伊通地堑——走滑断陷盆地的构造特征及演化

伊通地堑是一个主体在海西期褶皱基底上发育起来的第三纪含油气走滑断陷盆地。它具有狭长不对称的地堑结构,断裂构造复杂,发育有正滑动断裂和逆滑动断裂。张扭和压扭共同作用所形成的复合型叠加构造为其主要构造样式。地堑的形成演化经历了初始断陷期、主断陷期和重新活动期3个阶段。地堑在形成过程中,由于边界断裂的限制造成应力不均匀分布,导致地堑内部东西差异沉降和南北隆凹相间,沉降中心和沉积中心随着断裂活动期次的不同而发生迁移。

THE YITONG GRABEN-THE STRUCTURAL FEATURES AND EVOLUTION OF A STRIKE-SLIP FAULT BASIN

The Yitong Graben is a Tertiary petroliferous strike-slip fault basin developed on the Hercynian fold basement.It has long and narrow asymmetric graben structure.Its fault structure is complex,developing normal-slip faults and reverse-slip faults.The compound superimposed structure formed by the joint action of tenso-shearing and compresso-shearing is its main structural pattern.The formation and evolution of the graben includes initial fault depression,main fault depression and renew action three stages. During the formation of the graben,the inhomogeneous distribution of stress due to the restriction of boundary faults resulted in differential subsidence between east and west and uplift and sag interval change from south to north within the graben, the depocenter and the subsidence center migrating with different faulting stages.