Audio Transcript Excerpt:
PROFESSOR: 'In glaciology, we study the thermal regime of glaciers by classifying them as either cold-based or warm-based (t

Question

Audio Transcript Excerpt:
PROFESSOR: 'In glaciology, we study the thermal regime of glaciers by classifying them as either cold-based or warm-based (temperate). In a cold-based glacier, the ice at the glacier bed remains below the pressure melting point, causing the basal ice to remain frozen solid to the underlying bedrock. Consequently, internal plastic deformation is the only mechanism of movement, resulting in minimal basal erosion. In a warm-based glacier, geothermal heat and overlying ice overburden elevate the basal ice to its pressure melting point. This produces a thin, pressurized layer of subglacial meltwater that decouples the ice from the rock. As a result, the glacier moves predominantly via basal sliding, dramatically accelerating both glacial velocity and physical bedrock abrasion.'

How does the presence of basal meltwater affect the movement and erosive capacity of a warm-based glacier?

Accepted Answer

It lubricates the boundary between ice and bedrock, enabling rapid basal sliding and intensifying mechanical bedrock abrasion.

Answer

It freezes the glacier in place, completely halting all forward motion.

Answer

It dissolves the bedrock into liquid mud without moving the overlying ice.

Answer

It causes the glacier to evaporate into the atmosphere within several weeks.

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