西北冰洋冰筏碎屑指示的MIS 5以来冰盖和洋流的演化历史  

THE EVOLUTION OF ICE SHEET AND SURFICIAL CURRENTS INDICATED BY ICE RAFTED DEBRIS IN THE WESTERN ARCTIC OCEAN SINCE MIS5

作　　者：章陶亮 王汝建[2] Leonid Polyak 肖文申[2] ZHANG Taoliang;WANG Rujian;Leonid POLYAK;XIAO Wenshen(School of Oceanography,Shanghai Jiao Tong University,Shanghai 200240;State Key laboratory of Marine Geology,Tongji University,Shanghai 200092;Byrd Polar and Climate Research Center,the Ohio State University,Columbus,43210)

机构地区：[1]上海交通大学海洋学院,上海200240 [2]同济大学海洋地质国家重点实验室,上海200092 [3]Byrd Polar and Climate Research Center,Columbus OH 43210

出　　处：《第四纪研究》2021年第3期646-661,共16页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41776187、41030859和42006186);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：通过西北冰洋楚科奇边缘地区4个柱状沉积物组成的岩芯断面,分析MIS5以来粗颗粒(>250μm)冰筏碎屑(IRD)的岩矿组成,确定西北冰洋不同时期IRD的来源和搬运模式,进而重建MIS5以来欧亚冰盖和北美冰盖的消长以及北冰洋海盆中表层洋流的演化历史。研究结果显示MIS5.5和MIS5.1期间,波弗特环流的影响范围大于MIS1期,而在MIS5.4~5.2期间,波弗特环流的影响范围小于现代;MIS4期间,岩芯中发现了大量来源于欧亚冰盖或东西伯利亚海冰盖的冰川浊积物,冰盖可能扩张到了楚科奇边缘地区南部;在同一时期,在楚科奇边缘地区南部的岩芯中IRD几乎全部为铁锰结核,可能受到了欧亚冰盖或东西伯利亚海冰盖的影响,但铁锰结核与欧亚冰盖的关系仍需进一步研究;MIS3期间,波弗特环流的影响范围和强度略弱于现代;在末次冰盛期,研究区受到以劳伦冰盖为主要来源的冰川浊积物输入;在末次冰消期,研究区发生了一次来源于北美劳伦冰盖的冰融水排泄事件;在MIS1期,西北冰洋主要受到波弗特环流的控制,将来源于加拿大北极富含碎屑碳酸岩的IRD带入北冰洋海盆。In this article,Ice Rafted Debris(IRD)petrological and lithological identification were performed on 4 gravity cores collected in the Chukchi Borderland,western Arctic Ocean,including core ARC6-C15(75.62°N,163.23°W,2016 m water depth,418 cm core length,bottom age MIS 4),core ARC7-P12(78.29°N,162.69°W,2086 m water depth,256 cm core length,bottom age MIS5),core P1-92-AR-P25(74.82N,157.37°W,1625 m water depth,550 cm core length,bottom age MIS5)and core HLY0503-8 JPC(79.59°,172.50°W,2792 m water depth,402 cm core length,bottom age MIS5).Our research purpose is to determine the IRD provenances by the IRD composition(variation in detrital carbonates,clastic rocks,coal fragments and Fe-Mn nodules content),and further indicate the Eurasian Ice Sheet(EAIS)and Laurentide Ice Sheet(LIS)evolution and surficial circulation variability since MIS5.During MIS5.5 and MIS5.1,the Beaufort Gyre(BG)expanded compare to modern condition.During MIS4,thick glacioturbidites from EAIS or East Siberia Ice Sheet(ESIS)were found in sediments which indicate that EAIS or ESIS may expand to southern Chukchi Borderland.At the same time,abundant Fe-Mn nodules were found in MIS4 sediments.We assume they were affected by the EAIS or ESIS expansion.Meanwhile,the relationship between Fe-Mn nodules and EAIS or ESIS is uncertain and more works are required.During MIS3,the BG slightly shrink and the range is smaller than current BG.During Last Glacial Maximum(LGM),sediments are mainly composed by glacioturbidites originated from LIS,and a drainage event from LIS were found in study area within the last deglaciation.During MIS1,the study area is controlled by BG and carbonate-rich IRD from the Canadian Arctic Archipelago(CAA)are transported by BG into the Arctic Basin.

关 键 词：西北冰洋 冰筏碎屑 岩矿鉴定 北半球冰盖 表层洋流 

分 类 号：P727[天文地球—海洋科学] P736.213