A 130 Thousand-Years Record of the East Asian Summer Monsoon from the South China Sea

Piston Core MD972151 (9°N) obtained from the South China Sea off the southern end of Indochina Peninsula has offered a multiform of high-resolution records including planktic and benthic foraminifera δ18O, alkenone-based SST, and %CaCO3. This study constructed an independent chronology differing from the conventional SPECMAP time-scale and compared the various proxy records to the East Asian monsoon proxy of Chinese speleothem (Wang et al., 2008) over the past 130 kyrs. Among the various proxies evaluated, the profile of seawater 18O displays remarkable similarity with the Sanbao-Hulu speleothem record. The 25 Chinese interstadial events (CIS) events (A1-A25) during the last glacial period as well as the various cold stadial intervals, such as the Younger-Dryas and five Heinrich events (H1-H5.2) are readily recognizable. After removing the long-term ice-volume related variation, the residual sea-water δ18O shows a strong precession period of 23 kyrs, indicative of dominant control of low-latitude solar insolation. We interpret that the southern South China Sea serves as a major vapor source for the East Asian Summer Monsoon, and the positive feedback through the increased runoff from the Indochina Peninsula may further amplify the summer monsoon signal in the southern South China Sea.