Glacier Movement
Glacier movement occurs through two primary mechanisms: internal deformation (plastic flow of ice crystals under pressure) and basal sliding (movement of the glacier base over underlying sediments or bedrock lubricated by meltwater). Movement rates vary spatially and temporally.
Real World
The Jakobshavn Glacier in Greenland moves at up to 46 metres per day through rapid basal sliding, making it one of the fastest-flowing glaciers on Earth and a major contributor to sea-level rise.
Exam Focus
Explain both internal deformation and basal sliding mechanisms — 'describe' questions expect you to cover the full range of processes.
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