Pervious rock Water dissolves rock Solution reaction equation Dissolves to form cavern Increases over time Cavern roof collapses Forms gorge with stream and scree at bottom How is a gorge formed? Plan:
Limestone is a pervious rock meaning that it has joints and bedding planes . Water travels along these joints and bedding planes and dissolves some of the rock by solution weathering. Calcium carbonate + Rainwater + Carbon dioxide Calcium Bicarbonate . This reaction continues over a long period of time and a cavern is formed. The cavern grows in size due to the continuous weathering. Eventually the cavern roof can no longer be supported and it collapses. This forms a steep-sided gorge with a stream running at the bottom of it. The broken fragments of rock form scree at the bottom.