Features of Erosion
Position A shows the cliff before another retreat. Remember that the cliff face is always retreating landwards.
Position B shows the cliffs prosition before it retreated again
Position C shows the current position of the cliff face. As you can see the cliff face above the notch created by wave action at shown at position F is becoming unsupported. The cliff will gradually slump forwards as it becomes to unsupported and falls due to gravity.
Position F shows the notch created by errosive wave action. Attack from waves occurs during high tide shown at E.
Position D is the wave cut platform, which is the area of fallen material collects and transported.
Quiz
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Wave Cut Notch
Wave cut platforms are found at the base of cliffs beneath a wave cut notch. This is where the fallen material from the cliff face is broken up and transported.
Rember that waves erode, transport and deposit.
The power of waves can be tremendous. Waves hit the base of the cliffs during high tide and it is continually degraded and worn by the action of waves and erosional processes:
Definitions of these words can be found at Erosion
The power of waves cut into bedding plains and faults within the rocks. Trapped air within these rocks cause the joints to widen, and all processes of erosion, Hydraulic action, Abrasion and Corrasion cause undercutting at the base of the cliff creating a 'wave cut notch'. Wave cut notches also feature an unsupported overhang. This rock is minimally touched by waves and so apart from the weathering effects is not degraded and worn by waves.
At the base of a cliff where the waves hit, the rock structure is continually weekened. It is beaten and made wet with salty sea water and then begins to dry out during the periods of low tide. Cracking created cause weekening ready for the next high tide, making it more easily eroded.
The notch gradually created creates pressure on the untouched layers of rock above. As the notch becomes larger and the upper cliff face is very top heavy, it eventually comes crashing down on the beach below leveling the cliff face. This is how our coastal landscape is consantly retreating landward.
A field trip to Walton-On the Naze revealed this process. A photograph of this formation taken by meself is featured below.
On the East Coast erosion is very evident. The geology of the area plays a big part. Soft rocks on the East coast visible at such places like Walton-On-the-Naze consist of red crag, boulder clay and glacier till.
