Characteristics And Genesis Of Dune Sediments Along The Eastern Coast Of The Yellow River In The Ulanbuh Desert

Wind sediments are the basis of wind-blown sand activities and the formation of wind-blown sand landforms.The basic characteristics of wind-blown sediments are related to the initial material of sand source and wind force.In order to reveal the characteristics and genesis of dune sediments along the eastern coast of the Yellow River in the Ulanbuh Desert,based on field experiments and laboratory analysis,the surface sediments,spring dust fall and wind speed on different underlying surfaces along the Yellow River in the Ulanbuh Desert are studied in this paper.The wind direction,topography,and underlying surface cover are studied.The grain size characteristics and sediment genesis of dune sediments along the Eastern Bank of the Yellow River are analyzed.The results show that:(1)the surface sediments along both banks of the Yellow River Ulanbuh Desert are mainly fine sand(100?250?m).Compared with the West Bank,the sediments on the eastern bank are finer,the wind energy is weaker,and the sediments are sinking.The depositional environment is complex,and the sandy material of mobile dunes on the east coast mainly comes from semi-fixed sandy land,road shelter forest and farmland near the source area.(2)In the east bank>the West Bank of the two banks of the Yellow River in spring,the dust particle size parameters(MZ,?1)and multiple parameters(D0,D1,D2,?0,??,?f absolute value)are also shown as the east bank>the West bank.The dust particle size attributes of the east bank are quite different and the precipitation process is complex;the main factors influencing the dust components are powder and very fine particles.Sand contributes more to the east coast(68.73%)than to the west coast(64.39%).Dust in the east coast comes from Ulanbuh Desert and its windward area.(3)The dominant wind along the Yellow River in Ulanbuh Desert is westerly-northwest wind.In the past 1990?2017,the frequency of sandstorm was 73.19%.The average speed of sandstorm was 7.61?8.77 m/s.The regional topography was Eastern>Western>central.The highest elevation difference between the two sides was 1038.455 M.The area in front of Tabletop on the east coast was downwind sediment deposit area.(4)From 1990 to 2015,the decrease of wind power,the increase of vegetation coverage and the enhancement of wind and sediment control efficiency of the east bank sand barrier in the study area are the main reasons for the decrease of sand dune surface in the East Bank of the Yellow River due to the decrease of sand material transported from the upper wind to the sand source area to the East Bank of the Yellow River in the study area.