末次冰期以来西太平洋暖池变化的浮游有孔虫记录

PLANKTONIC FORAMINIFERA RESPONDENCE TO CHANGES OF WEST PACIFIC WARM POOL SINCE LAST GLACIAL

探讨了末次冰期以来西太平洋暖池区浮游有孔虫动物群变化对环境和全球气候变化的响应。对取自西太平洋暖池核心区WP92 5柱样中的浮游有孔虫及其壳体δ18O的分析结果表明,西太平洋暖池末次冰期的冬季表层水温比全新世低 2℃以上;浮游有孔虫 Neoglobo quadrina pachyderma 的含量变化与Globigerinoides sacculifer 的δ18 O值呈明显相关,各时段的峰值可能与YD事件和Heinrich事件H1、H2和H3大致对应,分别出现在21—29、38—46、64—72和106—117cm, 14C年龄约为9.7—11.1、12.8—14.7、19—20.9 和 26.2—27.4kaB.P.;浮游有孔虫N. pachyderma的含量与G. sacculifer的δ18O在各峰值之间含有数个频次不等的亚级变化,反映了末次冰期以来西太平洋暖池区气候的短尺度快速变化特征。

Variation of planktonic foraminiferal fauna in the Western Pacific Warm Pool (WPWP) since the last glacial and its respondence to global changes are discussed. Based on the analyses of planktonic foraminiferal composition and δ^(18)O value of G. sacculifer in the high-resolution sampling core WP92-5 from the central area of the WPWP, some important results are obtained about the changing history of the WPWP. The winter SST in the last glacial is at least 2℃ lower than that in the Holocene in the WPWP. The content variation of N. pachyderma shows a close correlation with the δ^(18)O value of G. sacculifer, and 4 cold events are revealed by the peak of N. pachyderma, the δ^(18)O value of G. sacculifer and the ratio of warm/cold species of planktonic foraminifera at depths of 21—29,38—46,64—72 and 106—117 cm in core WP92-5 respectively, with corresponding ^(14)C ages at about 9.7—11.1,12.8—14.7,19—20.9 and (26.2)—27.4 ka B.P. respectively. These cold events may correspond to the YD event and H1 to H3 of the Heinrich event respectively. Many sub-changes can also be found between these 4 cold events, suggesting that rapid climatic change is also a characteristic of the WPWP since the last glacial.