Exploring variations in upper ocean structure for the last 2 Ma of the Nansha area by means of calcareous nannofossils

摘要

A great number of calcareous nannofossils have been found in the deep-sea sediments of 2.32 Ma at ODP Site 1143 located in the Nansha area, the southern South China Sea. The number of coccoliths varies from about 0.5x10~6 up to almost 53x10~6 coccoliths/g sediment with an average of 16x10~6 coccoliths/cm~2 ka. The nannofossil assemblages are usually dominated by a lower-photic species-Florisphaera profunda, of which the average percentage is about 70/100 in all samples.