Weathering Flashcards
What is de denudation
The wearing down of the surface of the earth.mot is done by weathering and erosion
What is weathering
The breakdown of rock, usually by the forces of the weather. The broken rock lies where it has been broken. There are two types of weathering - mechanical and chemical
What is chemical weathering
Weathering that occurs when rocks broken apart by physical force applied by frost and plants
What is freeze - thaw action
Mechanical
Where the temperature rises above and falls below 0°
Where precipitation occurs
Water gets in the cracks of rocks, freezes and expands during the night, contracts during the day and the cycle goes over and over again till the rocks fall down the mountains and break up into scree
What is exfoliation
Mechanical
A difference up to 32° between day and night.
Onion weathering
Outer layer of rock expands during the day and contracts during the night. Day after day eventually the outer layer cracks
What is chemical weathering
Occurs when chemical change in the rocks causes them to dissolve
What is carbonation
Chemical
Limestone is dissolved by carbon dioxide in rainwater
Carbonic acid opens cracks and joints in the limestone by dissolving it
E.g. Burren co. Clare
What is a karst landscape
The burren
Limestone pavements, swallow holes, underground rivers and
caves
Surface features;
Clints - the blocks of limestone that for the limestone pavement
Grikes - the gaps between the blocks. Joints in the rock were opened wider when the limestone was dissolved by rainwater through the process of carbonation
Swallow holes - rivers that disappear underground
Underground features;
Stalactites - cone-shaped deposits of materials hanging down (calcite)
Stalagmites - built up from the floor of a limestone cave
Pillars - when stalactites and stalagmites join
E.g. Aillwee cave, Co. Clare