Karst
From GeoClasses
Exploring Karst: Blanchard Springs Caverns - an excellent discussion of karst from an extra-credit project.
Reading
- Karst landscapes
- Cave formations
The disolution of soluble rocks like limestone and dolomite form karst. Typical karst features are usually produced by erosion along limestone shores, including a sharp surface above the normal reach of the sea and undercuts that are mostly the result of biological activity or bioerosion at or a little above mean sea level.
Cave formations are created when acid reacts with limestone or rocks containing 80% or more calcium carbonate. These formations are found on the walls, ceilings and floors of caves. A number of conditions are needed to be present for speleothems(deposits) to form within a karst environment. First the types of rocks within and surrounding the cave need to have an 80% content of calcium carbonate which is usually limestone, dolomite or a similar type of rock. The bedrock(rock that underlies the earth's surface) also needs to be highly fractured or jointed so the water can flow through or follow these joints or fractures, also the bedrock needs to be relatively close or at the surface. The more water there is the more karst form and the less water there is the less karst form. The fourth requirement for karst and spelethem formation is a relatively moderate annual rainfall. The final condition is vegetation, this enhances the karst process by producing more available acids. A few variable factors including humidity, temperature and air flow through the cave also play an important role in speleothem formation.
Where do you typically find karst and how are they formed?
