Quantitative geochemistry as a provenance indicator for surface sediments in the north Jiangsu radial sand ridges (NJRSR) in the South Yellow Sea, East China

The North Jiangsu radial sand ridges (NJRSR) are typical sedimentary bodies distributed along the continental margin of China. Historically, the Yellow and Changjiang Rivers transported terrigenous sediments into the sea, depositing them in the study area. However, the provenance of the sediments in the NJRSR is not conclusively understood. In this study, the grain sizes and major elemental geochemistry of 33 surface sediment samples were investigated to discern the provenance of the sediments in the NJRSR. The results indicate that the sedimentary components are primarily silt (53.60%), sand (35.60%), and clay (10.80%). The grain size (Mz) of the NJRSR coastal surface sediments was 2.5-8.5 Phi, with an average of 5.1 Phi, and had high SiO2 and Al2O3 contents (on average, SiO2 and Al2O3 accounted for >68%). The statistical results of the geochemical analyses were reflected in the control on sediment elemental components by riverine transport in the study area, which were then used to divide the study area into three sedimentary provinces. Elemental ratios (Mg/Al, Fe/Al, K/Al) were used to discern the provenance of the NJRSR surface sediments, indicating that the inputs from the Yellow and Yangtze rivers are the dominant sediment sources in the study area. Using the inverse model, a quantitative estimation revealed that average sediment contributions of the Abandoned Yellow and Yangtze rivers were 67.4% and 32.6%, respectively. In addition, modern current systems play an important role in controlling sediment transport from the Abandoned Yellow and Yangtze rivers to the NJRSR. This study demonstrates the importance of geochemistry for quantitatively determining the provenance of the NJRSR, which is especially useful for quantitatively investigating Earth surface processes in global shelf-marginal seas.