摘要
东海西湖第三纪凹陷经历了早期裂陷和晚期挤压的构造作用 ,形成了现今规模宏大的反转构造。反转构造是先存的张性断裂后期受到挤压逆冲反转而形成的一种挤压构造与拉伸构造在垂向上叠加的复合构造。按反转强度的差异 ,本区的反转构造可划分为简单断展型和穿透断展型 2种基本类型 ;按反转构造的几何样式 ,又可分为简单后冲反转、复合“Y”字型反转、“火”字型反转和花状反转等。凹陷内发育有东缘、中部、西斜坡边缘等 3个反转构造带。沿中央凹陷带的反转作用最强 ,东缘次之 ,西斜坡边缘最弱。
Inversion structure is a compressive extensional composite structure resulting from thrusting along the early extension fault due to the late compression.The Tertiary Xihu trough in East China Sea underwent earlier rifting and later compression stages,which led to the formation of widespread and large scale inversion structures.In terms of deformation intensty,these features can be assigned to two categories,namely,the simple fault extended inversion folds and the fault penetrated inversion folds.The inversion structures in the basin can be classified into several types based on their differences in geometry:the simple back thrusting inversion,complex Y shaped inversion,H shaped inversion and flower like inversion.There are three inversion structure belts recognizedin the Xihu trough:(1)the western slope fault belt,(2)the central basin deformed belt and (3)the eastern margin fault belt.The central inversion structure belt was intensively deformed and is the largest in size.The eastern margin inversion belt is the second in size,and the western slope fault belt is the weakest in inversion.This paper deals mainly with characteristics of inversion structures and their organization and distribuation.The influence of the basin inversion on the accumulation of oil and gas in the basin is also discussed in the paper.
基金
国家攀登计划预选项目! (95 预 39)资助
