营口—佟二堡断裂带成因机制的构造物理模拟实验研究

营口—佟二堡断裂带是控制辽河坳陷东部凹陷形成和演化的主体构造体系，是郯庐断裂带的北延部分。根据地质资料分析和构造物理模拟实验研究，营口佟二堡断裂带在新生代经历了早期的拉张应力和后期右行剪应力的复合作用。拉张构造运动发生在古新世房身泡组沉积期至始新世沙河街组一段沉积期(距今约37．0～63．0Ma)，在大陆裂谷演化阶段因地幔上涌而派生；右行走滑构造运动发生在渐新世东营组沉积期(距今约24．5～36．9Ma)，后期右行剪应力作用使早期断裂再活动并形成新的断裂。基于构造物理模拟实验结果和对地质资料的分析，渐新世右行走滑构造运动导致的辽河坳陷水平位移约为4～8km。图5参12

Modeling experiments of generation mechanism of Yingkou-Tongerbu fracture zone in the Liaohe Depression

The Yingkou-Tongerbu fracture zone is a major structural system of controlling formation and evolution of the East Sag, Liaohe Depression, and the extended part of Tanlu Fault Zone northward. The geological information analyses and studies of the modeling experiments suggest that the Yingkou-Tongerbu fracture zone has underwent a composite action of older extensional stresses and younger dextral shear stresses in Cenozoic. The extensional structure movement occurred during the sedimentary phase of Fangshenpao Formation, Paleocene and Shahejie Formation in age of Eocene (37-63Ma). The upwelling of the mantle during evolutionary stage of the continental rift generates the extensional stresses. The dextral strike-slip structural movement occurred in sedimentary phase of the Dongying Formation, Oligocene ( 24.5-36.9 Ma ). Action of younger dextral strike-slip structural movement reactivated older extensional fractures and produced new fractures. The results from modeling experiments and analyses of geological information suggest that the displacement magnitudes of the Liaohe Depression caused by dextral strike-slip structural movement during the Paleogene should be about 4-8km.