Coupling between Cenozoic extensional exhumation in North China and the subduction of the Pacific Plate

Abstract

Both the timing and mechanism for the formation of the topographic stepping in East Asia along the North-South Gravity Lineament (NSGL) are critical to understand the coupled influence of tectonics, climate, and surface processes on landscape evolution. The Yanshan Mountains lie in the central portion of the NSGL and offer a chance to reveal the link between surficial tectonic deformation and the underlying subduction to understand the continental dynamics and paleoclimate of NSGL. In this study, we report 22 new apatite (UTh)/He (AHe) data from the Yanshan Mountains. Age-elevation profiles indicate a period of rapid exhumation initiated at ∼27–26 Ma, while the AHe ages generally increase with the distance from the fault coincides with northwestward tilting of the fault footwall. Combining a series of shallow extensional events in East Asia with deep process of the Pacific plate subduction, we suggest that the widely-distributed late Oligocene rapid exhumation represents a phase of Cenozoic re-destruction of the North China Craton (NCC). The Cenozoic re-destruction of the NCC and topographic stepping along the NSGL may be related to the retreat, dehydration, and decarbonization of the underlying stagnant Pacific slab.