松辽盆地南部茫汉断陷结构特征及成因机制分析

Analysis of the Structure Feature and Genetic Mechanism of Manghan Fault Depression in South Songliao Basin

茫汉断陷为后期改造型断陷,构造演化复杂。采用构造—地层分析方法,通过对多条地震剖面的二维构造解译、构造恢复、断裂三维立体分析,揭示茫汉断陷的发育过程,分析断陷结构特征和断陷成因机制。研究表明,茫汉断陷为复式断陷,总体上具有两洼夹一隆的构造格局,发育走向斜坡和中央斜向背斜两类一级构造变换带;断陷成因复杂,具有幕式活动的特征,主要经历早白垩世断陷、早白垩世末—晚白垩世坳陷、晚白垩世末盆地反转3个时期,其中早白垩世断陷细分为两幕断陷、两次挤压反转等4个阶段。

Manghan depression is the late reformation fault depression,of complex structural evolution.Using construction-stratigraphic analysis method,through the two-dimensional structure interpretation of multiple seismic sections,structural recovery,three-dimensional fracture analysis,this study revealed the development process of Manghan depression,analyzed the structure feature and genetic mechanism of Manghan depression.The research results showed that Manghan fault depression is a complicated fault depression,generally has two sags and one uplift,develop trend of slope and central obliciue anticline of two tectonic transformation belts.The depression has complex causes,features of episodic activities,mainly through three periods of the early Cretaceous rifting,early Cretaceous and late Cretaceous depression and late Cretaceous basin inversion,the early Cretaceous faulted rift subdivided into four stages of two act and two inversion.