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.