Grain-size distribution of surface sediments of climbing and falling dunes in the Zedang valley of the Yarlung Zangbo River, southern Tibetan plateau

Journal of earth system science

Qing Li^2¹  Chunlai Zhang^2²  Jiaqiong Zhang^1³ 

[1] Hydrology and Water Resources Survey Bureau of Weifang, Weifang 261061, Shandong, People’s Republic of China.^3;State Key Laboratory of Earth Surface Processes and Resource Ecology, MOE Engineering Research Center of Desertification and Blown-Sand Control, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, People’s Republic of China.^2;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, People’s Republic of China.^1

关键词: Climbing and falling dunes;    grain-size distribution;    sand transport pattern;    wide river valleys;    terrain factors;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Climbing and falling dunes are widespread in the wide valleys of the middle reaches of the Yarlung Zangbo River. Along a sampling transect running from northeast to southwest through 10 climbing dunes and two falling dunes in the Langsailing area, the surface sediments were sampled to analyse the grain-size characteristics, to clarify the transport pattern of particles with different grain sizes, and to discuss the effects of terrain factors including dune slope, mountain slope, elevation and transport distance to sand transport. Sand dunes on both sides of the ridge are mainly transverse dunes. Fine and medium sands were the main particles, with few very fine and coarse particles in the surface sediments. Particles >4.00$\Phi$ were blown upslope by suspension, particles 1.00${-}$4.00$\Phi$ were mainly transported upslope by saltation with opposite change tendency, and particles <1.00$\Phi$ mainly moved by creep were found almost exclusively at the bottom of the slopes. As terrain factors, elevation and transport distance were more important factors influencing the distribution of grain size and particle fraction on dunes. Local winds observation might be helpful for the transport mechanism study of particles on climbing and falling dunes, while the wind data from nearby weather station was hardly helpful.

【 授权许可】

CC BY