摘要
对南海北部大洋钻探ODP1 1 48站进行稳定同位素和有孔虫分析 ,采用多种替代性指标 ,追溯上新世晚期以来东亚冬季风的演变。发现约 3 1～ 2 2MaB .P .之间 ,浮游有孔虫Globigerinoidesruber的δ13C值显著降低 ,而Neogloboquadrinadutertrei的相对丰度明显增大 ,指示冬季风急剧增强 ,并伴随表层海水温度的降低和古生产力的增高。此后 ,冬季风还有几次明显的增强 ,特别是在约 1 7MaB .P .,1 .3MaB .P .,0 .9MaB .P .,0 .6MaB .P .和0 2MaB .P .。频谱分析揭示冬季风主要受冰盖体积大小的控制 。
In order to reconstruct the evolution and variability of the East Asian winter monsoon, this study proposes the δ 13 C of Globigerinoides ruber and relative abundance of Neogloboquadrina dutertrei as the winter monsoon proxy indicators based on their modern distribution as well as the research results of sediment trap in the South China Sea (SCS).\;ODP Site 1148 has yielded an almost continuous record of the Pliocene Pleistocene paleoclimatic and paleoceanographic history in the northern SCS. Based on the stable isotopic analyses of more than 400 samples of planktonic foraminifers at this site, Pliocene Pleistocene isotope stratigraphy and events have been unraveled. Compared with the records of the equatorial Pacific Ocean, the decrease in planktonic ( G. ruber ) δ 13 C during 3.1～2.2Ma B.P. at Site 1148 is very striking, indicating that the fertility of surface water remarkably increased. Meanwhile, the relative abundance of N. dutertrei obviously increased at the same time. It is inferred that the East Asian winter monsoon remarkably strengthened during 3.1～ 2.2Ma B.P. Consequently, the enhanced winter monsoon resulted in (1) stepwise decrease in winter sea surface temperature (SSTw) since 2.2Ma B.P., estimated by planktonic foraminiferal transfer functions; (2) increased surface productivity, reflected by the increased abundance of benthic foraminifer Uvigerina peregrina indicative of high organic carbon flux. The evolution of East Asian winter monsoon in the northern SCS is well correlated to land based records from the Tibetan Plateau and Chinese loess sections.\;Since then, the East Asian winter monsoon were remarkably strengthened further again several times, reflected by low δ 13 C of G. ruber and SSTw, and high abundance of N. dutertrei and U. peregrina , that is, about every 0.4Ma, particularly at about 1.7Ma B.P., 1.3Ma B.P., 0.9Ma B.P. 0.6Ma B.P. and 0.2Ma B.P. Spectral analyses reveal that East Asian winter monsoon is probably forced by changes in ice volume but with less important insolation forcing.
出处
《第四纪研究》
CAS
CSCD
北大核心
2001年第5期461-469,共9页
Quaternary Sciences
基金
国家自然科学基金 (批准号 :4 99995 60 )资助重大项目
国家重点基础研究发展规划项目 (批准号 :G2 0 0 0 0 785 0 2 )
