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Charity I. Mulig
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Definition A glacier is a thick mass of ice that forms over land from the compaction and recrystallization of snow and shows evidence of past or present flow
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Types of Glaciers
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Valley/Alpine Glaciers
Ice masses that slowly advance down mountain valleys originally occupied by streams. A stream of ice that flows between steep rock walls from near the top of the mountain valley.
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Ice Sheets/Continental Glaciers
A stream of ice that flows between steep rock walls from near the top of the mountain valley. Ice sheets are sometimes called continental ice sheets because they cover large regions where the climate is extremely cold. They are huge compared to valley glaciers. They currently cover Greenland and Antarctica.
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Currently continental ice sheets cover Greenland and Antarctica
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Glacial Movement Plastic flow involves movement within the ice
Basal slip slipping and sliding downward due to gravity
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Glacial Budget The glacial budget is the balance, or lack of balance, between accumulation at the upper end of a glacier and loss, or wastage, at the lower end.
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Calving & Iceberg
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How Glaciers Erode Plucking lifting of rock blocks Abrasion
Rock flour (pulverized rock) Striations (grooves in the bedrock)
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Glacial Erosional Landforms
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Glaciated Valleys A glacial trough is a U-shaped valley that was once V-shaped but was deepen by a glacier.
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cirque a bowl-shaped depression at the head of a glacial valley.
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Arêtes and Horns - Snaking, sharp-edged ridges and sharp pyramid-like peaks which project above mountain landscapes.
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Glacial Deposits (Glacial drift)
Till is material deposited directly by the glacier. Stratified drift is sediment laid down by glacial meltwater.
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Glacial Depositional Features
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Moraines layers or ridges of till Lateral Medial End Terminal end
Recessional end Ground
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Outwash Plains sloping plains consisting of deposits from meltwater streams in front of the margin of an ice sheet
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Kettles depressions created when a block of ice becomes lodged in glacial deposits and subsequently melts
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Drumlins streamlined, asymmetrical hills composed of glacial dirt
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Eskers ridges composed largely of sand and gravel deposited by a stream flowing beneath a glacier near its terminus
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fjord a glacial valley that has been invaded by the sea
fjord a glacial valley that has been invaded by the sea. "Fjord" is a Norwegian word.
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Extent of the Northern Hemisphere Ice Sheets
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