What type of waves will erode the coastline? What type of waves will create beaches?

Starter

Coastal Landforms

Cliffs and Wave-cut Platforms One of the most common features of a coastline is a cliff. Cliffs are shaped through a combination of erosion and weathering - the breakdown of rocks caused by weather conditions. Soft rock, eg sand and clay, erodes easily to create gently sloping cliffs. Hard rock, eg chalk, is more resistant and erodes slowly to create steep cliffs. Challenge: Can you name any famous cliffs?

The process of cliff erosion Activity Copy the diagram and annotate with the labels: The process of cliff erosion Weathering weakens the top of the cliff. 2. The sea attacks the base of the cliff forming a wave-cut platform. 3. The notch increases in size causing the cliff to collapse. 4. The backwash carries the rubble towards the sea forming a wave-cut platform. 5. The process repeats and the cliff continues to retreat. Challenge: Add in the 4 different types of erosion

What landforms are found in ‘hard’ coastlines? https://www.youtube.com/watch?v=7Th56dhs4Fc You are going to watch a video that shows how caves, arches, stacks and stumps are formed. You need to pay attention so you can create your own diagram.

HEADLAND SMALL STACK LARGE ARCH ARCH CAVE STUMP Click once – this animation runs automatically… now click again for instructions.

Activity You need to put your cards into the correct order to explain how a crack in the cliff eventually creates a stump.

Now draw a diagram showing how the erosional landforms are created. Activity Now draw a diagram showing how the erosional landforms are created. Extension: Use the previous task to add more detail to your diagram by adding annotations. Challenge: How is a blowhole formed? How does it work? Write a description.

EXAM Q: Explain how a coastal stump is formed. (8) Tips: IDENTIFY the types of erosion needed DESCRIBE how each type of erosion works EXPLAIN how each landform on the way to erosion is formed CASE STUDY!

Model answer- Explain how a coastal stump is formed. (8)   Waves attack the base of a cliff. The continuous smashing of rocks, pebbles and waves against a cliff is known as abrasion. This may eventually crack a fault in the headland. Hydraulic power, the force of pressure from water and trapped air, and abrasion attack cracks in the headland at the base of the cliff, forming caves over time. This process of weathering and erosion continues on both sides of the headland until the caves break through, creating an arch. Continued erosion and weathering attack the sides and roof of the arch until it becomes weak and collapse, forming a stack, which is separated from the headland. Over time, the waves will continue to erode and dissolve the weaker rock and reduce it to a stump. A wave-cut platform appears along the coastline, highlighting the areas most vulnerable to erosion. An example of this can be found at Old Harry in Dorset, along the Purbeck coast.

E. Describe what you see. A. what physical processes are happening here? C. What activities (primary/secondary/tertiary) could you make money from in this landscape?

Answers… Long shore drift Deposition = beach Constructive waves Destructive waves activities –secondary = fish restaurant for tourists Hydraulic action Abrasion Solution Attrition = beach Bay headland village beach activities –primary = fishing activities –secondary = putting the fish in tins