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In this lesson we are going to discuss the resultant features of wind erosion

Answer Text:
Resultant Features of Wind
Erosion
a) Millet seeds

- Sand grains which have been rounded to the shape of millet seeds by wind attrition.
b) Ventifacts

- Boulders, stones and pebbles which are flattened by wind abrasion one or more sides due to changes in wind direction.
- Dreikanter - Ventifact with three wind faceted surfaces formed when wind is blowing in different directions.
c) Mushroom Block

- Mushroom shaped rock in desert landscape.
Formation
- Wind abrasion acts on a rock with uniform hardness.
- It’s intensely undercut at the base and top part is slowly polished by light and less effective abrasive materials.
- There results a rock with broad smoothed rounded top and a narrow base resembling a mushroom
d) Rock Pedestal

- Irregular rock pillar with a broad top and a narrow base found in the desert landscape.
Formation
-Wind abrasion acts upon rock with alternating hard and soft layers.
- Soft layers are eroded more than hard layers leaving hollows and protrusions.
- There is more undercutting at the base where there is more abrasion.
- There results an irregular rock with a narrow base.
e) Deflation Hollows

- Shallow depressions found in desert landscapes formed by deflation.
- Wind scoops and blows away unconsolidated materials such as dust and sand in a desert.
- Circulating wind deepen the depression.
- The hollow reach the water table forming an oasis.
- If the depression doesn’t reach the water table flash floods water may accumulate into them to form temporary lakes called pans e.g. Etosha
pan in Namib.
f) Zeugen (Singular zeuge)

- Ridges and furrows on a desert landscape.
- First there is a landscape with horizontal alternating layers of hard and soft rocks.
- Weathering opens joints and cracks on the top resistant layer.
-Abrasion erodes the opened joints while deflation carries away the eroded materials.
- The process continues and with time causes a ridge and furrow landscape to develop.
- The ridges are zeugen.
g) Yardangs

- Narrow elongated rock ridges about 6m high on a desert landscape.
- At first there is a surface with vertical alternating hard and soft rocks lying parallel to wind path.
- Wind abrasion acts more on soft rocks and deflation carries away worn out particles.
- The undercut rocks are left standing forming ridges called Yardangs.