Durdle Door

Durdle Door is a coastal arch located on the Dorset Coast in the south of England.

Durdle Door is formed from a layer of hard limestone standing almost vertically out of the sea. Normally layers of limestone would be horizontal. Only the most fundamental force in geology could have altered these rocks in this way – plate tectonics.

Durdle Door, a coastal arch in Dorset.

Around 25 million years ago the African tectonic plate collided with the European plate. The huge pressures generated heaved and folded rocks to create the mountain chain we know as the Alps. Ripples from that collision spread north through the Earth’s crust and gently folded the rocks here, in what would become south Dorset and Purbeck.

Durdle Door and Lulworth Cove lie in the heart of one of these folds, where the rock layers have been tilted steeply. As the sea broke through the hard limestone it eroded the softer rocks behind creating the arch, the cove and the beautiful coastline where Durdle Door and Lulworth Cove are both found.

Want to know how coastal arches are formed? Take a look at our erosion of a headland section.

Durdle Door, Dorset

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