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How are coastlines shaped?

Waves crash against the cliffs.Waves crash against the cliffs.The coast is where the land meets the sea or ocean. Some coasts are shaped by the action of waves crashing against them. The rocks are gradually worn away, sometimes creating cliffs, the steep edge between the land and the sea. Bays are carved out where the coastal rocks are softer. In other places, the sea shapes the coast by piling up sand and shingle to make new land.

A bay and beachA bay and beachAn illustration showing typical coastline featuresAn illustration showing typical coastline features

Wave erosion

Hard rocks erode slowly. They stand out as headlands. Waves wear away softer rocks more easily. The waves undercut cliffs by gnawing away at the bottom, causing them to collapse. Eventually, a small cove widens into a bay.

A cliff gradually “retreats” after more and more rock is worn away by the waves. A flat area forms at the base of the cliffs, called a wave-cut platform. It may become covered by sand or shingle, forming a beach.

At the height of the last Ice Age (26,500 years ago), the world sea level was about 120 metres (400 ft) lower than it is today. This was because a huge amount of water was frozen in the vast ice caps that covered large areas of the land.

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