Waterfall Formation

Waterfall Formation

• A waterfall begins when a river crosses hard rock on soft rock, for example granite on limestone.
• Due to hydraulic action, the limestone is eroded first creating an over hang from the granite and a plunge pool.
• The overhang eventually collapses and falls into the plunge pool. Attrition cause the plunge pool to get deeper and wider.
• The water will also get in the bedding planes and joints and break up more of the limestone making the plunge pool even bigger.
• The waterfall then retreats back up stream, it leaves a steep sided gorge as it retreats.
• https://www.youtube.com/watch?v=jqCR-9nBgWQ (Embed)