Glaciers - Erosional Landforms

Question 1

u-shaped valley formation

Answer 1

1. snow accumulates in mountain hollows -> compresses into neve -> compresses into ice (1 mark)
2. glacier takes path of least resistance along v-shaped valley, moves downhill bc gravity
3. plucking (define) = makes valley sides steeper
4. abrasion (define) = makes deeper
5. weight of glacier widens & deepens valley into U shape w/ flat floor and steep sides
6. interlocking spurs are bulldozed = truncated spurs & crags or steep valley sides
7. original river = misfit stream

Question 2

corrie

Answer 2

1. snow accumulates in north facing mountain hollows (1 mark) –> compresses into névé –> glacial ice. (1 mark)
2. glacier moves downhill due to gravity/weight (1 mark) assisted by subglacial meltwater bc heat & pressure of the ice (1)
3. explain plucking (2 P marks)
4. explain abrasion (2 P marks)
5. frost shattering/freeze thaw weathering in rock above ice when water in cracks in the rock freezes, expands, contracts weakening rock till angular fragments break off (2 marks)
6. ice melts = armchair shaped hollow remains (1) eg: Coire Cas
7. rock lip = traps glacial meltwater forming a tarn (1)

Question 3

pyramidal peak

Answer 3

1. snow accumulates in north facing mountain hollows (1 mark) –> compresses into névé –> glacial ice. (1 mark)
2. glacier moves downhill due to gravity/weight (1 mark) assisted by subglacial meltwater bc heat & pressure of the ice (1)
3. explain plucking (2 P marks)
4. explain abrasion (2 P marks)
5. frost shattering/freeze thaw weathering in rock above ice when water in cracks in the rock freezes, expands, contracts weakening rock till angular fragments break off (2 marks)
6. ice melts = armchair shaped hollow remains (1)
7. pyrsmidal peak = 3 or more corries eroding back to back, eg: Matterhorn, Alps

Question 4

arete

Answer 4

1. snow accumulates in north facing mountain hollows (1 mark) –> compresses into névé –> glacial ice. (1 mark)
2. glacier moves downhill due to gravity/weight (1 mark) assisted by subglacial meltwater bc heat & pressure of the ice (1)
3. explain plucking (2 P marks)
4. explain abrasion (2 P marks)
5. frost shattering/freeze thaw weathering in rock above ice when water in cracks in the rock freezes, expands, contracts weakening rock till angular fragments break off (2 marks)
6. ice melts = armchair shaped hollow remains (1)
7. arete = 2 corries eroding back to back, eg: Carn Mord Dearg, Ben Nevis

Question 5

hanging valley

Answer 5

1. formed in a tributary’s valley above a U-shaped valley 
2. snow compressed –> neve –> glacial ice (1) & glacier moves downhill bc its weight under gravity (1)
3. explain plucking (1)
4. explain abrasion (1)
5. interlocking spurs are cut off by glacier = truncated spurs = steep & deep sides of the U-shaped valley  (1)
6. where tributary river valley was reaching the main channel is now suspended above deepened U-shaped valley = hanging (1)
7. smaller glacier has not eroded as deeply as main glacier (1)
8. if trib river flows in this valley it will reach the main misfit stream via waterfall. (1) e.g. Grey Mare’s Tail, Moffat (1)

Question 6

plucking

Answer 6

ice freezes on bedrock pulling loose rocks away from the backwall as the glacier moves, steepens the back wall

Question 7

abrasion

Answer 7

angular rock embedded in ice grinds the hollow as glacier moves = sandpaper effect deepens the hollow