UPSC Prelims 2012 Q48: Geography – Indian Physical Geography
When you travel in Himalayas, you will see the following :
1. Deep gorges
2. U - turn river courses
3. Parallel mountain ranges
4. Steep gradients causing landsliding
Which of the above can be said to be the evidences for Himalayas being young fold mountains?
- (a) 1 and 2 only
- (b) 1, 2 and 4 only
- (c) 3 and 4 only
- (d) 1, 2, 3 and 4
Answer: (d) 1, 2, 3 and 4
Explanation
Evidence that the Himalayas are young fold mountains
| Feature | Evidence of young fold mountains? | Why |
|---|---|---|
| 1. Deep gorges | Yes | Rivers cut down fast as the land keeps rising |
| 2. U-turn river courses | Yes | Rivers bend sharply around the syntaxial bends of the folds |
| 3. Parallel mountain ranges | Yes | Folding gave three ranges: Himadri, Himachal and Shiwalik |
| 4. Steep gradients causing landsliding | Yes | Slopes are still unstable; erosion has not smoothed them |
Other signs of youth:
| Sign | Detail |
|---|---|
| Earthquakes | The Indian plate still pushes under the Eurasian plate |
| High peaks | Not yet worn down |
| V-shaped valleys | Rivers in the youthful stage |
Old mountains such as the Aravallis are low and rounded.
Answer: (d) 1, 2, 3 and 4.
Why each option is right or wrong
- (a) Incorrect. Parallel mountain ranges and steep gradients are also evidence.
- (b) Incorrect. Parallel mountain ranges are a direct result of folding.
- (c) Incorrect. Deep gorges and U-turn river courses are also evidence.
- (d) CORRECT. All four features show that the Himalayas are young fold mountains.
Key point
Young fold mountains: deep gorges, syntaxial (U-turn) bends, parallel ranges, steep unstable slopes, earthquakes, high peaks. Old mountains: Aravallis.
Remember
Gorges, U-turns, parallel ranges, landslides: all signs of young folds.
Common mistakes
- Treating landslides as only a result of rain, not of young, steep slopes.
- Missing that parallel ranges come from folding.
- Not linking the U-turn of the Indus and Brahmaputra to the syntaxial bends.
Exam tip
Young mountains are tall, steep and unstable. Every feature in the list fits that picture.
Sources
- NCERT Class XI — India: Physical Environment, Ch 2 (Structure and Physiography)
- D.R. Khullar — India: A Comprehensive Geography, Ch on Physiography (The Himalayas)