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Glaciers

Glaciers. Explain how glaciers move. Compare and contrast glacial erosion and deposition. Glaciers. Glaciers. Glacier: Large mass of ice and snow moving on land under its own weight. Glaciers. Glaciers are agents of erosion.

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Glaciers

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  1. Glaciers • Explain how glaciers move. • Compare and contrast glacial erosion and deposition.

  2. Glaciers

  3. Glaciers • Glacier:Large mass of ice and snow moving on land under its own weight.

  4. Glaciers • Glaciers are agents of erosion. • Glacial erosion and deposition change large areas of Earth’s surface. • As glaciers move forward over land they can transport huge volumes of sediment and rock.

  5. Glaciers • How do glaciers move? • The weight of the glacier causes the ice to flow outward like pancake batter on a griddle.

  6. Glaciers • Plucking: process that adds gravel, sand, and boulders to a glacier’s bottom and sides as water freezes and thaws, breaking off pieces of surrounding rock.

  7. Glaciers • These plucked rock fragments and sand at a glaciers base scour and scrape the ground below like sandpaper against wood. • Glacial striations.

  8. Glaciers • Glacial groovesoccur when bedrock is gouged deeply by rock fragments.

  9. Glaciers • When glaciers melt they can no longer carry much sediment. • The sediment is deposited on land. • As the glacier retreats it leaves a mixture of boulders, sand, clay and silt calledtill.

  10. Glaciers • Till deposits can cover huge areas of land. • Enough till has been left behind in the U.S. to fill valleys completely. • Iowa, Montana, parts of Ohio, Indiana, Illinois and New England contain till.

  11. Glacial Till

  12. Glaciers • Moraine deposits:Rocks and soil deposited at the end of a glacier creating a ridge. • These deposits occur much like a grocery store conveyor belt as it piles up items at its end.

  13. Glaciers • Outwash: material deposited by the meltwater from a glacier. • Eskers: outwash deposits resulting in winding ridges of gravel and sand.

  14. Types of Glaciers • Continental Glaciers: • Cover 10% of the Earth. • Mostly near the poles. • Huge masses of ice and snow.

  15. Types of Glaciers • Continental glaciers in the past covered 28% of the Earth. • This period was known as the Ice Age.

  16. Types of Glaciers • Glaciers have advanced many times during the last 2 million to 3 million years. • The last major advance of glaciers was about 18,000 years ago.

  17. Types of Glaciers • Valley Glaciers: Occur in high mountains where the average temperature is low enough to prevent snow from melting. • Valley glaciers grow and creep along.

  18. Types of Glaciers • Valley glaciers erode mountains creating valleys. • Glacially eroded valleys are U-shaped. • Stream eroded valleys are V-shaped.

  19. Types of Glaciers Valley glaciers

  20. Glaciers • Question: How do glaciers cause erosion? Rock fragments and sand scour the soil and bedrock eroding the ground below.

  21. Glaciers • http://www.unique-southamerica-travel-experience.com/glaciers-national-park.html • http://theresilientearth.com/?q=content/himalayan-glaciers-not-melting • http://www.grid.unep.ch/glaciers/graphics.php • http://www.sup.org.uk/moving_mountains.htm

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