Coastal Erosion Processes
There are 4 main types of erosion which actively erode the coastline. Two of these
processes involve water, whilst the other two involve rocks/vibrations.
When answering questions about how coastal erosion features (cliffs, headlands, bays,
caves, arches, stacks and stumps) you can embed these explanations in your jotter,
which will pick you up extra marks!
Hydraulic Action
Hydraulic action is the sheer force of the wave power hitting off weaknesses or faults
in the rock. The force of the wave power pressurizes weaknesses/faults/cracks making
them wider.
Solution
Solution is when the salts or acids in the water chemically react with the rock and
dissolve it. Eg. Limestone is one of the easiest rocks to be eroded by the process of
solution.
Corrasion (AKA Abrasion)
Corrasion is caused by waves throwing beach material against cliffs. The wave launches
rocks and rock particles out of the sea towards the cliff. The vibrations cause the rock
to fracture. After this has occurred numerous times, the vibrations cause the rock to
become weak and erode.
Attrition
Some debate whether or not this is a process of coastal erosion- technically it does not
erode the coastline, it erodes the rocks which can be deposited along the coastline [but
the SQA still give you marks for this ;) ]
Attrition is when rocks being carried by the wave either ‘rub together’ or ‘bounce off’
each other. This causes the rocks to become round and smooth.