Characteristics of Paleontological Communities in Surface Sediments of the Southern South China Sea and Their Paleoclimatic and Paleoenvironmental Significance

Understanding the spatial and temporal distribution of different paleontological communities in the southern South China Sea (SCS) is fundamental to explore its paleoclimatic and paleoenvironmental changes. In this study, foraminifera, pollen and diatoms from 100 surface sediment samples covering 40 000 km² of sea floor in the southern SCS were comprehensively investigated in terms of their assemblage and distribution. The results showed the existence of abundant foraminifera and pollen in most of the samples, although diatom communities were relatively scarce. Foraminifera were dominated by G. sacculifer, G. menardii, G. ruber, while diatoms were characterized by T. simonsenii, T. nitzschioides and T. longissima, indicating a typical tropical marine environment. The pollen assemblages showed a better reflection of montane rainforest, tropical rainforest and mangrove. The spatial differences among foraminifera assemblages may indicate the effect of water depth and a warmer environment in the southeast part of the study area, while the spatial patterns of diatom and pollen assemblages imply the influence of coastal current. Our study also noted that the compositions of paleontological communities in the SCS can vary significantly in a short distance, and synthesized studies on multiple biological groups are needed to reconstruct the Quaternary climate and the oceanographic environment.