EVOLUTION OF UPWELLING IN THE NORTH OF THE OKINAWA TROUGH SINCE ABOUT 7 300 aBP

Cores DOC024, retrieved from the northern Okinawa Trough in the East China Sea, are used to reconstruct the upwelling evolution over the last 7 300 years based on a multi-proxy approach including the combination of planktonic foraminifer fauna, Neogloboquadrina dutertrei δ¹⁸O, sea surface temperature (SST) and depth of thermocline. At about 7 300~47 000 aBP, light δ¹⁸O, high SST, low Globigerina bulloides% and deep thermocline show that the region was controlled by the warm Kuroshio current and there was no upwelling; 7 000~44 800 aBP, the environment kept stable, but the upwelling began to develop; during 4 800~44 200 aBP, all proxies changed quickly,which indicates that the upwelling developed rapidly and gradually and controlled the environment; from 1 900 to 1 200 aBP, the upwelling declined slightly; around 1 2004400 aBP,the upwelling gradually increased; since 400 aBP, δ¹⁸O of N. dutertrei increased quickly, SST declined rapidly, Globigerina bulloides% increased fast and depth of thermocline declined obviously, all varieties of proxies point out that the upwelling developed strongly.