南海西部浮游有孔虫记录的MIS3期表层海洋环境变化  

ENVIRONMENTAL CHANGES OF SURFACE SEA RECORDED IN PLANKTONIC FORAMINIFERA DURING MIS 3 IN THE WESTERN SOUTH CHINA SEA

作　　者：杨文瑜[1] 黄宝琦[2] 肖洁[2] 周力平[1] 

机构地区：[1]北京大学环境科学学院,北京100871 [2]北京大学地球与空间科学学院,北京100871

出　　处：《第四纪研究》2008年第3期437-446,共10页Quaternary Sciences

基　　金：国家自然科学基金青年基金项目(批准号:40306007);国家重点基础研究发展规划项目(批准号:2007CB815901)资助

摘　　要：对南海西部越南岸外上升流区17954—2站浮游有孔虫属种组合变化、浮游有孔虫氧同位素、AMS ^14C测年的分析以及浮游有孔虫表层海水温度、温跃层转换函数的研究结果表明：在MIS3期，南海西部表层海水温度大体呈现暖-冷-暖的变化趋势；温跃层深度由浅到深阶段性变化；短时间尺度上温度与温跃层发生幅度较大的快速变化。暖事件（IS）对应于浮游有孔虫暖水种、混合层属种含量的增加，冷水种、温跃层属种含量的减少以及冬夏SST的升高；冷事件则与之相反。表层海水生产力亦大致呈现3个阶段（61～51ka，51～42ka和42～32ka）的变化，在千年尺度的快速气候事件中，暖事件对应浮游有孔虫生产力属种含量降低，冷事件对应升高。此外，在MIS3内部分暖事件（IS6和IS 11～13）表现出表层海水温度降低，温跃层深度变浅和表层海水生产力升高的状况，表明该区此时上升流的存在，其形成原因推测是由于东亚夏季风加强的结果。Marine Isotope Stage 3 （MIS 3） is an interstadial in the Last Glaciation. The climate of MIS 3 was extremely variable on a millennial time-scale, that has drawn attention of many paleoclimatologists and marine geologists. In this work, 168 samples were taken from the upper part （ 140 - 370cm） of Core 17954 - 2 （ 14°47.8＇N, 111°31.5＇E） ,which is located at upwelling area off the Vietnam coast in the western South China Sea（SCS）, yielding hemipelagic deposits with a very high sendimentation rate. These samples with a high-resolution of 247a, were analyzed to reveal rapid climate changes recorded in planktonic foraminifera in this region. Micro-fossils of planktonic foraminifera should be picked out from the sediments and be identified firstly. In that case, abundance of the identified species which were related with sea surface temperature （SST）, depth of thermocline （DOT） , and surface sea-water productivity, were used as the indexes to obtain information about surface environment in the western SCS during MIS 3. Changes of SST, DOT, and surface sea-water productivity had been discussed with AMS ^14C dating and stable oxygen isotope analysis on the basis of analysis of planktonic foraminifera species. Abundance of warm-species G. rubber, P G. crassaformis, and N. pachyderma had been obliquiloculata, and G. sacculifer and cool-species G. inflata, figured out, and transfer function （FP-12E）had estimated the corresponding SST. In a similar way, abundance of mix-layer species G. ruber, G. sacculifer, and G. glutinat and thermocline species N. pachyderma,N, dutertrei, and G. mendardii had been calculated,and the corresponding DOT had been estimated too. The SST and DOT results showed that MIS 3 began with a warm period,followed by a cool one, and ended up with another warm one. Rapid climate changes were taking place on millennial and sub-millennial timescales over the whole MIS 3. During most interstadials（IS） , SST was higher with the abundance of warm-species increasing and tha

关 键 词：深海氧同位素3期 浮游有孔虫 快速气候事件 东亚夏季风 南海 

分 类 号：P722.7[天文地球—海洋科学] Q178.53[生物学—水生生物学]