Mass movement , Wind & Glaciers

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Mass movement, wind and glacial erosion and deposition.

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Mass movement , Wind & Glaciers

  1. 1. Mass Movement Wind & Glaciers by Ann C. Cloutier 2011 Earth’s surfaces are in constant change Nothing ever stays the same…
  2. 2. The downslope movement of loose sediments and weathered rock resulting from the force of gravity is called mass movement <ul><li>creep </li></ul><ul><li>slump </li></ul><ul><li>mudflow </li></ul><ul><li>avalanche </li></ul><ul><li>landslide </li></ul>
  3. 3. Variables that influence mass movement: <ul><li>Material’s weight resulting from gravity </li></ul><ul><li>Materials resistance to move sliding or flowing </li></ul><ul><li>Triggered by earthquakes that shake material loose </li></ul><ul><li>Mass movement will happen when the forces working to pull materials down a slope are stronger than the material’s resistance to sliding, flowing or falling </li></ul>
  4. 4. Water is a variable that increases the material’s ability to flow
  5. 5. Angle of slope influences avalanches at a 35 * angle or more <ul><li>10,000 avalanches happen each year just in the mountains of North America </li></ul>
  6. 6. WIND is the rapid movement of air due to convection currents by the irregular heating of Earth’s surfaces causing particles to move in irregular paths
  7. 7. Types of wind movements <ul><li>deflation </li></ul><ul><li>abrasion </li></ul><ul><li>ventifacts </li></ul><ul><li>dunes </li></ul><ul><li>loess </li></ul>
  8. 8. Dunes
  9. 9. Loess in USA
  10. 10. What makes loess soil ?
  11. 11. Rock and pebble armored land and beaches > deflation
  12. 12. Glaciers <ul><li>The mass movement of ice </li></ul><ul><li>Two types continental and valley </li></ul><ul><li>Certain conditions > cold temperatures </li></ul><ul><li>Less snow melts than years before allows build up of ice pack </li></ul><ul><li>Downward pressure compacts snow and makes it recrystallize into ice </li></ul>
  13. 13. 10,000 years ago glaciers cover 30% of Earth today only 10% or less cover Earth <ul><li>Cold temperature allow snow to accumulate </li></ul><ul><li>The last ICE AGE started 1.6 million years ago </li></ul><ul><li>The last ICE AGE ended about 10,000 years ago </li></ul><ul><li>Movement is usually very slow down slope </li></ul><ul><li>The extreme weight in the middle of a glacier forces the glacier outward flattening it out </li></ul>
  14. 14. Types of glacial erosion <ul><li>Hanging valleys </li></ul><ul><li>Cirques </li></ul><ul><li>Waterfalls </li></ul><ul><li>U shaped valleys </li></ul><ul><li>Horns </li></ul><ul><li>Aretes </li></ul>
  15. 15. How a glacier erodes the land
  16. 16. Glacial deposition <ul><li>Outwash plain </li></ul><ul><li>Drumlins and eskers </li></ul><ul><li>Glacial lakes </li></ul><ul><li>Kettle ponds (or a glacial lakes if large enough) </li></ul><ul><li>Moraine </li></ul>
  17. 17. Cape Cod will continue to change
  18. 18. Cape Cod is a “child “ of the Ice Age”
  19. 19. The end Are we there yet ?

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