How Do Caves Form in Limestone Short Answer
Caves form in limestone areas as a result of chemical erosion. Carbon dioxide from the soil and air dissolves in streams and rainwater, producing a weak acid which dissolves some of the limestone rock away. When a stream flows over limestone ground, it dissolves a vertical channel though the rock, called a swallow hole. This hole goes down as a far as the water table which is the level where ground water seeping up from below has reached. The horizontal caves are formed at this level. If the water table drops, the caves are left dry and new caves are dissolved deeper down. As the ground water seeps through the limestone, it dissolves the weak areas, enlarging the natural spaces and cracks in the rocks into caves.