6. How is a cirque formed?
• Snow collects in a natural hollow on the side of a
mountain. Over time, further snow collects in the hollow.
This extra weight compresses the snow
underneath, turning it into ice.
• The ice is pulled downhill by gravity, it doesn’t move
straight down, it moves in a curved way
• The hollow is deepened and widened by the corrie glacier
through the processes of abrasion and plucking.
• This over deepening leads to an ‘armchair’ shape
characteristic of a corrie and causes a ‘rock lip’ to be
formed.
• Plucking and freeze-thaw mean that the back wall of the
corrie is very steep.
• When the ice melts, a small lake may be left behind the
lip, this is called a corrie-lake or a tarn.
7. Arêtes are ‘knife- Pyramidal peaks formed when
edged’ ridges formed three or more corries form
between two corries around a mountain. They cut
which have formed backwards to leave a “horn” or
next to each other. “pyramidal peak” in the middle.
8. Characteristics of a glacial trough
1. Between truncated spurs are hanging
valleys which have not been eroded as
deeply as the main valley.
2. Interlocking spurs are truncated as the
glacier cuts straight through the landscape.
3. The river that flows through the valley
after the ice age is described as a misfit
stream.
9.
10. FEATURES OF GLACIAL DEPOSITION
1. Till 7. Drumlins
2. Terminal moraine 8. Esker
3. Recessional moraine 9. Kames
4. Lateral moraine 10. Kettles
5. Medial moraine 11. Outwash Plains
6. Push moraine