There is an exciting chemical process behind the impressive landscapes of karst. For karstification to occur, two key factors are needed:
Wie in der vorherigen Station „Karst und seine Landschaftsformen“ erklärt, beschreibt der Begriff Karst Geländeformen, die durch Lösungsverwitterung und den Abtransport des gelösten Materials von Gesteinen entstehen. Damit dieser chemische Prozess ablaufen kann, müssen zwei wesentliche Faktoren erfüllt sein:
Factor 1: The type of rock
Not every rock karsts. Karstification mainly occurs in carbonate rocks such as limestone or dolomite, which consist of the mineral calcite or dolomite and dissolve on contact with acid. However, there are also karst forms in other water-soluble rocks such as gypsum or rock salt.
An example from everyday life: if you clean your kettle with citric acid, it starts to foam and the limescale dissolves – water reacts similarly to limestone, only much more slowly. But how does our rainwater and groundwater become acidic?
Factor 2: Acidic water
Rainwater absorbs carbon dioxide (CO₂) in the air and soil and carbonic acid is formed.
You may know carbonic acid from sparkling water or other fizzy drinks. Rainwater, however, does not bubble because it contains much less carbon dioxide and lacks excess CO₂ pressure. Despite this, the carbonic acid in rainwater reacts with limestone, gradually dissolving it. The dissolved limestone is then carried away by the water.