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中国沙漠 ›› 2023, Vol. 43 ›› Issue (6): 1-9.DOI: 10.7522/j.issn.1000-694X.2023.00048

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塔克拉玛干沙漠东北部纵向沙垄粒度分布特征

刘建宗(), 张峰(), 卞红炜, 李璇, 苏谌杰   

  1. 新疆大学 地理与遥感科学学院,新疆 乌鲁木齐 830017
  • 收稿日期:2023-02-10 修回日期:2023-04-18 出版日期:2023-11-20 发布日期:2023-11-30
  • 通讯作者: 张峰
  • 作者简介:张峰(E-mail: zhang-f-eng@sohu.com
    刘建宗(1998—),男,甘肃武威人,硕士研究生,研究方向为自然地理。E-mail: ljianzong@163.com
  • 基金资助:
    国家科技基础资源调查专题(2017FY101004);国家自然科学基金项目(U1503381);第三次新疆综合科学考察项目(2021xjkk030201)

Grain size distribution characteristics of longitudinal dunes in northeastern Taklamakan Desert

Jianzong Liu(), Feng Zhang(), Hongwei Bian, Xuan Li, Chenjie Su   

  1. College of Geography and Remote Sensing Sciences,Xinjiang University,Urumqi 830017,China
  • Received:2023-02-10 Revised:2023-04-18 Online:2023-11-20 Published:2023-11-30
  • Contact: Feng Zhang

摘要:

塔克拉玛干沙漠东北部纵向沙垄广泛发育,但沉积物粒度特征鲜有报道。基于筛析法测定了塔克拉玛干沙漠东北部一条上覆次级沙丘的纵向沙垄断面沉积物粒度特征。结果显示:(1)沙垄沉积物颗粒自垄顶向两侧坡底逐渐变细,分选变差;沙垄上覆次级沙丘亦同。(2)沙垄沙的频率分布曲线以双峰为主。(3)沙垄迎风坡中部沉积物平均粒径细于中下部;上覆次级沙丘迎风坡底部沉积物颗粒粗于迎风坡中部。该区域纵向沙垄粒度分布特征与前人提出的“脊部较粗型”一致。沉积物样品所表现的双峰分布特征受物源、风选影响显著。上覆沙丘断面上迎风坡底部粗化,可能是粗颗粒无法被带走而发生富集的缘故。沙垄上覆次级沙丘局部形态的变化影响了风沙流,从而导致了平均粒径和分选系数局部上的变化。在沙垄迎风坡一侧存在风沙流的二次输移过程。

关键词: 塔克拉玛干沙漠, 纵向沙垄, 粒度分析, 粒度分布模式

Abstract:

Longitudinal dunes are widely developed in the northeastern Taklamakan Desert, but the particle size characteristics of sediments have rarely been reported. The sediment grain-size characteristics of a longitudinal dune profile and an overlying secondary dune profile in the northeastern Taklamakan Desert were determined by sieve analysis. The results showed that: (1) The sediment particles of the longitudinal dunes gradually became finer and poorly sorted from the top of the dune to the bottom of the slope on both sides; the same was true for the overlying secondary dunes. (2) The frequency distribution curves of the longitudinal dunes sediments was mainly bimodal. (3) The average sediment size in the middle of the windward slope of the longitudinal dune was finer than that in the middle and lower parts; the sediment particles in the bottom of the windward slope of the overlying dunes is coarser than that in the middle of the windward slope. It is concluded that the particle size distribution of the longitudinal dunes in this area is consistent with the "coarser ridge type" proposed by previous authors. The bimodal distribution of sediment samples is significantly influenced by the source and wind selection. The coarsening of the bottom of the windward slope on the overlying dune profile may be due to the enrichment of coarse particles that cannot be carried away. Local changes in the morphology of the overlying secondary dunes of the longitudinal dunes affect the wind-sand flow, which leads to local changes in the mean particle size and sorting coefficient. There is a secondary transport process of wind and sand flow on the windward side of the sand monopoly.

Key words: Taklamakan Desert, longitudinal dunes, grain size analysis, grain size distribution pattern

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