CollectHomepage AdvertisementContact usMessage

Arid Land Geography ›› 2022, Vol. 45 ›› Issue (1): 141-152.doi: 10.12118/j.issn.1000–6060.2021.176

• Earth Surface Process • Previous Articles     Next Articles

Grain-size characteristics of yardang strata sediment in the Dunhuang Yardang National Geopark, northwest China

LIANG Xiaolei1(),ZHAI Xiaohui1(),NIU Qinghe2,HU Zihao3,WANG Tianhu4,LIU Wancheng4   

  1. 1. Department of Management, Taiyuan Normal University, Jinzhong 030619, Shanxi, China
    2. Dunhuang Gobi and Desert Research Station/Gansu Center for Sand Hazard Reduction and Engineering and Technology/Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China
    3. Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, China
    4. Dunhuang Yardang Scenic Area Service Center, Jiuquan 736200, Gansu, China
  • Received:2021-04-19 Revised:2021-11-15 Online:2022-01-25 Published:2022-01-21
  • Contact: Xiaohui ZHAI E-mail:liangxl@lzb.ac.cn;zhaixiaohui@lzb.ac.cn

Abstract:

The yardang strata is the material manifestation of the sedimentary system before the yardang landform developed. It collects a large amount of data about the deposition process, and sediment analysis is the foundation for interpreting its key findings. The research object in this paper is the Dunhuang yardang landforms in the Dunhuang Yardang Geopark, Gansu Province of northwest China and it is a preliminary study on the grain-size characteristics of the exposed strata sediments. The results indicated that: (1) The grain-size composition of Dunhuang yardang strata sediments is dominated by silt, with an average content of 41.08% (profile YA), 36.82% (profile YB), and 35.41% (profile YC), and its content decreases from east to west. It also contains coarse sand components with higher specific gravity, and the spatial change trend is the inverse of that of silty sand. (2) There are considerably vertical changes in the grain-size composition and parameters of the yardang strata, which are characterized by the alternation of coarse sand (primarily medium and fine sand) and fine sand (mainly silt and clay). Meanwhile, the interface is highly consistent with the shape of yardang’s three-level ladder. (3) The yardang stratum is the result of the mixed accumulation of various sediments formed under different sedimentary environments and dynamic mechanisms. It is primarily the result of alternate aeolian, fluvial, and lacustrine deposition. The subenvironmental types of fluvial and lacustrine sedimentary environments are the most complex and diverse, necessitating extensive research.

Key words: yardang strata, sediment, grain-size analysis, grain-size frequency distribution curve, grain-size parameter