GCSECoastalZone2

Distinctive landforms result from different processes.

BBC Bitesize coastal landforms video

BBC Coastal processes and landforms video

Landforms resulting from erosion

Wave-cut platforms and stacks video

Cliffs and wave cut platforms

        1. Waves most often hit the base of a cliff and therefore most erosion is concentrated there.
        2. This continued erosion at the base of the cliff causes a wave cut notch to be created which is enlarged as the erosion continues.
        3. The rock above the notch is left unsupported, becomes unstable and eventually collapses.
        4. The collapsed material is washed away and a new wave cut notch starts to form.
        5. Repeated collapsing of the cliff causes the cliff to retreat inland.
        6. A wave cut platform is the rock platform that’s left behind as the cliffs retreats.

 

 

 

 

 

 

Headlands and bays

Image result for formation of bays and headlands

  1. Headlands and bays form on discordant coastlines where the rock type alternates between more resistant and less resistant rock at right angles to the sea.
  2. Differential erosion occurs as more resistant (harder) rock erodes slower than the less resistant rock.
  3. As the less resistant rock is eroded away quicker it creates a bay leaving the more resistant rock jutting out into the sea as headlands.

 

Caves, arches and stacks

Image result for formation of caves, arches, stacks

  1. Headlands are usually made of more resistant rocks that have weaknesses like cracks.
  2. Waves crash into the headlands due to wave refraction and enlarge the cracks mainly by hydraulic action and abrasion.
  3. Repeated erosion and enlargement of the cracks causes a cave to form.
  4. Continued erosion deepens the cave until it breaks through the headland forming an arch.
  5. Erosion continues to wear away the base of the arch and weathering weakens the roof.
  6. The arch eventually collapses to form a stack – an isolated rock that seperate from the headland

Landforms resulting from deposition

Beaches

  1. Beaches are formed by constructive waves depositing matieral which has often been eroded further along the coast and transported by longshore drift.
  2. Sand beaches are flat and wide – sand particles are small and the weak backwash can move them back down the beach, creating a long, gentle slope.
  3. Shingle beaches are steep and narrow – shingle particles are large and the weak backwash can’t move them back down the beach. The shingle partciles build up to create a steep slope.

Spits and bars

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                      1. Spits from where there is a sharp change in the direction of the coastline e.g. at a river estuary.
                      2. Longshore drift transports material along the coastline and past the bend. Then deposits it in the sea as the waves loose energy in the deeper water.
                      3. This process repeats and the spit gets bigger over time.
                      4. Changes in the direction of the wind can cause the spit to become curved at the end (a hook).
                      5. The spit won’t grow across the whole river estuary due to the river current flowing out into the sea.
                      6. Behind the spit a saltmarsh is created as the area is protected from the waves and plants start to grow there.

                      Image result for formation of a bar

                   

                       

A bar is created when a spit grows across a bay joining up two headlands.

 

 

Formation of a spit video

 

 

 

 

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