Depositional landform of Wind Upsc

Plain formed by Wind Deposition

The two features that are formed by wind deposition are Sand dunes and loess deposits. The dunes are also called Aeolian Landforms. The wind is a good sorting agent. Based on the velocity of the wind, varying sizes of grains are moved along the floor by saltation, or by rolling, carried in suspension.

During this process of transportation, the material gets sorted. The lighter material is carried long, and heavy materials stay grounded.

When the wind slows or begins to die down, based on the sizes of grains and their critical velocities, the grains will begin to settle.

So, in depositional landforms made by wind, good sorting of grains can be found. Since wind is there everywhere and wherever there is a good source of sand and with constant wind directions, depositional features in arid regions can develop anywhere.

Sand Dunes

Dry hot deserts are good places for sand dune formation. Obstacles to initiating dune formation are equally important. There can be a great variety of dune forms.

Crescent-shaped dunes called barchans with the points or wings directed away from wind direction i.e., downwind, form where the wind direction is constant and moderate and where the original surface over which sand is moving is almost uniform.

Parabolic dunes form when sandy surfaces are partially covered with vegetation. That means parabolic dunes are reversed barchans with wind direction being the same.

Seif is similar to barchan with a small difference. Seif has only one wing or point. This happens when there is a shift in wind conditions.

The lone wings of seifs can grow very long and high. Longitudinal dunes form when the supply of sand is poor and wind direction is constant. They appear as long ridges of considerable length but are low in height.

Transverse dunes are aligned perpendicular to the wind direction. These dunes form when the wind direction is constant and the source of sand is an elongated feature at right angles to the wind direction. They may be very long and low in height.

When sand is plenty, quite often, the regular shaped dunes coalesce and lose their individual characteristics. Most of the dunes in the deserts shift and a few of them will get stabilised especially near human habitations.

Conclusion

Deposition landforms of Wind such as a Sand Dune is a mound of sand that is deposited by wind. The landforms vary in size and shape. The Layers of sand and silt which are deposited in the same area are called Loess, it is very fertile.