Weathering

• What is weathering?

  The action of breaking down rock in situ (in its original place) or close to the ground's surface.
• What is weathering?

  The disintegration and decomposition of rock in situ.
• 𝐖𝐀𝐓𝐄𝐑:

  • can corrode and dissolve
• 𝐅𝐑𝐄𝐄𝐙𝐄-𝐓𝐇𝐀𝐖:

  • water seeps into rock cracks/joints and expands as it freezes
  • mechanical
• 𝐕𝐈𝐍𝐄𝐆𝐀𝐑:

  • corrosion and dissolving
  • acid
  • chemical weathering
  • can also neutralise alkaline rock (e.g. limestone and chalk) (process of carbonation)
• 𝐁𝐈𝐎𝐋𝐎𝐆𝐈𝐂𝐀𝐋:

  • tree/plant roots grow and expand into cracks
• Weathering is part of the slow carbon cycle.
• What is oxidation?

  Minerals in the rock (e.g. iron) react with oxygen and oxidise (rust) so are more easily eroded.
• How does freeze-thaw weathering work?

  • water seeps into cracks in the rock
  • when water freezes it expands in volume
  • the cracks are enlargened
  • the water thaws and the process is repeated
• How does carbonation work?

  • slightly acidic (carbonic) rain comes into contact with sedimentary rock
  • the rock is dissolved
• How does biological weathering work?

  • roots enter a small crack in the rock
  • growing roots put pressure on the rock
  • the the cracks become larger
  • the rock breaks away from the cliff face
• What is an example of mechanical (physical) weathering?

  Freeze-thaw
• What is an example of chemical weathering?

  Carbonation
• What is an example of biological weathering?

  Plant roots