青藏高原中部当穹错末次冰消期以来湖面变化研究  

Lake level variations of Tanqung Co since last deglaciation,central Tibetan Plateau

作　　者：丛禄 王懿萱[1] 孙爱军 高东林 刘向军 CONG Lu;WANG Yixuan;SUN Aijun;GAO Donglin;LIU Xiangjun(Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,Qinghai;Key Laboratory of Salt Lake Geology and Environment of Qinghai Province,Xining 810008,Qinghai;University of Chinese Academy of Sciences,Beijing 100049;Key Laboratory of Western China's Environmental Systems,Ministry of Education,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,Gansu;Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Science,Lanzhou 730000,Gansu;College of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,Gansu;Key Laboratory of Resource Environment and Sustainable Development of Oasis,Gansu Province,Lanzhou 730070,Gansu)

机构地区：[1]中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁810008 [2]青海省盐湖地质与环境重点实验室,青海西宁810008 [3]中国科学院大学,北京100049 [4]兰州大学资源环境学院,西部环境教育部重点实验室,甘肃兰州730000 [5]中国科学院西北生态环境资源研究院,中国科学院沙漠与沙漠化重点实验室,甘肃兰州730000 [6]西北师范大学地理与环境科学学院,甘肃兰州730070 [7]甘肃省绿洲科学与可持续发展重点实验室,甘肃兰州730070

出　　处：《第四纪研究》2021年第6期1619-1631,共13页Quaternary Sciences

基　　金：国家自然科学基金项目(批准号:41671006);第二次青藏高原综合科学考察研究(批准号:2019QZKK0202)共同资助。

摘　　要：青藏高原是西风与季风相互作用的关键区域,高原上的湖泊水位对气候变化响应极为敏感。本研究利用光释光测年方法对青藏高原中部当穹错东北岸高出现代湖面235 m的一个湖相沉积剖面(DQ)进行了测年,丰富了全新世当穹错湖泊演化的年代数据,并对前人重建的该湖末次冰消期以来的水位波动曲线进行了修订。之后结合TraCE-21 ka古气候模型模拟的当穹错-当惹雍错-许如错湖区古降水和古温度变化,分析了当穹错末次冰消期以来湖泊水位变化的原因。研究结果显示:当穹错湖泊水位在末次冰消期和早全新世(15.4~7.8 ka)期间比现在高235 m以上(高于DQ剖面),7.8 ka之后湖泊水位下降到该剖面以下,全新世期间最高水位出现在8.8~8.2 ka期间,此时湖泊面积可达2154.71 km^(2)。TraCE-21 ka模拟的年降水量在15 ka左右突然增加,自8 ka开始逐渐减少。模拟的降水变化与湖泊水位波动过程几乎同步,因此印度季风加强所导致的降水增加可能是当穹错末次冰消期和早全新世出现高湖面的主要原因。The Tibetan Plateau(TP)is located in the interaction area of the monsoon and westerly circulation.The lake level fluctuated significantly with the changing of this monsoon system since the last deglacial on the TP.The remnant paleoshoreline sediments formed associated with the recession of the lake during the last lake expansion and recession cycle.Therefore,the lake level changing procession on the TP can be reconstructed based on the paleoshoreline sediment dating and their elevation measurements.Tanqung Co(31°30'~31°40'N,86°38'~86°49'E)which is also named as Dangqiong Co,Dangxiongcuo and Dangxiong Co.It is located within the central Tibetan Plateau with an altitude of 4470 m above sea level(a.s.l.).The inflows are mainly from the southern and northern parts of the lake.The DQ section(31°37'28″N,86°46'19″E;4705 m a.s.l.)located in the northeast of Tanqung Co which was investigated in this study to retrieve the lake level fluctuations since the last deglaciation.The section is about 300 cm thick with three stratigraphic units.In the uppermost part(0~50 cm),the sediment consists of coarse sands and gravels.The second part(51~300 cm)is nearshore lacustrine sand sediments.In the bottommost part(below 300 cm)is bedrocks.Four Optically Stimulated Luminescence dating(OSL)samples were collected at 51~300 cm.We used OSL dating to obtain age of the lacustrine sediments from DQ section,and combined with previously reported paleoshorelines age in this area to reconstruct a more robust water level fluctuation curve for Tanqung Co since the last deglacial.Our results indicate that the lake experienced severe oscillations since the last deglacial:the water level of Tanqung Co was several meters higher than the DQ section during the last deglaciation and early Holocene(15.4~7.8 ka).After 7.8 ka,the water level dropped below section DQ.The highest lake level occurred during 8.8~8.2 ka,and the lake area reached 2154.71 km^(2) in this period.Then,the lake level declined since 8.2 ka.The TraCE-21 ka simulated annual prec

关 键 词：青藏高原 当穹错 湖泊水位 光释光测年 季风 

分 类 号：P941.78[天文地球—自然地理学] P597.3