| 西藏定结地区爬坡沙丘粒度特征分析 |
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| 引用本文： | 潘美慧,薛雯轩,伍永秋,黄文敏,马建军,杨安娜,陈玉林.西藏定结地区爬坡沙丘粒度特征分析[J].干旱区地理,2019,42(6):1337-1345. |
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| 作者姓名： | 潘美慧 薛雯轩 伍永秋 黄文敏 马建军 杨安娜 陈玉林 |
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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;北京师范大学防沙治沙教育部工程研究中心,北京,100875;北京师范大学第二附属中学未来科技城学校,北京,102209 |
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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： | 通过对西藏定结地区典型爬坡沙丘表层沉积物的形态参数、粒度组成和粒度参数等进行分析，揭示其粒度特征。结果表明：（1）爬坡沙丘表层沉积物以细砂和中砂为主，极细砂含量较少，同时含有少量粉砂和粗砂，不含粘土成分。（2）沙丘平均粒径范围1.98~2.41 Ф，分选系数变化范围为0.45~0.75，属中等分选，偏度变化范围为0.01~0.12，呈近对称至正偏分布，峰度变化范围为0.94~1.01，呈中等尖锐峰态。（3）从样品PPSQ1~PPSQ6，随着高度和距离的增加，沙丘表层沉积物平均粒径先变细后变粗，分选不断变好。（4）爬坡沙丘表层沉积物主要来源于河漫滩。（5）与雅鲁藏布江、东昆仑山地区爬坡沙丘对比可知，定结地区的沙丘粒径较粗，分选较好，主要是物源及风力分选作用的共同结果。
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| 关 键 词： | 爬坡沙丘 粒度特征 定结地区 |
| 收稿时间： | 2019-04-11 |
Grain size characteristics of the climbing dunes in Dinggye area of Tibet |
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| PAN Mei-hui,XUE Wen-xuan,WU Yong-qiu,HUANG Wen-min,MA Jian-jun,YANG An-na,CHEN Yu-lin.Grain size characteristics of the climbing dunes in Dinggye area of Tibet[J].Arid Land Geography,2019,42(6):1337-1345. |
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| Authors: | PAN Mei-hui XUE Wen-xuan WU Yong-qiu HUANG Wen-min MA Jian-jun YANG An-na CHEN Yu-lin |
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| Institution: | 1
College of Geography and Environment Science,Northwest Normal
University,Lanzhou 730070,Gansu,China;
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Engineering Research Center of Ministry of Education,Beijing Normal
University,Beijing 100875,China;
3 The Second Affiliated
Middle School Future Science City School of Beijing Normal University,Beijing
102209,China |
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| Abstract: | The
climbing dunes are widely distributed in Dinggye area of Zigaze Prefecture, Tibet,
China, and the surface sediment grain size characteristics are of great
significance for exploring the development process of sand dunes. In this
paper, six climbing dunes sand were collected in the area. In order to reveal
the grain size characteristics, the study analyzed the morphological
parameters, mechanical composition and grain size parameters of surface sediments
of the dunes, which provide a theoretical basis to reveal the climbing dune’s formation mechanism on the
Qinghai-Tibet Plateau. The current researches were mainly concentrated on the
climbing dunes in coastal areas rather than that in arid areas. Studying the
climbing dunes on the Qinghai-Tibet Plateau can explore the grain size
characteristics of climbing dunes in inland arid regions. The results are
summarized as follows：The surface sediments of
climbing dunes are mainly composed of silver sand and medium sand, accounting
for 55.25% and 32.73% respectively. Fine sand accounts for 9.98%.The content of
silty and coarse sand are less than 3%.The frequency curves of grain size are
showing an approximate symmetrical unimodal distribution, and sand dunes have a
slender tail on one side of the fine particles. The range of Mz is 1.98-2.41 Ф and the mean value is 2.23 Ф.The range ofσis 0.45-0.75 and the mean value is
0.57,which is good for middling sorting. The range of SK is 0.01-0.12,the mean value is 0.04,and kurtosis is positive. The
range of KG is 0.94-1.01,the mean value is 0.97,and kurtosis presents a single
peak. As the height and distance increasing, the Mz of the climbing dunes trends to be thinner first and later
coarser, the sorting gets better.The variation trend of grain size
characteristics of different parts of sand dunes is as follows: The Mz from the windward and the leeward
slope to the top of the leeward is generally coarser, and the sorting is worse.
The variation trend of SK is from
near symmetry to positive deviation, and the KG has a medium sharp. The reason for its differentiation is mainly
affected by the source and wind sorting. The analysis of the sources of the
sediment reveals that the dune surface sediment is mainly from the floodplain. Comparing
with the climbing dunes in the Yarlung Tsangpo River and the eastern Kunlun
Mountains, the surface sediments of the climbing dunes in the study area is
coarser and the sorting is relatively better. It indicates that the climbing
sand dunes are closer to the source area, and the wind sorting effect is
stronger in Dinggye than the other two areas. |
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| Keywords: | Times New Roman" serif font-size:10 5pt climbing dune" target="_blank">">climbing dune grain size characteristics Dinggye area |
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