东海陆架盆地中新生代构造背景及演化

从东海中生界的分布和闽浙东部岩浆构造事件来看,侏罗纪-早白垩世库拉-太平洋板块已对中国大陆有较强的俯冲作用,东海及其以南地区应为弧前盆地性质。晚白垩世晚期-始新世,火山岛弧向东移动,东海陆架盆地变为弧后盆地。古新世的断陷中心在东海陆架盆地西部的长江凹陷、瓯江凹陷。始新世时,断陷中心向东迁移,以陆架盆地东部的西湖凹陷为主。到了渐新世,由于太平洋板块俯冲方向的改变以及菲律宾海板块的作用,东海陆架盆地发生坳陷,坳陷中心以东部为主。中新世晚期,冲绳海槽和疏球岛弧形成。晚中新世(约6Ma),吕宋岛弧在台湾地区与中国大陆发生碰撞,台湾岛上升露出水面,形成了台西盆地现今的面貌。

Meso-Cenozoic tectonic setting and evolution of East China Sea shelf basin

Based on distribution of Mesozoic in East China Sea and magmatic-tectonic events in the eastern Fujian and Zhejiang provinces, Kula-Pacific plate would have relatively strong subduction toward China's mainland during Jurassic-Early Cretaceous, thus East China Sea and the area to the south should be of fore-arc basin. During late Late Cretaceous-Eocene, volcanic island arc moved eastward and the East China Sea shelf basin was turned into a back-arc basin. The centers of fault subsidence were located in Changjiang and Oujiang sags in the western part of the shelf basin during Palaeocene, and they moved eastward during Eocene and consisted mainly of the Xihu sag in the eastern part of the shelf basin. East China Sea shelf basin was downwarped in Oligocene, due to the change of subduction direction of Pacific plate and the effect of Philippine Sea plate, and the center of depression was mainly located in the eastern part. Okinawa ocean trough and Ryukyu island arc were formed in late Miocene. During late Miocene (approx. 6 Ma), Luzon island arc collided with China's mainland in Taiwan area, resulting in the emergence of Taiwan Island, and the formation of the present features of Taixi(or West Taiwan) basin.