Successor Characteristics of the Mesozoic and Cenozoic Songliao Basins

Abstract: The Songliao basin is a complex successor basin that was initiated in the Mesozoic and experienced multiple periods of reactivation. Based on seismic and drilling data, as well as regional geologic research, we suggest that the Songliao basin contains several different successor basins resting on top of Carboniferous‐Permian folded strata forming the basement to the Songliao basin. These basins include the Triassic‐Mid Jurassic Paleo‐foreland basin, the Late Jurassic‐Early Cretaceous downfaulted basin, and an early Cretaceous depressed basin (since the Denglouku Group). This paper presents a systematic study of the basin‐mountain interactions, and reveals that there are different types of prototype basin at different geologic times. These prototype basins sequentially superimposed and formed the large Songliao basin. Discovery of the Triassic‐early Middle Jurassic paleo‐foreland basin fills a Triassic‐early Middle Jurassic gap in the geologic history of the Songliao basin. The paleo‐foreland basin, downfaulted basin, and depressed thermal subsidence basin all together represent the whole Mesozoic‐Cenozoic geologic history and deformation of the Songliao basin. Discovery of the Triassic‐early Middle Jurassic paleo‐foreland basin plays an important role both for deep natural gas exploration and the study of basin‐mountain coupling in north China and eastern China in general. This example gives dramatic evidence that we should give much more attention to the polyphase tectonic evolution of related basins for the next phase of exploration and study.