Grain-size characteristics of linear dunes on the northern margin of Qarhan Salt Lake, northwestern China

作     者：LI Jiyan DONG Zhibao ZHANG Zhengcai QIAN Guangqiang LUO Wanyin LU Junfeng 

作者机构：Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 

出 版 物：《Journal of Arid Land》 (干旱区科学（英文版）)

年 卷 期：2015年第7卷第4期

页      面：438-449页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 09[农学] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境] 

基　　金：funded by the National Natural Science Foundation of China (41171010  41130533  41301003) 

主　　题：linear dune longitudinal dune grain-size parameters Qarhan Salt Lake Qaidam Basin 

摘      要：In order to clarify the formation mechanism of linear dunes on the northern margin of Qarhan Salt Lake, northwestern China, we analyzed the grain-size and sorting parameters of the dune and interdune sands. The surface sands （0-30 ram） from the dune base to the crest of both flanks and interdune corridors were sampled along transects from upwind to downwind through the dune field. The results indicated that the grain-size distribution differed at different positions between and within the dunes. The frequency curve for dune sands mainly showed a bimodal distribution, while the interdune sediments showed a trimodal distribution. The grain size distribution of the linear dunes showed a finer crest pattern, i.e. the crests were composed of sands that were generally finer, better sorted than those of base sands. In addition, at the dune field scale, the dune crest sands were tending to become much finer but sorting became worse along the downwind transects. However, the grain-size parameters of sediments in the interdune corridors showed no clear pattern. The results demonstrated that the grain size and sorting parameters exhibited a systematic change not only at the individual scale but also at the dune field scale. Our results quantitatively estimate the limited role of cohesive sediments on the formation of linear dune under unidirectional wind regime. More attention should be paid to a long-term wind regime observation, internal sedimentary structures and their formation ages.