WEATHERING

• Denudation


  Weathering and erosion
• Weathering


  1. A process

  2. Causes rocks to be broken

  3. Over time
• Weathering


  Happens in situ (the place where a rock happens to be)
• Erosion


  A process that breaks rocks into smaller pieces by transporting sediments by agents of erosion (rivers, sea, glaciers and wind)
• Types of weathering


  • Mechanical weathering
  • Chemical weathering
  • Biological weathering
• Mechanical weathering


  • Physically breaks rocks apart
  • Produces broken rock called scree
• Chemical weathering


  Involves rock being dissolved gradually over time
• Biological weathering


  Occurs when rock is broken apart by burrowing animals or by plant growth
• Freeze-thaw action


  1. Rainwater gathers in rock joints

  2. Water freezes and expands by 10%

  3. Expansion widens joints

  4. Over time, rock breaks and collapses into scree
• Carbonation


  A chemical weathering process where rock is dissolved by weak carbonic acid
• Limestone


  • Soft sedimentary rock
  • Composed of calcium carbonate from fossils
  • Has bedding planes and joints that make it permeable
• Acid rain falls on limestone


  Dissolves the weaker parts of the limestone surface
• Karst landscape


  Pattern of joints and grikes formed by carbonation weathering of limestone
• Features of the Burren

  • Varied flora and fauna
  • Spring gentians, early-purple orchid and mountain avens
  • Feral goats, stoat, pine marten and Irish hare, rare insects and butterflies
• The Burren is a large area of exposed limestone, or karst, in Co. Clare
• The limestone rock in the Burren was deposited under a shallow ocean when Ireland lay at the equator, 365 million years ago
• Most of the soil in the Burren was removed by glacial erosion, leaving the rock bare and exposed to the weather
• Stalactites


  Slender columns of calcite that hang from the ceiling of a cave, formed by water evaporation
• Stalagmites


  Thick columns of calcite that build up on the floor of a cave, formed by water evaporation
• If a stalactite and stalagmite meet they form a pillar