What is carbonation? Give two examples of the landforms formed by carbonation?

Carbonation is the reaction of carbonic acid on minerals. Rainwater, when mixed with carbon dioxide in the atmosphere forms a weak solution of carbonic acid. It acts on rocks containing limestone and chalk. The reaction results in calcium bicarbonate which is highly soluble and gets easily washed away in solution as it flows through the rocks or seeps below the surface.

Two examples of the landforms formed by carbonation are stalactites and stalagmites.