The Brahmaputra, Irrawady and Mekong rivers originate in Tibet and flow through narrow and parallel mountain ranges in their upper reaches. Of these rivers, Brahmaputra makes a “U” turn in its course to flow into India. This “U” turn is due to
- AUplift of folded Himalayan series
- BSyntaxal bending of geologically young HimalayasCorrect
- CGeo-tectonic disturbance in the tertiary folded mountain chains
- DBoth (a) and (b) above
Explanation
The correct answer is B because of a geological phenomenon known as syntaxial bending. The Himalayas are geologically young fold mountains that do not run in a straight line but terminate in sharp, hairpin like bends at both ends. In the east, this bend occurs at Namcha Barwa. The Brahmaputra river, which flows eastwards as the Tsangpo in Tibet, reaches this syntaxial bend and is forced to take a sharp U turn to enter India through Arunachal Pradesh. While the uplift of the Himalayas influenced the terrain, it is specifically this structural bending of the mountain range that dictates the sudden change in the rivers direction.
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