近7300 aBP以来冲绳海槽北部上升流的演化  

EVOLUTION OF UPWELLING IN THE NORTH OF THE OKINAWA TROUGH SINCE ABOUT 7300 aBP

作　　者：李青[1] 李铁刚[1] 常凤鸣[1] 曹奇原[1] 

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室

出　　处：《海洋地质与第四纪地质》2008年第2期65-70,共6页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(90411014,40506015,40676071);国家重点基础研究发展规划项目(2007CB815903);中国科学院知识创新工程项目(KZCX3-SW-233)

摘　　要：对取自冲绳海槽北部的DOC024岩心进行了浮游有孔虫氧同位素和统计分析，依据浮游有孔虫群落组合和Neogloboquadrina dutertrei δ^18O的记录以及表层海水温度、温跃层深度的变化揭示了近7300 aBP以来日本九州西南海区上升流的演化过程。7300～7000 aBP期间，较轻的δ^18O值、较高的年平均表层海水温度以及典型上升流种Globigerina bulloides的低含量和较大的温跃层深度指示这一时期该海区上升流尚不发育，其环境主要受黑潮暖流的控制；7000～4800 aBP期间，区域环境略有变化，上升流开始出现，但发育程度不高；在4800～4200 aBP期间，各环境参数的变化都说明该时期为上升流的迅速发育期，并逐渐取代黑潮成为该区环境的主要控制因素。1900～1200 aBP期间上升流发育程度有所减弱，1200～400 aBP之间上升流的发育又逐渐增强，到约400aBP以后，N．dutertrei δ^18O的明显加重、年平均表层海水温度的显著下降、Globigerina bulloides含量的快速增加和温跃层的明显变浅指示近400 aBP以来是区域上升流发育程度最强的时期。Cores DOC024, retrieved from the northern Okinawa Trough in the East China Sea, are used to reconstruct the upwelling evolution over the last 7 300 years based on a multi-proxy approach including the combination of planktonic foraminifer fauna, Neogloboquadrina dutertrei δ^18 O, sea surface temperature （SST） and depth of thermocline. At about 7 300～47 000 aBP, light δ^18O, high SST, low Globigerina bulloides % and deep thermocline show that the region was controlled by the warm Kuroshio current and there was no upwelling; 7 000～44 800 aBP, the environment kept stable, but the upwelling began to develop; during 4 800～44 200 aBP, all proxies changed quickly,which indicates that the upwelling developed rapidly and gradually and controlled the environment; from 1 900 to 1 200 aBP, the upwelling declined slightly; around 1 2004400 aBP,the upwelling gradually increased; since 400 aBP, δ^18O of N. dutertrei increased quickly, SST declined rapidly, Globigerina bulloides% increased fast and depth of thermocline declined obviously, all varieties of proxies point out that the upwelling developed strongly.

关 键 词：浮游有孔虫群落 表层海水温度 温跃层深度 上升流 冲绳海槽北部 

分 类 号：P736.22[天文地球—海洋地质]