南海南部表层海水古温度估算与次表层海水特征变化

南海南部～2 MaBP以来的表层海水古温度估算表明,表层海水温度变化在更新世冰期旋回中波动比南海北部为小、保持比较温暖,但在长时间尺度上转换函数古水温仍然存在一定的变化趋势。转换函数古温度计算的低温时期并不与冰期相对应,表明南海南部具有独特的表层海洋演化特征,可能与次表层水体性质、上部水体结构等密切相关。过去2 MaBP以来的浮游有孔虫组合演化表明,南海南部海水温跃层呈现由氧同位素MIS79期向～53期相对变浅,自MIS 53期向布容／松山(B／M)古地磁界线附近变深,然后,自布容／松山界线以来又相对变浅的演化过程。

SEA SURFACE TEMPERATURE ESTIMATE AND SUBSURFACE WATER EVOLUTION IN THE SOUTHERN SOUTH CHINA SEA

Sea surface temperature (SST) estimates of the southern South China Sea over the last 2 Ma indicate that, the water temperature kept warm with lower variation compared with the northern South China Sea during the Pleistocene glacial-interglacial cycles. However, for the long-time scale, the transfer-function estimated SST still has an evident trend. The low-temperature periods were not consistent with the glacial times, which implies that there exists characteristic evolution for the sea surface water in the southern South China Sea. The transfer-function estimated SST might reflect the subsurface water and upper water-column structure of the low-latitude marine environment. Evolution of planktonic foraminiferal fauna over the last 2 Ma indicated that the thermocline of the southern South China Sea shoaled gradually from marine isotope stage (MIS) 79 to ~53, deepened from MIS 53 to the Brunhes/Matuyama boundary, and shoaled again after B/M boundary.