Question

One of the main reasons for the formation of 'I'-shaped valley in the upper course of a river is ?​

Answer 1

A straight river is known as the 'I' shaped river.As the river erodes downwards the sides of the valley are exposed to freeze-thaw weathering which loosens the rocks (some of which will fall into the river) and steepens the valley sides. The rocks which have fallen into the river assist the process of corrasion and this leads to further erosion.

Answer 2

Answer:

Erosion is the major reason for the formation of I-shaped valley in the upper course of the river.

Explanation:

• The sides of the valley are exposed to freeze-thaw weathering as the river erodes downwards.
• Freeze-thaw weathering loosens the rocks and steepens the valley sides.
• The process of corrasion will happen if the rocks fallen into the river.
• Corrasion further leads to erosion.