Question

Explain how Dun valleys are formed and where, along with some examples? (3 marks)

Answer 1

Dun valleys are longitudinal shaped valleys which are found in the himalayan mountain ranges between the Himachal Himalayas and the Shiwaliks.

Formation:
When a river flowing on its path encounters an obstacle it stops.The river then spreads in the horizontal direction and forms a temporary lake.Over time the river is able to find some weak rocks and erodes them and creates some gap and moves on.The accumulated water of the lake flows along with the river leaving behind an empty space which forms the dun valley.

Examples: Dehradun kotli-dun, Paat-idun.