哈萨克斯坦南部Shayan黄土粒度端元指示的14.4cal.ka B.P.以来的风尘历史  

Aeolian dust history since 14.4 cal.ka B.P.indicated by grain-size end members of Shayan loess in the southern Kazakhstan

作　　者：苏谌杰 许仲林[2] 张东良[3,4,5] 刘奇 刘建宗[1] SU Chenjie;XU Zhonglin;ZHANG Dongliang;LIU Qi;LIU Jianzong(College of Geography and Remote Sensing Sciences,Xinjiang University,Vrümqi 830017,Xinjiang;College of Ecology and Environment,Xinjiang University,Vrümqi 830017,Xinjiang;Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Vrümqi 830011,Xinjiang;Research Center for Ecology and Environment of Central Asia,Chinese Academy of Sciences,Vrümqi 830011,Xinjiang;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]新疆大学地理与遥感科学学院,新疆乌鲁木齐830017 [2]新疆大学生态与环境学院,新疆乌鲁木齐830017 [3]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [4]中国科学院中亚生态与环境研究中心,新疆乌鲁木齐830011 [5]中国科学院大学,北京100049

出　　处：《第四纪研究》2023年第1期46-56,共11页Quaternary Sciences

基　　金：中国科学院青年创新促进会专项项目(批准号:2022447);国家自然科学基金面上项目(批准号:41771234)共同资助。

摘　　要：中亚干旱区不仅是全球主要的风尘源区之一,也是气候变化的敏感区域之一。重建中亚干旱区风尘历史、解释其驱动机制对治理现代沙尘天气和改善人类生存环境至关重要。然而,关于中亚干旱区风尘驱动机制的问题仍存在不同观点。本研究采用参数化粒度端元分析方法对哈萨克斯坦南部的Shayan黄土剖面(厚度约650cm)进行了分析。结果表明:1)Shayan剖面沉积物粒度组分分为4个端元,EM1代表高空西风远距离搬运和以团聚体的形式被粗颗粒携带的粘土组分,EM2代表沉积时期大气粉尘的背景,以浮尘的形式存在的细粉砂组分,EM3代表低空短距离搬运的近源粗粉砂组分,EM4代表较强风力条件下被搬运的局地砂粒组分;2)EM3+EM4含量指示的风尘历史显示,14.4cal.ka B.P.至早全新世阶段(14.4~8.2cal.ka B.P.)风力较强,中全新世(8.2~4.2cal.ka B.P.)风力较弱,晚全新世(4.2~0cal.ka B.P.)再次增强;3)西伯利亚高压强度变化是中亚干旱区过去风尘活动变化的主要驱动力。The arid Central Asia is not only the main dust source area in the world,is also the sensitive area to climate change.It is very important to reconstruct the past history of aeolian dust and investigate its driving mechanism in the arid Central Asia in order to govern modern dust and improve human living environment.However,there are still three different views on the driving mechanism of aeolian dust in the arid Central Asia.In this study,we obtain the Shayan loess profile(SY profile:42.86°N,69.07°E;200m a.s.l.;650cm in thickness)which is located on the bank of Shayan River in the Southern Kazakhstan.The SY profile is homogeneous and massive without obvious stratification and light yellow in appearance,indicating that there is no obvious soil formation.Six AMS 14C samples were collected at 98cm,200cm,302cm,402cm,502cm and 602cm in the SY profile,and total 162 samples were sampled at 4cm intervals for particle size analysis.Based on the six AMS 14C dates in the Bacon program,we established the depth-date model of SY profile and the age at the bottom of SY profile is 14.4cal.ka B.P.The parametric grain size end-member analysis was used to investigate the aeolian dust history since 14.4cal.ka B.P.inferred from the Shayan profile and four end-member components were extracted to reflect the sedimentary dynamic characteristics.The results indicated that:(1)The grain size compositions can be divided into four components(EM1,EM2,EM3 and EM4),EM1(modal grain size is 1.59μm)is the clay component transported over long distances by the strong westerlies winds and carried by the coarse particles in the form of aggregates,EM2(modal grain size is 14.16μm)represents the background of atmospheric dust in the deposition period and the fine silt component in the form of floating dust,EM3(modal grain size is 39.91μm)indicates the near-source coarse silt component transported at low altitude and short distance,EM4(modal grain size is 89.34μm)shows local sand components resulted from strong wind conditions.(2)The aeolian dust h

关 键 词：黄土 粒度端元分析 风尘历史 西伯利亚高压 

分 类 号：P534.631[天文地球—第四纪地质学] P512.2[天文地球—古生物学与地层学]