Content adapted with permission from the Nature Conservancy in Indiana, a partner in the Natural Heritage of Indiana project. More information can be found here.
What is Karst and what is a cave? Karst is a landscape; caves are features of the landscape.
Karst = distinctive type of landscape that is largely shaped by the dissolving action of groundwater on carbonate bedrock, usually limestone. This geological process, which will take thousands of years, is characterized by unique features such as sinkholes, fissures, caves, disappearing streams, springs, rolling topography, and underground drainage systems.
Caves = natural cavity containing a series of chamber found beneath the earth and large enough for an adult to enter into it. Caves are features of Karst topography.
Underneath the rolling hills and glistening streams of Southern Indiana lies an extraordinary world practically unknown to man. The mysterious underground world of caves with their intricate passageways and dramatic formations is a wonderland just waiting to be explored. However, care must be taken not only to protect the animals that rely on these caves, but the citizens who are fortunate to live on this phenomenal landscape known as karst.
The karst formation process involves what scientists refer to as "the carbon dioxide cascade." As rain falls, it picks up CO2 which dissipates in the droplets. When the rain seeps into the soil, it picks up more carbon dioxide and forms a weak solution on carbonic acid (H2O + CO2 = H2CO3). Over long periods of time, a continuous flow of this acidic water will dissolve carbonate bedrock and create larger openings in cracks and crevices already in the rock. An underground drainage system will eventually from, allowing more water to pass and will lead to the development of caves and other karst formations.
There are two areas of karst landscape in Indiana – the Mitchell Plateau and the Muscatatuck Plateau. Mitchell is located in southern Indiana, extending from eastern Owen County southward towards the Ohio River in Harrison County. Muscatatuck is found in southeastern Indiana. Both were developed by limestone with Mitchell created by Mississippian limestone and Muscatatuck on Silurian and Devonian age bedrock.
Why Does Karst Matter?
Caves provide essential habitat for unique plants and animals, some of which spend their entire lives in complete darkness - many of them that would not be able to survive otherwise. With our biodiversity at risk, it is important to be careful above and below our karst regions. With some of the species at risk of extinction, it is important to take care when caving as not to disturb what is down below.
Another important reason to be concerned about karst and caved is because these systems carry water from the surface to the underground aquifers where most of our drinking water originates. In fact, almost 25% of the groundwater is located in caves and karst regions. The protection and management of these vital water resources are critical to public health and to sustainable economic development. Once a cave is damaged, its formations and the creatures that live within it cannot be recovered.
Karst systems are critical environmental resources. In fact, 40% of our drinking water passes through cave and karst systems. According the the USGS's Ground Water Resources Program, "the importance of ground-water in complex geologic environments can no longer be overlooked." More»
Interested in visiting Indiana's caves? Check out these sites:
Bluespring Caverns in Bedford
Marengo Cave in Marengo
Spring Mill State Park in Mitchell
Squire Boon Caverns in Corydon
Wyandotte Caves in Leavenworth