第八届青年地学论坛

Insufficient data on coastal sea surface temperature (SST) records in the South China Sea (SCS) poses a challenge to investigate the dynamics of ocean-atmosphere-land interactions that are associated with the Asian monsoon system. Here, we use a sediment core collected at the northern coast of the SCS, where oceanic conditions such as SST intensively interact with the East Asian Winter Monsoon (EAWM), to investigate alkenone-SST and n-alkanes variations since mid-Holocene. This record reveals relatively stable, warm temperature during 7.6-3 ka BP, and abnormal cool temperature (~2 °C) occurred during 3-2 ka BP and the Little Ice Age (LIA). Two short-period cooling events appeared in the SST record of HKA2 coincided with a sharp reduction of long chain n-alkanes which indicate terrestrial organic matter supply. Our results, together with augmented SST gradient between the SCS coastal and open ocean, is consistently possibly interpreted to link to strengthened winter monsoon and coastal current toward the late Holocene.

offshore upwelling area of western Guangdong;East Asian Monsoon;alkenone unsaturation index