3.2.2

Coastal Formations

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Wave-Cut Platforms and Cliffs

Over time, cliffs are eroded by destructive waves, resulting in the formation of wave-cut platforms. This process is described below:

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1) Formation of wave-cut notch

  • Cliffs are created when erosion, weathering and mass movement processes cause the undercutting and collapse of unsupported rock.
  • Destructive waves are responsible for most of the erosion at the base of cliffs.
  • When destructive waves lead to abrasion undercutting the cliff face, a curved indent in the cliff forms and a wave-cut notch is created.
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2) Collapse of wave-cut notch

  • Continued erosion of the wave-cut notch causes the rock above it to become less and less stable, until it eventually collapses.
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3) Formation of new wave-cut notch

  • Waves wash away the collapsed material and begin eroding away at the cliff again, causing a new wave-cut notch to form.
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4) Formation of wave-cut platform

  • Over time, multiple collapsing events lead to the cliff retreating. What is left behind is called a wave-cut platform.

Erosion of Headlands

Resistant rocks with weaknesses called joints or cracks are what headlands are made of.

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1) Corrosion and hydraulic action

  • Destructive waves can erode weaknesses in headlands by the processes of corrosion and hydraulic action.
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2) Abrasion

  • When the weaknesses in the rock widen, abrasion becomes more important.
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3) Formation of coastal landforms

  • Over time, these erosional processes lead to the formation of coastal landforms such as caves, arches, stacks and stumps.

Coastal Landforms Caused by Headland Erosion

The erosion of headlands can create the following landforms:

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Caves

  • Erosion attacks lines of weaknesses in the headland.
  • When the crack widens into a small hollowed out area, a cave has formed.
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Arches

  • When caves are eroded right the way through the headland, an arch is created.
  • Arches have no back and you can walk or swim through them like a doorway.
    • E.g. Durdle Door on the Dorset Coast.
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Stacks

  • When the top of an arch collapses because of gravity, a column called a stack is left behind.
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Stumps

  • Continued erosion and weathering cause the stack to breakdown, forming a stump.
  • At times of high tide, the stump can become submerged.
  • Eventually, the stump will erode and there will be nothing left of it.

Jump to other topics

1Tectonic Processes & Hazards

2Option 2A: Glaciated Landscapes & Change

3Option 2B: Coastal Landscapes & Change

4Globalisation

5Option 4A: Regenerating Places

6Option 4B: Diverse Places

7The Water Cycle & Water Insecurity (A2 only)

8The Carbon Cycle & Energy Security (A2 only)

9Superpowers (A2 only)

10Option 8A: Health & Human Rights (A2 only)

11Option 8B: Migration & Identity (A2 only)

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