glacial erosion landforms

Question 1

corrie

Answer 1

for corries to form there needs to be a hollow slope
1) snow collects in this hollow and turns into ice
2) basal slip, abrasion and plucking deepen the hollow (the amount of abrasion that takes place depends on the amount of material that is eroded)
3) when the ice in the hollow is thick enough it flows over the lip and down hill has a glacier
4) freeze thaw weathering and plucking deepen the back wall of the corrie creating a large arm chair-shaped depression
5) once the glacier has melted, a corrie lake(tarn) remains. a lip of deposited scree ramains

Question 2

Arete

Answer 2

an arete is a narrow steep sided ridge
an arete forms when two glaciers flow in parallel valleys
the glaciers erode the sides of the valley sharpening the mountain ridge between them

Question 3

pyrimidal peak

Answer 3

it is a pointed mountain with at least three sides
1) it forrms where three or more corries form back to back
2) their steep back walls make the mountain peak

Question 4

u- shaped valley

Answer 4

steep sided valleys with flat bottoms
1) u-shaped vallies form through the erosion of v-shaped river valleys by glaciers
2) the glacier erodes straight through the valley making it deeper and wider
3) once the glacier has melted, a long narrow lake forms on the valley floor known as a ribbon lake
4) truncated spurs from when the glacier truncates (chops off) the ridges of land (spurs) that stick out into the main valley as it moves past.
5) the glacier erodes the end of the spurs through plucking and abrasion

Question 5

hanging valley

Answer 5

hanging valleys are formed by tributary glaciers
1) tributary glaciers erode the valley flow much less deeply than the main glacier because they are small
2) this means that when the tributary glaciers melt, the valleys remain at a higher level than the glacial trough formed by the main glacier

Question 6

roche moutonnes

Answer 6

roches moutonnees are resistant masses of rock on the valley floor
- as the glacier moves over the mass of rock, it makes the upglacier side (the stoss) smooth by the action of abrasion.
- the downglacier side (the lee) is steep and rough where the glacier plucked at it

made up of solid rock

Question 7

crag and tail

Answer 7

• the harder rock on the stoss side will be able to resist the abrasivness of the glacier which will make it quite steep. this will cause the glacier to slow down
• the more resistant stoss side will produce a sofer, less resistant rock on the lee side from erosiom.
• as the ice moves around the resistant stoss, it will deposit material giving the rock the apperance of having a long sloping tail

made up of half glacial till and half solid rock