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中国沙漠 ›› 2024, Vol. 44 ›› Issue (6): 287-298.DOI: 10.7522/j.issn.1000-694X.2024.00136

• • 上一篇    下一篇

砾波纹地表风沙颗粒蠕移特征及其地貌学意义

钱广强1(), 杨转玲2, 邢学刚2, 董治宝3, 潘凯佳1, 孟雨萱1, 郭酉元1   

  1. 1.中国科学院西北生态环境资源研究院 干旱区生态安全与可持续发展重点实验室,甘肃 兰州 730000
    2.贵州师范学院 地理与资源学院,贵州 贵阳 550018
    3.陕西师范大学 行星风沙科学研究院,陕西 西安 710119
  • 收稿日期:2024-09-10 修回日期:2024-09-24 出版日期:2024-11-20 发布日期:2024-12-06
  • 作者简介:钱广强(1978—),男,山东嘉祥人,研究员,主要从事风沙物理与风沙地貌研究。E-mail: gqqian@lzb.ac.cn
  • 基金资助:
    国家自然科学基金项目(42071016)

Creep of aeolian sediments on the surface of granule ripples and its geomorphological significance

Guangqiang Qian1(), Zhuanling Yang2, Xuegang Xing2, Zhibao Dong3, Kaijia Pan1, Yuxuan Meng1, Youyuan Guo1   

  1. 1.Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China
    2.School of Geography and Resource Science,Guizhou Education University,Guiyang 550018,China
    3.Planetary Aeolian Research Institute,Shaanxi Normal University,Xi'an 710119,China
  • Received:2024-09-10 Revised:2024-09-24 Online:2024-11-20 Published:2024-12-06

摘要:

蠕移是风沙颗粒传输的3种基本形式之一,也是目前较少关注的研究领域。砾波纹作为一种独特风沙地貌形态,由双峰型沉积物组成,表面被粗颗粒覆盖,其形成演化与蠕移运动密切相关,但学界对其形态动力过程认知非常有限。因此,以砾波纹为载体,研究了蠕移运动规律并探讨其地貌学意义。本研究在库姆塔格沙漠北部三垄沙地区开展,借助新型蠕移集沙仪,在14个月内进行了10次连续原位观测。结果表明:砾波纹地表的蠕移输沙通量为0.047~0.352 g·cm-2·min-1,且随季节存在明显的变化。蠕移质的粒度分布为双峰型,分选较好,粗偏,宽至极宽峰态,中沙和细沙含量可达85%,粗沙及以上颗粒占10%强;不同粒级的蠕移输沙通量存在较大差异,中细沙输沙通量最大,极粗沙和极细砾则呈量级减少。蠕移输沙通量与起沙风平均风速之间存在相关性,最强的蠕移输沙过程发生在夏季沙尘暴期间,而最弱的发生在冬季。除了风况之外,沉积物粒度特征、不同方向的沙源供应程度均影响蠕移输沙通量和物质组成。从沉积学上来看,砾波纹表面的蠕移运动,对其内部“渗入”结构和粗细互层的前积纹层形成具有重要贡献。本研究对揭示风沙蠕移物理过程和砾波纹地貌演化提供了一些新的认识。传统上以粒径划分蠕移的方法值得商榷,更为深入的蠕移运动机理及其在地貌学意义值得深入研究。

关键词: 蠕移, 砾波纹, 集沙仪, 输沙通量, 风况

Abstract:

Creep is one of the three fundamental forms of blown sand movement and is currently a less-studied research area. Granule ripples, as a unique aeolian landform, are characterized by surfaces covered with coarse particles and composed of bimodal sediments. Their formation and evolution are closely related to creep movement, and the scientific community's understanding of their morphodynamic processes is quite limited. Therefore, this paper uses granule ripples as a study subject to investigate the laws of creep movement and explore their geomorphological significance. The research was conducted in the Sanlunsha area of the northern Kumtagh Desert, using a novel creep sand trap. We conducted 10 continuous in-situ observations over a period of 14 months. The results indicate that the creep sand flux on the surface of granule ripples ranges from 0.047 g·cm-2·min-1 to 0.352 g·cm-2·min-1, with significant seasonal variations. The grain size distribution of the creep material is bimodal, well-sorted, coarse-skewed, and has platy kurtosis. The content of medium and fine sand can reach 85%, while coarse sand and larger particles account for more than 10%. Creep sand fluxes exhibited clear variations depending on grain size, with the highest fluxes occurring in medium and fine sands, and measurably lower fluxes in very coarse sands and very fine gravels. There is a correlation between the creep sand flux and the average sand-driving wind speed. The strongest creep sand flux occurred during summer dust storms, while the weakest occurred in winter. In addition to wind conditions, the grain size characteristics of the sediments and the supply of sand from different directions also influence the creep sand flux and material composition. From a sedimentological perspective, the creep movement on the surface of granule ripples significantly contributes to the formation of their internal poured-in structures and coarse-fine interlayered forest laminations. This research provides new insights into the physical processes of wind-driven creep and the evolution of granule ripple bedforms. The traditional method of classifying creep based on grain size is questionable, and a more in-depth study of the mechanisms of creep movement and its geomorphological significance is necessary.

Key words: creep, granule ripple, sand trap, sand flux, wind regime

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