WEATHERING AND MASS WASTING LECTURE NOTES

VOCABULARY: erosion; agents; base level; weathering; physical or mechanical; frost wedging; exfoliation; plant wedging; chemical; carbonation; oxidation; hydration; hydrolosis; solution; mass wasting; talus; talus cones; block falls; avalanches; rock glaciers; landslides; mudflows; slump; creep; solifluction

erosion--the wearing away of the earth's surface by natural processes
agents--gravity, wind, running water, ground water, glaciers, waves; acts to lower land to base level
weathering--the breakdown of existing surface and near surface material

2 classes of weathering

• Mechanical or Physical--disintegration--smaller pieces
  • frost wedging--water freezes and expands in crack
  • salt wedging--water evaporates and crystals grow
  • exfoliation--rocks peel like an onion, especially intrusive igneous bodies; Stone Mountain, Georgia (accelerated by chemical weathering)
  • plant wedging--plant roots grow
  • differential heating; (fire)
  • granular disintegration
  • animals
  
  
• Chemical--decomposition
  • carbonation--CO₂ + H₂ yields H₂CO₃ (carbonic acid)
  • oxidation
  • hydration--water joins to cause expansion or swelling
  • hydrolosis--water joins and weakens the rocks
  •solution (leaching)
  •plants and animals
  

factors affect rate

• nature of rock--material quartz, calcite, cement
  
• size of particles
  
• climate--greatest, warm humid
  
• topography--altitude, slope
  

erosion--involves an agent

One agent of erosion is gravity.

Agent = Gravity
Process = MASS WASTING
Mass Wasting--downslope movement of solid, solid and liquid material under the influence of gravity

3 variables:

• size of particles
  
• amount of moisture
  
• speed
  

Mass Movements

talus
solifluction--slow downslope movement of saturated soil at high latitudes

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Go to the Weathering and Mass Wasting Review Questions.

Go to the Glossary of Landform Terms.

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