Limestone and Karst Features

Section 1What limestone is

Limestone is a sedimentary rock made mostly from calcium carbonate. It often forms from the remains of sea organisms such as shells and coral. In Jamaica, limestone is common across large parts of the island, including the Cockpit Country.

Section 2Chemical characteristics

Limestone reacts with weak acids because calcium carbonate dissolves in acid. Rainwater becomes slightly acidic when it mixes with carbon dioxide in the air and soil, forming weak carbonic acid. Here's the trick: this weak acid is slow, but over many years it can shape whole landscapes.

Section 3Carbonation

Carbonation is the process where carbonic acid dissolves limestone. Water enters cracks and joints in the rock, slowly widening them. Watch out: carbonation is chemical weathering, not the same thing as a river simply carrying rock pieces away.

Section 4Karst features

A karst landscape has features formed by limestone solution. Sinkholes are depressions where the surface has dissolved or collapsed. Caves form underground where limestone has been dissolved along cracks.

Section 5Cave decorations

Stalactites hang from cave roofs, while stalagmites grow up from cave floors. They form when mineral-rich water drips and leaves behind calcium carbonate. In plain words, drip by drip, dissolved limestone builds new cave shapes.