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Erosion and Weathering

Erosion and Weathering

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Erosion and Weathering

Erosion

A landslide like the one in Madison River Canyon is a spectacular example of erosion. Erosion is

the process by which natural forces move weathered rock and soil from one place to another. A landslide is a very rapid type of

erosion. Other types of erosion move soil and rock more slowly. Gravity, running water,

glaciers, waves, and wind can all cause erosion. You may have seen water carrying soil and

gravel down a driveway after it rains. That’s an example of erosion.

What type of erosion has occurred? How many years did it take for the erosion to change the landscape?

• Sand dunes move over time. Little by little, the sand shifts with the wind from one side of the dune to the other. Sometimes plants begin growing on a dune. Plant roots can help to anchor the dune in one place

• Chemical weathering is the process that breaks down rock through chemical changes. The agents of chemical weathering include water, oxygen, carbon dioxide, living organisms, and acid rain

What type of weathering shaped the Granite rocks?

• Mechanical weathering breaks rock into pieces by freezing and thawing, release of pressure, growth of plants, and actions of animals.

• the most important force of mechanical weathering is freezing and thawing of water.

• Water seeps into cracks in rocks and then freezes when the temperature drops. Water expands when it freezes. Ice therefore acts like a wedge, a simple machine that forces things apart.

Weathering

• Weathering is the process that breaks down rock and other substances at Earth’s surface. Heat, cold, water, and ice all contribute to weathering. So do the oxygen and carbon dioxide in the atmosphere. Repeated freezing and thawing, for example, can crack rock apart into smaller pieces. Rainwater can dissolve minerals that bind rock together.

Land Subsidence The sinking of the land surface that results

when water is lost from spaces between loose particles of soil and rock underground is called land subsidence