南海海盆东-西部地质特征存在巨大差异

Large geological differences between the East and Southwest Subbasins of the South China Sea

南海中部存在巨大的中南断裂将南海海盆分割为东-西两部分,至少自1亿年以来,在沉积环境与沉积厚度、洋陆边界的属性与特征、大陆破裂的时代、岩浆活动的来源与程度、减薄大陆架和大陆坡的宽度、洋壳年龄与磁性层结构、磁异常条带特征、岩石化学等诸多方面都存在巨大差异,它们主要受控于早期地质构造背景的差异、东西部大陆减薄伸展速率的变化以及海底扩张的构造环境的不同,并深刻影响了之后的区域沉积分区和沉降特征。

The South China Sea is roughly divided by the Zhongnan Fault into the eastern and western parts,with big differences in the Mesozoic sedimentation and the residual thickness,the nature and the characteristics of the continent-oceanic boundary,the age of the continental breakup,the width of the thinned continental lithosphere,the age and the magnetic layer structure of the oceanic crust,the magnetic anomaly,the lithochemistry,and the magmatic activity.They are mainly controlled by the east-west difference in the pre-rift tectonic background,the lithospheric extension rates,and the tectonic settings related with seafloor spreading.These factors profoundly affect the subsequent regional sedimentary zonation and thermal subsidence.