张强凹陷及邻区的构造应力分析

TECTONIC STRESS ANALYSIS FOR ZHANGQIANG DEPRESSION AND ITS ADJACENT AREA

通过对张强凹陷及邻区露头构造形迹和岩心裂缝测量的应力分析，把该地区的地质历史划分出自太古代以来的８个构造期，确定了各期构造应力场状态及构造组合形式，认为晚侏罗世及白垩纪古构造应力场是断陷盆地形成、发展的主要应力场，晚侏罗世为近东西向拉张的构造应力状态；阜新组沉积期末至泉头组沉积前，由东西向拉张转为近东西向挤压，导致断陷阶段结束和上侏罗统变形；白垩纪为东西向挤压，早期区域整体沉降，晚期大面积隆升遭受剥蚀。早第三纪期为北西－南东向挤压，晚第三纪以来北东东－南西西向挤压。新生代的两期应力场仅使一些断裂继续活动，变形强度小于前两期。

By the analysis of deformation in outcrop area and fissure measurement of core rocks in Zhangqiang depression and its adjacent area, we divide the geological history of this region into eight tectonic stress phases and determine the tectonic stress states and deformation forms of each phase. We conclude that the tectonic stress fields of the late Jurassic and the Cretaceous resulted in the formation and development of faulted basins, and the stress state of the late Jurassic was nearly E W extension. Between the end of Fuxin Group and the beginning of Quantou Group sedimentation stages, the stress fields resulted in the close of basin faulting stage and deformation of the late Jurassic caused by the change of stress states from E W extension to E W compression. In the Cretaceous phase, the principal stress direction was E W compression which caused the regional depression as a whole in the early period and uplifting and erosion widely in the later time. The principal stress direction was NW SE compression in the Eogene, and was NEE SWW compression since the Neogene. Two phases of stress fields in Cenozoic only caused some reactive faults, the deformational strength was less than that in Jurassic and the Cretaceous.