毛乌素沙地东南缘全新世气候不稳定性  

Holocene climatic instability record in the southeastern margin of Mu Us Desert

作　　者：李想 苏志珠[2] 马义娟 张彩霞 柳苗苗 Li Xiang;Su Zhizhu;Ma Yijuan;Zhang Caixia;Liu Miaomiao(College of Environment and Resources,Shanxi University,Taiyuan 030006,China;Historical Culture School,Shanxi University,Taiyuan 030006,China;College of Geography Science,Taiyuan Normal University,Jinzhong 030619,Shanxi,China;Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]山西大学环境与资源学院,山西太原030006 [2]山西大学历史文化学院,山西太原030006 [3]太原师范学院地理科学学院,山西晋中030619 [4]中国科学院西北生态环境资源研究院沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2020年第2期109-117,共9页Journal of Desert Research

基　　金：国家自然科学基金重点项目(41330748);国家重点研发计划项目第5课题(2016YFC0500805);山西省研究生创新项目(2019SY025)。

摘　　要：毛乌素沙地处于中国季风区的西北边缘,对气候变化敏感,是古气候演化和古环境变迁研究的理想场所。全新世气温回暖期,气候整体稳定但存在暖湿冷干的次级波动,不同类型沉积相组成的地层序列记录了全新世千年、百年尺度的气候不稳定性。对毛乌素沙地不同沉积序列的研究表明:(1)毛乌素沙地东南缘的沙漠/黄土边界带DLT、NB剖面粒度及Rb/Sr比值可作为气候变化的代用指标。>63μm砂含量增加,Rb/Sr比值降低,揭示东亚冬季风增强,风成砂堆积,风沙活动加剧,气候干冷;反之,东亚夏季风增强,降水增多,风化成壤程度加大,气候暖湿。(2)毛乌素沙地东南缘沙漠/黄土边界带及低洼沟谷区年代概率密度函数的分析显示,全新世早期~8.5 ka BP风成砂堆积,风沙活动加剧,气候表现为干冷;全新世中期8.5 ka^3.0 ka BP地势较高处古土壤广泛发育,地势低洼处发育湖沼相/泥炭层,但在6.0 ka BP左右存在气候转冷过程;全新世晚期3.0 ka BP以来气候波动频繁。(3)毛乌素沙地气候变化与北大西洋冰筏冷事件、董哥洞石笋、季风边缘区湖泊、东部沙地等记录具有可对比性和相对一致性,反映出全新世千年和百年尺度上的气候变化主要受全球变化的影响,这对预测和模拟未来气候变化具有借鉴意义。Since Holocene,the temperature has risen and the climate is generally stable,but there are still climate fluctuations.Located in the northwestern edge of the East Asian monsoon,Mu Us Desert stratigraphic sedimentary sequence reveals the climatic instability on the millennium and centennial scales in Holocene.The result shows:(1)The grain and Rb/Sr ratio of DLT and NB section in the desert/loess boundary zone can be used as climate and environment index.The increase of>63μm sand content and the decrease of Rb/Sr ratio revealed the east Asian winter monsoon enhanced,aeolian sand accumulated,aeolian sand activity intensified and the climate was cold and dry.Controversially,the east Asian summer monsoon strengthened,precipitation increased,pedogenesis strengthened,and the climate was warm and humid.(2)The analysis of the age probability density of the desert/loess boundary zone and low-lying valley in the southeast margin of the Mu Us Desert indicated that the aeolian sand accumulated at-8.5 ka BP in the early Holocene,aeolian sand activity intensified and the climate was cold and dry.In the middle of Holocene,the paleosol strata were widely developed between 8.5 ka and 3.0 ka BP in the highland,and the lacustrine/peat layers were generally deposited in the low-lying areas.While there were sedimentary interruption near 6.0 ka BP and the climate turned cold.After 3.0 ka BP,climate fluctuated frequently in the late Holocene.(3)The climate change in Mu Us Desert is consistent with the records of ice-raft cold events in the North Atlantic,Dongge Cave stalagmite,lakes and eastern sandy land in the monsoon marginal areas in China.The millennium/centennial scale climate change in Mu Us Desert during Holocene is influenced by the global and regional climate change,which is significance for predicting climate change.

关 键 词：气候变化 年代数据 概率密度 全新世 毛乌素沙地 

分 类 号：P531[天文地球—古生物学与地层学]