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Landscapes shaped by dissolving
Words to learn: limestone • dissolve • cave • swallow hole
How can water slowly remove enough solid rock to make caves and valleys?
WATER CAN DISSOLVE ROCK
Rainwater picks up a little carbon dioxide and becomes weakly acidic. As it moves through limestone, it can slowly dissolve some of the rock.
CRACKS BECOME PASSAGES
Water enters joints and cracks. Over very long periods these widen into channels and caves. Streams can disappear underground through swallow holes.
THE LANDSCAPE SHOWS THE CLUES
Limestone pavements, sink holes, caves and gorges show where rock has been removed. Inside caves, dissolved material can later form stalactites, stalagmites and flowstone.
WHAT YOU NEED TO KNOW
LIMESTONE LANDSCAPE
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