Study On Electrical Structure Of East Qinling Orogenic Belt And Adjacent Region

Qinling orogenic belt,which across the central of China,is a giant belt which formed by convergence and collision of the North China Block and Yangtze Block.The orogenic belt comes through superposition of different tectonic movementand includes rock units and structures which formd by orogenesis of different ages and types.The material composition and structure feature of Qinling belt is very complex.With the theory of plate tectonics applied in the research of Qinling belt,the researchers discovered two ophiolite zones,and put forward Shangdan suture zone and Mianlue suture zone.The belt can be divided four parts by the two suture zone and Luoluan fault: North China Block,North Qinling,South Qinling,and northern margin of Yangtze Block.The Phanerozoic evolutionary process of Qinling orogenic belt is getting clear(Zhang etc,2003;Dong etc,2008,2011).Qingling orogenic belt is more than the boundary of south and north of China.it is very important for the research on inland orogenic belt of China mainland.The 3D electrical structure of Qinling has an important significance for the tectonic evolution of Qinling and the relationship of plates.This thesis is based on “The MT array observation of the intersection area of Central Orogenic Belt and the North-South Seismic Belt” and “The experiment research of MT standard network observation in the area of Qinghai-Tibetan Plateau and the North-China(Sinoprobe-01-02)”.Then we get impedance tensor of high quality through advanced analysis method of data processing,which is used for NLCG 2-d and 3-d inversion to get a reliable electrical model of the research area.Discussing the concerned geological problems such as the contract of relationship of North-China plate,East Qinling micro plate and Yangtze plate.According to the results of Bostick 1-d frequency-depth conversion,NLCG 2-d&3-d inversion,analyzing the electrical characteristics of the plates in research area.The North Qinling Terrane shows basically high resistivity,the east Qinling micro plate shows small pieces of low resistivity body at the depth of mid-low crust,which is incoherent upward in the East-West distribution.The subduction and collision between the SCB and SQB along the Mianlue suture zone,depth to 40 km or more,cutting the Moho surface to the upper mantle.The subduction and collision between the SQB and NQB along the Shangdan suture zone,depth to about 30 km.