Processes of glacial deposition - Ice ablation

Question 1

Where is ablation concentrated?

Answer 1

Ablation is concentrated near the snout of ice masses that are stagnant or in recession and is caused by the direct release of debris due to melting (melt-out).

Question 2

Why does ablation cause rock debris to be deposited?

Answer 2

Rock debris is deposited or ‘dumped’ because of the melting away of the ice around it.

Question 3

Describe the two ways which ice ablation deposition occurs?

Answer 3

• Deposition occurs subglacially due to the melting of basal ice by geothermal heat
• Deposition occurs supraglacially when solar radiation melts ice surrounding surface and englacial rock debris.

Question 4

Describe the rock debris that it deposited due to ablation?

Answer 4

Melt out can involve the release of a thick debris layer or single clasts.