库姆塔格沙漠羽毛状沙丘表面沙粒度分布特征  

Grain size parameters and their distribution on feather-like dune of Kumtag Desert

作　　者：唐进年[1] 王继和[1] 苏志珠[2] 丁峰[1] 廖空太[1] 刘虎俊[1] 张国中[1] 郑庆中[1] 张锦春[1] 俄有浩[1] 

机构地区：[1]甘肃省荒漠化防治重点实验室甘肃省治沙研究所,甘肃武威733000 [2]中国林业科学研究院林业研究所,北京100091

出　　处：《干旱区地理》2008年第6期918-925,共8页Arid Land Geography

基　　金：甘肃省科学事业费项目(QS041-C31-03);甘肃省自然科学基金项目(0710RJZH084和0803RJZH086)资助

摘　　要：对库姆塔格沙漠羽毛状沙丘不同部位表面沙物质进行的粒度分析结果表明，羽毛状沙丘“羽轴”-新月形沙垄沙以细沙（0．125-0．25mm）为主，含量占60．8％，平均粒径2．42φ，分选较好（σ1值0．33—1．09，平均0．65），偏度以对称为主（Sk值-0．31～0．35，平均0．08），峰度以中峰态为主（KG值0．70～1．57，平均1．08）。“羽轴”-新月形沙垄沙粒径在横剖面方向上即从新月形沙丘两翼坡脚至丘顶部变细，东南翼角略粗于西北翼角；在纵剖面方向上从新月形沙丘迎风侧经丘顶至背风侧也逐渐变细。随着平均粒径变细，分选变好，正偏的趋势也越显著。“羽枝”-垄间沙以粗沙为主，分选较差，宽峰态为主。羽毛状沙丘沙累计概率曲线主为4段式或3段式，“羽轴”-沙垄沙以单峰态为主，占96．7％；“羽枝”-垄间沙则以双峰态为主，占54．2％。大尺度地形（沙垄和垄间地）和局部地形对粒度分布有一定程度的影响。Feather-like dune is a kind of dune with unique shape, mainly distributed at the north of Kumtag desert. The dune, looking like a feather, is composed of two parts as ＂quill＂ and ＂plume＂. ＂Quill＂ are the longitudinal sand ridges formed by individual barchan dunes with clear profile which have coalesced （ the plinth of the windward slop of the former dune is coalesced with the southeast flank of the latter one） and elongated. ＂Plume＂ is composed of the inter-ridge undulate sand land. The peaks and valleys of the wavy land are almost perpendicular to the sand ridge, from which, the ＂feather-like dune＂ is formed. It can be viewed from the aerial and satellite photos. There is no report concerning systematic observation and sampling research on the substance deposition process and the variation of grain size in the feather-like dunes. This paper, based on sampling analysis of the sediments on the surface of feather-like dune, preliminarily discussed the distribution characteristics of grain size on the dune. One hundred and eight sand samples were taken from feather-like dunes in Kumtag Desert. The samples were collected from different sites with areas of approximately 20 cm × 20 cm and to a depth of 0 - 5 cm, and analyzed with the sieving method. The results show that the grain size of barchan sand ridge sands ranges from 1.57φ to 3.14φ with a mean value of 2.42φ（0.187 mm） ; the fine sands with diameter of 0. 125 -0.25 mm are the dominant one, averagely making up 60.8% in each sample. The sands become gradually finer from the feet of both slopes to the tip of the barchan sand ridge. The sand on northwestern slope is finer than that on southeastern slope. The sands also become gradually finer from the upwind slope to the dune tip and to the downwind slope of barchan dune along the direction of sand ridge, which indicates that the ridge is growing up. Most of the ridge sands are better sorted. The standard deviation ranges from 1.09 to 0.33, with the mean value of 0.65. The skewness ran

关 键 词：库姆塔格沙漠 羽毛状沙丘 粒度参数 分布规律 

分 类 号：P931.3[天文地球—自然地理学]