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Wind Erosional Features

1. Deflation Basin. Many depressions are formed by deflation action of wind. These depressions are known as deflation basins. Most of them have a diameter less than 1.5 km. and depth of a few meters.

2. Deflation Armour. Winds blowing very speedily carry away light and small dust particles but leave behind pebbles and large fragments rolling behind on the ground. Slowly the number of such fragments increases. Due to the deflation action, the land is so much lowered that these fragments form a layer. This layer preserves the land from deflation action. It is why the layer of the pebbles is called deflation armour. 3. Deserts Pavements. Some fine pebbles go on escaping from the deflation armour even after its formation. The stone pieces get much compacted as if they have been ham-meted together. This compact layer is called desert pavements.

4. Blow-out. Many sand dunes are formed in deserts. Deflation action does not affect the dunes because of a protective covering of grass that grows over it. Due to the trampling by animals the grass is destroyed and bare patches of sand are uncovered where grass has been destroyed. Deflation at these bare patches produces depressions. Such depressions are known as blow-outs. In fact these blow-outs are deflation basins on the sand dunes.

5. Desert Varnish. There are many stones in the desert pavement which have a black or brown coloured polish. It is due to the presence of iron-manganese oxide and is known as desert varnish.

6. Dreikanter. It is also known as beveled stone. The stones which lie in a certain position and are subjected to abrasion act ion by wind blowing in one direction, develop one edged shape or sometimes three-edged shape. These stone pieces are known as Einkanter. When these stones roll from their places, they develop many edged shapes. Such stones are known as Dreikanter. Due to abrasion, their shape resembles a Tetrahedron. Sometimes they are also called Ventifacts.

7. Polish. The abrasion of rocks by wind resembles the action of a sandpaper. It produces polish like shine on the rocks. This shine is specially bright on quartzite.

8. Grooves. The sand particles in wind scour and produce grooves on rocks. If the direction of the wind changes slowly, the rocks develop grooves which are usually parallel to one another.

9. Stone Lattice. Many rocks are composed of hard and soft crystals. The wind erodes the soft particles but the hard particles are not much affected. When the soft particles are eroded, the rocks get fluted. Such rocks, fluted by erosion, are known as stone lattice.

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