Sequence stratigraphic research of volcanic and clastic sediment basins: A case study of Changling Fault Depression in Songliao Basin

The Early Cretaceous is complicated and hard to compare since it was influenced by multiple tectonic movements and volcanism. In order to resolve the problems mentioned above, we studied stratum structure and sequence stratigraphy based on freshly obtained outcrop, core, well logs, seismic and dating data, using basic principles of sequence stratigraphy and sedimentology. The kinetic mechanism and volcanism in this area were also considered in the research. Some identification methods for dual-structure basins with "volcanic rocks and sedimentary rocks" were put forward, and the stratigraphic sequence framework of the Early Cretaceous in the Changling Fault Depression was set up. Three sequence patterns were proposed:volcanic fault lake sequence, gentle slope composed of "volcanic and sedimentary rocks" in a dual structure sequence, and "volcanic and sedimentary rocks" constitute straticulate (finely laminated) sequence. These sequence patterns have a guiding significance for identifying source, reservoir and cap rock assemblages.