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中国沙漠 ›› 2026, Vol. 46 ›› Issue (2): 11-23.DOI: 10.7522/j.issn.1000-694X.2025.00058

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共和盆地藏锦鸡儿( Caragana tibetica )灌丛沙堆形态和沉积物粒度特征

李悦(), 郝雪萌, 肖锋军(), 南维鸽, 胡光印, 尚毅力, 王利杰   

  1. 陕西师范大学 地理科学与旅游学院,陕西 西安 710119
  • 收稿日期:2025-03-31 修回日期:2025-04-25 出版日期:2026-03-20 发布日期:2026-04-13
  • 通讯作者: 肖锋军
  • 作者简介:李悦(2001—),女,山东泰安人,硕士研究生,主要从事风沙地貌学研究。E-mail: liyuesnnu@163.com
  • 基金资助:
    国家自然科学基金项目(42071009);国家自然科学基金项目(42171004);第二次青藏高原综合科学考察研究项目(2019QZKK0403);科技部科技基础资源调查专项(2022FY202304);陕西省2021年自然科学基础研究计划(定向委托)项目(2021JCW-17)

Morphology and sediment grain size of Caragana tibetica nebkhas in the Gonghe Basin

Yue Li(), Xuemeng Hao, Fengjun Xiao(), Weige Nan, Guangyin Hu, Yili Shang, Lijie Wang   

  1. School of Geography and Tourism,Shaanxi Normal University,Xi'an 710119,China
  • Received:2025-03-31 Revised:2025-04-25 Online:2026-03-20 Published:2026-04-13
  • Contact: Fengjun Xiao

摘要:

沙源是灌丛沙堆形成的物质基础。在共和盆地荒漠化草原,以新月形沙丘右翼角下风向流沙带和平行于主风向相邻无流沙荒漠草原上的藏锦鸡儿(Caragana tibetica)灌丛沙堆为研究对象,测量灌丛沙堆的形态参数并采集地表沉积物样品,分析藏锦鸡儿灌丛沙堆形态演化和沉积物粒度特征对不同沙源供给的响应。结果表明:(1)流沙带有较稳定沙源输入,藏锦鸡儿灌丛生长态势良好,形成风影沙丘且处于发育阶段;荒漠草原受限于沙源匮乏,藏锦鸡儿灌丛老化,灌丛沙堆呈半椭球体且处于稳定至活化阶段之间。藏锦鸡儿灌丛沙堆的形态参数间存在显著相关性,灌丛高度是灌丛沙堆形态的控制因子之一。沙源控制着藏锦鸡儿灌丛沙堆的规模,随沙源供给的增加,除短轴未出现显著分异外,其他形态参数显著增加(P<0.05)。(2)流沙带中,短轴长度与风影沙丘长度呈显著线性响应,揭示短轴长度对风影沙丘延伸的核心控制作用。受风程效应影响,风影沙丘长度、底面积和体积在新月形沙丘翼角流沙带下风向30~60 m处达到最大值。(3)流沙带和荒漠草原中藏锦鸡儿灌丛沙堆表层沉积物均以中沙和细沙为主,粒度频率曲线均为双峰型,沙粒的搬运方式均以跃移为主,但荒漠草原中悬移组分显著增加。沙源供给的不同,使流沙带的中沙占比增加,粉沙和极细沙含量减少,趋向窄峰态,平均粒径高于荒漠草原,且分选更好。

关键词: 灌丛沙堆, 沙源供给, 藏锦鸡儿, 形态特征, 沉积物粒度特征

Abstract:

Sand source serves as the material basis for nebkha formation. In the desertified steppe of the Gonghe Basin, this study focused on Caragana tibetica nebkhas in different sand supply: a downwind quicksand belt at one flank of barchan dune, and in its adjacent desert steppe without quicksand parallel to the dominant wind direction. Morphological parameters of nebkhas were measured, and surface sediment samples were collected to analyze the evolutionary patterns of Caragana tibetica nebkhas morphology and sediment grain size characteristics in response to varying sand supply. Key findings include: (1) Stable sand input in quicksand belt promoted vigorous growth of Caragana tibetica, forming shadow dunes in the developmental stage; in desert steppe, sand scarcity led to Caragana tibetica senescence, resulting in semi-ellipsoidal nebkhas in the stage of stabilization to recession. There was a significant correlation among the morphological parameters of nebkhas and shrub height emerged as the dominant morphological driver. Morphological parameters except for the short axis significantly increased with sand supply (P<0.05), confirming sand availability as the primary control on Caragana tibetica nebkha dimensions. (2) In the quicksand belt, the significant linear relationship between the short axis length and the elongation of shadow dunes revealed the dominant control of short axis length over the extension of shadow dunes Under the influence of wind fetch effects, the length, bottom area, and volume of shadow dunes in the quicksand belt reached their maximum values at 30-60 m downwind of quicksand belt at the flank of the barchan dune. (3) The surface sediments of Caragana tibetica nebkhas in both the quicksand belt and desert steppe are dominated by medium and fine sands, with bimodal grain-size distributions, and saltation as the primary transport mode, but the desert steppe showed a significant increase in suspension components. Differences in sand supply led to distinct sedimentary characteristics: In the quicksand belt, medium sand content increased, silt and very fine sand fractions reduced, exhibiting a narrower kurtosis, a coarser mean grain size (1.88 Φ vs. 2.32 Φ) and better sorting.

Key words: nebkha, sand supply, Caragana tibetica, morphological characteristics, sediment grain size characteristics

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