Limestone Caves
Storyboard Tekst
- This river is flowing along impermeable rock, which means that the water cannot penetrate the rock.
- Whenever it flows onto limestone, the water will chemically react with the calcium carbonate, causing it to dissolve away.This forms a sinkhole.
- The water chemically erodes along the horizontal bedding planes and vertical joints.
- Over time, the joints and bedding planes get wider as the water flows through the cracks and erodes the calcium carbonate.When there are lots of joints close together, the rock opens up, leaving a cave system.
- When dripping water in the cave is evaporated, calcite that has been picked up by the water is left behind.This can either form a stalactite that hangs from the roof, or a stalagmite on the ground.
- When the river hits impermeable rock again, it cannot erode downwards any further, and it will eventually re-emerge from the limestone.
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