Karst Landscapes

2590 WordsApr 14, 201311 Pages
1. Introduction The word ‘Karst’ comes from the Krs Plateau in Slovenia, where karst environments were first studied closely. The Slav people use ‘Krs’ to refere to ‘bare stony ground’. More specifically geomorphology refers to karst as a type of terrain characterised mainly by caves, sinkholes and complex drainage networks. The majority of karst formations occur in soluble rocks such as limestone and dolomite (although recent discoveries have revealed karst formations in more resistant rocks such as quartz, but are rare) and the reason for this is connected to the underlying processes. The two chief processes responsible for the weathering of rocks are physical weathering and chemical weathering, but it chemical weathering that is…show more content…
Figure 4: Pinnacle karst in Shilin National Park, Yunnan, China (Huggett 2011) 2.4 Relief The vadose zone is the layer above the water table. A shallow vadose zone means the water table is relatively high, this high water table supports the earth above it. A reduction in the water table could leave the ground above unsupported and a depression can be formed and in extreme cases collapse can occur. 2.5 Hydrology 2.5.1 Carbonates(Limestone and Dolomite) As mentioned before the chief process of erosion in karst systems is chemical weathering. Limestone is moderately soluble in pure water, but in water that contains carbonic acid the solubility of limestone increases greatly (Huggett 2011). There are three components present in chemical weathering of limestone. This process usually starts in the atmosphere(or in the soil for that matter) where water molecules mix with carbon dioxide and forms carbonic acid. CO2 + H20 H2CO3 As this solution of water and carbonic acid infiltrates carbonate rocks, especially limestone, the carbonic acid dissolves the calcite. CaCO3 + H20 + C02 Ca++ + 2HCO3- Limestone Dissolved Limestone Once this reaction reaches equilibrium it will remain in that state until pressure decreases or temperature increases at which point the dissolved limestone will return to limestone that will be deposited again, similar reactions are responsible for the
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