Weathering, Erosion and Deposition

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Weathering, Erosion and Deposition
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Weathering

• The breakdown do the materials of Earths crust
  into smaller pieces.

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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

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Frost Wedging
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Frost Heaving
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Plant Roots
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Friction and Repeated Impact
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Burrowing of Animals
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Temperature Changes
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Chemical Weathering

• The process that breaks down rock through
  chemical changes.
• The agents of chemical weathering
• Water
• Oxygen
• Carbon dioxide
• Living organisms
• Acid rain

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Water

• Water weathers rock by dissolving it

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Oxygen

• Iron combines with oxygen in the presence of
  water in a processes called oxidation
• The product of oxidation is rust

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Carbon Dioxide

• CO2 dissolves in rain water and creates carbonic
  acid
• Carbonic acid easily weathers limestone and marble

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Living Organisms

• Lichens that grow on rocks produce weak acids
  that chemically weather rock

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Acid Rain

• Compounds from burning coal, oil and gas react
  chemically with water forming acids.
• Acid rain causes very rapid chemical weathering

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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

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Features of Karst Sinkholes
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Features of Karst Caves
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Features of Karst Disappearing Streams
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What Caused This?
http//commons.wikimedia.org/wiki/FileWater_erosi
on_below_Hay_Bluff_-_geograph.org.uk_-_1074175.jpg
http//commons.wikimedia.org/wiki/FileWind_erosio
n_Seminole_Canyon.JPG
THATS RIGHT! EROSION!
http//commons.wikimedia.org/wiki/FileBaventian_C
lay_Beds_-_geograph.org.uk_-_1776748.jpg
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Erosion

• The process by which water, ice, wind or gravity
  moves fragments of rock and soil.

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Water Erosion

• Rivers, streams, and runoff

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Ice Erosion

• Glaciers

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Wind Erosion
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Mass Movements

• Landslides, mudslides, slump and creep

landslide clip.mpeg
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What is Deposition?

• Laying down of sediment that has been transported
  by a medium such as wind, water, or ice
• Process of erosion stops
• when the moving particles fall out of the
  transporting medium and settle on a surface
• Speed of the medium slows or the resistance of
  the particles increases, the balance changes and
  causes deposition
• Speed can be reduced by large rocks, hills,
  vegetation, etc.

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Deposition - Wind

• Wind speed can be related to variations in
  heating and cooling.
• Transportation of particles in wind
• Fine particles in suspension hundreds of km from
  its original source in the desert
• Heavier material may be blown along the ground.
• Material is deposited when the wind changes
  direction or loses its strength.

http//commons.wikimedia.org/wiki/FileDesert_Chih
uahuan_Big_Bend.JPG
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Deposition - Water

• Running water enters a large, fairly still body
  of water and its speed decreases.
• SPEED
• As the speed of the water decreases, the water's
  ability to carry sediment also decreases.
• Deposited in streams, rivers, and oceans
• Running water deposits sediments where the
  slowing water can no longer move them.
• Largest particles are deposited near the shore.
• Increasingly smaller particles settle out farther
  from the shore where the water is calmer.

http//commons.wikimedia.org/wiki/FileEnchanted_R
ock,_stream.jpg
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Delta a fan shaped deposit that forms at the
mouth of a river/stream when it enters a larger
body of water like an ocean or lake
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Alluvial Fan - a fan shaped deposit of sediments
that forms when a stream/river flows out of a
mountain on to flat, dry plains. These are not
under water and are very visible. This only
happens on the land. You can call it a land
delta.
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Deposition - Ice

• Glacial flows of ice become slower when the ice
  begins melting
• Deposits left by glaciers
• The deposits of these rivers look similar to
  normal river deposits and are called outwashes.
• Moraines are large chunks of broken rock left at
  the base and sides of the glacier as it melts and
  recedes.
• Finer material is carried in the rivers that form
  when the glacial ice melts.

http//commons.wikimedia.org/wiki/FileCavell_Glac
ier_with_Crevices_and_Annual_Rings.jpg
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Whats the Difference?

• WEATHERING Think of weather wearing rock down.
• EROSION Think of a road and traveling.
• DEPOSITION Think of depositing money into a
  bank.