The Coastal Zone (AQA GCSE Geography A) Revision Notes

Some revision notes on the coastal zone for AQA geography A GCSE. 

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  • Created on: 12-06-11 09:25
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AQA GCSE Geography A ­ The Coastal Zone
AQA Geography - The Coastal Zone Revision Notes
Biological ­ The break up of rocks due to the action of plants and animals e.g. plants roots going into the cracks of
Chemical ­ the break up of rock by a chemical reaction e.g. carbonation is when carbonic acid (formed by the water
and the CO2 in the air) reacts with rocks, such as limestone, and dissolves them away.
Mechanical weathering ­ the break up of rocks without a chemical change occurring. There are two main types of
chemical weathering.
Exfoliation ­ Because rocks are poor conductors of heat, only the outer layer is affected by temperature change.
Heat causes it to expand; lower temperatures cause contraction. Repeated expansion and contraction cause the
outer layer to be peeled away.
Freeze-thaw action ­ water gets into the cracks in the rock. Because of sub-zero temperatures in the night, this
water freezes into ice and expands, which puts pressure on the crack. In the day, the water melts and releases the
pressure. Repeated cycles eventually cause parts of the rock to break off.
Mass movement
Mass movement is when a lot of material is removed from the coastline at one time. It causes a large retreat in the
coastline too. There are two types ­ slides and slumps. Slides are when material slides off the coast in a straight line.
Slumps are when the material shifts at a rotation.
Erosional processes
Hydraulic action ­ the sheer impact of the waves cause air to be forced into the cracks of the rocks, which cause
them to break off.
Abrasion ­ eroded material carried in the waves grind against the cliff face, and this causes more material to be
taken from the cliffs.
Attrition ­ eroded material bang against each other, and become smaller in size. Their edges are also rounded.
Solution ­ carbonic acid in seawater dissolves some types of rock e.g. limestone and chalk.
Types of Waves
Constructive waves
Low frequency (6-8 waves per minute)
Strong swash, weak backwash, which causes them to deposit material on the beach.
Low in height, and they are quite long.
Destructive waves
High frequency (10-14 per minute)
Strong backwash, weak swash, which causes them to take material from the beach.
Caused by storms further out into the sea.
Long fetch
Tall waves, so they crash onto the beach with great force.

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AQA GCSE Geography A ­ The Coastal Zone
Wave cut platforms
These landforms may be found on any coastline, mainly where there are destructive waves. These waves cause
undercutting on the cliffs, which creates a dent in the bottom of the cliff edge. This is called a wave-cut notch. This
gets deeper, and eventually, the rock which is over the undercut area becomes unstable and falls. The material is
then cleared, and the cycle repeats again.…read more

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AQA GCSE Geography A ­ The Coastal Zone
People have died because of flooding.
Loss of jobs.
Loss of housing.
Water supplies can be contaminated with salt and sewage.
Increased erosion.
Damage to ecosystems.
Vegetation killed because force of water can uproot them.
Governments have to make policies to reduce future flooding. They could build better flood defences.
Coastal management strategies
Hard engineering
Defence Advantages Disadvantages
Sea wall ­ a wall which absorbs wave Prevents erosion. Very expensive to build and maintain.…read more



these notes are really good! have you anymore on other geography topics? :)


these notes are really good! have you anymore on other geography topics? :)

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