Buffalo National River has over 300 caves within its boundary. The Ozark Plateau is one of the most caverniculous areas in the United States. Karst is a type of topography that is usually formed in rocks such as limestone and dolomite. It is characterized by an integration of surface and ground water via sinkholes, caves, losing streams, and springs. These features and networks are formed, most typically, as rain water becomes charged with carbon dioxide when it falls through the atmosphere. When the drops hit the surface, they pick up additional acids and enzymes as they percolate through the soil layers. Upon reaching the carbonate rock surface, they begin to dissolve some of the rock and carry the calcium and magnesium ions in solution. Sometimes, the water finds a fracture going down toward the water table. As it runs down the fracture, it can pick up more mineral ions from the rock, thereby enlarging the fracture. When this water reaches the water table and mixes with the groundwater, it further enlarges the fracture or conduit it followed to get there. As the water runs laterally near the water table, large horizontally trending passages can be dissolved out of the rock. Eventually this water will come back to the surface at a cave mouth or spring. From there it can be re-evaporated and begin the cycle again. Sometimes the rainwater drop that has filtered through the soil and into the rock encounters an air filled void on its way to the water table. If the drop has picked up some ions, and the partial pressure of gasses dissolved in the drop is greater than in the cave air, it will deposit some of its load as it gives off some of its gasses to the air. This occurs when the drop falls from the ceiling, and when it hits the floor or another obstruction. As its gases try to reach equilibrium with the cave air, the drop will continue to deposit its mineral load, usually as calcium carbonate.
Calcium carbonate, otherwise known as calcite or aragonite (depending on the crystal structure) is the mineral that makes the most commonly seen cave formations or speleothems. This drop of rainwater could easily help form stalactites, stalagmites, draperies, flowstone, or rimstone dams on its journey through the rocks. The longest known cave in Arkansas occurs in Buffalo National River. Fitton Cave contains approximately twelve miles of humanly traversable passage. The cave is gated and locked. A permit is required to enter. Because of its complexity and difficulty level, only experienced cavers may obtain a permit to enter this cave. The permit requires the caving party to consist of four to eight cavers. Everyone entering the cave must have three reliable light sources, a caving helmet, food and water adequate for the planned trip duration, and a means of carrying out all litter, refuse, and body waste. Permits are available by contacting the park geologist at (870) 741-5446, ext. 275. There are other caves in the park available for unguided wild caving trips, a list of these may be obtained by contacting the park geologist. Coon Cave at Buffalo Point is open for guided trips during the summer months. To schedule a trip, contact the park interpreters at Buffalo Point.