Cosmogenic^(10)Be dating of the oldest moraine in the Hengduan Mountains  

作　　者：Zhigang ZHANG Jiahong ZHENG Haitao CUI Zhijun ZHAO Xinggong KONG Chaogang ZHENG Hong ZHANG Fei GUO Zhiyang CHANG Xue YUAN Mingyang YAN Jie ZHANG Jian WANG 

机构地区：[1]School of Geography,Nanjing Normal University,Nanjing,210023,China [2]Key Laboratory of Virtual Geographic Environment(Nanjing Normal University),Ministry of Education,Nanjing,210023,China [3]Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,Nanjing,210023,China [4]Tourism and Social Administration College,NanJing XiaoZhuang University,Nangjing,211171,China

出　　处：《Science China Earth Sciences》2023年第10期2211-2223,共13页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41971009&41503054);the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2000300)。

摘　　要：The Hengduan Mountains is in the transitional zone between the Qinghai-Tibet Plateau(QTP)and the YunnanGuizhou Plateau in China,and a key area for elucidating the Quaternary environmental changes in Asia.The paleo-Daocheng ice cap was located on the Shaluli Hilly Plateau in the northeastern Hengduan Mountains,the oldest moraines in the Hengduan Mountains region were found in the ice cap area.Such glacial landforms provide key evidence to study the timing when this area entered the cryosphere with the uplift of the QTP.However,it is difficult to collect suitable glacial boulders from these moraines for traditional terrestrial in-situ cosmogenic nuclide(TCN)exposure dating because of long-term severe moraine degradation.Here,we collected clast samples from the moraine surface and depth profile to constrain the age of the oldest moraine in Kuzhaori(moraine E)using TCN^(10)Be dating technique.The minimum^(10)Be ages of five clast samples from the moraine surface range from 187.4±1.5 to 576.8±4.3 ka,implying that the moraine has been seriously degraded since deposition.Based on the TCN^(10)Be concentrations of the samples from a depth profile and simulations,the exposure-erosion-inheritance history of the profile was obtained.By fitting to the profile^(10)Be concentrations using the chi-square test,the simulations yielded a reliable age of 626.0±52.5 ka for the moraine.Therefore,the oldest moraine(moraine E)in Kuzhaori was most likely formed at about 0.63Ma ago,corresponding to the marine isotope stage(MIS)16.This glaciation represents the maximum Quaternary glaciation after the QTP was elevated into the cryosphere by the Kunlun-Yellow River Tectonic Movement.

关 键 词：Hengduan Mountains Paleo-Daocheng ice cap Terrestrial in-situ cosmogenic nuclide^(10)Be Depth profile Exposure dating 

分 类 号：P597.3[天文地球—地球化学]