System of Crust-Mantle Ductile Shear Zone in the Continental Lithosphere in China

Abstract

On the basis of the tectonic analysis of many seismic sounding profiles, there are two fracture systems in the continental lithosphere of China, which are obviously different but closely interrelated. One is the shallow fracture system composed of brittle shear zones mainly in upper crust, and the other is the deep fracture system composed of crust-mantle ductile shear zone which penetrate the Moho discontinuity. Combined with the structural characteristics of seismic wave velocity, the petrology and geochemistry of deep tectonic and the crust-mantle ductile shear zones can be divided into five types: the trench subduction zone at the border of continental lithosphere, collision suture in continental lithosphere, compressive crust-mantle ductile shear zone, extensional ductile shear zone, and strike-slip ductile shear zone in the crust and the mantle. Therefore, it is considered that the continental lithosphere in China is a bidirectional development model, development from the surface to the deep crust and from the crust-mantle transition zone to the mid-upper crust. The crust-mantle ductile shear zone is the channel for gas and fluids of inorganic origin, as well as the seismic activity area. The research of the crust-mantle ductile shear zone is of great academic value and realistic significance.