Aeolian geomorphy in the Dinggye area, South Tibet, China: Distribution and morphology
,4, Meihui Pan2, Lihua Tan3
1State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China, 2College of Geography and Environment Science, Northwest Normal University, Lanzhou,Gansu Province, China, 3School of Geography, Beijing Normal University, Beijing, China, 4MOE Engineering Research Centre of Desertification and Blown-sand Control, Beijing Normal University, Beijing, China
Aeolian depositon is widely distributed and aeolian activity is strongly in the Dinggye area in Southern Tibet, China. The Aeolian geomorphy in Dinggye area lies in the valley of Peng Qu River, and its tributaries including Yairu Zangbo, Xielin Zangbo and Jilong Zangbo. Diferrent from the other rivers in the south Tibetan Plateau, Peng Qu flows southward and cuts through the Himalaya Range to the Indian Ocean. The aim of the present study was to describe the distribution, aeolian geomorphological type and morphology of these aeolian deposition, and analyze the cause of formation of these aeolian geomorphy. Aeolian deposition is mostly distributed on the flood plains, lower terraces and piedmont slopes in the valleys. The aeolian geomorphological types are divided into the valley-bottom aeolian geomorphy and the valley-slope aeolian geomorphy. The valley-bottom aeolian geomorphy is main of barchan dunes, dune chains and nebkhas. The movement direction of the valley-bottom dunes is nearly northern in response to the dominant wind direction in Peng Qu Basin. The valley-slope aeolian geomorphy is main of mountain climbing dunes, sand sheets and nebkhas, and its movement direction is upward slope. This distribution pattern can be attributed to regional tectogenesis which control the river flow derection, and its corresponding environmental impacts that the wind blows from the south of Himalaya Mountains. The surface deposit of dunes is consisted of fine and medium sands mainly with well sorting, and the frequency curve of grain-size is normal distribution with moderate kurtosis. All of these characteristics are similar to the grain-size characteristics of deposit from Peng Qu River. It shows that the material source of the aeolian deposition is mainly from Peng Qu River.