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中国沙漠 ›› 2001, Vol. 21 ›› Issue (2): 129-134.

• 研究论文 • 上一篇    下一篇

河流演变在科尔沁沙地形成和演化中的作用初探——以科尔沁沙地南部教来河中游沙地为例

韩广1, 张桂芳2   

  1. 1. 湖南师范大学国土学院, 湖南长沙 410081;
    2. 湖南大学土木工程系, 湖南长沙 410082
  • 收稿日期:2000-02-03 修回日期:2000-05-08 出版日期:2001-06-20 发布日期:2001-06-20
  • 作者简介:韩广(1964-),男(汉族),内蒙古包头市人,副教授,现主要从事自然地理学和生态学方面的教学工作

Effects of River Evolution on Formation and Development of Horqin Sandy Land

HAN Guang1, ZHANG Gui-fang2   

  1. 1. College of Land Science, Hunan Normal University, Changsha 410081, China; 2. Department of Civil Engineering, Hunan University, Changsha 410082, China
  • Received:2000-02-03 Revised:2000-05-08 Online:2001-06-20 Published:2001-06-20

摘要: 由于河流洪枯水交替变化,加之新构造运动的影响,本区的河流改道频繁。河流作用所形成的各种松散砂堆积体,在枯水季节受风力作用而形成大量沙丘,进而对洪水期的河道演变施加重要影响;当河流改道或发生大的变迁时,已成沙丘会在盛行风的影响下移动变形,相互连接而形成沙丘群,经长期的发展演化则可形成大范围的沙地;同时,河流在横向摆动过程中,会夷平一部分已成沙丘,但由于沙丘群本身的障碍作用、植被的积极作用和河流改道的不均匀性,使得本区的地表过程以沙丘群的形成为主。相应地,改道后的河流又在新流路上重复上述过程。其中河流的部位(凸岸和凹岸、上游和下游)及其与风向的对应关系(迎风侧与背风侧、直交和外交或平行)不同,所起的作用有很大差异。在研究区内的现代河流及古河道两岸,沙丘群、湖沼、草甸及干草原相间和交错分布,沙带线状延伸,而在第四纪地层中,风成砂、湖沼相、河流相堆积物交替变化,有些地段甚至相互过渡。这些足以说明,在自然状况下,河流演变在沙丘群和沙地形成演化中起着非常重要的促进作用。

关键词: 科尔沁沙地, 河流演变, 松散砂堆积体, 河流地貌, 第四纪地层

Abstract: Due to alternative occurrence of floods and droughts as well as the influence of neo-tectonic movement, the channels of rivers in Horqin Sandy Land change frequently. In dry seasons, a large amount of sand-dunnes formed from various deposit bodies of loose sand under strong winds. Further, these sanddunes exert significant effects on the channels of rivers in flood period. When the channels change or have a big leap, formed sand-dunes would move and change their shapes under prevalent wind and groups of sand-dunes form by mutual linkage. After a long development period, a large stretch of sandy land emerges. Meanwhile,in the process of transverse swing, river can destroy some formed dunes through gradation. However, the land surface process in the region is mainly the formation of sand-dune groups because of the hindrance of sand-dune group itself, active vegetation action and non-evenness of river change. Accordingly, the river changed its way does the same work in the new channel. The effects of river is changeable with the Positions such as concave and convex beaches, upper or lower reaches, and the corresponding relations to the wind direction i. e. windward and leeward, perpendicular or oblique as well as parallel. In this region, sand-dune groups, lakes and marshes, meadows and pitches of steppe distribute interlacingly and at intervals,and sand-dune zones arrange in line along the beaches of present and ancient channels. Also, aeolian sand limnological facies, riverine factes change alternatively and further transit mutually in Quaternary strata. Therefore, river evolution has very vital initiative and promoting effects on the formation and development of sand——dune groups and sandy land in natural conditions.

Key words: Horqin Sandy Land, river evolution, loose sand deposit body, riverine landform, Quaternary strata

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