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| 南海西部浮游有孔虫记录的MIS 3期表层海洋环境变化 | |
| 引用本文： | 杨文瑜,黄宝琦,肖洁,周力平.南海西部浮游有孔虫记录的MIS 3期表层海洋环境变化[J].第四纪研究,2008,28(3):437-446. |
| 作者姓名： | 杨文瑜 黄宝琦 肖洁 周力平 |
| 作者单位： | 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 |
| 基金项目： | 国家自然科学基金 , 国家重点基础研究发展计划(973计划) |
| 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、AMS14C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IS11～13）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。 |
| 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 |
| 文章编号： | 1001-7410(2008)03-437-10 |
| 收稿时间： | 2007-12-30 |
| 修稿时间： | 2007年12月30 |
ENVIRONMENTAL CHANGES OF SURFACE SEA RECORDED IN PLANKTONIC FORAMINIFERA DURING MIS 3 IN THE WESTERN SOUTH CHINA SEA |
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| Yang Wenyu,Huang Baoqi,Xiao Jie,Zhou Liping.ENVIRONMENTAL CHANGES OF SURFACE SEA RECORDED IN PLANKTONIC FORAMINIFERA DURING MIS 3 IN THE WESTERN SOUTH CHINA SEA[J].Quaternary Sciences,2008,28(3):437-446. | |
| Authors: | Yang Wenyu Huang Baoqi Xiao Jie Zhou Liping |
| Institution: | 1. College of Environmental Sciences, Peking University, Beijing 100871; 2. School of Earth and Space Sciences, Peking University, Beijing 100871 |
| Abstract: | 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 AMS14 C dating and stable oxygen isotope analysis on the basis of analysis of planktonic foraminifera species.Abundance of warm-species G.rubber,P.obliquiloculata,and G.sacculifer and cool-species G.inflata,G.crassaformis,and N.pachyderma had been 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 that of cool-species decreasing,and thermocline was deeper with the abundance of mix-layer species increasing and that of thermocline species decreasing.And when Heinrich events happened,it displayed absolutely opposite responses.However,sometimes there were exceptions to set out lower SST and shallower thermocline in certain IS events.The surface sea-water productivity was mainly discussed by abundance of N.dutertrei and G.bulloides.The analysis results of how the surface sea-water productivity changed displayed three stages during MIS 3 ,which were 61-51ka,51-42ka,and 42-32ka.Similarly,indexes of productivity also varied frequently and abruptly.In most rapid climate events,the abundance of high-productivity species N.dutertrei and G.bulloides reduced when it was warm and increased when it was cool.But there were exceptions in some IS events likewise,such as IS 4-6,IS 9-14,and IS 16,which were characterized by an increasing percentage of the two species.In addition,in certain IS events,such as IS 6 and IS 11-13,the conditions of low SST,shallow thermocline,and high productivity could imply upwelling taking place when it was warm.It was estimated that East Asian summer monsoon was enhanced during these warm events.On the other hand,three stages presented in some indexes also supported a concept that enhanced East Asian summer monsoon could influence this region. |
| Keywords: | Marine Isotope Stage 3(MIS 3) planktonic foraminifera rapid climate event East Asian summer monsoon the South China Sea(SCS) |
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