Late Miocene provenance evolution at the head of Central Canyon in the Qiongdongnan Basin, Northern South China Sea

Abstract

Abstract The head of the Central Canyon system in the Qiongdongnan Basin has been suggested as the key region for understanding the deposition and transportation processes in the northern South China Sea but the sedimentary provenance of this region remains uncertain. In this study, U–Pb geochronology of detrital zircon was used to constrain the source terranes, understand the sedimentary provenance, and reconstruct the provenance evolution in the late Miocene. Measured age populations from the upper Miocene sediments indicate that the sediments in the Central Canyon were mainly derived from the sources of the Red River and central Vietnam, whereas the nearby Hainan Island was not the major source terrane. The southwestern Yangtze Block was likely the primary source for the head of the Central Canyon through the Red River system and played an important role in contributing detritus to the northwestern South China Sea during the late Miocene. The results of this study also showed slight provenance variations in the vertical stratigraphic successions of the upper Miocene, suggesting a relatively stable and continuous detritus supply from the Red River at 10.5–8.2\u202fMa. In addition, the provenance study is capable to provide important insights in reservoir distribution and quality evaluation in future exploration and production.