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Geography

Processes

When rock is exposed, there are a number of processes that break it down. Watch this video to find out more.

Video

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Key points

  • Freeze thaw weathering is when water gets trapped in a crack or joint in the rock.
  • When the air temperature drops the water will freeze and expand. When the temperature rises, the ice melts.
  • If this process repeats, the rock will weaken and eventually shatter into angular fragments.
  • Limestone solution is where carbon dioxide dissolves in rainwater to make carbonic acid.
  • When this comes into contact with limestone, it reacts to form calcium bicarbonate. This is carried away in solution, gradually weathering the limestone.

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