STEPWISE PALEOCEANOGRAPHIC CHANGES DURING THE LAST DEGLACIATION IN THE SOUTHERN SOUTH CHINA SEA - RECORDS OF STABLE-ISOTOPE AND MICROFOSSILS

Quantitative analyses of microfossils and stable isotopic analysis wer e carried out for Core SCS-12 in the southwestern slope of the South C hina Sea (SCS). A high-resolution paleoceanographic record for the las t 13 ka was revealed with the AMS C-14 dates. The southern SCS has exp erienced stepwise paleoceanographic changes since the last deglaciatio n. The oxygen isotopic stage 1/2 boundary around 12.05 ka B.P. and the end of the last deglaciation around 7.70 ka B.P. are two rapid change periods (corresponding to the termination I-A and termination I-B, re spectively), in between is a slow change period. The authors infer tha t the sea level stood at -110 m before the termination I-A, roughly th e same as today after the termination I-B, and about -50 m in between. Subsequently, the average winter sea surface temperature and salinity obviously increased while paleo-productivity decreased since 12.05 ha B.P. The early Holocene CaCO3 preservation spike, coupled with a high abundance of pteropoda and CaCO3 content, occurred around 7.70 ka B.P .