Landforms of Glacier- Cirque, ‘U’ shaped and Hanging Valley


As a glacier moves over the land, it drags rock fragments, gravel and sand along with it.

With their help glacier scrapes and scours the surface rocks with which it comes in contact.

This action of glacier leaves behind scratches and grooves on rocks.

The landforms created by glacial erosion are:

[1] Cirque (or Corrie)

Snow collects at the upper end in a bowl shaped depression, is called cirque.

Layers of snow in the process of compaction and recrystallization are called firn.

Sometimes the deepest parts of these hollows are occupied by accumulated-water, to form Corrie Lake (or Tarn).

 

[2] ‘U’ – shaped Valley

The glacier does not carve a new valley like a river but deepens and widens a preexisting valley by smoothening away the irregularities.

In this process the glacier broadens the sides of the valley.

The shape of the valley formed in this manner resembles the letter ‘U’.

It is therefore called a ‘U’ – shaped valley.

Such a valley is relatively straight, has a flat floor and vertical sides.

 

[3] Hanging Valley

Just like tributary streams of river, there are tributary glaciers also which join the main glacier after moving over their mountainous path.

These tributary glaciers like the main glaciers carve U – shaped valleys.

They have less volume of ice than the main glaciers and their rate of erosion is less rapid.

As a result their val1eys are smaller and not as deep as that of the main glacier.

Due to this difference in deepening; the valley of the tributary glacier is left at a higher level than that of the main glacier.

The val1ey of the tributary glacier just looks like hanging downwards at the point of its confluence with the main valley.

This type of a topographical feature is cal1ed a hanging val1ey.

This feature is visible when ice has melted in both the val1eys.

When the ice in the hanging valley melts, a waterfall is formed at the point of confluence of this stream with the main river.