Karst

Karst is a landscape and topographic system formed from the dissolution of soluble rocks, notably limestone, dolostone, and gypsum. It is named after the Karst Plateau in southwestern Slovenia, a classic early described example.

The key process is chemical weathering: rainwater absorbs CO2 from the atmosphere and soil, forming carbonic acid, which dissolves calcite in the rock as water percolates downward. Over long timescales, this produces caverns, underground drainage networks, and surface depressions.

Surface expressions include sinkholes (dolines), poljes (large flat-floored depressions), and limestone pavements with ruling joints (karren). Caves form when fractures are widened and channels enlarge, often hosting underground rivers and speleothems such as stalactites and stalagmites formed from mineral deposition.

Hydrology: karst aquifers are highly heterogeneous; much groundwater flows through conduits with rapid transmission, leaving springs and ponors where water exits; groundwater flow can be difficult to map; vulnerability to contamination is high for soluble rock areas.

Distribution and examples: karst occurs worldwide wherever suitable rocks occur, notably the Dinaric Karst of the Balkans, the South China Karst (a UNESCO site), and extensive karst systems in Florida and China.

Human use and conservation: karst regions provide important water resources, support cave tourism and scientific study, and host unique ecosystems. Management emphasizes protecting groundwater quality, safeguarding cave habitats, and mitigating hazards such as sinkholes.