cliffs and wave cut platforms

• cliffs and wave cut platforms are examples of erosion
• cliffs

  cliffs are usually vertical with deposits at the base
• wave cut platforms

  wave cut platforms are an area of bedrock visible at the base of cliffs which slopes gently to the sea and is usually only visible at low tide
• characteristics of cliffs:

  • soft rocks produce slumping cliffs whereas hard rocks produce high cliffs and wave cut platforms
  • hard rock cliffs will have layers of rock jutting out and horizontal bedding planes
  • near vertical, bare rock
  • wave-cut notch at base
  • fallen rocks at the base
• characteristics of wave cut platforms:

  • slopes gently down to sea at an angle of 3-4 degrees
  • has a pitted appearance of bare rock smoothed by attrition and rock pools
  • deep cracks in places
  • barnacles clinging to rocks with seaweed
  • covered at high tide and exposed at low tide
• stage 1

  the land slopes down to sea. freeze thaw weathering weakens the rock
• stage 2

  marine erosion is concentrated between the high and low watermark. wave pounding by hydraulic action and abrasion by shingle hurled at the land, erode the base
• stage 3

  continued erosion causes rock to break away and collect at the base of the cliff. destructive waves remove this material. the cliff now has a notch at its base. the section of cliff above the notch is now unsupported and becomes more precarious as erosion continues
• stage 4

  eventually the notch is enlarged to the point where the overhanging cliff can no longer defy gravity. it breaks away and falls onto the beach. the resulting steep drop is called a cliff
• stage 5

  aided by freeze-thaw weathering this process of erosion, notch formation and cliff collapse continues. this causes the cliff to retreat back towards the land and, if the land is still sloping, to increase in height
• stage 6

  as the cliff retreats, the former base of the cliff is left as a wave cut platform. in places, it will be continuously smoothed by shingle grinding over it. elsewhere, it may become encrusted with barnacles or covered with algae. joints will become enlarged by abrasion and hydraulic action
• what does this show

  cliffs and a wave cut platform

  
• label the diagram

  here

  A) wave cut notch

  B) sea attacks base

  C) wave cut platform

  D) cliff collapses

  E) cliff retreats