Rates of Weathering

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Rates of Weathering

• Topic 9
• Regents Earth Science

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The rate of weathering is affected by
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1. Climate

• Humidity - frost action generally increases with
  humidity (if temperatures are right) need
  temperatures above and below freezing
• Temperature - chemical weathering increases with
  increasing humidity and higher temperatures

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1. Climate continued . . .

• Local prevailing winds - weathering greatest on
  windward side
• Other local conditions such as carbon dioxide
  concentration (more CO2, more weathering) urban
  heat islands (higher temperature, more weathering)

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Dominant weathering for various climate conditions
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Weathering and direction
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Remember

• Hot humid highest rate of weathering
• Cold and dry slowest weathering

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2. Particle size

• The smaller the particle, the greater the surface
  area
• Small particles weather faster than large
  particles under the same conditions

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3. Mineral composition

• Rock of different composition weather at
  different rates

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4. Exposure

• The degree to which a rock comes into contact
  with weathering agents
• Protected rocks weather more slowly than those
  completely exposed at the surface
• Also affects each particle causing it to become
  more rounded