1. Presence of soluble rock: This is most commonly limestone or dolomite, but other soluble rocks like gypsum and rock salt can also contribute. These rocks are susceptible to dissolution by slightly acidic rainwater.
2. Favorable climate: A humid climate with sufficient rainfall is needed to provide the acidic water necessary for dissolution. This water, combined with the presence of carbon dioxide from the atmosphere and decaying organic matter, forms carbonic acid, which dissolves the soluble rocks.
These two factors, together, create the conditions necessary for the formation of karst features like sinkholes, caves, and underground drainage systems.
