库姆塔格沙漠的“羽毛状沙丘”形态的观测

参照卫星照片和地形图,实地观测了库姆塔格沙漠“羽毛状沙丘”分布区域的地貌。新月型“沙垄”是该区域的主导性地貌类型,垄间地形波状起伏。如果将“沙垄”喻为“羽轴”,垄间的波状起伏地形为“羽枝”,则可构成卫星照片所显示的“羽毛状沙丘”。新月型“沙垄”的走向为NE-SW,由新月形沙丘前一沙丘的迎风坡与后一沙丘的东翼相连而成,高3~19m,宽约50m,长15~22km。“垄”间起伏地形的波长为100~300m,振幅为40~100cm,与“沙垄”成60~105°夹角。在波状起伏地形的波峰与波谷过渡区堆积颜色较浅的细沙,厚2~7cm,构成了“大沙波”。实地观测的“羽毛状沙丘”的形态与卫星照片显示的形态有一定差异。

A morphologic observation of the "featherlike dune ridge" in the Kumtag Desert

By consulting satellite photos and relief maps, we conducted an observation on the landform of the Kumtag Desert where "featherlike dune ridges" are distributed. The crescent dune ridge is a dominated physiognomy in the Kumtag Desert while the landform between the dune ridges is undulating. If we figure the crescent dune ridge as the "quill", and the wavy landform is like the "plume", then a complex morphology of a "featherlike dune ridge" will be formed in the central-northern area of the Kumtag Desert. The crescent dune ridge is formed in such a fashion that the windward slope of a front dune joins the eastern wing of the following dune, with strike direction of NE-WS, height of 3-19 m, width of some 50 m, and length of 15-22 km. The wavy landform, with wavelength of 100-300 m, and amplitude of 40-100 cm, links the crescent dune ridge at an angle of 60-105°. Between the dune ridges, the fine sands, showing a light color, with the thickness of 2-7 cm, pile up at the transitional area between a wave crest and a trough of the wavy landform, and it manifests itself as a "huge sandy wave". The morphology of the "featherlike dune ridge" viewed in field is a little different from that on satellite photos.