"Many coastlines are made up almost entirely of rock. Wave erosion dominates these coasts. Storm waves undermine cliffs and gradually wear away headlands. Sometimes the largest waves that break on coasts are caused by storms hundreds of kilometres away. The wind may be so strong that it builds up huge waves that travel uninterrupted across the sea."
Power of Waves:
- Waves are formed by the circular motion of the water
- As the waves get closer to shore, the bottom part of this circular motion becomes interrupted by the ocean floor causing the bottom of the wave to move more slowly
- The wave will continue "rolling" until it plunges forward and breaks onto the shore
- The energy from the wave is transferred onto the shoreline and the work of erosion, transportation and deposition takes place.
- What time of the day does high tide occur?
- What time of the day does low tide occur?
- Explain why waves are usually bigger during high tide and draw this in a diagram
Coastal Erosion:
On coasts with cliffs, wave action is concentrated at the base of the cliff. Coastal erosion occurs very quickly when the cliffs are formed from softer rock, such as sandstone,
Using the image below, explain what has happened to this coastal cliff. What are the potential dangers?
(Use the figure 8.8 on page 142 to help answer this question)
On coasts with cliffs, wave action is concentrated at the base of the cliff. Coastal erosion occurs very quickly when the cliffs are formed from softer rock, such as sandstone,
Using the image below, explain what has happened to this coastal cliff. What are the potential dangers?
(Use the figure 8.8 on page 142 to help answer this question)
Stacks and Arches:
Softer rock around more harder, resistant rock erodes quicker, leaving the harder rock as outcrop along the cost. The sea may then eventually erode the softer rock on all sides of this outcrop. The resistant rock is left as a small island or stack.
Occasionally the stack may be left linked to the headland by an arch. This arch will eventually fall as more weathering and erosion occurs.
Pick one of the following coastal landforms and explain the processes involved with its current formation:
Softer rock around more harder, resistant rock erodes quicker, leaving the harder rock as outcrop along the cost. The sea may then eventually erode the softer rock on all sides of this outcrop. The resistant rock is left as a small island or stack.
Occasionally the stack may be left linked to the headland by an arch. This arch will eventually fall as more weathering and erosion occurs.
Pick one of the following coastal landforms and explain the processes involved with its current formation: