OCR GCSE (9-1) Geography A: Geographical Themes (J383) · Spec 1.1.4 and 1.1.5
Coasts: waves, erosion and deposition
Read the notes, then try the questions. Each one is marked the moment you press Check, and shows the right answer and why.
Key ideas
- Waves with a strong backwash are destructive and erode. Waves with a strong swash are constructive and build beaches.
- Where bands of hard and soft rock meet the sea, the soft rock erodes faster into bays. The hard rock is left as headlands.
- Stack sequence: a crack in a headland is widened into a cave by hydraulic action and abrasion. The cave cuts through to form an arch. The arch roof collapses and leaves a stack.
- A wave-cut platform forms when waves undercut the foot of a cliff. The cliff collapses, and as it retreats it leaves a flat rocky platform.
- Longshore drift moves sediment along the coast. Where the coastline changes direction, deposition carries on out into open water and builds a spit.
- Your case study is one UK coastal landscape. Explain how its rock type and structure (its geology) and its climate shape the landforms. Show how sea walls and groynes change things too.
Key terms
- Swash
- The movement of a wave up the beach.
- Backwash
- The movement of water back down the beach.
- Longshore drift
- The movement of sediment along the coast in a zigzag, in the direction of the prevailing wind.
- Headland
- A piece of land sticking out into the sea, made of harder rock.
- Wave-cut platform
- A flat rocky area at the foot of a retreating cliff.
- Stack
- A column of rock left standing when an arch roof collapses.
- Spit
- A ridge of sand or shingle joined to the land at one end and ending in open water.
- Groyne
- A barrier built across a beach to trap sediment and make the beach wider.
Common mistakes
- Saying waves make the first crack in a headland. The crack is a weakness that is already in the rock. Waves make it bigger.
- Thinking geology means the shape of the coast. Geology is the type and structure of the rock.
- Writing a coastal case study answer only about sea defences and their cost. The question is about how the landscape forms and changes.
Exam tip
On a case study question, name your coast and keep to it. Explain at least two processes and the landform each one makes, with places. The longer Paper 1 questions use words like 'examine' and 'to what extent'. Weigh the processes against each other and give a judgement. The 12-marker also carries 3 extra marks for spelling, punctuation and grammar.
Free practice questions
7 questions, 12 marks. Answer, then press Check. The marking guide explains how the marks are worked out. Nothing is saved.
- Question 1 · Put in order[1 mark]
Put the stages of stack formation in the correct order, starting with the crack.
Use the arrows to put these in the right order, first at the top.
- 1The crack is enlarged into a cave
- 2The arch roof collapses, leaving a stack
- 3A crack in the headland is attacked by waves
- 4The cave is cut through to form an arch
- Question 2 · Fill the gaps[1 mark]
A crack becomes a cave, then an arch. When the arch roof collapses, a ___ is left.
Word bank: bar · spit · stack
- Question 3 · Matching[3 marks]
Match each event to the landform it leaves.
- Question 4 · Multiple choice[1 mark]
Which condition is needed for a spit to grow out from the coast?
- Question 5 · True or false[3 marks]
Decide whether each statement about deposition landforms is true or false.
1. Marram grass helps to stabilise sand dunes.
2. A bar forms when a spit grows across a bay, trapping a lagoon.
3. A spit can form without any change in the direction of the coastline.
- Question 6 · Multiple choice[1 mark]
Swanage Bay has chalk to the north, Purbeck Limestone to the south and softer Wealden clay between them. Which statement best explains why a bay has formed?
- Question 7 · Fill the gaps[2 marks]
Waves with a strong swash are ___ waves; waves with a strong backwash are ___ waves.
Word bank: tidal · constructive · destructive