Waterfall revision presentation
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Waterfalls form when harder rock layers overlay softer rock, allowing the river to erode the softer rock faster and create a notch. Over time, the notch deepens into a plunge pool, leading to the eventual collapse of the harder rock and the formation of a gorge as the waterfall retreats upstream. The process of erosion continues, with hydraulic action and corrasion contributing to the expansion of the notch and plunge pool.
Waterfall revision presentation
- 3. 1. Waterfalls are often formed where a layer of harder rock overlays a layer of softer rock. Harder rock Softer rock
- 4. 2. As the river passes over the softer rock, it is able to erode it at a faster rate, forming a step in the river bed. Harder rock Harder rock Softer rock Softer rock
- 5. Harder rock Softer rock ii. it undercuts the harder rock to form a notch 3. The force of hydraulic action does two things: i. deepens the step to form a plunge pool at the base of the waterfall Further erosion makes the plunge pool and notch bigger over time.
- 6. Harder rock Softer rock As the notch grows, eventually there isn’t enough support under the harder rock and so it collapses into the plunge pool.
- 7. Harder rock Softer rock This adds rocks and boulders to the plunge pool, and so the process of corrasion works with hydraulic action to further erode the plunge pool and notch.
- 8. Harder rock Softer rock The processes of erosion continue, further eroding out the notch and plunge pool. Eventually the harder rock above will collapse again, meaning that the waterfall will retreat upstream over time.
- 9. As it retreats, it leaves behind a steep sided gorge.
- 10. And this is also Gorge This is Gorge
- 11. Gorges Most gorges are formed through water erosion. For example, waterfalls erode the rocks they fall over and the falls move gradually back - leaving a gorge behind them.
- 12. Nature is the best artist When allmighty wants to create a masterpiece, he uses nature… Let me show you why…
- 19. Now you know how waterfalls are formed You can nail that exam! Good luck!
- 20. CREDITS Used material: • A. Hamill • S. Rackley • And special thanks to SlideShare.net resource You can find some good stuff there.