伸展构造盆地的平衡剖面及其构造意义——以松辽盆地南部为例

挤压构造的平衡地质剖面分析已经广泛应用于造山带构造分析, 但伸展构造区的平衡地质剖面分析实例仍然很少.运用盆地分析的技术与方法, 分层序或阶段将地质构造依次恢复、地层逐层回剥, 并通过在松辽盆地南部吉林两井油田扶余油层4条剖面的实践, 复原出不同时代盆地构造与地层发育的连续剖面, 揭示出松辽盆地南部主要构造样式是以浅表构造层次的负花状构造及深层剥离断层发育为特征; 断层生长指数、盆地的伸展史和伸展量等参数显示, 晚白垩世是构造转型的重要阶段, 此前主要为走滑构造样式形成阶段, 此后则主要为伸展滑脱构造发育阶段.在此基础上, 提出松辽盆地具有伸展-走滑双重力学构造性质, 可能是一个弧后构造盆地. 

Balanced Geological Section for Extensional Tectonic Basin and Its Implication: An Example from Southern Songliao Basin

The balanced geological section has been widely used for the analysis of orogenic belt, but it is infrequent for extensional basins. In this paper, 4 extensional balanced geological section analysis were practiced in Fuyu oil layer of Liangjing, Jilin oilfield, southern Songliao basin with the technology and method, including deformation history restoration, decompaction and erosion restoration. The structure of different ages and the continuous sedimentary sections have been restored. The results show that the structural styles possess the characteristics of negative flower structure in the shallow level and extensional detachment in deep level. The parameters, including fault growth index, the basin extensional history and fault detachment depth, indicate that Late Cretaceous is an important stage for the structure transferring mainly with a strike-slip style before this time and an extensional structure and detachment after this time. Therefore, a basin model with twin dynamic property and back-arc characters is proposed.