Sediment provenance in the Northern South China Sea since the Late Miocene

Abstract

Abstract The timing of the onset of Taiwan sediment input to the northern South China Sea (SCS) is still controversial even though many provenance proxies had been used. To analyze the change of Taiwan input since the Late Miocene (11.63–0 Ma), we applied the major-element-based proxies R AK and R KCN, combined with the published clay mineral and Sr–Nd isotope data, to study the sediment provenance near the northern SCS slope. The results show that significant Taiwan sediment input began at ∼6.5 Ma in the Late Miocene, consistent with the timing of Taiwan uplift. Moreover, Pearl River input increased after ∼3.6 Ma, corresponding to the sea level fall caused by the ice sheet expansion in the Northern Hemisphere. The Taiwan input increased during the Mid-Pleistocene Transition (MPT, 1.25–0.7 Ma) because of the Northern Pacific Intermediate Water expansion. After the MPT, the Pearl River input re-increased in response to the lowered sea level in glacials. In general, tectonic activities such as the Taiwan uplift control the sediment provenance in the northern SCS from 6.5 to 3.6 Ma. After 3.6 Ma, as the weathering regime of Taiwan sediment became more stable, climate change became a more important factor in influencing sediment provenance.