Waterfall and Gorge Formation PDF

Step 1 of a waterfall and gorge formation Waterfalls are steep drops in the course of the river usually formed due to a band of harder rock. Step 2 The river is unable to erode the overlaying harder more resistant rock as quickly as the surrounding softer rock. Step 3 This may initially lead to...

Step 1 of a waterfall and gorge formation Waterfalls are steep drops in the course of the river usually formed due to a band of harder rock. Step 2 The river is unable to erode the overlaying harder more resistant rock as quickly as the surrounding softer rock. Step 3 This may initially lead to a steepening gradient or the rivers course may create rapids which is a steeper gradient of faster flowing water Step 4 This process continues creating a vertical drop as the softer rock is eroded more quickly by processes like hydraulic action. Step 5 Abrasion creates a deep plunge pool and splashback erosion starts to undercut leading to the formation of an overhang. Step 6 This overhang is no longer supported so it collapses into the plunge pool causing the waterfall to retreat. LArge angular blocks that have fallen into the plunge pool from the collapse of the overhang allowing more abrasion Step 7 The process of undercutting and collapse is repeated overtime and the waterfall retreats upstream, as it retreats it leaves behind a steep sided valley known as a gorge of recession