CLASSIFICATION AND NOMENCLATURE OF DEEP SEA SEDIMENTS

Shallow marine sediments are mainly composed of terrigenous sediments.The classification and nomenclature of them with grain-size triangle have been widely accepted since 1993 in oceanographic survey.Due to the nature of the difference for deep sea from that of the shallow sediments in provenance,digenesis,and sedimentation,the triangle scheme of classification is not applicable for deep sea sediments.Based on our investigation in the South China Sea and the Pacific on deep sea sedimentation,a simplified scheme is proposed in this paper,with which the surface sediments in the eastern South China Sea can be classified into 10 categories.They are named as pelagic clay,siliceous clay,calcareous clay,siliceous calcareous clay,calcareous ooze,clayey calcareous ooze,clayey-siliceous calcareous ooze,clay-siliceous-calcareous mixed ooze,siliceous-calcareous mixed ooze,and calcareous siliceous-clay mixed ooze.The ten sediment types can largely describe the sedimentation and distribution in the eastern South China Sea.