毛乌素沙地中部风成沙的组成与微形态特征  

Composition and Micro-morphological Characteristics of Aeolian Sand in the Middle of the Mu Us Sandy Land

作　　者：陈国祥 董治宝 崔徐甲[1] 肖巍强 李露露 杨军怀 石唯康 Chen Guoxiang;Dong Zhibao;Cui Xujia;Xiao Weiqiang;Li Lulu;Yang Junhuai;Shi Weikang(a. School of Geography and Tourism/b. National Demonstration Center for Experimental Geography Education, Shaanxi Normal University, Xi＇an 710062, China;Key Laboratory of Desert and Deserti fication, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China)

机构地区：[1]陕西师范大学地理科学与旅游学院,陕西西安710062 [2]陕西师范大学地理学国家级实验教学示范中心,陕西西安710062 [3]中国科学院西北生态环境资源研究所沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2018年第3期473-483,共11页Journal of Desert Research

基　　金：国家自然科学基金项目(41401310);中央高校基本科研业务费专项资金项目(GK201604011)

摘　　要：分析了毛乌素沙地中部流动沙丘与固定-半固定沙丘沉积物粒度、元素和微形态特征。结果表明:流动沙丘沙和固定-半固定沙丘沙均以细沙和中沙为主,流动沙丘沙的分选性较好,而固定-半固定沙丘沙的分选性较差,沙丘在频繁强烈的风沙活动环境下跃移搬运,且搬运方式一定,搬运动力稳定。与上部陆壳平均化学组成(UCC)相比,常量元素SiO_2和Na_2O富集,其余均亏损,而微量元素中,Co富集明显。沙丘沙物质CIA值与上部陆壳平均值接近,表明沙丘经历了低等的化学风化。流动沙丘和固定-半固定沙丘颗粒磨圆度普遍较差,大多呈现棱角状或次棱角状外形,真正圆状外形较少。风成环境的典型标志碟形撞击坑占比很大,推断毛乌素沙地中部气候相对干燥,机械作用占主导地位,化学风化作用甚微。In this paper,the grain size,element and micro-morphological characteristics of mobile dune and fixed/semi-fixed dune in the middle of the Mu Us Sandy Land are analyzed.The results show that both the mobile dune and the fixed/semi-fixed dune are composed of fine sand and medium sand,while the sorting of mobile dune is better,and the sorting of fixed/semi-fixed dune is poor.The transport style of dunes is saltation in a frequent and strong wind activity environment,and the way of transportation is fixed and the power of transportation is stable.Compared with UCC,SiO2 and Na2O are rich in major elements,others are loss,and Co is enriched obviously for trace element.Values of CIA of dunes are close to the average of the upper continental crust,indicating that the dune has experienced a low degree of chemical weathering.The roundness of mobile dune and fixed/semi-fixed dune is poor,and most of them are angular shape or sub-angular shape,and the real round shape is less;The typical mark of the windy environment is dish-shaped pits accounted for a large proportion,and it is inferred that the climate of the Mu Us Sandy Land is relatively dry,the mechanical action occupies a dominant position while the chemical weathering plays a small role.

关 键 词：微形态 沉积物 粒度 地球化学元素 毛乌素沙地 

分 类 号：P931.3[天文地球—自然地理学]