Karst Landforms – Cavern, Arch/Natural Bridge, Sink Hole/Swallow Hole, Karst Window, Sinking Creeks/Bogas, Stalactite and Stalagmite.

Landforms and Cycle of Erosion

• Fluvial Erosional Landforms [Done]
• Fluvial Depositional Landforms [Done]
• Glacial landforms and Cycle of Erosion [Done]
• Marine landforms and Cycle of Erosion [Done]
• Arid landforms and Cycle of Erosion [Previous Post]
• Karst landforms and Cycle of Erosion [This Post]

Karst Landforms and Cycle of Erosion

• Karst is a landscape which is underlain by limestone which has been eroded by dissolution, producing towers, fissures, sinkholes, etc.
• It is so named after a province of Yugoslavia on the Adriatic sea coast where such formations are most noticeable.
• Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum.
• It is characterized by underground drainage systems with sinkholes, caves etc..

Conditions Essential for Full Development of Karst Topography

• Presence of soluble rocks, preferably limestone at the surface or sub-surface level.
• These rocks should be dense, highly jointed and thinly bedded.

Cavern

• This is an underground cave formed by water action by various methods in a limestone or chalk area.

Arch/Natural Bridge

• When a part of the cavern collapses the portion which keeps standing forms an arch.

Sink Hole/Swallow Hole

• Sink holes are funnel-shaped depressions having an average depth of three to nine metres.
• These holes are developed by enlargement of the cracks found in such rocks, as a result of continuous solvent action of the rainwater.
• The surface streams which sink disappear underground through swallow holes.

Karst Window

• When a number of adjoining sink holes collapse, they form an open, broad area called a karst window.

Sinking Creeks/Bogas

• In a valley, the water often gets lost through cracks and fissures in the bed. These are called sinking creeks, and if their tops are open, they are called bogas.

Stalactite and Stalagmite

• The water containing limestone in solution, seeps through the roof in the form of a continuous chain of drops.
• A portion of the roof hangs on the roof and on evaporation of water, a small deposit of limestone is left behind contributing to the formation of a stalactite, growing downwards from the roof.
• The remaining portion of the drop falls to the floor. This also evaporates, leaving behind a small deposit of limestone aiding the formation of a stalagmite, thicker and flatter, rising upwards from the floor.
• Sometimes, stalactite and stalagmite join together to form a complete pillar known as the column.