MT Exploration and Research on the Lithosphere Structure of Crust-mantle in Northeast China

Abstract

Summary As the Northeast China is located in the overlapping parts of ancient Asia tectonic domain and Pacific tectonic domain and the region was experienced a period of tectonic activity and strong magmatism. Plate mosaic and orogenesis gone through in pre-Mesozoic, interpolate tectonic transformation gone through in Mesozoic-Cenozoic, and there are some complex geological structure. To build the crust-mantle electrical structure model of regional standard electromagnetic in Northeast China, the latitude and longitude 4°×4°parameters observation network of array regional magnetotelluric was laid, high-quality magnetotelluric sounding data was obtained, researches of 1D,2D and 3D inversion has been done. Based on the inversion characteristics of electrical structure models and combined with relevant information (such as geothermal data, gravity and magnetic data …), The crust-mantle electrical structure of Northeast China has been obtained finally. The results are as follows. The types of electrical structure can be divided into two types that are basin type and orogenic type in the Northeast China. There are different micro-plate blocks in different crust-mantle electrical structure types. The lithosphere thickness of Northeast China shows: the eastern is thin, the western is thick, both of the western and the eastern are thick and the central is thin, and both of the southern and the northern are thick and the central is thin. As the impact of complex fracture system or suture zone in the south and the east of the study area, so the electrical structure of these areas is complex and changeable.