深海氧同位素13期以来北冰洋西部中心海区冰筏输入历史  

ICEBERG RAFTING HISTORY IN THE WESTERN CENTRAL ARCTIC OCEAN SINCE MIS13

作　　者：石端平 肖文申[1] 王汝建[1] 章陶亮 SHI Duanping;XIAO Wenshen;WANG Rujian;ZHANG Taoliang(State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092;School of Oceanography,Shanghai Jiao Tong University,Shanghai 200240)

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]上海交通大学海洋学院,上海200240

出　　处：《第四纪研究》2021年第3期621-631,共11页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41776187);自然资源部国家海洋局极地考察办公室中国北极考察专项项目(批准号:CHINARE2012-2017-03-02);自然资源部国家海洋局极地考察办公室2020年度极地科学协同创新平台项目(批准号:CXPT2020008)共同资助。

摘　　要：更新世以来,北极冰盖的发育对北冰洋环流和沉积环境产生了重大影响,进而深刻地影响了全球气候演变。文章通过定量分析西北冰洋位于阿尔法脊的ARC4-BN10岩芯(240 cm,约330 ka,MIS9~1)和马卡洛夫海盆的ARC5-ICE6岩芯(426 cm,约500 ka,MIS13~1)中冰筏碎屑的含量及其岩矿组成,揭示MIS13以来北极冰盖及西北冰洋表层洋流的演化历史;现代环境中二者分别受波弗特环流和穿极流影响;冰筏碎屑的岩矿组成表明北美大陆和欧亚大陆的冰盖发育不平衡。在研究时期内,北美劳伦冰盖在冰期一直较发育,通过波弗特环流向加拿大海盆排泄北美沉积物;而在MIS6和MIS4,欧亚冰盖最为发育,此时穿极流影响范围扩大,将西伯利亚沉积物带入加拿大海盆;MIS7期以来IRD含量显著增加的现象与北冰洋整体变冷、季节性海冰向永久海冰转化的过程一致。两根岩芯均记录到MIS5d和5a的两次劳伦冰盖排泄事件,表明波弗特环流的影响范围扩大到马卡洛夫海盆;MIS5b主要接收穿极流和西伯利亚物源的输入,其岩矿组成差异显示了冰阶-间冰阶搬运冰盖发育和洋流模式的差别。而在MIS3劳伦冰盖的排泄事件并未显著影响到马卡洛夫海盆。Since the Pleistocene,the development of the Arctic ice sheet has significant impacted on the circulation and sedimentary environment of the Arctic Ocean,and further influenced the global climate evolution.Based on quantitative analysis of the Ice Rafted Debris(IRD)contents and its lithogenic composition in cores ARC4-BN10(85°30.21’N,178°38.60’W;240 cm,Marine Isotope Stage 9~1)from the Alpha Ridge and ARC5-ICE6(83°37.696’N,161°45’E;426 cm,MIS13~1)from the Makarov Basin,this study reveals the evolution history of the Arctic ice sheet and the surface circulation in the western Arctic Ocean since MIS 13.Under modern conditions,the two cores are located under the influence of the Beaufort Gyre(BG)and the Transpolar Drift(TPD),respectively.Changes in IRD lithogenic composition suggests heterogeneous development of ice sheets on North American and Eurasian continents.During the studied time interval,the Laurentide Ice Sheet on North American developed during the glacial periods of MIS 12,10 and 8,discharging North America material to the Canada Basin by the BG.In contrast,the Eurasian ice sheet was most developed during MIS6 and 4,when TPD expanded and delivered Siberian sediments to the Canada Basin.The increase in IRD since MIS7 signifies the overall cooling with the establishment of perennial sea ice cover in the Arctic Ocean.Two distinct LIS discharge events are recorded in both cores in estimated MIS5d and 5a,suggesting BG extension to the Makarov Basin.In contrast,a TPD and Eurasian provenance dominate the sediment discharge during MIS5b.During MIS3,LIS discharge barely reach Makarov Basin.

关 键 词：北冰洋 劳伦冰盖 欧亚冰盖 冰筏碎屑 波弗特环流 穿极流 

分 类 号：P727[天文地球—海洋科学] P534.63