巴丹吉林沙漠边缘沉积物粒度和微形态特征空间分异

为了探讨巴丹吉林沙漠风沙沉积物特征分异规律，采用野外实地采集和实验分析的方法，对沙漠边缘表层沉积物的粒度和微形态进行分析。结果表明：（1）巴丹吉林沙漠边缘地区整体以细沙为主，中沙与极细沙次之；从局部上看，东南部以中沙为主，北部以粉沙黏土为主，西部地区以粗沙和极粗沙为主，与主导风向（西风和西北风）的分选作用一致。（2）北部和南部分别受河流和山脉影响，平均粒径较小，其余地区无明显差异。分选性在东南部最佳。粒度参数关系表明分选性在南部地区随着粒径变小而变好，偏度值随粒径变小而降低，峰度值随粒径变小而变宽，而在其他地区并没有明显的规律。（3）石英沙颗粒形态多为长形和圆形。整体磨圆度适中，其中西北部磨圆度最好，西南部和南部磨圆度最差。表面特征标志以干旱风成环境下的机械沉积作用的坑状为主，西北和东南部出现大量硅质球和硅质鳞片表明除机械沉积作用外，还具备化学沉积作用。

Grain size and Micro-morphology Characteristics of the Surface Sediments in the Marginal Area of the Badan Jaran Desert

In order to explore the characteristics of sediment in the Badain Jaran Desert,the grain size characteristics and micro-morphololgy characteristics of the surface of the desert surface were studied by field collection and experimental analysis.The results show that:(1)On the whole,the marginal area of the Badain Jaran Desert is dominated by fine sand,the middle sand and the very fine sand are the second.From the local perspective,the southeast is dominated by the middle sand,and the northern part mainly consists of powdery sand.The western region is dominated by coarse sand and extremely coarse sand,which is consistent with the sorting effect of the dominant wind direction (W and NW).(2) In the north and south,the average particle size of rivers and mountains was small,and there was no significant difference in the rest areas.Sorting is best in the southeast.The relation of grain size parameters in the study area shows that σ_I is better in the southern region as M_z becomes larger,but there is no obvious rule in the region.The SK value becomes smaller as σ_I becomes smaller,and the K_g value becomes smaller as σ_I becomes smaller.(3) The quartz sand morphology is mostly long and round.The roundness of the whole is moderate,with the northwest grinding to the best,the southwest and the south the least rounded.The surface feature marks are mainly in the form of mechanical sedimentation under the environment of arid wind,and a large number of siliceous spheres and siliceous scales are present in the northwest and southeast of desert.