辽河东部凹陷中新生代火山事件与构造作用

辽河东部凹陷是一个东断西超的箕状断陷,其发育经历了中生代、早第三纪、晚第三纪三个重要时期,而每个时期都是从引张期开始至收缩期结束,即断陷的发育经历了由拉张期到收缩旋回式递进的过程。拉张期发育拉张构造样式,收缩期产生挤压构造形迹。伴随着拉张和挤压的周期性变化,凹陷内发育有中生代、新生代房身泡组、沙三段、沙二—沙一段、东营组、馆陶组沉积时期等6个火山事件旋回,在各火山事件中,火山活动的强度和火山岩的分布受到构造应力场性质、强度和方向的控制,与各阶段重要断裂的活动密切相关。

Mesozoic-Cenozoic Volcanic Events and Structure Effects in the Eastern Sag in Liaohe Depression

The eastern Sag of Liaohe Depression is a half-graben rift subsidence structure, characterized by it was faulted in the east and overlapped in the west, and its development has undergone through three important periods, i.e., Mesozoic Period, Paleogene, and Neogene with each period beginning with the extensional movement and ending with the shrinkage movement, which means that the rift subsidence structure has experienced a cyclic progressive process from extensional period to shrinkage period. In the extension period. the extension structure is developed and in the shrinkage period the compression structure vestige appears.Six cycles of volcano events are developed within the sag in Mesozoic,Cenozoic Fangshenpao Formation, the first and third members of Shahejie Formation, Dongying Formation, Guantao Formation of Cenozoic, accompanied by the cyclic changes of the extension and compression movement. In each volcanic event, the intensity of volcanic activity and the distribution of volcanic rock are controlled by structure stress field feature, stress intensity and stress direction and are closely related with the fracture activity in various stages.