Elemental and Sr‐Nd Isotope Geochemistry of Sinking Particles in the Northern South China Sea: Implications for Provenance and Transportation

Abstract

AbstractMajor and trace elements, Sr and Nd isotopes of bulk particles from the SCS‐NW and SCS‐N‐03 traps were studied to trace the provenance of sinking particles in the northern South China Sea (SCS). About 63% of biogenic materials and most of lithogenic materials from the SCS‐NW trap may be contributed from resuspended sediments, and more biogenic materials are collected in winter than in summer. The immobile‐element discrimination diagrams also indicate that the lithogenic materials of particles are, to a large degree, from local seafloor sediments, and that the lithogenic materials of particles from SCS‐N and SCS‐W traps have seasonal variations. Sr isotopes (87Sr/86Sr and δ88Sr) of bulk particles are significantly influenced by biogenic materials and cannot be used in provenance tracing. In contrast, Nd isotopes are ideal tools to trace particle provenance. However, the traditional Nd isotope (143Nd/144Nd) shows no statistical difference on the particles of the SCS‐NW and SCS‐N‐03 traps, making it unable to identify their provenance. Fortunately, the stable Nd isotope, ε146Nd, shows different correlation trends to ε143Nd in these two traps, suggesting that stable Nd isotope can potentially identify the sources of lithogenic materials in the northern SCS. Our results indicate that distribution and transportation of sinking particles are controlled by currents of the SCS mainly driven by the East Asian Monsoon.