Coastal processes and erosional landforms
Waves, rock type and time. That is the whole of coastal erosion, and this lesson shows how those three produce the landforms you must be able to draw.
Lesson overview
What you'll learn in this lesson
Explain coastal processes, erosional and depositional landforms and hard and soft engineering.
Key learning points
- • Waves and weathering
- • Headlands, bays and the cave sequence
- • Wave-cut platforms
- • Depositional landforms
This lesson at a glance
- 30 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
Coastal processes and erosional landforms
Waves, rock type and time. That is the whole of coastal erosion, and this lesson shows how those three produce the landforms you must be able to draw.
In a nutshell
Explain coastal processes, erosional and depositional landforms and hard and soft engineering.
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Waves and weathering
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Waves and weathering
Constructive waves have a strong swash, low frequency and build beaches; destructive waves have a strong backwash, high frequency and comb material away. Mechanical weathering such as freeze-thaw, chemical weathering such as carbonation, and mass movement including slumping and rockfall all prepare material for the sea to remove.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
Headlands, bays and the cave sequence
Alternating hard and soft rock produces headlands and bays through differential erosion. On a headland, hydraulic action and abrasion widen a line of weakness into a crack, then a cave; the cave erodes through to form an arch; the arch roof collapses leaving a stack, and continued erosion reduces the stack to a stump.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · Wave-cut platforms
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
Wave-cut platforms
Erosion concentrated between high and low tide undercuts the cliff to form a notch. The overhang collapses, the cliff retreats landwards and leaves a gently sloping wave-cut platform exposed at low tide.
Explore the idea
Part 11 of 20
Learn
Depositional landforms
Longshore drift moves sediment along the coast in a zig-zag: swash at the prevailing wind angle, backwash straight down the beach. Where the coast changes direction, deposition builds a spit, often curved by a secondary wind, with a salt marsh in the sheltered water behind it. Bars form where a spit crosses a bay.
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Quick check
Part 14 of 20
Explore the idea
Part 15 of 20
Worked example
Model answer: 'Explain the formation of a stack' (4 marks)
Hydraulic action and abrasion concentrate on a joint or fault in a resistant headland, widening it into a crack and then a cave. Continued erosion on both sides of the headland deepens the cave until it cuts right through, forming an arch. Weathering weakens the roof of the arch while wave erosion undercuts its base, and eventually the unsupported roof collapses. This leaves an isolated pillar of rock detached from the headland, known as a stack.
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 18 of 20
Game · Recall cards
Which wave type builds beaches?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Coastal processes and erosional landforms
4 questions, marked with the reasoning shown. No timer.
1. Which wave type builds beaches?
2. Why do headlands and bays form?
3. What immediately precedes a stack in the erosion sequence?
4. What causes the zig-zag movement of longshore drift?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
Quiz score
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Points this lesson
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Best run
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Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 20 · Watch & discover