Landforms of Glacial erosion

Cirques:
A cirque is a large armchair-shaped hollow high up in the mountains. It has three steep sides and may contain a lake. it is the birth place of a glacier.

It is formed by snow collecting in the mountain hollows was compressed to form ice. The ice plucked rocks from the sides of the hollow. It used them to deepen the and widen the hollow by abrasion. The ice continued to build up until it overflowed the hollow and began to move down hill. As the Glacier finally moves away and the ice finally melts a small lake , called a tarn will be trapped in th hollow

Here is a picture to help you understand.

I got this image from About.com
An example of this a cirque is the Coomshingaun in the Comeragh Mountains.


Aretes:
An Arete is a narrow steep-sided ridge.

When two cirques form side by side the land between them was eroded until only a narrow ridged remained.

When three or more cirques form around one mountain, only a steep-sided remnant of the original mountain remains. this is called a Pyramidal peak.


This is an example of aretes and pyramidal peaks. I got this image from www.uwsp.edu.

Glaciated valleys:
A Glaciated or U- shaped valley has a wide, flat floor and steep sides. It normally follows a direct coarse.
After the glacier moved out if the cirque it moved down the mountainside, taking the easiest route available. That route was through the existing river (V-shaped valley) valley.
The glacier widened, deepened and straightened the river valley changing it to a U-shaped valley. In doing this it cut off the heads off the interlocking spurs, leaving truncated spurs.

I got this image from www.geo.umn.edu