Karst Landscape Formation
Karst is the surface expression of cave-forming processes. Where limestone dissolves underground, the same chemistry produces distinctive surface features: sinkholes, dolines, karst towers, disappearing rivers, and barren limestone pavements.
The dissolution mechanism
Rainwater absorbs atmospheric CO2 to form weak carbonic acid; percolating through soil, the acid concentration increases as organic matter releases more CO2. This mildly acidic water dissolves calcium carbonate: CaCO3 + H2CO3 -> Ca(HCO3)2. The dissolved bicarbonate is carried away in solution.
Dolines and sinkholes
The most characteristic karst feature. Solution dolines form slowly by progressive dissolution; collapse dolines form when a cave ceiling fails and the surface drops abruptly. The Big Hole in Switzerland and Skocjan in Slovenia are spectacular examples.
Karst towers and conical hills
In tropical karst, dissolution proceeds rapidly enough to leave isolated tower hills with vertical sides — the Guilin landscape of China, Halong Bay's sea karst, and the Phong Nha-Ke Bang spires. The vertical walls are maintained by saturated water at their base.
Karren and limestone pavement
Bare limestone surfaces develop characteristic dissolution patterns: small runnels (rinnenkarren), pits (kamenitzas), and sharp ridges (spitzkarren). The British Burren and Yorkshire pavements are classic examples.
Disappearing rivers and resurgences
Rivers crossing karst landscapes often sink underground into cave systems and reappear at lower elevation. The Reka River at Skocjan, the Cetina in Croatia, and the Sotano in Mexico are classic examples.
Polje and uvala
Polje are large flat-floored karst depressions, often with internal drainage. Uvala are smaller, with merged dolines. The Lika polje in Croatia is the largest in Europe.
Conservation
Karst aquifers supply drinking water to 25% of the world's population. They are also exceptionally vulnerable: surface pollution moves rapidly to groundwater because karst soils are thin and water reaches the aquifer through open fissures.
Explore on the map
See karst landscapes on the interactive map.