waterfalls

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WATERFALLS

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How waterfalls are formed Hard rock River The river is flowing downhill, and flows over an area of hard rock.

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Soft rock starts to erode The soft rock erodes down, but as the water cannot erode the hard rock that stays in the same formation. A small drop is made from the hard rock to the soft.

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Eventually most of the soft rock is completely eroded, and the water flows off the hard rock and drops down. The force of the water landing makes a plunge pool at the bottom

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After a long period of time, the force of the hydraulic action in the pool could wear away the hard rock, forming a cave behind the waterfall. Eventually, the undercutting could cause the rock above to collapse, making the cliff retreat. This process would, in time, form a gorge.

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CASE STUDY Victoria Falls Victoria Falls are situated on the Zambezi river in Zimbabwe. At 5600 feet wide, and 328 feet deep, it is the largest waterfall in the world. The majority of the rock is basalt, but near the falls is criss-crossed with traverse faults of softer material. The force of the river is eroding these faults and forming a gorge. As well as being a great geological feature, the falls generate substantial income for Zimbabwe, most of which ending up in the hands of… Robert Mugabe!

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