sea stack

geology

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July 13, 2026

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Oregon coast Sea stacks on the Oregon coast.

Sea stacks are geological formations found along erosional coastlines. They are remnants of rock left behind after wave erosion has worn away the surrounding land. These isolated pinnacles stand on wave-cut platforms, which are smooth, horizontal surfaces created by wave action at the base of sea cliffs.

The formation of sea stacks is a continuous process. Initially, erosion can create sea arches. When these arches eventually collapse, a sea stack is left standing. Over time, further erosion will wear down the sea stack until it disappears, leaving only the wave-cut platform and the coastal cliff. The rate of erosion depends on the type of rock and the energy of the waves.123

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coastal landforms
Sea stacks
Erosion along rocky coasts occurs at various rates and is dependent both on the rock type and on the wave energy at a particular site. As a result of the above-mentioned conditions, wave-cut platforms may be incomplete, with erosional remnants on the horizontal…
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Erosion along rocky coasts occurs at various rates and is dependent both on the rock type and on the wave energy at a particular site. As a result of the above-mentioned conditions, wave-cut platforms may be incomplete, with erosional remnants on the horizontal…
Read More

natural bridge
…sea arch commonly produces a sea stack.
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…sea arch commonly produces a sea stack.
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