What is karst topography?

 

                        

The topography which is generally formed by action of water on the soluble rocks is called karst topography.

Mostly it is due to the action of drainage/ running water.

Soluble rocks are mostly carbonate sedimentary rocks.

Limestone, dolomite, gypsum are the carbonate sedimentary rocks.

And there exist the dissolved carbondioxide in the water.

When the water and dissolved carbondioxide comes together they react to form carbonic acid.

H2O

+

CO2

→

H2CO3

 Carbondioxide is also absorbed by the water from the atmosphere and from the ground through where it passes.

So formed the carbonic acids then comes in contact with carbonate rocks like limestone and others resulting them to dissolve.

Hence the carbonic acid dissolves the carbonate sedimentary rocks resulting to form karst topography.

                      CaCO₃ + H₂CO₃→ Ca²⁺+ 2 HCO₃⁻

                                                                             

Here in the above reaction the calcium carbonate rock (limestone) reacts with carbonic acid to get itself dissolved as calcium ion and bicarbonate.

The reaction leads to form a underground topography known as krast topography.

Generally, krast topography is dominated by underground flowage/drainage of the water.

The geological structures like caves are the result of this process and geologically known as the krast topography.

Karst topography are mostly formed due to the presence of features like crack, fractures etc on the surface.

These cracks and fracture allows the water to enter through it and it might be also due to the action of weathering of the rocks under suitable circumstances.

Krast topography is both geologically and sometimes economically important.

More often karst topography reserves/hosts hydrocarbons like petroleum products.

According to the survey, krast topography reserves more than 50% of world's hydrocarbon deposits.

In petroleum geology it is very important and also in the economic point of view.

 

References

Howells, M.F (2007). British Regional Geology:Wales. Keyworth, Nottingham: British Geological Survey.

Geomorphological Landscapes of the World.