COASTAL LANDFORMS

Coastlines are formed by erosion (where water wears away parts of the land) and deposition (where sediment is moved into new places by water).

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The incredible power of the ocean carves the coastline into all sorts of shapes, forming towering cliffs, magical caves and more… 2

When waves crash continually against a section of coast made up of both hard and soft rock, the soft rock erodes first, leaving a headland jutting into the sea.

Seawater carries rough grains of sand that wear away rock. When water finds a crack in a cliff or headland, it can eventually erode into a sea cave . This huge sea cave is filled with stalactites and stalagmites!

This hidden beach in the Marietas Islands, Mexico, was once inside a huge sea cave, but the roof collapsed! 3 5

As erosion continues, a natural arch will gradually get bigger until eventually it collapses, leaving a sea stack . Reynisdrangar basalt sea stacks in Iceland tower up to 66 metres into the air!

When a cave is part of a headland, it can erode all the way through, creating an arch shape in the rock. This is Durdle Door, a natural arch in Dorset.