新疆柴窝堡湖湖滨带干涸湖底沉积物风蚀特征分析

Aeolian Erosion Characteristics of Desiccated Lakebed Sediments in the Littoral Zone of Chaiwopu Lake, Xinjiang

  • 摘要: 柴窝堡湖湖滨带干涸湖底风沙活动强烈,是区域盐碱化与荒漠化的重要物源,本研究通过系统分析沉积物粒度特征及风蚀输沙过程,以期为生态修复提供依据. 结果表明:(1)沉积物主要由极细砂(27.58%)、细砂(20.27%)和极粗粉砂(18.36%)构成,整体呈分选差、负偏与窄峰态特征,局部含有 >2 mm 泥砾,反映其沉积过程可能受浊流与风成双重作用、稳定性较低. 沿主风向,平均粒径呈“细—粗—细”的波动变化,且粒径越细,分形维数越大. (2)地表输沙量随高度呈幂函数衰减(R2 > 0.99),0–10 cm 高度层贡献超过70的输沙量. 草席覆盖能显著抑制风沙流,而起沙风频率升高则显著增强输沙强度. (3)风沙流物质平均粒径为119.81 μm,整体分选差、偏度近对称、峰态窄. 随高度增加,粗粉砂–极细砂组分比例上升,而细砂及更粗颗粒比例下降,使沙粒平均粒径变细、偏度增大. 研究区风蚀过程表现出对细砂的选择性搬运特征,而粗颗粒多滞留于地表,该分异机制受风力条件、地表结构与沉积物组成的共同控制.

     

    Abstract: Wind and sand activity is intense on the dried-up lakebed of the Chaiwopu Lake littoral zone, making it a significant material source for regional salinization and desertification. This study systematically analyzes the sediment grain-size characteristics and aeolian sand transport processes to provide a basis for ecological restoration. The results indicate that: (1)The sediments are primarily composed of very fine sand (27.58%), fine sand (20.27%), and very coarse silt (18.36%), exhibiting overall poor sorting, negative skewness, and leptokurtic characteristics. Local presence of >2 mm mud gravels suggests that the depositional processes were likely influenced by both turbidity currents and aeolian actions, with low stability. Along the dominant wind direction, the mean grain size shows a “fine–coarse–fine” fluctuating pattern, and the fractal dimension increases as the grain size becomes finer. (2)The surface sediment transport rate decays as a power function with height (R2 > 0.99), with the 0–10 cm layer contributing over 70% of the total transport. Straw mat coverage can significantly suppress the aeolian sand flow, while an increase in the frequency of sand-driving winds markedly enhances the transport intensity. (3)The average grain size of the aeolian sand flow is 119.81 μm, characterized by poor sorting, nearly symmetrical skewness, and narrow kurtosis. With increasing height, the proportion of coarse silt to very fine sand increases, while the proportion of fine sand and coarser particles decreases, resulting in a finer mean grain size and increasing skewness. The aeolian erosion process in the study area exhibits selective transport of fine sand, while coarser particles tend to remain on the surface. This differentiation mechanism is jointly controlled by wind conditions, surface structure, and sediment composition.

     

/

返回文章
返回