Southwest monsoon changes indicated by oxygen isotope of ostracode shells from sediments in Qinghai Lake since the late Glacial  

作　　者：LIU XingQi SHEN Ji WANG SuMin WANG YongBo LIU WeiGuo 

机构地区：[1]Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China [2]Graduate University, Chinese Academy of Sciences, Beijing 100049, China [3]Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710054, China

出　　处：《Chinese Science Bulletin》2007年第4期539-544,共6页

基　　金：Supported by the National Basic Research Program of China (Grant Nos. 2004CB720200 and 2005CB422002);the National Natural Science Foundation of China (Grant No. 40373016);the National Natural Science Foundation of Dis-tinguished Young Scholars of China (Grant No. 40625007)

摘　　要：The δ 18O records of ostracode shells in sediments of core QH-2000 from Qinghai Lake can be used as a better proxy to reflect monsoon changes. Low monsoon precipitation between 17.5 and 11 cal. ka BP is indicated by positive δ 18O values averaging 2.37‰. A fast shift in δ 18O from positive at 11 cal. ka BP to negative at 10 cal. ka BP indicates sharp increase of monsoon precipitation. An interval of generally high monsoon precipitation is observed between 10 and 6 cal. ka BP with δ 18O values averaging -2.15‰. Decrease of monsoon precipitation between 6 and 2.5 cal. ka BP is indicated by positive δ 18O values. δ 18O keeps positive values averaging 3.0‰ between 2.5 and 0 cal. ka BP suggesting low high monsoon precipitation. The climatic changes indicated by δ 18O records of ostracode shells in sedi- ments of core QH-2000 from Qinghai Lake and our broader regional comparison show that the climate in Qinghai Lake since the late Glacial is probably controlled by southwest monsoon other than southeast monsoon.The δ^18O records of ostracode shells in sediments of core QH-2000 from Qinghai Lake can be used as a better proxy to reflect monsoon changes. Low monsoon precipitation between 17.5 and 11 cal. ka BP is indicated by positive δ^18O values averaging 2.37‰. A fast shift in δ^18O from positive at 11 cal. ka BP to negative at 10 cal. ka BP indicates sharp increase of monsoon precipitation. An interval of generally high monsoon precipitation is observed between 10 and 6 cal. ka BP with δ^18O values averaging -2.15‰. Decrease of monsoon precipitation between 6 and 2.5 cal. ka BP is indicated by positive δ^18O values. δ^18O keeps positive values averaging 3.0‰ between 2.5 and 0 cal. ka BP suggesting low high monsoon precipitation. The climatic changes indicated by δ^18O records of ostracode shells in sediments of core QH-2000 from Qinghai Lake and our broader regional comparison show that the climate in Qinghai Lake since the late Glacial is probably controlled by southwest monsoon other than southeast monsoon.

关 键 词：冰河晚期 青海湖 沉积物 介形亚纲动物壳 氧同位素 西南季风 

分 类 号：P532[天文地球—古生物学与地层学] P462.41[天文地球—地质学]