南海西北部89PC柱样沉积物中浮游有孔虫特征及其古环境意义

PLANKTONIC FORAMINIFERA IN CORE 89PC FROM THE NORTHWESTERN SOUTH CHINA SEA AND THEIR PALEOENVIRONMENT SIGNIFICANCE

对南海北部89PC柱状样进行了浮游有孔虫定量统计分析、氧碳同位素测试、碳酸钙含量分析和AMS^14C测年，并采用古生态转换函数计算了表层海水古温度和温跃层深度，揭示了该海区约127ka以来的古海洋学特征。温跃层转换函数计算的温跃层深度结果表明，在MIS5-MIS4期，温跃层深度没有大的变化，在MIS3-MIS1期，温跃层的深度逐渐变深。古温度转换函数计算的古温度结果表明，夏季温度的变化范围为27.9-29.3℃，变化幅度为1.4℃，冬季温度变化范围为20.6-26.3℃，变化幅度为5.7℃。与南海南部的冬夏古水温资料进行对比，南海南部的温度比南海北部的温度要高，这种差异在冬季时表现更为突出，且在冰期时南海南部和北部的温度差异梯度进一步增大，指示了冰期时冬季风更加强盛。

Planktonic foraminifera（PF） from core 89PC in the northwest of the South China Sea（SCS） were quantitatively studied. Together with SST and thermocline analysis, PF oxygen-carbon isotopes and calcium carbonate analysis and AMS^14C dating, the fauna revealed major evolutionary paleoceanographic characteristics in the northwest SCS over the last 127 ka. The depth of thermocline showed no obvious fluctuations during MIS5-MIS4, but deepened gradually since MIS3. The sea surface paleotemperature（SST） estimated by the transfer function FP-12E showed that the summer SST ranged from 27.9 to 29.3℃, and the winter SST from 20.6 to 26.3℃. The comparison of SST data between the southern and the northern SCS indicated that SST in southern SCS was higher than that in northern SCS. The SST difference was more obvious in winter. Especially, this difference increased most markedly in the glacial periods, indica- ting stronger winter monsoon.