摘要
对塔克拉玛干沙漠腹地沙粒胶结体进行溶蚀分散获取组成沙粒,采用激光粒度仪分析粒度成分,并与区域内沙丘沙、垄间平地沙和风沙流输沙的粒度特征进行对比,分析沙粒胶结体的粒度特征。结果表明:(1)沙粒胶结体中沙粒粒径呈多峰态分布,垄间平地沙呈双峰态分布,而沙丘沙和风沙流输沙呈单峰态分布;(2)沙粒胶结体内沙粒分选性较差,偏度属正偏,平均粒径(3.17Φ)介于沙丘沙(3.10Φ)和垄间地沙(3.28Φ)、风沙流输沙(3.67Φ)之间;(3)沙粒胶结体中沙物质主要组分为细沙和极细沙,与沙丘沙、垄间平沙地沙一致,而与风沙流输沙(极细沙和粉沙)不一致。与沙丘沙、垄间平地沙以及风沙流输沙相比,沙粒胶结体中粉沙、黏土和中沙相对富集,是现代地表物质的混合物;(4)与沙丘沙、垄间平地沙和风沙流输沙相比,沙粒胶结体内沙粒的蠕移-跃移、跃移-悬移截点粒径均偏细,蠕移组分所占比重很高。从组成颗粒的粒度组成来看,沙粒胶结体的形成受局地沙源和风动力的共同影响,是特殊环境条件下现代地表过程的产物。
The particles were gained by the dissolution and dispersion of sand cemented bodies（SCB）collected from the Taklimakan desert,and then the Laser Particle Characterization System was conducted to get the characteristic parameters of the particles.In order to analyze the grain-size characteristics of the SCB,the SCB particle characteristic parameters were compared with the sand particles from the local dunes,the inter-dune corridors and the transport sands.The results indicate that：（1）The grain-size distribution curve of the SCB is mutipeaked,both the dunes and the transport sands are single-peaked and the inter-dune corridors is double-peaked;（2）The sorting of the SCB particles is poor,the distribution is positive skewness,and the average particle size（3.17Φ）is between the size of the dune sands（2.10Φ）and the inter-dune corridor sands（3.28Φ）or the transport sands（3.67Φ）;（3）The SCB mainly consists of fine sand and silver sand.Compared with the dune sands,the inter-dune corridors sands and the transport sands,the SCB are enriched in silty sand,clay and medium sand relatively.In conclusion,the SCB is a mixture product of the modern desert on surface.（4）Compared with the dune sands,inter-dune corridor sands and the transport sands,the diameter of SCB creep-saltation and saltation-suspension particles tend to be fine,and the creep moving component proportion is very high.Therefore,from the perspective of the grain-size of the material compositions,the formation of the SCB is affected by the common local sands and the wind power,it is a product formed on the modern land surface influenced by special environment conditions.
出处
《中国沙漠》
CSCD
北大核心
2017年第6期1059-1065,共7页
Journal of Desert Research
基金
国家自然科学基金项目(41571011)
关键词
沙粒胶结体
粒度参数
形成环境
sand cemented bodies
grain-size parameters
formation environment
