Here's how it works:
* Carbonic Acid Formation: Rainwater absorbs carbon dioxide from the atmosphere, forming weak carbonic acid (H2CO3).
* Reaction with Calcium Carbonate: This carbonic acid reacts with calcium carbonate, the primary component of limestone, to form calcium bicarbonate (Ca(HCO3)2).
* Dissolution and Erosion: Calcium bicarbonate is soluble in water, so it dissolves and is carried away by groundwater. This process erodes the limestone, creating the characteristic features of karst topography like caves, sinkholes, and underground drainage systems.
In essence, the formation of karst topography relies on the chemical weathering of limestone through the dissolution of calcium carbonate by carbonic acid.
