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Published byMerilyn Ross Modified over 9 years ago
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Glaciers
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How Glaciers Form Form when snowfall exceeds melting. The heat and pressure from the mass cause a slight melting which lubricates the bottom of the glacier. Gravity pulls it down making it flow.
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Glacial Zones Firn Line – snowline from previous seasons (firn) that divides the glacier. Zone of Accumulation – colder upper portion of glacier where snowfall exceeds melting. Zone of Ablation – warmer lower portion of glacier where melting exceeds snowfall.
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Crevasse: Formed when the glacier flows over a bump or ridge causing the brittle surface to flex and form deep cracks.
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Moraines Lateral Moraine – rock debris on side of glacier Terminal Moraine – debris at end of glacier. Medial Moraine – debris lines formed where two glaciers meet.
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Features of Glacial Landscapes
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Cirque Bowl shaped head of an active or former glacier
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Horn Sharply pointed mounting peak bounded by three or more cirques.
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Hanging Valley A valley left by tributary valley where it meets a much larger glacier.
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Glacial Erosion Glaciers form giant U shaped valleys instead of steep V shaped ones that fast flowing rivers carve.
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Fjord: Narrow inlets from the ocean that were once occupied by valley glaciers.
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Loess Fine grained glacial silt, also called rock flour.
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Glacial Erratics Boulders that are transported and deposited by a retreating glacier.
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Types of Glaciers
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Tropical Glaciers Occur in the tropics in Peru, New Guinea and Africa Appear to be disappearing fast with warming climate
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Icefield Large area of valley glaciers that connect together. Harding Icefield on the Kenai Peninsula is one.
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Icefield at Mt Kilimanjaro, Africa
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Alpine Glaciers Form at high altitudes in places where the winter snow does not melt.
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Valley Glacier Flows for almost all its length in a mountain valley Matanuska Glacier is an example.
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Outlet Glacier A valley glacier pouring out of an icefield. Exit Glacier is an example.
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Tidewater Glacier Has a terminus (end) at a large body of water that constantly melts causing large chunks to fall off (calving).
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Icebergs Break off of tidewater glaciers and continental glaciers.
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