glaciers - Glacier is a mass of ice that moves under its...

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Glacier is a mass of ice that moves under its own weight o Natural body of ice formed by the accumulation, compaction, and Recrystallization of snow that is thick enough to flow Types of glaciers o Valley glaciers (alpine glaciers) Confined to canyons and valleys of mountainous terrains Flow from mountain areas o Continental glaciers Huge ice sheets that spread out over the large parts of a continent Cover underlying terrain Glaciers move due to pressure from overlying ice o Gravity is driving force o Ice at bottom cant take the pressure- will start to move o Shifting/rotation of ice grains o Pressure melting lubricates o Displacement along slip planes Movement dependent upon snow accumulation and slope o Accumulation greatest at glacier head o Flows parallel to surface Ice balance o Zone of accumulation may have melting, but has a net gain of ice Where snow is transformed into glacial ice Freshly fallen snow is 90% empty space- ice crystals or needles Ice at points of snowflakes melts from pressure of snow buildup, migrates towards center of flakes, forms elliptical granule of recrystallized ice approximately 1 mm in diameter o In between the two has a balance- snow line/glacier’s equilibrium line o In zone of ablation ice leaves the system and usually enters a body of water by: Melting Calving- how we end up with icebergs- piece of glacier breaks off onto sea Evaporation- dry air evaporates ice Ice flows by: o Rotation of grains- Basal slidng Glaciers always flow in one direction- downhill/downgradient If input=output, equilibrium
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This note was uploaded on 04/07/2008 for the course GEOLOGY 111 taught by Professor Sheldon during the Fall '07 term at SUNY Geneseo.

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glaciers - Glacier is a mass of ice that moves under its...

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