Sedimentary responses to climatic variations and Kuroshio intrusion into the northern South China Sea since the last deglaciation

Abstract

The terrigenous sediment source-to-sink processes in marginal seas are governed by intricate interactions among climate, sea level, and ocean currents. The continental slope of the northern South China Sea (SCS) provides an excellent setting to examine these processes due to its substantial terrigenous influx and continuous sedimentation. In this study, we present a high-resolution sedimentary record from the northern SCS continental slope covering the last deglaciation. Analyses of Rare Earth Elements (REEs) and Sr–Nd isotopic compositions in the NH07 core indicate that the predominant source of terrigenous sediment was Taiwan. Grain size-standard deviation analysis identified two sensitive grain size components, with the sensitive component 2 used as a marker of the Kuroshio intrusion into the northern SCS through Luzon Strait. The intensity of the Kuroshio intrusion into the northern SCS was found to be inversely related to that of the open Pacific. The Asian monsoon and El Niño-Southern Oscillation (ENSO) significantly influenced the variability of the Kuroshio Current throughout the deglaciation period. During the interval 16, 000–11, 700 cal yr BP, variations in terrigenous influx were collectively driven by sea level changes and the intensity of the Kuroshio intrusion, while chemical weathering intensity was affected by the reworking of previously exposed shelf sediments due to sea level fluctuations. During the Holocene, however, the East Asian summer monsoon intensity became the primary factor influencing variations in terrigenous influx and chemical weathering.