Paleoceanographic events of the southern Okinawa Trough during last 20 000 years

Two high resolution down-mres(92-255,92-170) are used to study the paleoceanographic events of the southern Okinawa Trough during the last 20 000 years.Planktonic foraminifera are quantitatively analyzed and three paleoceanographic events are recognized.Glacial/post-glacial variations in sea surface temperature(SST),water masses,and upper water mlumn structure are the most important environmental changes recorded by planktonic foramirtifera.There is also an abrupt climatic event(about 10 710-9 170 a BP) during the Termination Ⅰ,planktonic foraminifera(PF) δ18O and SST have a same return pattern,but benthic foraminifera(BF) δ18O doesn't have.Discrepancy between PF δ18O and BF δ18O may reflect that the sea surface water is more sensitive to abrupt,short term envirorunental change than the sea bottom water.High-resolution strata also suggest a middle-Holocene Pulleniatina obliquiloculata minimum event.