Weathering

Weathering

1. Chemical

   • Carbonation
     • Carbon dioxide
       • mixes with rain water
         • weak carbonic acid
           • weathers away calcium calbonate
             • grikes are formed when joints are widened
               • blocks of limestone are left behind
                 • called clints
       • CO2 + H2O=H2C03 (weak carbonic acid)
         • H2CO3 + CaCO3 (calcium carbonate) =weathering
     • Example: TheBurren, Co. Clare

2. Physical

   • Freeze-thaw action
     • Occurs in areas where the temperate fluctuates
       • & where rain is present
     • By Day: Water fills into cracks in the rock
     • By Night: The temperature drops below freezing
       • -0 degrees Celcius
         • This causes the water in the rock to freeze & expand
           • the rock also expands
     • Overtime: This repeats
       • causes the rock to shatter
         • fall down the side of a mountain
           • known as scree
     • Example: Ben Bulben, Co. Sligo

3. Underground Karst Features

   • Carbonation (as below)
     • Weak carbonic acid percolates through the limestone
       • as it is a permeable rock
         • water can flow through.
           • As the water flows through the limestone
             • carves out channels
               • caverns & caves
                 • In a cave
                   • weak carbonic acid drips from the ceiling
                     • leaves behind calcite
                       • calcite builds up to form straws
                         • eventually grow into stalictites
                           • Calcite deposits on the floor
                             • build to form stalagmites
                 • Example: Ailiwee Caves, Co. Clare

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