GPHY 102 Lecture 21: GPHY102 Notes 21

• School: Queen's University
• Department: Geography
• Course: GPHY 102
• Professor: Ryan K Danby

Document Summary

Gphy102 lecture 21 glaciers and glacial processes. Accumulation > ablation: form when snowfall exceeds melt over successive years. More snow falls than melts = build-up: snow compacts and compresses into ice with a density of 850kg. m3, thick layers of ice behave in a plastic fashion, and movement/flow occurs when significant mass accumulates. Glacier types: pattern of glacier movements varies depending on quantity of ice and terrain environment, variations best understood by considering two basic types of glaciers. Alpine glaciers: icefield is a term used for occupying large expanses of mountain terrain, valley glaciers flow out of icefields, smaller glaciers may form in cirques, referred to as a cirque glacier. Glacier flow: movement occurs in response to gravity, internal deformation generated by mass of ice, tends to be highest near equilibrium line. In zone of accumulation, ice is colder and more ridged. In zone of ablation, ice is thinner: flow also varies vertically within ice.