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Erosion and Deposition
What is Erosion?
• Erosion is the carrying away of pieces of weathered rock.
• Rock is carried away by– Gravity– Water– Wind and– Ice
• Water is the GREATEST cause of erosion.
When and How does Erosion Occur?
• Erosion occurs the moment the first drop of water falls from the sky.
• Changes may not occur over night but over time obvious changes occur.
• Once water hits the ground it begins to flow downhill.
• Moving water is very powerful and can push and carry things along.– The faster the water is moving, the bigger rocks it can
move.
Erosion at work.
• The steeper the slope the more erosion occurs.
• http://www.glencoe.com/sites/common_assets/science/virtual_labs/ES08/ES08.html
Humans and Erosion
• We have an affect on erosion and the land around us.
• Clear cutting and planting are just some of the ways humans can affect erosion.
• Clear cutting is the stripping away of trees and other vegetation of a mountain.
• Planting vegetation helps stabilize the land.
Positive
Negative
Wind and Erosion • Wind is moving air and can push things along,
like water.• Wind is not as powerful as water so it erodes
smaller pieces of rock, like sand.
Ice and Erosion
• Ice also causes erosion. • Glaciers are an example of ice that is effected by
erosion.• Ice does not move as quickly as water but it is still
very powerful.• When the ice of a glacier freezes onto rocks and
then the glacier moves downhill, the rock is torn right out of the ground.
• Glaciers can move rocks bigger than your house!
Deposition
• Deposition is the rocks that are dropped off into streams, lakes and oceans because of erosion.
• When the wind slows down, the ice melts and the water slows down deposition occurs.
• Rocks that are deposited by water, wind and ice build up earth’s surface.
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