RAS question
Barchan sand dunes are commonly found in which part of Rajasthan?
Correct answer: (A) Western Thar Desert.
Barchans, or crescent-shaped sand dunes, are commonly found in the western Thar Desert of Rajasthan.
Explanation
Barchans are crescent-shaped sand dunes formed by wind action in arid regions. In Rajasthan, they occur in the Western Sandy Plain. Rajasthan Forest Department's A Manual for Dryland Afforestation and Management identifies the western portion of this plain as the Thar Desert. The Sandy Arid Plain, which includes Bikaner, Barmer, Jaisalmer, Jodhpur, Nagaur and Churu, is called Marusthali. Sand dunes are common there, and crescent-shaped dunes are among the main dune types. Barchans are therefore common in the western Thar Desert, especially around Jaisalmer, Barmer and Jodhpur, rather than in Rajasthan's plateau, hill or fertile plain regions.
Why the other options are wrong
- (B) Mewar lies in southern Rajasthan and has hilly terrain, so it does not match the arid, windblown sandy setting in which barchan dunes form.
- (C) The eastern plains are fertile agricultural land, not the desert landscape associated with crescent-shaped sand dunes.
- (D) Hadoti Plateau lies in southeastern Rajasthan, whereas dune-rich sandy terrain lies in the western sandy and Thar Desert belt.
Concept
This question tests Rajasthan's physical geography and landforms, especially how wind forms different dune types and where they occur in the Thar Desert. It recurs in RAS because western Rajasthan's climate, dune types, arid-region landform processes and regional physiographic divisions are important Rajasthan geography themes.