2.5

Question 1

Fundamental cause for ice movement

Answer 1

Gravity

Ice moves downslope in higher altitudes to lower areas either on land or at sea.

Question 2

What is Basal Slip

Answer 2

Base of glacier is at pressure melting point, causing meltwater

meltwater present acts as lubricant enabling glacier to slide more rapidly over bedrock

75% of glacier movement

Question 3

Polar (cold-based) glacier

Answer 3

Move only by internal deformation

Question 4

Internal Deformation

Answer 4

Two subdivisions:

Inter-granular & Intra-granular movement

Question 5

Temperate (warm-based) glaciers

Answer 5

75% basal slip and 25% internal deformation

Question 6

Subdivisions of basal slip

Answer 6

Extending and Compressing Flow

Question 7

What is Extending and Compressing Flow

Answer 7

Over steep slopes, rate of basal slip increase and ice will accelerate and thin. (Extending Flow)

Over shallower slopes, basal slip slows and ice decelerates and thickens. (Compressing Flow)

Question 8

Subdivisions of internal deformation

Answer 8

Inter-granular & Intra-granular movement

Question 9

Inter-granular movement

Answer 9

Individual ice crystals slip and slide over each other

Question 10

Intra-granular movement

Answer 10

Individual ice crystals become deformed or fractured due to intense stresses within ice

Gradually, mass of ice deforms and moves downhill in response to gravity