Formations in Glaciated Landscapes

Question 1

Explain the formation of a corrie (4)

Answer 1

Snow collects in a north facing hollow and compresses to ice. The ice moves and erodes the hollow. Rocks frozen on to the bottom layer of the ice scrape away at the base of the hollow. This is known as abrasion. When the ice melts, a tarn or corrie loch is left.

Question 2

Explain the formation of a arete (4)

Answer 2

An arete is a narrow ridge between two corries which are side by side or back-to-back. Snow collects in the hollow and compresses down to form ice. As the ice moves it pulls away from the back wall. This causes plucking which steepens the back wall to form a narrow ridge between to two corries, known as an arete.

Question 3

Explain the formation of a pyramidal peak (4)

Answer 3

A pyramidal peak is a pointed mountain top which is formed when there are three or more corries around it. Snow collects in the hollows and compresses down to form ice. As the ice moves it pulls away from the back wall. This causes plucking which steepens the back wall. Freeze thaw weathering breaks down the mountain top to form a sharp point.

Question 4

Explain the formation of a u-shaped valley (4)

Answer 4

Snow compresses down to form a glacier. The glacier moves and uses the process of plucking to steepen the sides of the valley. The valley is also weathered above and below the glacier by frost shattering. Interlocking spurs are cut off by ice creating truncated spurs.