rates of weathering

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					Rates of Weathering
       Topic 9
 Regents Earth Science
The rate of weathering is
affected by
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
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)
Dominant weathering for
various climate conditions
Weathering and direction
 Hot humid = highest rate of weathering
 Cold and dry = slowest weathering
2. Particle size
 The  smaller the particle, the greater the
  surface area
 Small particles weather faster than large
  particles under the same conditions
3. Mineral composition
 Rock  of different composition weather at
 different rates
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
 Also affects each particle causing it to
  become more rounded