面地区的缝合带与断裂带分布情况.根据电性结构特征, 推断了雅江缝合带、班公-怒江缝合带以及龙木措、噶尔藏布等主要断裂的构造特征与空间分布.
- 青藏高原西缘 /
- 大地电磁探测 /
- 地壳高导层 /
- 电性结构 /
- 断裂构造特征
Abstract: The research of magnetotelluric (MT) on the profile along Zhada-Quanshuihu on the west of the Tibetan plateau shows that the area is divided into three structural parts by Yalung Tsangpo suture and Bangong-Nujiang suture. From south to north they are Himalaya terrane, Gandese terrane and Qiangtang terrane. The area is widely distributed with high conductive layers, with fluctuating tops. The high conductive layer of Gandese terrane is deeper while that of Qiangtang terrane and Himalaya terrane is shallower. And the deepest high conductive layer is along the south of Bangong-Nujiang suture. The top surface of high conductive layer in the south Bangong-Nujiang suture is at the depth of about 20 km, which is lower than that in north of Bangong-Nujiang suture. The high conductive layer inside Gandese terrane extends northward and in the southern Qiangtang there exist double high conductive layers. In the upper crust along the profile there are groups of lateral electrical gradient zones or distortion zones of different scale and attitude, indicating the distribution of faults and sutures along the profile. According to the character of electrical structure, the structural characteristic and spatial distribution of Yalung Tsangpo suture, Bangong-Nujiang suture and the major faults of Longmucuo and Ger-Zangbo were inferred.
- west of the Tibetan plateau /
- magnetotelluric (MT) /
- high conductive layers of crust /
- electrical structure /
- structural characteristic of fault

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图 1 测线位置

Fig. 1. Sketch map of MT profile (0 Line)

下载: 全尺寸图片幻灯片

图 2 札达-泉水湖剖面地下介质电性主轴分析结果

Fig. 2. Fig2. Geoelectric strike directions of MT profile from Zhada to Quanshuihu

下载: 全尺寸图片幻灯片

图 3 札达—泉水湖剖面壳幔二维导电性结构模型

Fig. 3. Resistivity model of MT profile from Zhada to Quanshuihu from 2D inversion

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图 4 札达—泉水湖剖面TMTE模式二维非线性共轭梯度反演拟合结果

Fig. 4. Fitting results of Zhada Quanshuihu profile from NLCG 2D inversion

下载: 全尺寸图片幻灯片

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