Comprehensive geophysical research on the deep structure of Northeastern South China Sea
南海东北部及邻区深部结构的综合地球物理研究

The feature of complex crustal structure in Northeastern South China Sea and adjacent region,especially in continental-oceanic boundary zone,is a keystone for lithosphere structure research of the South China Sea.The 2.5D density models are given in this paper according to gravity data constrained by Pn wave velocity tomography result and deep seismic sounding profiles.The 2.5D density modeling results support the view point that a high velocity layer exists in the lower crust in northeastern region(from Qiongyue lift to Luzon island arc) and indicate that the crust of southern depression of Taixinan basin should belong to transitional crust type.Although the tectonic feature in northeastern shelf of South China Sea belongs to volcanic type,the density and tectonic features of the two models are different,which indicates the complexity of crustal structure in northeastern shelf of South China Sea.