Erosion

Question 1

Abrasion

Answer 1

Base of ice mass slides over bedrock
Grinding/scratching/polishing
Smooth surface produced

Question 2

Plucking

Answer 2

Glacier detaches
Removes chunks of rock from bed

Question 3

2 steps involved with plucking

Answer 3

Fracturing of bedrock
Entrainment of loose debris

Question 4

What does abrasion depend on

Answer 4

Angularity of clasts
Relative hardness
Basal sliding velocity

Question 5

What does plucking depend on

Answer 5

Thermal regime
Ice thickness
Meltwater presence + velocity
Geology + fracturing

Question 6

When is abrasion most effective?

Answer 6

Warm based
Thick ice
Fast movement
Weak bedrock

Question 7

When is plucking most effective?

Answer 7

Fractured bedrock
Semi-permeable bedrock
High velocity

Question 8

Why is velocity important for plucking?

Answer 8

Increases shear stress

Question 9

Meltwater erosion

Answer 9

Abrasion, hydraulic action, attrition, solution

Question 10

Factors affecting erosion rates

Answer 10

Ice thickness
Bedrock resistance
Basal ice temp
Gradient
Debris hardness
Velocity
Supply of debris