Coastal landforms made by erosion Cambridge IGCSE Geography (9–1) revision
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In plain words
Where waves attack a coast of mixed rock, the soft parts go first and the hard parts are left sticking out. Then the sea starts on the hard parts, and carves them into some of the most recognisable shapes in geography.
6 things to know
- A discordant coastline has bands of hard and soft rock at right angles to the sea. The soft rock erodes into bays, and the hard rock is left as headlands.
- A concordant coastline has bands of rock running parallel to the sea. The hard outer band protects the softer rock behind it, so the coast is straighter. Where the sea breaks through, it hollows out a cove.
- A cliff is attacked at its base, between high and low tide, forming a wave-cut notch. The rock above is left unsupported and collapses.
- As this repeats, the cliff retreats, leaving a gently sloping wave-cut platform of rock at its foot.
- On a headland, waves widen a crack into a cave. Caves on either side of the headland meet, or one cuts through, to form an arch.
- The roof of the arch collapses, leaving a tall pillar of rock, a stack. The stack is eroded at its base and falls, leaving a stump.
Worked example
Explain the formation of a stack.
- Waves attack a weakness, such as a crack, in a headland. Hydraulic action and corrasion widen it into a cave.
- The cave is eroded right through the headland to form an arch.
- The arch is widened by more erosion at its base and weathering of its roof.
- The roof becomes too heavy and collapses, leaving a separate pillar of rock: a stack.
Tips and tricks
- The sequence is crack, cave, arch, stack, stump. Miss one out and the explanation has a hole in it.
- Discordant: bands across, giving headlands and bays. Concordant: bands along, giving a straighter coast with coves.
It lands in your notebook with its questions as flashcards.
Coastal landforms made by erosion: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What forms where soft rock is eroded faster than hard rock on a discordant coast?
The hard rock is left as headlands.
What is the correct order of formation?
Each one is made from the one before.
What is a wave-cut notch?
It undercuts the cliff, which then collapses.
On a concordant coastline, the bands of rock run:
The outer band protects the rock behind it.
What is left when a stack collapses?
A low remnant, often covered at high tide.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
2 questions, 8 marks. Write your answers on paper, then check them.
Coastal landforms made by erosion
Cambridge IGCSE Geography (9–1) 0976 · 8 marks · papermunch.org
Name ______________________________ Date ______________
Explain how headlands and bays are formed.[4]
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The coast has bands of hard and soft rock at right angles to the sea. The soft rock is eroded faster and forms bays. The hard rock is more resistant and is left jutting out as headlands.
Explain how a wave-cut platform is formed.[4]
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Waves erode the base of a cliff to form a wave-cut notch. The rock above collapses and the cliff retreats. This repeats, leaving a flat platform of rock where the cliff used to be.
Answers: Coastal landforms made by erosion
- 1. The coast has bands of hard and soft rock at right angles to the sea. The soft rock is eroded faster and forms bays. The hard rock is more resistant and is left jutting out as headlands.
- 2. Waves erode the base of a cliff to form a wave-cut notch. The rock above collapses and the cliff retreats. This repeats, leaving a flat platform of rock where the cliff used to be.