Coastal Erosion: Headlands, Bays and Landforms

Coastal Erosion: Headlands, Bays and Landforms

Year 9 Geography Understanding how waves shape our coastlines From headlands to sea stacks

What is Coastal Erosion?

The wearing away of land by the sea Waves crash against rocks and cliffs Different rocks erode at different speeds Creates amazing coastal features over time

Hard vs Soft Rock

Hard rocks resist erosion (granite, limestone) Soft rocks erode quickly (clay, sandstone) Different erosion rates create varied landscapes This difference is key to landform creation

How Headlands and Bays Form

Spot the Headland and Bay

Look at the coastal photograph Identify one headland (rocky point) Identify one bay (curved inlet) Discuss what type of rock each area might be

Cave Formation

Waves attack cracks in headland cliffs Hydraulic action forces water into cracks Cracks slowly widen into caves Caves form at the base of cliffs

From Cave to Arch

Caves on both sides of a headland grow larger Eventually caves meet in the middle This creates a natural arch The arch has sea on both sides

Think and Discuss

What do you think happens to an arch over time? Will it stay the same forever? What forces might cause it to change?

Stack Formation

The arch roof becomes too weak to support itself The top collapses into the sea This leaves a tall pillar of rock - a stack The stack stands alone in the water

The Final Stage: Stumps

Even stacks continue to be eroded Waves wear away the base of the stack Eventually the stack collapses This leaves a low rocky stump at low tide

The Complete Erosion Sequence

Draw Your Own Erosion Sequence

Use your ruler and pencil Draw 4 boxes showing the sequence Label each stage clearly Add arrows to show the direction of change Include waves hitting the rocks