东海陆架盆地构造反转特征及成因机制探讨

通过对东海陆架盆地各二级构造单元内反转构造的梳理与分析，认为盆内新生代反转构造以形态各异的背斜为主，伴有逆断层发育。主要存在瓯江运动(T80)、玉泉运动(T30)、花港运动(T20)和龙井运动(T12)4期构造反转，在时间和空间上具有明显的差异性。在时间演变上：西部坳陷带构造反转从瓯江运动(T80)到花港运动(T20)有相对减弱的趋势，龙井运动(T12)特征不明显；东部坳陷带构造反转从玉泉运动(T30)、花港运动(T20)到龙井运动(T12)有相对增强的趋势。在空间演变上：东部坳陷带西湖凹陷和钓北凹陷龙井运动(T12)构造反转具有显著的自北向南减弱的趋势。东海陆架盆地新生代构造反转强弱分布、迁移演化是太平洋板块与欧亚板块、印度板块与欧亚板块之间汇聚俯冲速率和方向的变化在盆内叠加的局部响应。

A discussion on the tectonic inversion and its genetic mechanism in the East China Sea Shelf Basin

Through the analysis of the inversion structures in each secondary tectonic unit of the East China Sea Shelf Basin, we considered that the Cenozoic inversion structures were mainly as anticline，associated with thrust fault. There were four main tectonic inversions: Oujiang movement(T80)，Yuquan movement(T30)，Huagang movement(T20) and Longjing movement(T12); while such tectonic inversions had significant differences in time and space. In time evolution scale，the tectonic inversions were relatively weakened from Oujiang movement(T80) to Huagang movement(T20) in the West Depression Belt，and on the other hand they were relatively enhanced from Yuquan movement(T30)，Huagang movement(T20) to Longjing movement(T12) in the East Depression Belt. In space evolution scale，The Longjing movement(T12) in Xihu Sag and Diaobei Sag of the East Depression Belt had weakened trend significantly from north to south. The intensity distribution and migration evolution of Cenozoic tectonic inversions were the local response in the East China Sea Shelf Basin affected by the subduction rate and direction of plates interactions between Indian Plate with Eurasian Plate and Pacific Plate with Eurasian Plate.