摘要
在塔克拉玛干沙漠腹地的部分垄间平沙地中,天然分布有一种特殊物质——沙粒胶结体,其与地表的粗沙和极粗沙呈复区分布,共同构成了覆盖沙面的大颗粒层。实地调查和取样分析表明：沙粒胶结体直径不一,能达到粗沙级、极粗沙级和砾石级（细粒和中砾）,最大可达23.5mm;颗粒形状不规则,质地较硬,手捏不碎;密度为2.51g·cm-3,略小于砾石和当地沙丘沙;可溶物的pH值呈中性,电导率2.56mS·cm-1,主要成分为CaSO4。砾石尺度的沙粒胶结体在地表的分布密度可达807粒·m-2,覆盖度2%～3%,由于其尺度和密度与砾石接近,它也应具有与砾石类似的风沙效应。沙粒胶结体也是一种天然固沙材料,研究其形成机制有助于开发新型固沙技术和固沙产品;沙粒胶结体可以抑制沙面风蚀、调节风沙流输沙强度、影响沙丘形态演变,探讨其风沙效应有助于深入认识塔克拉玛干沙漠垄间地的沙面稳定机制。沙粒胶结体的形成应与特殊的地质历史环境背景有关,可以作为沙漠地区历史时期气候变化的一个证据。因此,沙粒胶结体在防沙治沙技术开发、沙漠地区特殊下垫面风沙运动过程、沙漠环境形成演变等方面具有重要的研究价值,值得今后进行深入研究。
There are some sand cemented bodies naturally distributed on some inter-dune corridor in central Taklimakan Desert They form a special large granular layer covering the sand surface together with coarse sand and very coarse sand.Field investigation and sampling analysis indicate that the grain diameter of sand cemented body is uniform,the size can reach the level of coarse sand,very coarse sand and gravel.The diameter of larger ones is more than10 mm,and the diameter of maximal one is up to 23.5 mm.The shapes of sand cemented bodies are very diverse and irregular.It is very hard and can＇t been crumbled and even not scattered with water soak.Its specific gravity is about 2.51 g·cm-3,less than gravel and local dune sand.The salt content of sand cemented body is so high that its electrical conductivity can reach 2.56 ms·cm-1 just like heavy saline soil.Its ingredients in its water extract of crushed material are dominated by calcium sulphate.It is in neutral conditions with pH value of 7.40.The gravel-size sand cemented body lies on the sand surface with a density of807 particles per a square meter and its coverage can reach 2 to 3 percent.Due to its main features similar to gravel,we can supposed that sand cemented body has an effect on aeolian process like gravel.The sand cemented bodies are a natural sand-fixation material.To study the formation mechanism will help to develop new types of sand-fixation technology and sand-fixation products.It should play an important role in some key aeolian processes such as wind erosion control,sand transport regulation,dune morphology revolution on inter-dune corridors in the Taklimakan Desert.So the research on the effect of sand cemented bodies on windblown sand movement is of great academic significance to understand the relative stability mechanism of sand surface on some inter-dune corridor in the Taklimakan Desert.The formation of sand cemented bodies must concerned with a special geological history background,so they can be used as an evidence reflecting the historical of climate changes in the Taklimakan Desert.So the sand cemented bodies deserve further research for its value in basic theory research and practical application.
出处
《中国沙漠》
CSCD
北大核心
2016年第2期265-273,共9页
Journal of Desert Research
基金
新疆维吾尔自治区重大科技专项(201130106-3)
关键词
沙粒胶结体
粒度
化学组成
固沙作用
沙面稳定
气候变化
sand cemented bodies
grain size
chemical composition
sand fixation
sand surface relative stability
climate change
