Erosion and Weathering

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Erosion and Weathering
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What is erosion?

• (geology) the mechanical process of wearing or
  grinding something down (as by particles washing
  over it)
• The wearing away of the earths surface by
  natural processes
• corrosion erosion by chemical action

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Types of Erosion

• Water
• Wind
• Glacier
• Soil
• Sea

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Water

• Occurs from chemicals in the water and the force
  and flow of water
• Chemicals break down certain rocks like limestone
  or chalk
• Force of water creates cracks and crevasses
• These get bigger and bigger as it gets eroded,
  particles of the rock get carried in the water
  and further aid erosion

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Wind

• The wind picks up smaller particles of rock
  (pebbles and sand)
• These hit landforms and take pieces off them
• This friction causes the break up of landforms

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Glacier Erosion

• What is a GLACIER?
• A huge mass of ice slowly flowing over a land
  mass, formed from compacted snow in an area where
  snow accumulation exceeds melting
• These large bodies of ice that pick up rocks and
  earth and erode the earths surface
• Powerful eroding machine, picking up pieces of
  rock the size of houses in some places
• Glaciers are so powerful they can carve valleys
  and create landforms

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Sea Erosion

• Salts and other chemicals in the water erode
  coastal rocks
• These are dragged out to sea and deposited in
  other areas (Long shore Drift)
• Wave power creates erosion. Also particles of
  rock and sediment aid to the erosion process

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Soil Erosion

• Biggest problem for farmers
• Wind and rain remove topsoil and nutrients
• Makes the soil infertile and it breaks up leaving
  dongas

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TASK

• You are a forester in South Africa and you have
  just acquired some land and you are faced with a
  problem with soil erosion due to poor farming
  techniques
• YOUR PROBLEM
• DONGAS CASUED BY EROSION HAVE TAKEN UP CRITICAL
  SPACE FOR YOU TO PLANT AND GROW TREES
• WHAT STEPS ARE YOU GOING TO TAKE TO REPAIR THE
  DONGAS?
• WHAT IMPROVED PLANTING TECHNIQUES ARE YOU GOING
  TO USE?

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RUBRIC
Rubric for task 1 2 3 4 5
Steps to combat problem Just outline Just points No steps good points Good outline good points Very good step by step outline with relevant points and techniques
Repair Dongas Just technique no explanation No technique vague explanation Adequate technique and vague explanation Good technique, adequate explanation Relevant techniques and clear explanation of techniques
Improved faming methods Little effort made Adequate methods no explanation Adequate methods and adequate explanation Good methods and good explanation Excellent methods and explanations
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