腾格里沙漠北缘沙丘粒度特征及区域差异分析  

Analysis on Dune Grain Size Characteristic and Regional Difference of the North Rim of Tengger Desert

作　　者：庞红丽[1] 程捷[2] 丛殿阁 李杰[3] 

机构地区：[1]兰州大学西部环境与气候变化研究院,甘肃兰州730000 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]河北省区域地质矿产调查研究所,河北廊坊065000

出　　处：《宁夏大学学报（自然科学版）》2015年第3期267-273,共7页Journal of Ningxia University(Natural Science Edition)

基　　金：国家重点基础研究发展计划基金资助项目(2011CB403301);兰州大学中央高校基本科研费专项资金资助项目

摘　　要：以腾格里沙漠北缘沙丘为研究对象,选取不同形态的沙丘类型,进行系统的野外地貌调查,沙丘形态测量和沙丘沉积物粒度分析,研究了腾格里沙漠北缘沙丘的粒度特征以及空间变化规律.结果表明,沙丘沉积物主要由细沙和中沙组成,细沙含量为63.92%,中沙含量为32.82%.平均粒径为2.20Φ,分选系数为0.40~0.68,属于分选好和分选较好的范围.沙丘断面粒度曲线显示,沿主导风向背风坡和迎风坡沉积物粒度呈现微弱变细的规律,且沙丘高度与平均粒径具有较好的正相关性.说明腾格里沙漠北缘沙物质的粒度特征在空间上表现为从物源区向沉积区沉积物颗粒变细、分选性变好的规律.将腾格里沙漠北缘、孟根布拉格和乌力吉苏木3个沙区样品对比,从南向北沿纬度方向沙丘粒度组成中沙、粗沙和极粗沙含量呈现增加的趋势,细沙和极细沙含量呈现减小的特点.以新月形沙丘和沙垄为例,从南向北沿纬度方向新月形沙丘和沙垄同样具有粗沙含量增加,细沙含量减少,平均粒径变粗的趋势.以上变化表明,植被、风况、沙丘高度是控制沙丘形态及粒度变化的重要因素.The authors chose different forms of dune types to make systematic field geomorphic survey of the object of research-the sand dunes of Tengger desert north rim,measure its dune type and analyze the sand sediment granularity.They also studied the Grain size characteristics of sand dunes and the law of spatial variation in this area.The result shows that the sand sediments are mainly composed of fine sand（63.92% content）and medium sand（32.82%）,the average grain diameter is 2.20Φ）,and the 0.40~0.68 of sorting coefficient makes it in the good to better range.The cross section grading curve of dune shows that the grain size of sediment in leeward slope and windward slope along the dominant wind direction appears the law of slightly turning thinner,and the dune height is positively correlated to average grain diameter.The study shows the grain size characteristics of the sand material in the north rim of Tengger desert appears spatially the law of the sediment particles turning slimmer and sorting characteristic becoming better from provenance to sediment district.Comparing the samples from 3dune areas-The north rim of Tengger desert,Menggen and Wuliji,they found contents of medium-coarse sand,coarse sand and extreme coarse sand were rising along the across warp from south to north,while the contents of fine sand and top fine sand presented an opposite trend.The crescent dunes and sand ridge,for example,also appeared the tendency of coarse sand content increasing,fine sand content decreasing and average particle size thickening along the across warp from south to north.Based on the above variation,vegetation,wind conditions and sand dune height are the key factors of controlling dune formations and particle size variation.

关 键 词：腾格里沙漠 粒度特征 区域差异 

分 类 号：P931.3[天文地球—自然地理学]