The following are the Resultant Features of Wind Deposition:
Sand Dunes are Low ridge of sand accumulated by wind deposition.
Types of sand dunes
this is a crescent-shaped mound of sand in a desert.
barchans forming process
- Sand accumulates around an obstacle lying on the path of the wind.
- Deposition continues making the mound grow bigger.
- The wind blows sand over the leeward side creating a smooth gentle windward slope.
- Wind eddies act on the leeward slope, making it to be steep and concave.
- Sidewind moves the sand grains on the sides forward creating the two edges which are curved e.g. in the Sahara and Arabia Desert.
Characteristics of sand dunes
- Crescent/moon shaped
- Smooth gentle windward slope
- Steep concave leeward slope
- Horns or 2 curved edges
- Occurs individually or in groups
ii) Seif Dunes
this is Ridge shaped mounds of sand lying parallel to the path of the prevailing wind.
seif dunes forming process
- The wind blows between barchan dunes.
- Wind eddies move sand towards the sides.
- Sand accumulates on the sides resulting in ridge-shaped mounds e.g. in the Namib Desert.
iii) Transverse or Wake Dunes
These are Wave mounds of sand in a desert that lie at right angles to the prevailing wind.
They are formed in the following process
- Less strong winds blow over sand from one direction.
- The wind concentrates larger grains of sand into a series of transverse ridges.
- Wind may continue pushing the sand causing it to accumulate on the leeward side to form a wake dune e.g. in W. Sahara.
this is the biggest sand feature in a desert with a surface resembling a plateau and with a height of up to 200m. Barchans and Seif dunes may form on such features e.g. in the E. Sahara desert.
These are Fertile soils with a great thickness of about 100 m formed from the deposition of dust from deserts.
- Dust from deserts is carried beyond to wet areas.
- Its washed down by rain causing its deposition.
- It accumulates into layers.
- Deposition continues, and the layers are compacted forming sedimentary rocks.
- The sedimentary rocks wither to form fertile soils which favour cultivation e.g. Temperate lands of Europe along the Rhine valley from Sahara dust and along Huang He valley in N. China from the dust of the Gobi Desert.