What is marine erosion?
Marine erosion is the wearing away of rocks by the action of the sea. This includes wave power, the chemicals in the waves, and the way in which waves knock rocks together. Marine erosion can be caused by constructive and destructive waves, and longshore drift too, but it is the processes of erosion that you will be studying in this pack.
How does it differ from weathering?
Weathering is the wearing away of rocks by the action of the weather, plants, and animals. This occurs in situ; this means that it doesn't require anything to relocate or move for the rock to be worn away.
Marine erosion is just caused by the sea, so this is where the two things differ.
Erosion Process 1 - Abrasion
Abrasion is where the sea picks up pebbles and throws them at the cliff face. The pebbles knock off small pieces of rock, which are then thrown at the cliff in the next wave, and so on. It is a very effective form of erosion, as it supplies the waves with more rocks to do damage with.
Erosion Process 2 - Attrition
This is where the pebbles in the waves are hit against each other, not the cliff face. This makes the pebbles more rounded, and smaller too. In places with more angular rocks, attrition isn't affecting that part of coastline in great amounts, whereas more rounded rocks are a sign of attrition.
Erosion Process 3 - Hydraulic Action
This is where the sheer force of the waves hitting the cliff causes rock to crumble off. The way this works is that the waves compress air inside cracks on the cliff face, and as it does this, the rock around that crack is smashed apart. This process is very forceful and brutal to cliffs.
Erosion Process 4 - Corrosion/Solution
This is the last process. Solution (or corrosion) is where the chemicals in the sea water react with the minerals in the rock, and start a chemical reaction that wears the rock away. This is seen mostly in limestone and chalk, which are soft rocks and are easily corroded.
So what have you learnt?
Now summarise what you have learnt into small paragraphs, WITHOUT looking back at the information. Include the words;
- hydraulic action
- marine erosion
This will help the information stay in your brain, and it will be easier to revise before the exam without having to re-learn it all.