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Geolens

Case study UK

Jurassic Coast

Dorset and East Devon

The changing rocks of the Dorset and East Devon coast produce contrasting cliffs, bays and arches. Durdle Door and Old Harry Rocks show how coastal erosion works with geological structure.

White chalk cliffs, offshore remnants and a wave-cut base near the Pinnacles in Purbeck.
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The Pinnacles coast, Purbeck, Dorset. Erosion leaves isolated stacks and lower remnants called stumps beside the retreating chalk cliffs.
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Location: 50.62°, -2.25°

Rock resistance and the orientation of beds help determine where headlands and bays develop. Durdle Door is a limestone arch, while Old Harry Rocks are chalk stacks. These are separate examples that help illustrate stages of coastal erosion, rather than a single landform observed through time.

Waves exploit joints and other weaknesses, while weathering and gravity also weaken cliffs. Compare the model’s cave–arch–stack sequence with the photographs and ask what evidence would be needed to reconstruct a particular headland’s history.

Open this state in the lab

Exam-style question

Using a named Jurassic Coast landform, describe the sequence from cave to stump.

Teacher hint: Explain how erosion enlarges weaknesses into a cave and arch, then how collapse can leave a stack and eventually a stump.

Process labs

CoastsRock cycle

Sources

  • Jurassic Coast Trust / UNESCO
  • BGS — Dorset coast