中央亚细亚的八种雅丹地貌类型

Eight yardang types in Central Asia

柴达木盆地是中央亚细亚的极端干旱盆地之一,风力搬运及侵蚀是该地最为明显的地貌动力。在其东部,风成沉积普遍,西部则为地球上延伸最长的雅丹地形。作者在文中将这种地貌特点划为八种不同类型,并认为其形态是一种逻辑循环。初始阶段多为隆起扇缘或湖盆平原,受水、风严重切割。地表风化物被吹蚀,基岩被沙吹。形态各异的水、风蚀低丘残体完全被破坏,剥蚀残留的部分为低矮的流线状鲸背状残体。其长、宽、高比例为10∶2∶1。这一点与沃德(WARD)1979年经过200个小时的风洞实验中所发现的事实相符。最后形成低海拔新平原。

In a extremely arid basin of Central Asia,the Qaidam Depression,wind transport and corrosion are the strongest geomorphological forces. In the eastern part,wind sedimentation prevails,in the western part is the largest yardang field on earth. The authors classify these hills into 8 groups and see the forms as a hypothetic cycle. It begins as an uplifted fan or lake plain, which is dissected by water and wind. Weathered material is removed and the bedrock sandblasted. The bizarre hills are totally destroyed, others remain for a while as low, streamilimed whalebacks. If the direction of the strongest gales change by 150 to 210 degrees,two windward fronts will develop. The ratio of their length,width and height is 10:2:1;tis is the same as that found by Ward(1979)in wind tunnel experiments after 200 hours. The end can be presumed as a new plain at a lower level, (with 13 figures and 2 tables).