Comprehensive Geophysical Research on the Deep Structure of Northeastern South China Sea

Abstract

Abstract The complex crustal structure of northeastern South China Sea and neighboring areas, especially the structure of the land‐sea transition zone, has been a hot subject of the lithospheric structure research of South China Sea. In this paper we construct the density model along two profiles based on gravity data and constraints from Pn wave tomography and deep seismic sounding. The result of 2.5D density modeling supports the point of view that a high velocity layer exists in the lower crust of the area from Qiongyue Uplift to Luzon island arc; and the fitting result to the Taixinan Basin indicates that the crust in the southern depressed region should belong to the transitional type. Although the tectonic feature of the northeastern shelf of South China Sea is generally of volcanic type, the structures of profile AA' and BB' are different, which indicates the lateral variation and the complexity of crustal structure in the northeastern margin of South China Sea.