RAS question
The Himalayas are geologically classified as:
Correct answer: (A) New fold mountains.
The Himalayas are geologically classified as new, or young, fold mountains.
Explanation
The Himalayas fit the category of new fold mountains because fold mountains are formed when rock strata are bent and uplifted by long-acting horizontal compressional forces. The Himalayas are young fold mountains formed during the Tertiary period by the collision of the Indian and Eurasian plates. The National Institute of Open Schooling lists the Himalayas among the world's prominent fold mountains and explains that ranges formed during the most recent mountain-building period are called young fold mountains. Some such ranges, including the Himalayas, are still rising, which reinforces why they are treated as geologically young rather than old or erosional landforms.
Why the other options are wrong
- (B) Old fold mountains are a different geological category; old ranges such as the Aravalli are Precambrian, while the Himalayas are young fold mountains.
- (C) Block mountains are formed by faulting, as in the Vindhyas, whereas the Himalayas are classified as fold mountains formed by compressional forces.
- (D) Residual mountains are erosion remnants, such as hills of peninsular India, but the Himalayas are not residual landforms; they are young fold mountains.
Concept
This tests the geomorphology concept of classifying mountains by mode of formation. It recurs in RAS because Himalayan origin links Indian physical geography, plate movement and landform classification in one standard question.