Landforms created by erosion

The coastline is constantly eroding. There are four key types of erosion:

  • Abrasion - waves transport material which hit the cliff and gradually wear it away.
  • Hydraulic action - as waves approach the coast they trap air and force it into gaps in the cliff. Eventually this weakens the rock.
  • Attrition - waves cause the rocks to crash against each other, breaking them down into smaller and rounder pieces.
  • Corrosion (also known as solution) - salts and acids in seawater dissolve the rock gradually over thousands of years.

In addition, changes in landforms can be a result of wind erosion, weathering and sub-aerial processes such as mass movement.

Headlands and bays

A headland and bay at Durdle Door Beach, Dorset

Headlands are usually formed of more resistant rock types than bays.

If there are different bands of rock along a coastline, the weaker or softer rock, such as clay, is eroded fastest. This leaves more resistant rock types, such as granite, sticking out.

Caves, arches, stacks and stumps

Headlands can be vulnerable to erosion because they stand out from the rest of the coast. Over time, other features may develop on a headland:

Waves cause weaknesses to form cracks at the base of the headland

Stump formation: Step 1

Waves cause weaknesses to form cracks at the base of the headland

Cliff erosion and wave-cut platforms

Stages in cliff retreat

  1. Waves attack the bottom of the cliff, particularly during storms and at high tide.
  2. Eventually a wave-cut notch is formed.
  3. At the same time weathering attacks and weakens the top of the cliff.
  4. The weakened cliff is left unsupported and eventually collapses.
  5. Once the sea has removed the fallen rocks it can start the process again.
  6. The cliff will move back and leave a rocky platform at the base called a wave-cut platform.