Aim: Weathering and Erosion

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Aim Weathering and Erosion
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Weathering

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

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1. 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
• Upward Expansion of Rock
• 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(Stream ABRASION)
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Burrowing of Animals
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Upward Expansion of Rock due to the releasing of
pressure of overlying rock unloading off the
surface. (notice the peeling of the rock) Ex.
Granite (Exfoliationpeeling)
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Temperature Changes
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Part II Chemical Weathering

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

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KEY IDEA Water plus humid and warm environments

• Water weathers rock by dissolving it

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Oxygen

• Iron (Fe) combines with oxygen (O2) in the
  presence of water in a process called oxidation
• The product of oxidation is rust

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Carbon Dioxide

• CO2 dissolves in rain water and makes carbonic
  acid
• Carbonic acid easily weathers Limestone and
  marble key mineral is CALCITE

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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.
• Made 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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Erosion

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

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A BIG KEY is Water Erosion

• Rivers, streams, and runoff

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Ice Erosion

• Glaciers-Ice moves and picks up rock

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Wind Erosion- mostly in dry climates
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Mass Movements

• Landslides, mudslides, slump and creep

landslide clip.mpeg
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SOME MOVIES (Brain Pop) PHOTOS

• http//glencoe.mcgraw-hill.com/sites/dl/free/0078
  600499/164213/00050754.html
• http//science.nationalgeographic.com/science/phot
  os/weathering-erosion-gallery.html
• ANIMATION http//ees.as.uky.edu/sites/default/fil
  es/elearning/module07swf.swf