High-resolution palynological record for vegetation and environment change during MIS 2 in the southern South China Sea

Abstract

Abstract Vegetation evolution and corresponding climate changes during Marine Isotope Stage (MIS) 2 on the exposed shelves in the southern South China Sea (SCS) region are still controversial. Palynomorph data, including percentage, concentration, and influx were used to reconstruct the history of vegetation and environment changes during MIS 2 and MIS 1. It recommends three significant changes occurred during these periods at 21.51 cal kyr B.P., 17.82 cal kyr B.P., and 12.36 cal kyr B.P. The findings indicate that during MIS 2 and the start of MIS 1, the northeastern part of exposed shelves were covered with tropical rainforests. Ferns were present in ground flora and sub-canopy of tree cover in the rainforests. In the coastal areas, mangrove forests survived up to the start of MIS 1 and then disappeared due to the rapid rise in sea level. Grassland was present to a limited extent and probably in the beach areas only. Winter monsoon was strong, although the temperature was lower than at present. From 11.70 cal kyr B.P., ferns were the dominating vegetation while herbs disappeared completely. Trees of lower and upper montane rainforests were present to some extent. The climate was warm, sea level rose, the continental shelf was submerged in the ocean, and the summer monsoon became stronger than in previous times. This study supports the previous works from the southern SCS region and suggests that a combination of pollens with other proxies give a better understanding of vegetation and climatic dynamics in the past.