- Soda straw
A soda straw (or simply straw) is a
speleothem in the form of a hollowmineral tube. They grow in places where water leaches slowly through cracks in rock, such as on the roofs ofcave s. A soda straw can turn into astalactite if the hole at the bottom is blocked, or if the water begins flowing on the outside surface of the tube.These tubes form when
calcium carbonate orcalcium sulfate dissolved in the water comes out of solution and is deposited. In soda straws, as each drop hovers at the tip, it deposits a ring of mineral at its edge. It then falls and a new drop takes its place. Each successive drop of water deposits a little more mineral before falling, and eventually a tube is built up.Stalagmite s orflowstone may form where the water drops hit the cave floor.Soda straws are some of the most fragile of speleothems. Like
helictite s, they can be easily crushed or broken by the slightest touch. Because of this, soda straws are rarely seen within arms' reach in tourist caves. When left alone, soda straws have been known to grow up to 9 metres (30 feet) long.Soda straws are also known as
Tubular Stalactites External links
* [http://www.showcaves.com/english/explain/Speleothem/Straw.html Showcaves.com definition and explanation]
* [http://www.goodearthgraphics.com/virtcave/sodastw/sodastw.html The Virtual Cave soda straw photos]
* [http://flickr.com/photos/newbluecat/2137632362/ A photo of some amazing soda straws in south eastern France]
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