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Describe the erosional and depositional landforms of the arid environment | 66th BPSC geography Optional Paper Solutions

 Question.

 Describe the erosional and depositional landforms of the arid environment. ( 25 Marks, 66th BPSC geography Optional Paper) 

Examine critically Characteristics of topographical features in arid regions. ( UPPSC 2006)

Give a reasoned account of the development of landforms in an arid region. ( UPPSC 1997)

Answer. 

A dry environment is an environment where evaporation is greater than precipitation. Hot deserts and cold deserts are examples of dry environments. Air and water are two geomorphic agents in a dry environment. In desert areas, torrential rainfall occurs for a limited period of time, due to which water along with wind is an active geomorphic agent.

The following are the erosional landforms in the arid environment:

  • Pediment
  • Monadnock or Inselberg
  • Pediplain
  • Mushroom rocks
  • Zeugen


The following are the depositional landforms in an arid environment:

  • Playas
  • Sand dunes
  • Longitudinal dunes.
  • Transverse dunes.

erosional and depositional landforms of the arid environment


Pediment:

The pediment is one of the most prominent erosional landforms in the arid region formed by water erosion with the following characteristics:

  • Pediments are rocky floors with a gentle slope.
  • Pediments are formed near the foot of the mountains.
  • There may or may not be debris on it.
  • Pediments are formed by horizontal erosion in the front of the mountains, which are usually formed by streams and floods.


Monadnock or Inselberg:

  • As we know, pediments are formed at the foot of the mountain. Over time, there is a parallel retreat in the slopes due to backwashing. 
  • With the retreat of the pediment, the mountain front also retreats parallelly. Gradually, the remainder of the mountain is made up of hard rocks called the Monadnock or Inselberg.


Pediplains :

  • Over time, relief landforms such as pediments and Inselberg get eroded to form a featureless plain called a  peneplain. Pediplains are erosional landforms in arid environments.


Mushroom Rocks:

When winds erode more of the bottom of the rocks than the top of the rocks, the rock looks like a mushroom with a narrow base and a wide top, this is called mushroom landform.


Zeugen:

  • When the rocks are eroded, the table shape is left, it is called Jeugen landform.


Playas:

Playas are depositional landforms in arid environments. Playas are formed in the following ways:

  • When it rains heavily in the desert region, sediments from the mountains and hills get deposited in the center of the valleys.
  • And an almost flat plain is formed, it is called playas.
  • When sufficient water is available for a short period, the plain is covered by a shallow water body.
  • There is also a good deposition of salts in the playa.


Loess

  • In hot desert areas, where sufficient sand is available, winds transport the sand and deposit it unsorted way over large areas, called Loess.


Sand dunes:

Where sand is available in sufficient quantity, sand dunes are formed.

There are several types of sand dunes:

  • Crescent Dunes
  • Longitudinal Dunes
  • Transverse Dunes

Crescent dunes:

Crescent dunes, also known as Barchans, are found in abundance in sandy deserts. The shape of the crescent-shaped dunes is like the letter "C". The wings of the crescent-shaped dunes come out in the direction of the wind.

Longitudinal Dunes:

  • When the wind direction is constant and there is a lack of sand supply, longitudinal dunes are formed. Longitudinal dunes are usually of great length but less in height.

Transverse Dunes:

  • Transverse dunes are formed perpendicular to the direction of the wind. It is formed when the wind direction is constant and there is a sufficient source of sand. It is of less height, the length is more.


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