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.
Arêtes are ‘knife- Pyramidal peaks formed whenedged’ ridges formed three or more corries formbetween 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.
Characteristics of a glacial trough1. Between truncated spurs are hangingvalleys which have not been eroded asdeeply as the main valley.2. Interlocking spurs are truncated as theglacier cuts straight through the landscape.3. The river that flows through the valleyafter the ice age is described as a misfitstream.
FEATURES OF GLACIAL DEPOSITION1. Till 7. Drumlins2. Terminal moraine 8. Esker3. Recessional moraine 9. Kames4. Lateral moraine 10. Kettles5. Medial moraine 11. Outwash Plains6. Push moraine