摘要
云南省西北部高山湖泊格贡错那卡湖（海拔4214 m）地处西南季风区，对气候变化十分敏感。文章以在格贡错那卡湖湖心钻取的1.84 m长的沉积岩芯为研究对象，对粒度、磁化率和总有机碳（TOC）含量等环境指标进行了高分辨率的分析，在精确测年的基础上（210Pb测年结合陆生植物残体的AMS 14C测年建立年代序列），重建了研究区距今约3570年来的气候与环境变化。结果表明，格贡错那卡湖所在地区近3570年来的气候与环境变化经历了5个较明显的演化阶段：1）在3570～3490 cal.a B.P.期间，气候明显降温、减湿；2）3490～1710 cal.a B.P.期间，气候总体偏冷、较干，其中3490～2860 cal.a B.P.期间气候处于较稳定的最冷干时期，随后在2860～1710 cal.a B.P.期间气候波动地有所增温、增湿；3）1710～930 cal.a B.P.（即240～1020A.D.）期间，为较稳定的暖湿期，年均温较高，温差较小；4）930～80 cal.a B.P.（即1020～1870A.D.）期间，气候总体偏冷较湿，但存在多次短暂变暖；降水总量或冰雪融水可能有所减少，但降水强度或冰雪融水强度变化较大；5）自80 cal.a B.P.（即1870 A.D.）以来，温度明显增加，可能是过去3570年以来温度最高的时期；降水有所减少，气候总体为暖偏湿。该气候特征与相邻地区泸沽湖的乔木花粉含量反映的气候变化非常一致，揭示了研究区气候变化的区域性。
Gegongcuonaka Lake（28°08＇47.65″～28°08＇58.47″N, 99°55＇05.85″～99°55＇32.24″E;4214 m a.s.l.） is located in the center of Zhongdian County in northwestern Yunnan Province. It is an alpine lake in the southeast of the Tibetan Plateau, which is mainly affected by the southwest monsoon. Gegongcuonaka Lake is sensitive to climate change, making it an ideal region for paleoclimate research. Two long sediment cores（A and B cores） and a 50-cm-long sediment core（C core） were drilled from the center of Gegongcuonaka Lake（28°08.893＇N, 99°55.255＇E; 37.5 m in depth） using a UWITEC Gravity Sampling Equipment in August, 2015. The 184-cm-long core（A core） was used for the AMS 14C dating and the analysis of environment proxies（grain size, magnetic susceptibility and TOC）, and 184 samples at 1 cm intervals were collected from the top to the bottom. The short core（C core） was used in 210Pb dating and three plant materials from the A core were dated by using the AMS 14C dating method. The age-depth model was established by combining the 210Pb measurement and the AMS 14C dating. The climate changes since 3570 cal. a B.P. in Gegongcuonaka area was reconstructed based on the high-resolution analysis of environment proxies. The results show that the climate changes since 3570 cal. a B.P. in Gegongcuonaka area experienced five significant periods. （1） From 3570 cal. a B.P. to 3490 cal. a B.P., the temperature declined obviously and the humidity decreased evidently. （2） During the period 3490～1710 cal. a B.P., the climate was moderately cold and dry as a whole. This period could be further divided into two sub-stages：the climate between 3490 cal. a B.P. and 2860 cal. a B.P. was the coldest and driest condition since 3570 cal. a B.P., whereas the temperature and humidity after 2860 cal. a B.P. began to increase compared with the former sub-stage. （3） During 1710～930 cal. a B.P.（240～1020 A.D.）, a stable warm-humid phase with high average annual temperature might have occurred in this region. （4） From 930～80 cal. a B.P.（1020～1870 A.D.）, the climate was generally moderately cold and humid with several transient warming phases, and the total amount of precipitation or the melting water might decrease, but the intensity of precipitation or melt water varies greatly. （5） Since 80 cal. a B.P.（1870 A.D.）, the temperature rose quickly and the warmest period might occur during the past 3570 years, which corresponds to the 20th century warm period（CWP）. This climate characteristics is evidently consistent with Lugu Lake where the climate changes were reconstructed based on the tree pollen percentages, which reveals that the climate in this studied area is regional.
作者
谭金凤
肖霞云
李艳玲
Tan Jinfeng;Xiao Xiayun;Li Yanling(State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, Jiangsu;University of Chinese Academy of Sciences, Beijing 100049)
出处
《第四纪研究》
CAS
CSCD
北大核心
2018年第4期900-911,共12页
Quaternary Sciences
基金
国家重点基础研究发展计划项目（批准号：2016YFA0600501）和国家自然科学基金项目（批准号：41572149和41672173）共同资助
关键词
气候变化
环境代用指标
湖泊沉积
晚全新世
高山湖泊
西南季风区
climatic change
environment proxies
lake sediment
Late Holocene
alpine lake
Southwest Monsoon region
