shell-rock
5.The surface sediments in the eastern South China Sea can be divided into 11 types based on the data of sediment color, grain size analysis, chemical and mineral compositions, microfossils, etc. These sediment types are named as clayey silt with rock debris, shell sand, clayey silt, calcareous clay, calcareous ooze, foraminifer ooze, pelagic clay, silty clay with micro-manganese nodules, siliceous clay, siliceous clay with volcanic ash, silty clay with volcanic ash.

