Here's why:
* Karst topography is primarily formed by dissolution. This means that the landscape is shaped by the chemical weathering of soluble rocks, mainly limestone and dolomite. Rainwater, which is naturally slightly acidic due to dissolved carbon dioxide, reacts with the rock, dissolving it over time.
* Mass wasting can play a secondary role. While not essential, mass wasting processes like landslides, rock falls, and soil creep can contribute to the development of karst features. These processes can expose fresh rock surfaces for further dissolution or alter the landscape to create sinkholes and other characteristic features.
Here's a breakdown of the typical karst formation process:
1. Dissolution: Rainwater reacts with the soluble rock, carving out underground cavities and channels.
2. Surface features: As dissolution continues, the surface collapses, forming sinkholes, dolines, and other depressions.
3. Underground features: The dissolved cavities and channels can become extensive, forming caves, underground streams, and complex networks of conduits.
In summary: While mass wasting can contribute to the evolution of karst landscapes, it's not a fundamental requirement. The primary driving force for karst formation is the chemical dissolution of soluble rock.
