Which glacial process creates tarns within cirques after glacial retreat?

💡 Explanation

When glacial ice retreats from a cirque, differential erosion occurs because the base of the cirque is eroded at a faster rate through abrasion, undercutting and ice plucking, creating a depression in underlying bedrock that later fills with meltwater to form a tarn. Therefore differential erosion creates the tarn, rather than isostatic rebound, or moraine damming, or simply sediment compaction, which form landforms in different environments from those associated with cirques.

• Which outcome accelerates when saturated soil exceeds its shear strength on moderate arctic slopes?
• Which landform change rapidly accelerates when surface permafrost degradation forms in cirques?
• Which mechanism strengthens subtropical high-pressure zones due to Hadley cell dynamics?
• Which mechanism drives the progressive headward erosion that leads to the formation of a cirque?
• Which mechanism causes increased crustal melting during oceanic plate subduction under continental crust?
• Which land deformation results when thawing permafrost causes widespread ground subsidence?