Coasts Aim: To be able to draw and describe some landforms of coastal erosion. <ul><li>Key Words </li></ul><ul><li>Cave </li></ul><ul><li>Arch </li></ul><ul><li>Stack </li></ul><ul><li>Wave Cut Platform </li></ul>
What factors affect rate of coastal erosion? Beaches Absorb wave energy which slows down erosion by protecting cliffs Rock structure Cliffs with weaknesses (joints) and cracks are more easily eroded Rock type Resistant rocks eg. granite erode very slowly. Less resistant eg. clay erode quickly Wave energy Erosion greatest when waves and big and frequent Weathering Sub-aerial attack on cliffs speed up erosion (wind & rain) and don’t forget …… PEOPLE
Headlands and Bays They form along coasts that have alternating bands of hard and soft rock Lulworth Cove Click on picture above for a short video on how bays are formed 2.03
Cliff Erosion Click diagram above for a short video about cliff collapse in Beachy Head 1.45
What happens at the cliff face? <ul><li>Is affected by sub-aerial weathering (impact of wind, rain, frost, temperature changes) </li></ul><ul><li>This may lead to mass movement ~ face of cliff slips/slides downwards </li></ul><ul><li>This often happens after prolonged or heavy rain – reduces frictional surfaces and makes rocks unstable </li></ul>
Wave Cut Platforms The sea cliff is the most widespread landform of coastal erosion.
Caves, Arches and Stacks Waves erode weaknesses in the rock. Cave eroded into cliff at line of weakness Size of cave is increased by erosion until headland is opened out at both sides Wave erosion causes roof of cave to collapse leaving the stack
Transport and Deposition Longshore Drift Click on diagram to start short video on longshore drift 2.06