Underground features

A cross section of a limestone pavement before the effects of chemical weathering have taken placeThe formation of a limestone cave – before chemical weathering

A crosssection of a limestone pavement showing what a limestone cave looks like after the effects of chemical weathering have taken placeThe formation of a limestone cave – after chemical weathering

Inside a cave with stalactites and stalagmites
Inside a cave with stalactites and stalagmites

The video below talks about the formation of caves.

Inside the cave are a number of distinctive features, which have formed over thousands of years. They are all the result of water infiltrating the rock and dissolving the limestone.

Underground caveUnderground cave

Inside of a limestone cave showing stalctites hanging from the ceiling and stalagmites on the ground

As water flows underground it dissolves the limestone. The dissolved limestone (calcium carbonate) is carried away by the water. Water drips from the roofs of caverns very slowly and evaporates.

As the water evaporates, solid calcium carbonate is deposited on the cavern roof. This will build-up over time to form long, thin deposits which grow downwards and look like icicles hanging from the ceiling of a cavern. These are called stalactites.

Some drops of water fall to the floor of the cavern where they splash and evaporate. The splash spreads the deposit of calcium carbonate.

As more and more calcium carbonate builds up on the floor, short, wide, dumpy features grow upwards from the ground. These are called stalagmites. Occasionally stalagmites and stalactites grow towards one another and join to form a rock pillar.