Cretaceous–Palaeogene sedimentary evolution of the South China Sea region: A preliminary synthesis

Abstract

Rocks in extensional settings are generally sensitive to destruction and erosion, resulting in poor preservation potential and accumulation of their eroded components. The South China margin was dominated by a prolonged extensional setting from Late Mesozoic to Early Cenozoic, and this geological history is exactly archived in sediments within and surrounding the present South China Sea. However, the sedimentary evolution of the region, especially prior to the continental breakup and oceanic spreading, remains an issue of uncertainty and controversy, mostly due to limited borehole penetration and poor seismic reflection data for deeply buried sequences, as well as the lack of reliable regional stratigraphic framework. Here, we illustrate the Cretaceous–Palaeogene sedimentary evolution of the South China Sea region by synthesizing relevant data from previous literature and our own observations and displaying the evolution of lithofacies in sequential palinspastic reconstructions. The preferred palaeogeographic scenarios incorporate the latest interpretations of the conjugate relationship between continental margins as well as the birth and demise of the hypothetical Proto‐South China Sea. The patterns of lithofacies and depositional environments at regional scales, along with available provenance data, clearly reveal sedimentary responses to the significant Mesozoic–Cenozoic transition of plate geodynamics and magmatism along the Asian margin and provide implications for the potential mechanism of Cenozoic extension represented by distinct yet continuous processes of continental rifting and oceanic spreading.