摘要
本文选取榆林市横山区柳树峁剖面,对其第3层黄土(L_(3))、第3层古土壤(S_(3))层位粒度数据进行分布特征分析和参数化端元分析,以此探讨沉积动力及其所代表的环境特征。结果表明:柳树峁剖面L_(3)、S_(3)层位粒度组成以粗粉砂(42.65%)和极细砂(32.40%)为主,中值粒径为47.11μm。剖面L_(3)、S_(3)层粒度数据可分为4个端元:EM1组分(众数粒径7.42μm)为大气中长期存在的、经过远距离携带搬运的细粒组分,EM2(众数粒径43.66μm)和EM3(众数粒径76.43μm)组分是由冬季风或沙尘暴所携带的近源组分,EM4(众数粒径161.20μm)组分为风成沙,物源来自于北部的毛乌素沙地,该组分含量变化可作为指示强冬季风或强沙暴的替代性指标。柳树峁剖面记录了L_(3)黄土沉积时期存在1个极冷期、2个冷期和1个较暖期,S_(3)古土壤发育时期存在2个暖期和1个冷期。同时,剖面也记录了L_(3)、S_(3)层位沉积发育时期毛乌素沙地的两次扩张事件和两次收缩事件。
Hengshan area in Yulin City,which is sensitive to environmental changes,is located in the trans-ition zone between the Mu Us Sandy Land and the Chinese Loess Plateau.There is a unique paleo aeolian sand loess sedimentary sequence in the Hengshan area,it is of great scientific value to reveal the evolution of East Asian monsoon and sandy land.In this study,the analysis of grain size distribution characteristics and paramet-erized end-member modeling of L_(3)and S_(3)layers in Liushumao section are used to discuss the sedimentary dy-namic characteristics and climatic environment in Hengshan area.The results show that the grain size composi-tion of L_(3)and S_(3)layers in the Liushumao section is mainly coarse silt(42.65%)and very fine sand(32.40%),and the median size(Md)is 47.11μm.The grain size components in L_(3)and S_(3)layers were divided into four end members:EM1(7.42μm)is the fine silt component through a long distance transported and exists for a long time in the atmosphere;EM2(43.66μm)and EM3(76.43μm)are short-distance components carried by Winter Monsoon or sandstorms,EM4(161.20μm)is aeolian sand from the Mu Us Sandy Land,it is an altern-ative indicator of strong Winter Monsoon and strong sandstorms.The Liushumao section recorded that there was an extremely cold period,two cold periods and a warm period in the L_(3)period,and two warm periods and a cold period in the S_(3)period.At the same time,the Liushumao section recorded two expansion events and two contraction events of the Mu Us Sandy Land in L_(3)and S_(3)layers sedimentary development period.
作者
杨宇哲
岳大鹏
赵景波
刘蓉
刘怡婷
赵艳
Yang Yuzhe;Yue Dapeng;Zhao Jingbo;Liu Rong;Liu Yiting;Zhao Yan(School of Geography and Tourism,Shaanxi Normal University,Xi'an 710119,Shaanxi,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,Shaanxi,China)
出处
《地理科学》
CSSCI
CSCD
北大核心
2023年第9期1680-1690,共11页
Scientia Geographica Sinica
基金
国家自然科学基金重点项目(42130507)资助。
关键词
粒度
端元分析
气候变化
沙进沙退
榆林地区
grain size
end member analysis
climate change
desert advance and retreat
Yulin area
