Mechanisms of ice movement - Basal sliding

Question 1

Which type of glaciers move mainly through basal sliding?

Answer 1

Warm based glaciers move primarily through basal sliding.

Question 2

When is basal sliding unable to occur?

Answer 2

Basal sliding is unable to occur when a glacier is frozen to its bed.

Question 3

Define basal sliding?

Answer 3

Basal sliding involves a glacier sliding over its bed, due to meltwater under the ice acting as a lubricant.

Question 4

What are the three specific processes in which basal sliding is achieved?

Answer 4

• Basal slip
• Enhanced basal creep
• Regulation flow

Question 5

What is basal creep?

Answer 5

As a glacier moves, the temperature of basal ice is increased through pressure and friction. As a result, a thin layer of meltwater at the interface between the ice and the underlying rock, allowing the ice to slide forward.

Question 6

What is enhanced basal creep?

Answer 6

As ice presses up against irregularities on the underlying bedrock surface, the associated increase in pressure causes ice to deform.

Question 7

What is regulation flow?

Answer 7

Ice melts under pressure up-ice side of a small obstacle and freezes again on the lee (downglacier) side, when the pressure is reduced. This process occurs where obstacles are small enough to enable the latent heat released by the lee-side refreezing to be conducted to the stoss side to promote further melting.