The genesis of tectono-magmatism in eastern China

Abstract

The tectono-magmatism in eastern China is a hotspot for the researches, and many hypotheses of that were discussed. There is a middle crust with solid, low velocity and high conductivity in eastern China, which is impossible to form “convection magmatic layer”. The subduction and compression of oceanic plate induced to the lateral pressure for the eastern China lithosphere in the condition of increasing pressure and decreasing temperature, it is also impossible to form an extensively melting magma layer. In South China, the granitic zone migrates from west to east, their evolution cannot be explained by plate subduction. The original magmatic reservoirs are controlled by main faults and spheres, which occurred the tectonic detachment and formed in the process of decreasing pressure and increasing temperature. The magma only originates in very small part of lithosphere. The tectono-magmatism and tectonic detachment of eastern China lithosphere during the Jurassic and the Cretaceous are concentrate mainly near the intersections between the regional faults and middle crust or the Moho discontinuity, and then magma intrudes or erupts along faults. The tectono-magmatism of Cenozoic originates near the intersections between the regional high-angle normal faults and the bottom of lithosphere. Obviously, the different penetration depth of faults induces a different kind of magmatism.