Structural features and evolution of the Sunwu-Jiayin basin from Mesozoic to Cenozoic

Abstract：Aimed at studying the complexity of tectonic evolution of the Mesozoic-Cenozoic ba- sins in Northeast Asia in particular. Base on comprehensive interpretation and analyses of the geological and geophysical data, and constructed regional geological section across the basin, the Mesozoic and Cenozoic fault systems of the Sunwu-Jiayin basin were studied and the evolu- tion of the basin discussed. The results show that the whole Sunwu-Jiayin basin is a faulted ba- sin controlled by early Cretaceous NNE extensional faults that occurred during the deposition period of the Ningyuancun formation. The Jiayin region, which is located in the eastern part of the study area, was uplifted and suffered erosion during the early stage of the deposition period of the Taoqihe formation, while the Sunwu region in the western part remained to be a faulted basin. The Jiayin region evolved as a depression, whereas the Sunwu region was uplift and subjected to erosion during the late stage of the deposition period of the Taoqihe formation. Then the whole basin entered the depression phase due to the thermal subsidence after rifting,and received a wide deposition during the late Cretaceous. The basin suffered compression a- gain at the end of the late Cretaceous, causing reactivation and reversion of the early faults. Since the Cenozoic, the compression stress has all along been existing in the study area, and a set of NWW-trending right-lateral transpressional strike-slip faults were thereby formed.