南黄海、东海陆架及冲绳海槽北部沉积物的^(10)Be和~9Be记录  

Be ISOTOPES IN SURFACE SEDIMENTS FROM THE SOUTHERN YELLOW SEA,THE EAST CHINA SEA CONTINENTAL SHELF AND IN A SEDIMENT CORE FROM THE NORTHERN OKINAWA TROUGH

作　　者：杨永亮[1] 刘振夏[2] 沈承德[3] 石学法[2] 李铁刚[4] 徐清[1] 潘静[5] 程振波[2] 熊应乾[2] H.Matsuzaki 

机构地区：[1]中国地质科学院国家地质实验测试中心,北京100037 [2]国家海洋局第一海洋研究所,青岛266071 [3]中国科学院广州地球化学研究所,广州510640 [4]中国科学院海洋研究所,青岛266071 [5]东华大学环境科学与工程学院,上海200051 [6]Micro Analysis Laboratory,Tandem Accelerator,The University of Tokyo,Tokyo 113-0032,Japan

出　　处：《第四纪研究》2007年第4期529-538,共10页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:40173027;40176018);国家自然科学基金重点项目(批准号:90411014);国家自然科学基金重大国际合作项目(批准号:4042115001);科学技术部国际合作项目(批准号:2003CB7167706)资助

摘　　要：文章讨论了南黄海泥质区、东海陆架及冲绳海槽北部表层沉积物和柱状岩芯中10Be及9Be含量的水平和垂直分布,并与重金属Pb的分布进行了比较。表层沉积物中的10Be,9Be和Pb三者表现出完全不同的分布特征。10Be的分布主要受黑潮及其支流黄海暖流所支配;9Be的分布受黄河陆源物质输入的影响,主要集中在南黄海泥质区;Pb则主要分布在长江口和琉球群岛附近,反映了人类活动的影响。冲绳海槽北部末次冰期和全新世时10Be的沉积通量变化在整体上反映了10Be大气生产率的变化,即地球磁场屏蔽效应的影响。03孔全新世时10Be的沉积通量(1·12×109atoms/cm2ka)基本上等于10Be的现代大气平均生产率,而在末次冰期时平均为4·06×109atoms/cm2ka,高于10Be的现代大气平均生产率3倍以上。在冲绳海槽由于黑潮的缘故,10Be对气候的变化响应要比极地冰芯的10Be变化响应灵敏的多,对气候变化信号起了放大的作用。冰期时冲绳海槽北部10Be的沉积通量远远高于太平洋大洋海区,充分反映了黑潮的传送带作用和边缘海的聚焦沉积作用,并表明末次冰期时在千年尺度上黑潮仍流经冲绳海槽,且强度并未减弱。10Be的通量在新仙女木时降到整个岩芯所跨时期的最低点,甚至低于10Be的现代大气平均生产率,因此推测在新仙女木事件时,黑潮的变动特别大,有可能改向或断流。Concentrations of beryllium isotopes in surface sediments from the Southern Yellow Sea and the East China Sea continental shelf and a sediment core DGKS9603 from the Okinawa Trough have been determined. ^10Be records in the Okinawa Trough sediment during the last glacial, the Younger Dryas cold period, and the Holocene show that the main part of the fluctuations in ^10Be content in the sediment can be attributed to variations in the ^10Be production rate. The average ^10Be flux in the Holocene was 1. 12 × 10^9atoms/cm^2ka, nearly the same as the present atmospheric ^10Be production rate, whereas the average ^10Be flux during the last glacial period was 4.06 × 10^9atoms/ cm^2ka, more than three times higher than at present and also higher than the ^10Be accumulation fluxes in the Pacific open ocean during the glacial period, indicating the conveyor rule of the Kuroshio Current and a boundary scavenging effect for ^10Be. The high ^10Be content and flux in the Okinawa Trough during the glacial period proved that on millennium scale the Kuroshio Current still flowed in the Okinawa Trough area with significantly high intensity. However, this does not disprove that short changes in intensity or direction of the Kuroshio ever occurred at certain short cooling events. The ^10Be minimum during the Younger Dryas event may indicate that the Kuroshio had been once greatly weakened or even terminated in the Okinawa Trough area which could be related to the response of the Pacific Ocean to the Younger Dryas. The ^10Be and ^9Be in surface sediment show totally different distribution patterns. The ^10Be distribution is dominated by the input from Kuroshio and its branch, the Yellow Sea Current, whereas ^9Be is mainly influenced by terrestrial input of suspended materials from the Yellow River discharge and deposited in the fine-grain size sediment zone southwest of the island of Jeju. Both ^10Be and ^9Be distribution patterns are different from anthropogenic pollutants such as heavy metal Pb which is dominantly distributed clo

关 键 词：铍同位素 沉积物 晚更新世新仙女木事件黑潮 冲绳海槽北部 

分 类 号：P736.4[天文地球—海洋地质]