Question

Explain the erosional landforms formed by underground water.

Answer 1

Most erosion takes place due to the process of solution. When rain water mixes with carbon-di-oxide and enters into a limestone region, it dissolves and destroys much of the limestone. As a result, landforms suph as Terra rossa, Lappies, sinkholes, swallow holes, dolines, uvalas, poljes, caves and caverns are formed.

1. Terra Rossa (Italian term for Red soil):
   Deposition of red clay soil on the surface of the Earth is due to the dissolution of limestone content in rocks. The redness of the soil is due to the presence of iron oxide.
2. Lappies:
   When the joints of limestone rocks are corrugated by groundwater, long furrows are formed and these are called lappies.
3. Sinkhole:
   A funnel shaped depressions formed due to dissolution of limestone rock is called sinkholes. Their average depth ranges between three and nine meters.
4. Caves and Caverns:
   Caves and caverns are subterranean features of karst topography. Caves are hollows that are formed by the dissolution of limestone rocks when carbon di oxide in air turns into carbonic acid after its reaction with water. They vary in size and shape. Caverns are the caves with irregular floors, e.g., Guptadham caves in Western Bihar.
   All types of deposits in the caves and caverns are collectively called speleothems which includes travertines, tufa, dripstones.
   Swallow Holes, Uvalas, Dolines, Poljis are other erossional Features of karst regions predominant in other parts of the world.