formation of glacial features

Question 1

explain the formation of a corrie

Answer 1

1. At the start of the ice age precipitation fell as snow and collected in north facing hollows where conditions were cooler
2. As layer upon layer of snow was laid it was compressed into ice. Once enough ice had accumulated it officially became a glacier
3. Under its own weight and the force of gravity the glacier began to move downhill in a rotational fashion
4. As it did this it plucked rocks away which steepend the back wall of the hollow
5. The rocks frozen to the glacier scraped away at the land in a sandpapering effect. This deepened the hollow
6. As the glacier moved up and out of the hollow it lost strength. This caused it to leave behind a notch of rock at the entrance of the corrie called a rock lip

Question 2

explain the formation of a U-shaped valley

Answer 2

1. At the beginning of the ice age precipitation fell as snow. This collected in north facing hollows were conditions were cooler. As layer upon layer of snow was laid it compressed into ice. Once enough ice had accumulated it was officially a glacier
2. Under its own weight and the force of gravity the glacier began to move downhill through a pre-existing V-shaped valley
3. The glacier froze onto the sides of the valley and as it began to move again it plucked pieces of rock away from the sides. This steepened the sides
4. The rocks frozen on the glacier scraped at the land beneath in a sandpaper effect, this deepend the valley.
5. Plucking and abrasion occured along the floor of the valley. Abrasion was greatest where the glacier was heaviest. This deepend the valley

Question 3

explain the formation of truncated spurs

Answer 3

1. Before the ice age valleys were narrow river V-shaped valleys with rounded, gently sloping hills
2. The foot of the hills formed interlocking spurs.
3. The river wound round because it did not have the erosive power to remove them. Glaciers were much bigger so had much more erosive power to remove them
4. During the ice age abrasion occurs when rocks frozen to the glacier scraped away at the interlocking spurs in a sandpapering motion
5. Sometimes the glacier would freeze onto the spurs and as it moved downhill it would pluck pieces of rock away with it
6. This caused the ends of the interlocking spurs to be removed which truncated them