| 西藏朋曲流域不同地貌部位流动沙丘粒度特征 |
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| 引用本文： | 潘美慧,郝泽文,齐宇涵,杨安娜,陈有桂,李晨露.西藏朋曲流域不同地貌部位流动沙丘粒度特征[J].中国沙漠,2021,41(6):138-147. |
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| 作者姓名： | 潘美慧 郝泽文 齐宇涵 杨安娜 陈有桂 李晨露 |
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| 作者单位： | 西北师范大学 地理与环境科学学院，甘肃 兰州 730070 |
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| 基金项目： | 国家自然科学基金项目(41807448) |
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| 摘 要： | 沙丘粒度特征不仅能反映沙丘沙物质的来源与动力，也可以体现地形对风沙流运移的改变。对西藏朋曲流域不同地貌部位流动沙丘表层沉积物的粒度特征进行分析。结果表明：（1）朋曲流域流动沙丘表层沉积物粒度组分以中沙（46.51%）和细沙（40.52%）为主，粗沙（5.87%）与极细沙（5.87%）次之，黏土（0.37%）与粉沙（0.85%）含量最低。流动沙丘表层沉积物平均粒径1.41—2.32 Φ，分选系数0.45—0.79 Φ，偏度0.01—0.24，峰度0.98—1.80。（2）从河漫滩到河流阶地到山坡，流动沙丘粒度逐渐变小，频率分布曲线逐渐变高变窄，粒径越来越集中，沿主导风向自西南向东北概率累积曲线斜率逐渐增大，分选性逐渐变好。（3）河漫滩至河流高级阶地流动沙丘表层沉积物随海拔升高粒径变小，坡麓至坡顶随海拔升高粒径变大，分选却变好，表明山坡上沙丘与阶地上沙丘的沙物质来自于不同河段的河床或河漫滩。
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| 关 键 词： | 朋曲流域 流动沙丘 粒度 河漫滩 河流阶地 山坡 |
| 收稿时间： | 2021-06-10 |
| 修稿时间： | 2021-07-20 |
Grain size characteristics of moving dune in different geomorphological locations in Pengqu Basin， Tibet， China |
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| Meihui Pan,Zewen Hao,Yuhan Qi,Annan Yang,Yougui Chen,Chenlu Li.Grain size characteristics of moving dune in different geomorphological locations in Pengqu Basin， Tibet， China[J].Journal of Desert Research,2021,41(6):138-147. |
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| Authors: | Meihui Pan Zewen Hao Yuhan Qi Annan Yang Yougui Chen Chenlu Li |
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| Institution: | College of Geography and Environment Science，Northwest Normal University，Lanzhou 730070，China |
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| Abstract: | Grain size analysis is one of the main methods to study the process of aeolian sand landform. The analysis of sand dune grain size characteristics can not only reflect the source and power of sand dunes， but also reflect the changes of the terrain to the movement of the sand flow. This paper analyzes the grain size characteristics of the surface sediments of the mobile dunes in different geomorphological positions in the Pengqu Basin of Tibet. The results show that： （1） Surface sediments on mobile dunes in Pengqu basin are mainly divided into medium sand （46.51%） and fine sand （40.52%）， followed by coarse sand （5.87%） and very fine sand （5.87%）， and the content of clay （0.37%） and silt sand is the least （0.85%） . The average grain of surface sediments on mobile dunes is in the range of 1.41-2.32 Φ， and the skewness is in the range of 0.01-0.24 . In general， the kurtosis range is 0.98-1.80， and the sorting coefficient is in the range of 0.45-0.79 Φ. （2） The grain size composition of different geomorphic units （river floodplain-river terrace-hillside） gradually becomes finer； the frequency distribution curve gradually becomes higher and steeper， and the probability accumulation curves from southwest to northeast along the dominant wind direction change from two-stage to one-stage， the slope gradually increases， and the sortability gradually becomes better. （3） The surface sediments of the flowing sand dunes from the floodplain to the high-level terraces of the river become finer with increasing altitude， and the particle size from the slope to the top of the slope becomes coarser with the increase in altitude， but the sorting becomes better， indicating the sand materials of the sand dunes on the hillside and the sand dunes on the terrace come from different river sections of riverbed or floodplain. The research results can provide a scientific basis for the prevention and control of desertification in different areas in the study area. |
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| Keywords: | Pengqu Basin moving dune grain size characteristics flood plain terrace mountain slope |
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