从微体化石看西太平洋暖池的形成与演化  

FORMATION AND EVOLUTION OF THE WESTERN PACIFIC WARM POOL RECORDED BY MICROFOSSILS

作　　者：翦知湣[1] 李保华[2] 王吉良[1] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092 [2]中国科学院南京地质古生物研究所,南京210008

出　　处：《第四纪研究》2003年第2期185-192,共8页Quaternary Sciences

基　　金：国家重点基础研究发展规划项目 (批准号 :G2 0 0 0 0 7850 2 );国家杰出青年科学基金 (批准号 :4 0 12 50 15)资助项目;教育部霍英东青年教师基金 (批准号 :810 15)资助项目

摘　　要：通过对南海大洋钻探ODP第 1 84航次的ODP1 1 4 3站和ODP1 1 4 6站以及中德合作“太阳号”95航次的南沙海区 1 7957- 2柱状样中微体化石进行定量分析 ,提取了近 1 8MaB .P .以来南海上部海水垂向结构的变化。结果发现 1 1 .5～ 1 0 .6MaB .P .之间和 3 .6～ 3 .3MaB .P .以来南海温跃层深度的南北梯度明显增大 ,指示了西太平洋暖池雏形的开始和现代暖池的最终形成 ,且分别对应于印度尼西亚海道和巴拿马地峡的关闭。此后 ,南沙海区的温跃层深度自约0 .9MaB .P .逐渐变浅 ,至约 0 .1 5MaB .P .又再变深 ,反映了西太平洋暖池的减弱和再次加强。因而 ,晚新生代西太平洋暖池的形成和演化呈现阶段性。Based on the quantitative analysis of microfossils from Sites 1143 and 1146 of the Ocean Drilling Program (ODP) Leg 184 and Core 17957 2 of Sino German joint expedition 'Sonne' Cruise 95, the variations in upper water structure during the last 18Ma was reconstructed. It has been found that before about 11.5Ma B.P. the changes in relative abundance of planktonic foraminiferal deep dwelling species, which is associated with shallow depth of thermocline (DOT), display similar trend in the southern and northern South China Sea (SCS), indicating that the western Pacific warm pool(WPWP) did not exist at that time. During the period of 11.5～10 6MaB.P., the south north gradient of the DOT in the SCS occurred for the first time, representing the beginning of the WPWP possibly in response to the close of the Indonesian Seaway. However, the south north gradient of the DOT in the SCS disappeared between 10.6Ma B.P. and 3.6Ma B.P., implying that the WPWP was remarkably weakened or extremely unstable. Since 3.6～3.3MaB.P., the relative abundance of planktonic foraminiferal deep dwelling species displayed an opposite trend in the northern and southern SCS, with high values in the north and low ones in the south, indicating that the DOT shoaled in the north and deepened in the south in the SCS. This means that the south north gradient of the DOT in the SCS conspicuously increased, representing the final formation of the modern WPWP. It is speculated that the emergence of the Isthmus of Panama between the Atlantic and the Pacific could result in shoaled DOT in the eastern Pacific and deepened DOT in the western Pacific, and hence intensified the WPWP. After the WPWP formed, it has still experienced remarkable changes. The DOT of the Nansha area gradually decreased since about 0.9Ma B.P., reached a minimum at about 0.15Ma B.P. and then began to deepen again, reflecting that the WPWP weakened since about 0.9Ma B.P. but strengthened again after about 0.15Ma B.P. Therefore, the formation and evolution of the WPWP c

关 键 词：西太平洋暖池 南海 大洋钻探 微体化石 温跃层 厄尔尼诺 海气相互作用 

分 类 号：P732[天文地球—海洋科学]