Characteristics and origin of rift migration within the East China Sea Basin: Coupling relation with deep mantle dynamics

Abstract

Tectonic migration is a significant geological phenomenon in rift basins, offering valuable insights into regional tectonic processes. This study comprehensively investigates the Cenozoic tectonic deformation, sedimentation, and magmatism of the East China Sea Basin. Through detailed analysis, we systematically outline the tectonic migration pattern and dynamic mechanism were systematically outlined, contributing novel and insightful findings to the field. Our results reveal that the basin experienced three episodic syn-rift stages during the Cenozoic, with the rift center migrated progressively oceanward. Differential deformation within the syn-depositional fault system caused spatial and temporal variations in the internal basin architecture. Based on these observation and numerical modeling results, we propose a new model to elucidate the mechanism of tectonic migration in back-arc rift basin. The initial rifting began in the West subbasins during the late Mesozoic and Paleocene, driven by the delamination-style removal of the younger Izanagi slab. During the Eocene, the second rifting episode migrated to the East subbasins, triggered by landward mantle wind and the resulting basal traction after detachment of the subduction of the former Izanagi slab. In contrast, the back-arc extension in the Okinawa Trough primarily resulted from slab rollback of the Philippine Sea Plate since the late Miocene. We emphasize that rifting mechanism within the basin varied significantly across time and space, reflecting the intricate interplay between plate dynamics and mantle processes. This refined understanding of the Cenozoic evolution of East Asia enhances our knowledge of crust-mantle interactions and provides deeper insights into lithosphere deformation.