Coastal Weathering And Erosion Flashcards
What is weathering?
Weathering is the breakdown of rocks where they are.
What is meant by erosion?
Erosion is when the rocks are broken down and carried away by something e.g by seawater.
What are the three types of weathering which are used to break down rock?
Mechanical,chemical and biological weathering.
What is meant by mechanical weathering?
Mechanical weathering is the breakdown of rock without changing its chemical composition.
What is the main type of mechanical weathering and its process?
Salt weathering:
- The seawater gets into cracks in the rock
- When water evaporate, salt crystals form this makes it expand and put pressure on the rock
- This repeats creating cracks in rocks and eventually the rock breaks up
What is meant by chemical weathering?
Chemical weathering is the breakdown of rock by changing its chemical composition.
A type of chemical weathering and its process?
Carbonation is a type of chemical weathering that happens in warm and wet conditions:
- seawater and rainwater have carbon dioxide dissolved in them which makes them weak carbonic acids.
- carbonic acid reacts with rock that contains calcium carbonate, e.g carboniferous limestone, so the rocks are dissolved by rainwater.
What is biological weathering?
Biological weathering is the breakdown is the breakdown of rock by living things, e.g plant roots break down by growing into cracks on their surface and pushing them apart.
What is mass movement?
mass movement is the shift of rocks and loose material down a slope, e.g a cliff.
How mass movement works?
- it happens when the force of gravity acting on a slope is greater than the force supporting it
- mass movement cause coast to retreat rapidly
- they’re more likely to happen when the material is full of water it acts a lubricant
- there are three types of mass movement: slides, slumps and rockfalls
What are the three process of erosion which waves wear away the coast?
Hydraulic power, abrasion and atttrition
What is hydraulic power?
Hydraulic power is where waves crash against rock and compress the air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and makes bits of rock break off.
What is attrition?
Attrition is when eroded particles in the water smash into each other and break into smaller fragments, their edges also get rounded off as they rub together.
