In geology, Deflation can be defined as the process by which loose, light weight and small particles formed by the weathering of rocks, erosion of top-soil of the earth crust or the dust and sand particles are carried from one place to another by the action of wind.
When these particles hit or strike an obstruction like a mountain or hill they fall down on the ground.
Gradually with time, numerous such particles fall down and accumulate on the ground after striking an obstruction and eventually result in the formation of a sand dune.
