Differential geological responses and geodynamic mechanisms of major Cenozoic tectonic Movements in the East China Sea Shelf basin

Abstract

The East China Sea Shelf Basin (ECSSB) underwent complex tectonic evolution during the Cenozoic, shaped by interactions with surrounding geotectonic processes. This study examines six key tectonic interfaces (T80, T50, T40, T20, T12, T10) using 2D seismic data to assess their characteristics, distribution, and genesis. The T80 interface marks the transition of the Changjiang Depression into a post-rift stage, driven by the initial subduction of the Pacific-Izanagi ridge. Subsequent ridge subduction formed the T50 interface, characterized by magmatic activity, compression, uplift, and the deposition of large alluvial fans in northern ECSSB. The T40 interface, formed during the breakup of the South China Sea, is associated with widespread erosion and a significant hiatus in the southern ECSSB. The T20 interface reflects the initial subduction of the Philippine Sea Plate, triggering magmatic belt migration and uplift in the Diaoyu Island Fold Zone. The T12 interface highlights lateral compression linked to the early rifting of the Okinawa Trough, forming a central anticline in the Xihu Sag. Finally, the T10 interface, caused by arc-continent collision, contributed to deltaic deposition in the southeastern basin. These interfaces exhibit significant spatiotemporal variations, revealing the interplay between subduction, rifting, compression, and uplift. This study refines the understanding of tectonic phases in the ECSSB. The findings provide new perspectives on the basin’s geological complexity, contributing to broader knowledge of West Pacific geodynamics and basin evolution.