浮游有孔虫壳体氧同位素的古水温及古盐度意义——以东北印度洋260ka以来沉积记录为例  

RECONSTRUCTION OF SEA SURFACE TEMPERATURE AND SALINITY BASED ON PLANKTONIC FORAMINIFERAL δ^(18)O: SEDIMENT RECORDS OF THE NE INDIAN OCEAN DURING THE LAST 260 ka

作　　者：陈萍[1] 方念乔[2] 胡超涌[2] 

机构地区：[1]安徽理工大学资源与环境工程系,安徽淮南232001 [2]中国地质大学海洋地学中心,北京100083

出　　处：《海洋地质与第四纪地质》2005年第2期141-145,共5页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(40272074);安徽省教育厅自然科学研究项目(2005KJ014);安徽理工大学博士基金项目

摘　　要：以东北印度洋的两支岩心为研究对象,由稳定同位素质谱仪获得浮游有孔虫壳体Globigerinoidesruber的δ18O。研究表明,利用壳体δ18O计算表层海水温度必须充分考虑盐度效应的影响,在近岸的边缘海,盐度影响甚至大于温度的影响。通过分析SSTMg/Ca与SSTδ18O的关系以及海水背景值δ18OW与盐度的关系,计算出了东北印度洋260ka以来各时期较准确的海水盐度值。结果表明,冰期盐度高而间冰期盐度低,且冰期时南北盐度梯度明显小于间冰期是该区显著的盐度分布和变化特征,这是特定的地理位置受南亚季风带来的蒸发—降水—淡水输入等诸多因素控制的结果。Two cores MD77181 and MD81349 were taken from the NE Indian Ocean as study materials, and δ^(18)O data were obtained from planktonic foraminifera shell Globigerinoides ruber by means of OPTIMA. We came to the conclusion that it was necessary to adequately take into account the influence from the salinity effect at the time of calculation of SST by use of the planktonic foraminifera shell δ(^(18)O), and even in the marginal sea near continent, the influence given by salinity was more than that by temperature, through detailed discussion and analyses of the interrelations between SST_(δ(^(18)O)) and SST_(Mg/Ca),and also between oxygen isotope δ(^(18)O) of sea water and sea water salinity (SSS). We give quite precise values of SSS in the NE Indian Ocean by means of calculation for the last 260 ka. The result shows that SSS in the glacial period was higher than that in the interglacial period, and furthermore, in this zone,prominent characters of SSS distribution and change are that the salinity gradient between the north and south in the glacial period was obviously less than that in the interglacial period. It was controlled by various factors such as evaporation, rainfall and input of fresh water and others that were brought by the South Asia monsoon in the specific geographical location.

关 键 词：有孔虫壳体 北印度洋 沉积记录 氧同位素 古盐度 古水温 同位素质谱仪 表层海水温度 Δ^18O Δ^18O 盐度效应 海水盐度 变化特征 盐度分布 盐度梯度 地理位置 间冰期 边缘海 背景值 SST 多因素 计算 近岸 降水 

分 类 号：P532[天文地球—古生物学与地层学] Q915.811.1[天文地球—地质学]