JEG100H1 Chapter Notes - Chapter 15: Cirque Glacier, U-Shaped Valley, Glacier Morphology
27 Nov 2016
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Temperature of snow flake very near melting point. Properties, relationship of layers determine susceptibility of avalanche. Snowline: lowest elevation where snow remains throughout year. 5000 meters above sea level at equatorial mountains. 2700 meters above sea level at midlatitude mountains. Form by recrystallization of snow under own mass. Firn: granular, partly compacted snow, intermediate between snow, ice. Length of time depends on wetness of climate, extent of snowfall. Lowers eustatic sea level (absolute volume of ocean water) Glacier: large mass of flowing land ice resting on land/floating in sea attached to landmass (ice shelf) Merge as tributary into large river of ice flowing to ocean. Rockfalls, processes floating material upward from glacial bed. Confined in valley, originally formed by stream action. Cirque: bowl -shaped recess at head of valley. Valley glaciers coalesce at base of mountain range. Accumulation begins in uplands, spreads outwards as it thickens. Ice sheets isostatically depress land below sea level.
