南海南部120ka以来元素地球化学记录的东亚夏季风变迁  

Element Geochemistry Record in Southern South China Sea Sediments during the Past 120ka and Its Implications for East Asian Summer Monsoon Variation

作　　者：梅西[1,2,3] 张训华[2] 郑洪波[4] 刘锐[2] 谢昕[5] 黄恩清[5] 

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]国土资源部海洋油气资源与环境地质重点实验室,山东青岛266071 [3]中国科学院研究生院,北京100049 [4]南京大学地球科学系表生地球化学研究所,南京210093 [5]同济大学海洋地质国家重点实验室,上海200092

出　　处：《矿物岩石地球化学通报》2010年第2期134-141,共8页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金(40676033);国家重点基础发展计划(2007CB815906);创新研究群体科学基金(40621063)

摘　　要：利用XRF岩芯元素扫描仪对南海南部MD05-2896孔岩芯样品进行1 cm间隔的元素测试。该孔底部年龄约为120ka。研究表明,南海南部间冰期夏季风活动增强,上升流发育;夏季风和降雨带来的陆源有机物输入增加,提高了表层的生产力;冰期夏季风减弱,陆源有机物输入减少,表层生产力降低。海洋表层生产力在MIS3早期（60-40 ka）较高,指示该时有特强的夏季风,上升流作用增强。Ba/Ti值表明东亚夏季风的强弱变化,并与北半球夏季日射量基本呈线性关系,体现了东亚夏季风演化的天文驱动机制。Element contents in every 1cm interval of the sediment core MD05-2896,which was collected in the southern area of South China Sea,were analyzed by XRF Core Scanner.The results indicated that the age of the bottom sediment was 120 ka,and elementary ratios are of significant indications in this core.The content of Ti can be used as an indicator for the variation of terrigenous debris contents;the ratio of Ba/Ti indicates the paleoproductivity change in the surface layer of the sea.It is showed that,during the interglacial period,the summer monsoon was intensified and upstream was developed,meanwhile,the terrigenous organic matter input brought by summer monsoon and rainfall was increased accordingly,which caused the increasing of surface productivity;during the glacial period,summer monsoon was weakened,the terrigenous organic matter input was decreased,therefore,the productivity in the surface layer was correspondingly decreased.Productivity in the surface layer was relatively high during early MIS3（60~40 ka）revealed extremely strong summer monsoon and enhancement of the upstream effect.The approximate linear correlation between the intensity variation of East Asia Summer Monsoon evolution,which could be indicated by the ratio of Ba/Ti,and summer insolation of the north hemisphere reveals the astronomical driving mechanism for the East Asia Summer Monsoon evolution.

关 键 词：南海南部 晚第四纪 元素地球化学 东亚夏季风 生产力 

分 类 号：P595[天文地球—地球化学]