Clay Mineral Assemblage Features of Major Rivers along the South China Coastand Their Contributions to the Northern South China Sea

In order to explain distribution characteristics of clay mineral composition in sediments from coastal rivers, and their contribution to sediments in the Northern South China Sea (NSCS), we collected sediment samples from six major rivers along the South China coast whose annual sediment discharge is greater than 500 thousand tons, together with surface sediment samples in the NSCS.The results show that (1) the total percentage of illite and kaolinite in sediments from the Han, Jiulong and Moyang Rivers is more than 90%, (2) smectite percentage in coastal river sediments is very low except for the Rong River (18%), (3) sediments in these six rivers have low chlorite percentage, and only the Jian and Pearl Rivers can reach 9%.The clay mineral assemblages in sediments from the above rivers are different from each other, which can be used to identify sediment sources in the NSCS.On the NSCS continental shelf, illite and chlorite mainly originate from the southwestern Taiwan, while kaolinite is primarily sourced from Jian, Moyang and Pearl Rivers.Smectite is largely derived from the Rong River, and area ranged from the Pearl River Delta to the Dapeng and Daya Bays.