PULLENIATINA OBLIQUILOCULATA AS A PALEOCEANOGRAPHIC INDICATOR IN THE SOUTHERN OKINAWA TROUGH DURING THE LAST 20,000 YEARS

Pulleniatina obliquiloculata, a tropical species of planktonic foramin ifera, is indicative of the Kuroshio current and sensitive to winter s ea surface temperature for the late Quaternary in the Okinawa Trough. Its relative abundance fluctuations are significant and correlatable b etween three gravity cores (cores 255, 170, 253) raised from the south ern Okinawa Trough. Four major changes in its abundances with paleocea nographic significance have been recognized during the last 20,000 pea rs: an abrupt increase at the Pleistocene/Holocene boundary, a short-t erm decrease indicative of a 'Younger Dryas'-type climate reversal at about 11.4-9.6 ka B.P., the P. obliquiloculata maximum zone (around 7- 6 ka B.P.) corresponding to the mid-Holocene climate optimum and the P . obliquiloculata minimum zone (around 4-2 ka B.P.) correlated probabl y to the Neoglacial cooling. The widespread occurrence of these events in the western Pacific and the correlated variations of its abundance between sea areas suggest that P. obliquiloculata is well promising a s a paleoceanographic and climatic monitor for high-resolution reconst ruction and sea-land correlation.