How do limestone caves form?
Limestone caves develop as water dissolves rock along fractures and bedding planes, enlarging underground openings. Chemical dissolution is central, although not all caves form in limestone or through the same mechanism.
From narrow fractures to passages
Water passing through soil can absorb carbon dioxide and become weakly acidic. It dissolves calcite in limestone, gradually enlarging initially narrow openings. Fracture positions, bedding inclination and groundwater levels guide circulation. Acidic waters rising from depth also contribute to some caves, so rainfall infiltrating from above is not a sufficient explanation for every example.
Distinguishing cavities from cave decorations
Stalactites and stalagmites can develop after a cavity exists, when chemical conditions permit mineral deposition. Excavating the void and depositing its decorations are different processes. Groundwater-level changes can dry some passages while others continue carrying streams. A cave system may extend far beyond its visible entrance. Because contaminants can travel rapidly through karst, protection matters for groundwater quality as well as tourism.