ESCI 1001 Lecture Notes - Lecture 20: Ocean Current, Ultraviolet, Cold Front
Document Summary
Definition: a river or sheet of ice that flows across the land surface and exists year-round. (key: perennial ice and flow) Brittle ice is near the surface, happens when it is dry and or very cold. Plastic ice is at high pressures and when wet. Most common in summer months when bed is water saturated. Can result in surges! (meters per day of motion) Basal sliding: ice column moves as one. Internal shear: ice deforms, flows like a fluid. Happens year round, but faster in summer (wet, soft ice) Flow is downslope (true even when glacier is retreating) Snow melts completely each year below the snowline (zone of ablation) Snow accumulates above it (zone of accumulation) Can be on top or in the ice. Mass wasting from valley walls (much of what is on top of ice) Till: unsorted mixture of mud, sand, and pebbles and larger rocks deposited by glaciers.
