Transcript Glaciers

Glaciers
Changing Earth’s Surface
5 Agents of Erosion
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Gravity
Running Water
Glaciers
Waves
Wind
Glaciers
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Glacier – any large mass of ice that
moves slowly over land.
Two Types
• Continental
• Valley
Continental Glaciers
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A glacier that covers much of a continent
or large island.
Ice Age
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Continental glaciers have covered larger
parts of Earth’s surface.
Valley Glaciers
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A long, narrow glacier that forms when
snow and ice build up high in a mountain
valley.
Valley Glaciers
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Once the depth of the snow and ice
reaches more than 30-40 meters, gravity
begins to pull the glacier downhill.
Valley Glaciers
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Rate – a few centimeters to a few meters
per day.
Glaciers Shape the Land
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Erosion
Deposition
Glacial Erosion
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Plucking – the process by which a
glacier picks up rocks as it flows over the
land.
Glacial Deposition
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When a glacier melts, it deposits the
sediment it eroded from the land,
creating various landforms.
Till
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The mixture of sediment that a glacier
deposits directly on the surface.
Clay, silt, sand, gravel, and boulders
Deposition Landforms
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Moraine
• The till deposited at the edges of a glacier
forms a ridge.
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Terminal Moraine
• The ridge of till at the farthest point reached
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by a glacier
Long Island NY is a terminal moraine from the
last ice age.
Deposition Landforms
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Kettle
• A small depression that forms when a chunk
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of ice is left in glacial till.
Kettles often fill with water. Many found in
Minnesota