Crescent-shaped sand dunes that move with the wind, common in the Thar Desert, are called
- A.Seif dunes
- B.Barchans
- C.Parabolic dunes
- D.Yardangs
Correct answer
Explanation
The correct answer is B, barchans. A barchan is a crescent-shaped dune with a gentle windward slope and a steep slip face, its two horns pointing downwind, and it migrates as sand is carried over the crest. Barchans are the most widespread dune form of the Thar, and shifting dunes of this kind are called dhrian in local speech.
Option A, seif or longitudinal dunes, are long ridges lying parallel to the direction of the wind and are found where the sand supply is smaller. Option C, parabolic dunes, are the mirror image of barchans, with their horns pointing upwind because vegetation holds the arms in place. Option D, yardangs, are not dunes at all but ridges of rock carved by wind abrasion, so the odd one out in the list. The other depositional forms worth remembering are transverse dunes, which lie across the wind.
Read the full article: Aravalli Range and Thar Desert: Peaks, Passes and Dunes
Practice Questions
View allGuru Shikhar, the highest peak of the Aravalli Range, lies in which district of Rajasthan?
- A.Udaipur
- B.Sirohi
- C.Rajsamand
- D.Ajmer
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Guru Shikhar stands on Mount Abu in Sirohi district and, at 1,722 metres, is the highest point of the Aravalli Range and of Rajasthan.
Read the full explanation →The Aravalli Range is an example of which type of mountains?
- A.Young fold mountains
- B.The oldest fold mountains of India
- C.Block mountains formed by faulting
- D.Volcanic mountains
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The Aravalli was folded in Precambrian times, long before the Himalaya existed, and hundreds of millions of years of erosion have worn it down to a chain of residual hills whose rocks carry zinc, lead, copper and marble.
Read the full explanation →The Luni river of Rajasthan rises near Ajmer and finally drains into
- A.The Arabian Sea at Kutch's Gulf
- B.The Rann of Kachchh
- C.The Chambal river
- D.The Sambhar lake
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The Luni rises in the Naga hills near Ajmer in the Aravalli, flows south-west through Pali, Jodhpur, Barmer and Jalore and loses itself in the marshes of the Rann of Kachchh in Gujarat.
Read the full explanation →Sambhar, the largest inland salt lake of India, lies in which state?
- A.Gujarat
- B.Rajasthan
- C.Haryana
- D.Madhya Pradesh
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Sambhar lake spreads across the Jaipur and Nagaur districts of Rajasthan and is the largest inland salt-water lake in India, a major source of common salt and a wetland where flamingos gather in winter.
Read the full explanation →The Desert National Park, known for the great Indian bustard, is spread over which districts of Rajasthan?
- A.Jodhpur and Pali
- B.Jaisalmer and Barmer
- C.Bikaner and Churu
- D.Nagaur and Jalore
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The Desert National Park covers about 3,162 square kilometres in the Jaisalmer and Barmer districts and protects the sand dunes, salt flats and thorn scrub of the Thar along with the great Indian bustard, called godawan locally, which is the state bird of Rajasthan.
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