The Pearl River Mouth Basin: A rift basin and its geodynamic relationship with the southeastern Eurasian margin

Abstract

Based on multichannel seismic reflection profiles, exploration well data and gravity studies, the tectonic development of the Pearl River Mouth basin is discussed in terms of the geodynamic evolution of the southeastern Eurasian margin. The area around the Pearl River Mouth basin has been dominated by two episodes of rifting of the attenuated continental crust along the South China margin from the late Cretaceous to the early Oligocene. The rifting brought about ruptures of various magnitudes in various segments of the basin. Regional normal faults have been produced and resulted in the formation of three major subbasins, Zhu 1, Zhu 2 and Zhu 3, which are separated by local uplifts and are characterized by horst and graben structures. Regional subsidence prevailed throughout the late Oligocene-Recent period and resulted in a tilted continental shelf upon which rests a unified rift basin—the Pearl River Mouth basin. A three-stage model involving doming, rifting and drifting is proposed for the tectonic evolution of the Pearl River Mouth basin. The uplifting and rifting of the continental crust along the South China margin are related to the late episodes of the Yanshan orogeny during the late Cretaceous-early Oligocene period. When the intensity of rifting decreased, the thermal subsidence of the continental margin of South China prevailed, during the late Oligocene-Recent period of the Himalaya orogeny.