Mon Prof Augmenté
From crack to stump on a headland
Age 13 · Geography
Waves hit a rocky headland and force water and air into weak spots, slowly wearing the rock away. Over thousands of years a small crack grows into a cave, then an arch, then a stack, and finally a stump.
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Age 13: open this week
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In the picture
- Crack: a weak line in the rock that waves start to widen
- Cave: the crack has been hollowed out into a hole at the waterline
- Arch: waves cut through the headland from both sides
- Stack: the arch roof collapsed, leaving a pillar standing alone
- Stump: the stack worn down until it is just above the waves
Examples
- Durdle Door in Dorset, England, is a famous natural sea arch.
- The Twelve Apostles in Australia are stacks left after arches collapsed.
Key takeaways
- Waves erode the weakest parts of rock first, such as cracks.
- The sequence is crack, cave, arch, stack, stump.
Quiz: From crack to stump on a headland (Age 13)
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Which parts of a rocky headland do waves wear away first?
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What does a cave become when waves cut right through the headland from both sides?
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How does a stack form on a headland?
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