Post-collisional extend record at crustal scale: Revealed by the deep electrical structure from the southern margin of the central Asian orogenic belt to the northern margin of the North China Craton
Liang Hongda1, Gao Rui1, Hou Hesheng1, Li Wenhui1, Han Jiangtao2, Liu Guoxing2, Han Song2
1. State Key Laboratory of Continental Tectonics and Dynamics, Key Laboratory of Earthprobe and Geodynamics, MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037;
2. Geo-exploration Science and Technology Institute, Jilin University, Changchun 130026
The Central Asian Orogenic Belt(CAOB)is one of the world's largest accretionary orogens and it is the most representative area of crustal accretion and transformation since Phanerozoic. The North China Craton(NCC), the oldest craton in China, experienced intraplate tectonism that formed the Yinshan-Yanshan belt and lithospheric destruction in the Mesozoic. Both the CAOB and the NCC are research hotspots for geologists, and they are natural field laboratories to study the continental orogeny and extension after orogeny. A 600 km long magnetotelluric sounding profile from the southern margin of the CAOB to the northern margin of the NCC has been completed and an electrical structure model of the crust and the upper mantle was finally obtained after data processing, qualitative analysis and 2D inversion of the observed data. High resistivity in the upper crust of the profile may represent the large scale outcrop of granites. The north-dipping conductive layer in the middle-lower crust connected with the below conductive bodies may indicate the uptrend channel of the mantle, and they are probably formed in post orogenic extensional environment, reflecting the rising of the mantle material is the major impetus of the extension.
. Post-collisional extend record at crustal scale: Revealed by the deep electrical structure from the southern margin of the central Asian orogenic belt to the northern margin of the North China Craton[J]. Chinese Journal of Geology, 2015, 50(2): 643-652.