粒度端元记录的靖边地区MIS 3以来的气候变化  

Climate change recorded by the grain size end member since MIS 3 in Jingbian area

作　　者：巩雪娇 王攀[2,3] 杨振京 董秋瑶[2,3] 宋超 郭娇[2,3] 陈洪云 Gong Xuejiao;Wang Pan;Yang Zhenjing;Dong Qiuyao;Song Chao;Guo Jiao;Chen Hongyun(College of Resources,Hebei GEO University,Shijiazhuang 050031,China;Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Shijiazhuang 050061,China;Key Laboratory of Quaternary Chronology and Hydro-Environmental Evolution,Chinese Geological Survey,Shijiazhuang 050061,China)

机构地区：[1]河北地质大学资源学院,石家庄050031 [2]中国地质科学院水文地质环境地质研究所,石家庄050061 [3]中国地质调查局第四纪年代学与水文环境演变重点实验室,石家庄050061

出　　处：《地质科技通报》2021年第1期184-191,共8页Bulletin of Geological Science and Technology

基　　金：中国地质科学院水文地质环境地质研究所基本科研业务费项目(SK201911;SK201310);中国地质调查局地质调查工作项目(12120113005900)。

摘　　要：黄土作为典型的多物源沉积物,粒度分布常呈现多峰分布。端元分析可以从复杂的沉积物粒度中分离出代表不同沉积物源和沉积动力的端元组分,在黄土研究中得到了广泛应用。利用Paterson参数化端元模型对处于毛乌素沙漠东南缘的靖边三道沟剖面粒度进行端元分离与解释,并讨论其代表的环境意义。靖边三道沟黄土可分为4个端元:EM1(众数粒径8.93μm)为背景粉尘;EM2(众数粒径25.18μm)为与季风环流有关的组分;EM3(众数粒径39.91μm)和EM4(众数粒径56.37μm)都是与冬季风有关的组分,其中EM3为黄土高原黄土主要组分,EM4与现代沙尘暴的粒级大致相同。通过对各端元组分随年龄变化的曲线进行分析,得到以下结论:该剖面记录了靖边地区自MIS 3以来经历了MIS 3(32.8~29.8 ka BP)、LGM(29.8~22.8 ka BP)、冰消期(22.8~11.3 ka BP)和全新世(8.7~1.7 ka BP)共4个气候时期。端元组分还记录了冰消期H 1事件(16.2~13.8 ka BP)、B/A事件(13.8~12.8 ka BP)、YD事件(12.8~11.3 ka BP)共3次气候快速变化事件和D-O旋回。该剖面还记录了毛乌素沙漠末次冰期经历的3次主要的扩张-收缩旋回以及全新世8.7~8.2,6.0~5.0,3.5~2.5 ka共3次干旱沙进事件。As a typical multisource sediment,the grain size distribution of loess presents multi-peak distribution.End member analysis can be used to separate the end member components representing different sediment sources and sedimentary dynamics from the complex sediment size,which has been widely used in loess research.In this paper,Paterson parametric end member model was used to separate and explained the end member size of Sandaogou profile located in the southeastern margin of the Mu Us Desert.The analyzed results indicated that the Sandaogou loess in Jingbian was divided into four end members:EM1(8.93μm)was the background dust;EM2(25.18μm)was a component related to monsoon circulation.EM 3(39.91μm)and EM 4(56.37μm)were components related to winter wind.Among them,EM3 was the main component of loess in the loess plateau and EM 4 was roughly the same grain size as modern sandstorms.Through the analysis of the curves of the end member components with age,the following conclusions were drawn:the profile recorded that the Jingbian area had experienced MIS 3(32.8-29.8 ka BP),LGM(29.8-22.8 ka BP),last deglacial(22.8-11.3 ka BP)and Holocene(8.7-1.7 ka BP)since MIS 3.Three climatic rapid change evented and cycles Dansgaard-Oeschger in deglaciation Heinrich 1(16.2-13.8 ka BP),B lling-Aller d(13.8-12.8 ka BP)and Younger Dryas(12.8-11.3 ka BP)were recorded.The profile also recorded three major expansion-contraction cycles during last glacial period of the Mu Us Desert,and three dry sand events during the Holocene(8.7-8.2 ka,6.0-5.0 ka,and 3.5-2.5 ka).

关 键 词：黄土 粒度 端元组分 气候变化 沙进沙退 靖边地区 

分 类 号：X141[环境科学与工程—环境科学] P532[天文地球—古生物学与地层学]