Depoist of fine silt blown by wind is called as
Answers
Answer:
On the right is a desert mountain in Arizona. The surface in the foreground is desert pavement. How did wind modify this landscape? On the left is a desert mountain with sand dunes in Death Valley, California. How did wind modify this landscape? Erosion and deposition by wind leave very different landscapes behind.
Wind Deposition
Like water, when wind slows down it drops the sediment it's carrying. This often happens when the wind has to move over or around an obstacle. A rock or tree may cause wind to slow down. As the wind slows, it deposits the largest particles first. Different types of deposits form depending on the size of the particles deposited.
Sand Dunes
When the wind deposits sand, it forms small hills. These hills are called sand dunes (Figure below). For sand dunes to form, there must be plenty of sand and wind. Sand dunes are found mainly in deserts and on beaches.
How Sand Dunes Form
What causes a sand dune to form? It starts with an obstacle, such as a rock. The obstacle causes the wind to slow down. The wind then drops some of its sand. As more sand is deposited, the dune gets bigger. The dune becomes the obstacle that slows the wind. This causes more sand to drop. The hill takes on the typical shape of a sand dune
Migration of Sand Dunes
Once a sand dune forms, it may slowly migrate over the land. The wind moves grains of sand up the gently sloping side of the dune. This is done by saltation. When the sand grains reach the top of the dune, they slip down the steeper side. The grains are pulled by gravity. The constant movement of sand up and over the dune causes the dune to move along the ground. A dune moves in the same direction that the wind usually blows.
Loess
When the wind drops fine particles of silt and clay, it forms deposits called loess . Loess deposits form vertical cliffs. Loess can become a thick, rich soil. That’s why loess deposits are used for farming in many parts of the world.