Sedimentary Filling of the Pearl River Mouth Basin and Its Response to the Evolution of the Pearl River

Key words: 
• South China Sea /
• Pearl River Mouth Basin /
• Baiyun Sag /
• sedimentology /
• provenance analysis

Abstract: The sediment geochemical composition between Oligocene and Miocene was different in the northern South China Sea, indicating a significant provenance change. This abrupt change coincided with a series of events including a seafloor spreading axis jump in the South China Sea and uplift of the Western Yunnan Plateau and Eastern Tibet Plateau, leading to obvious changes in drainage areas of the Pearl River and the sediment geochemical composition. The variations in Ca/Si, CIA and Al2O3 reflect that the erosion areas of the Pearl River transformed from closeto source neighboring areas in the Oligocene to the Western Yunnan Plateau and Eastern Tibet Plateau since the early Miocene, and the provenance rock types changed from silicate to carbonate, as well as the main sediment composition changed from sanddominated to muddominated material. Therefore, the evolution of the Pearl River and the uplift of the Tibet Plateau played a key role in the sedimentary transformation and accumulation in the Pearl River Mouth Basin. This abrupt change event has a profound influence on the evolution of petroleum offshore in the northern South China Sea.