Weathering, Erosion, Deposition by ZYlap3

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									Weathering, Erosion,
    Deposition


       Mr. Ahearn
   Earth Science 2010
              Weathering
• The breakdown do the materials of Earth’s
  crust into smaller pieces.
        Physical Weathering
• Process by which rocks are broken down
  into smaller pieces by external conditions.
• Types of Physical weathering
  – Frost heaving and Frost wedging
  – Plant roots
  – Friction and impact
  – Burrowing of animals
  – Temperature changes
                     Frost Wedging




Describe how ice causes
weathering?
Frost Heaving
Plant Roots
Friction and Repeated Impact
Burrowing of Animals
Temperature Changes
       Chemical Weathering
• The process that breaks down rock
  through chemical changes.
• The agents of chemical weathering
  – Water
  – Oxygen
  – Carbon dioxide
  – Living organisms
  – Acid rain
                           Water
  • Water weathers rock by dissolving it




What evidence of
weathering do you see in
this picture?
                 Oxygen
• Iron combines with
  oxygen in the
  presence of water in
  a processes called
  oxidation
• The product of
  oxidation is rust
           Carbon Dioxide
• CO2 dissolves in rain water and creates
  carbonic acid
• Carbonic acid easily weathers limestone
  and marble
         Living Organisms
• Lichens that grow on rocks produce weak
  acids that chemically weather rock
                Acid Rain
• Compounds from burning coal, oil and gas
  react chemically with water forming acids.
• Acid rain causes very rapid chemical
  weathering
         Karst Topography
• A type of landscape in rainy regions where
  there is limestone near the surface,
  characterized by caves, sinkholes, and
  disappearing streams.
• Created by chemical weathering of
  limestone
Features of Karst: Sinkholes
Features of Karst: Caves
Features of Karst: Disappearing
           Streams
Rates of Weathering will depend on:
• Climatic Conditions:
 – Cold and/or dry climates favor
   physical weathering.
 – Warm and wet climates favor
   chemical weathering.
 – Frost action works best in areas
   where the temperature fluctuates
   wildly.
Where is the rock more resistant to
           weathering?
Where is the rock least resistant to
           weathering?
Complete Questions #1-16
   Review Book p. 82
                Erosion
• The process by which water, ice, wind or
  gravity moves fragments of rock and soil.
       What is Erosion?
• Erosion, is gradually wearing down
       the surface of the earth.
  • Erosion is the process by which
weathered rock and soil (sediment) are
  moved from one place to another.
 • Erosion carves the Earth's surface
  creating canyons, gorges, and even
               beaches.
          Erosion
How much erosion takes place is
      determined by the:

            • Sum
           • Slope
           • Speed
          • Surface
            Water Erosion
• Rivers, streams, and runoff
            Water Erosion
When rain falls to the Earth it can evaporate,
 sink into the ground, or flow over the land
 as Runoff.
When it flows over land, erosion occurs.
Runoff picks up pieces of rock and "runs"
 downhill cutting tiny grooves (called rills)
 into the land.
             Ice Erosion
• Glaciers
                     Glaciers
Glaciers can pick up and carry sediment that ranges in
size from sand grains to boulders bigger than houses.




Moving like a conveyor belt and a bulldozer, a single
glacier can move millions of tons of material!
Wind Erosion
           Mass Movements
  • Landslides, mudslides, slump and creep
Slower                                       Faster




                                 landslide clip.mpeg
Plants Can Prevent Erosion
Complete Questions 24-37
   Review Book p. 88
                 Deposition
 Rock particles that are picked up and transported
     during erosion will ultimately be deposited
                   somewhere else

Deposition is the process by which sediments (small
   particles of rock) are laid down in new locations.
  • Together, Erosion and Deposition build new
                       landforms.
                       • Deltas
                      • Canyons
                     • Meanders
                    • Floodplains
                     Delta
• Where rivers meet the
  ocean is called the
  mouth of the river.
  Soil and dirt carried
  by these rivers is
  deposited at the
  mouth, and new land
  is formed. The new,
  soil-rich land is known
  as a Delta
                   Canyons




 Canyons are large valleys
created by a river or stream.
                     Meander




Meandering streams wander side to side as they constantly
              seek out the lowest elevation.
This constant motion creates a series of S-shaped “loops”.
                      Floodplains
• These are low-lying
  areas along the sides of
  a river channel that have
  regular times of heavy
  waterflow to cause the
  river to spill over and
  flood the land.
Complete Questions 38-56
   Review Book p. 91


         The End

								
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