UPSC Prelims 2012 · GS Paper I
Question 48: 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?
AnswerUPSC’s answer is (d).
The Himalayas are young fold mountains, still rising and being eroded. Steep gradients make rivers cut deep gorges and cause landslides; antecedent rivers such as the Brahmaputra make U-turns (the Dihang gorge near Namcha Barwa) as they cut through rising ranges; and the long, parallel ranges (Himadri, Himachal, Shiwaliks) show folding. All four are evidence.
- 1. Deep gorges show rivers cutting through rising mountains.
- 2. U-turn river courses, as of the Brahmaputra, show antecedent drainage in young mountains.
- 3. Parallel ranges are the result of folding.
- 4. Steep gradients causing landslides show an unstable, young range.
How you could have got this
- If you were sure statement 1 is correct, (c) goes: it leaves 1 out.
What you needed to know: Deep gorges show rivers cutting through rising mountains.
- Then, if you were sure statement 3 is correct, (a) and (b) go: each of them leaves 3 out.
What you needed to know: Parallel ranges are the result of folding.
Only (d) is left. You didn’t need statements 2 or 4.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Incomplete: parallel ranges and steep gradients are also evidence.
- (b) Incomplete: parallel mountain ranges are also evidence.
- (c) Incomplete: deep gorges and U-turn river courses are also evidence.
- (d) Correct: all four features point to young fold mountains.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2012, General Studies Paper I, Series A. The paper on upsc.gov.in.