以松辽盆地茫汉凹陷为对象,采用构造一地层分析方法,通过对多条地震剖面的二维构造一地层解译、平衡恢复,伸展量和伸展率计算,揭示茫汉凹陷的发育过程,分析盆地总体结构特征和盆地形成机制。研究表明,茫汉凹陷表现为明显的断坳叠置结构:下白垩统九佛堂组、沙海组及阜新组为受断裂控制断陷盆地,泉头组至嫩江组为坳陷盆地,两侧的控盆断裂已不控制盆地沉积,沉积范围向两侧扩大,地层向盆地边缘超覆。构造由深至浅趋于简单,深层构造较为复杂,断裂发育,而浅层为一简单的、平缓的坳陷构造形态。茫汉凹陷盆地结构充分显示了盆地发育受控于左旋转换伸展。
By means of structure-stratigraphy method, through systematic 2 dimension structure-stratigraphy interpretation of several seismic sections, structure-stratigraphy balance recovery, and calculating extension quantity and extension rates, the developing process of Manghan sag is revealed and the tectonic features and forming mechanisms of the basin are analyzed. The results show that Manghan sag is a fault depression superimposed structure. The fault depression is mainly controlled by the faults in the Lower Cretaceous Jiufotang group, Shahai group and Fuxin group periods, and the fault depression turned into depression basin which was not controlled by the faults on both sides of the basin, and its scope of deposition is extended to the both sides, and the strata onlapped to the basin margin from Quantou group to Nenjiang group. The basin structure becomes simple fi'om deep to shallow, and the deep structure is complicated relatively with faults and the shallow structure is simple and flat form of depression structure. Manghan trolled by the extension of the sinistral sag structure characteristic fully reveals that the basin developing was contransformation.