玉门关西雅丹地貌的分布和特征及形成时代问题

玉门关西雅丹地貌位于玉门关以西68 km的疏勒河故道北面北山剥蚀残丘准平原的东西向断层谷地中(90°00'~90°10'E, 40°30'~40°34'N),该区雅丹地貌组成的古湖相地层被推测形成于中更新世甚至早更新世,中更新世末的新构造运动湖水向西撤退,随即被晚更新世的戈壁砾石层覆盖。晚更新世末发育了东西向古河道,以后由蒙古高原南下的强劲北风吹蚀而成,雅丹一般高20~40 m,最高可达100 m,形态丰富多姿,为世界上所少见的大中型、密集的、形态奇特的雅丹地貌景观,是旅游观光和科研的宝地。

Distribution and Characteristics of Yardang Landform and Its Formation Period, West to Yumenguan, Gansu

The study area is located in the W-E fault valley 68 km west to Yumenguan, on a residual hill peneplain of the North Mountain north to Suleihe billabong (90°~90°10'E,40°30'~40°34'N). There, the paleo-lacustrine sediments composing Yardang landform is deposited in the period of Middle and even Early Pleistocene. Then the deposits were covered by Gobi gravel layer during the Late Pleistocene after the lake water retreating westward due to neotectonic movement in the Middle Pleistocene. There was a billabong with W-E trend developed in the end of Late Pleistocene, and then Yardangs formed in it resulted from strong N-wind from Mongolian Plateau. Here many with 20~40 m height generally, the highest Yardang reached about 100 m. These Yardangs are large-middle types, dense and with special shapes, which are scarce over the world. This place is one nice place for tourism, expedition and science research.