Study on Comparison Sedimentary Geochemistry of Mud Area on East China Sea Continental Shelf

The comparison of sedimentary geochemistry for mud areas on the East China Sea continental shelf (ECSCS) was carried out based on the contents of elements of surface sediments and concentrations of total suspended sediments (TSS) in the seawater from mud areas and their ambient sand areas. The results show that the processes of sedimentary geochemistry of different mud areas on ECSCS are very different. The surface sediments from the Zhejiang Coastal Mud Area (ZCMA) occupy high contents of Fe, Mn, Zn and low contents of Na, Sr, Al and Ca. The geochemical characters of surface sediments from ZCMA have a very close correspondence to those of Changjiang (Yangtze River) sediments, indicating that almost all sources of sediments in ZCMA are from modern Changjiang discharge sediments in addition to a little bit biogenic sediments. The modern Changjiang sediments to the sea are deposited in the Zhejiang Coast because of the obstruction of Taiwan Warm Current. Whereas, the surface sediments from the Southwestern Cheju Island Mud Area (SCIMA) are characterized with high contents of Na, Sr, relative high contents of Al, Ca and low contents of Fe, Mn, Zn. The geochemical characters of surface sediments from SCIMA have a good relation to those of Huanghe (Yellow River) source. But there are somewhat mixed characters including biogenic and other source sediments in SCIMA. It is indicated that the main source of sediments in SCIMA is from fine-grained sediments of Huanghe source. The Huanghe source sediments are chiefly from the resuspended sediments in the old Huanghe estuary located in the Northern Jiangsu province. Then, the Huanghai (Yellow Sea) Coastal Current transports the fine-grained sediments from old Huanghe estuary to the SCIMA. Therefore, the controlling factors for the sedimentary geochemistry of different mud areas on ECSCS are the current system in the East China Sea and the source of sediments. Especially, the Taiwan Warm Current plays a key role to the sedimentary geochemistry division between ZCMA and SCIMA in the study area.