中更新世气候转型期南海北部和南部的气候变化差异  

COMPARISION OF CLIMATE CHANGES BETWEEN NORTHERN AND SOUTHERN SOUTH CHINA SEA DURING THE MID-PLEISTOCENE CLIMATE TRANSITION PERIOD

作　　者：金海燕[1] 翦知湣[1] 

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092

出　　处：《第四纪研究》2008年第3期381-390,共10页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:40621063和40331002);国家重点基础研究发展规划项目(批准号:2007CB815900)联合资助

摘　　要：选取大洋钻探ODP184航次在南海北部采集的1144站为研究材料，通过分析中更新世0．4—1．4Ma期间506个样品中浮游有孔虫氧、碳稳定同位素的变化特征，并与南海南部ODP1143站和西太平洋暖池ODP807站的同位素资料进行比较，发现南海北部的氧、碳稳定同位素及其差值的变化响应中更新世气候转型事件，在中更新世距今约0．9Ma之后100ka的偏心率周期明显增强。在中更新世气候转型之前，南海北部、南海南部和赤道西太平洋都呈现出典型的热带气候特征，具有岁差和半岁差的气候周期；转型之后，随着北半球冰盖的进一步扩张，南海北部受东亚冬季风增强的影响而导致温度下降、温跃层变深，但南海南部与赤道西太平洋的温度变化较小且温跃层变浅，说明同属季风区的南海北部和南部对气候变化的响应有所不同。A total of 506 samples of the Site 1144, which was recovered during the Ocean Drilling Program（ODP） Leg 184 in the South China Sea （SCS）, was used in this study to investigate paleoceanographic changes during the past 0.4 - 1.4Ma. By measuring stable oxygen and carbon isotopes on shells of planktonic foraminifera at the Site 1144 and comparing the results with the data from ODP Site 1143 in the southern SCS and ODP Site 807 at the central Pacific Warm Pool, we found out that the stable isotopes and their differences reflected the mid-Pleistocene transition （MPT） event and showed a more obvious 100ka periodicity after 0.9Ma. Furthermore, before 0.9Ma, paleoceanographic records in the northern and southern SCS and the western Pacific Warm Pool （WPWP）showed distinctive precession- and semi-precession signals, which implied the typical tropical characteristics in the two areas during the MPT period. After 0.9Ma,the sea surface temperature（SST）decreased significantly and the depth of thermocline（ DOT） became deeper in the northern SCS which were likely resulted from the growth of the Northern Hemisphere ice sheet and the enhanced East Asian Monsoon（EAM）. While in the southern SCS and the WPWP, the SST decreased only slightly and the DOT shoaled. It reflects the different climate changes responding to the MPT event between the northern and southern SCS.

关 键 词：中更新世气候转型 南海 东亚季风 稳定同位素 

分 类 号：P534.631[天文地球—第四纪地质学] P736.2[天文地球—古生物学与地层学]