Karst
topography formed from the dissolution of soluble rocks / From Wikipedia, the free encyclopedia
Karst is a geological system of rocks where water has eroded (dissolved) the bedrock. If it is very extensive, karst can be a geographical or topographical feature. It is classed as a badland if it difficult to travel through the environment, which it often is.
Almost always, karst is formed in carbonate rocks, such as limestone or dolomite. Since carbonate sedimentary rocks are very common, karst areas occur all over the world.
Many karst regions display distinctive surface features, with sinkholes being the most common. However, karst surface features may be absent where the soluble rock is mantled (covered), such as by a non-soluble rock strata on top of the carbonate strata. Some karst regions include thousands of caves, and the water is generally underground.
The world's largest karst area is the Nullarbor Plain, part of the area of flat, almost treeless, dry country of southern Australia. It is on the Great Australian Bight coast with the Great Victoria Desert to its north. It is the world's largest single exposure of limestone bedrock, and occupies an area of about 200,000 square kilometres (77,000 sq mi).[1] At its widest point, it stretches about 1,100 kilometres (684 mi) from east to west across the border region between South Australia and Western Australia.