Spatiotemporal Differences in Tectonic Deformation and Its Dynamic Mechanisms in the East China Sea Shelf Basin

The study of back-arc sedimentary basins is key to understanding oceanic and continental geodynamic processes and mechanisms. The East China Sea Shelf Basin (ECSSB), a back-arc sedimentary basin in a continent-ocean transition zone of the western Pacific Ocean, exhibits remarkable differences in terms of the tectonic deformation characteristics of the basin and the evolutionary features of its sags. These features have led to varied understandings of deep dynamic mechanisms driving the evolution of the basin. In this study, which is based on a detailed interpretation of two-dimensional multichannel seismic data from the ECSSB, the tectonic deformation of the basin is analyzed and the tectonic evolutionary process of the basin is reconstructed. The above research work combines plate convergence processes and deep crust-mantle interactions to explore the controlling factors and deep dynamic mechanisms of the tectonic deformation in the ECSSB. The results of this study indicate that there are significant differences in tectonic deformation between the southern and northern parts of the basin and that the deformation is characterized by eastward migration. Deep crust-mantle interactions are coupled with the development of these differences. The tectonic deformation of the ECSSB is driven by the interactions of the paleo-Pacific, Pacific, Indian, and Philippine Sea Plates with the Eurasian Plate, which have shaped the tectonic pattern of the ECSSB, resulting in east-west zoning, north-south blocking, and pronounced spatiotemporal variability in tectonic deformation. This research provides new insights into the differential development of sags within the ECSSB and provides an important reference for studying back-arc sedimentary basins.