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In this lesson we are going to discuss about the underground features of limestone areas

Answer Text:
Underground Features in Limestone Areas

a) Stalactites
- Finger like masses of calcite hanging vertically from the roof of a limestone cave or cavern formed by repeated evaporation
of water and giving off of carbon dioxide from drops of water containing calcium bicarbonate hanging from the roof of the cave causing
crystallisation of calcium bicarbonate into calcite.
b) Stalagmite
- Stumpy rock masses of calcite which grow from the floor of a limestone cave upwards formed by repeated dripping of solution
of calcium bicarbonate from the end of stalactite to the floor of a limestone cave then it spreads out and crystallizes.
c) Limestone Pillars
- Pillar like structures in limestone caves formed when stalactites and stalagmites grow towards each other, stalagmite grows until it touches the roof
of a cave or when a stalactite grows until it touches the floor of the cave.
d) Limestone caves
- Underground chambers or cavities in limestone rocks.
- Underground rivers dissolve limestone in horizontal joints forming a horizontal tunnel.
- Surface water and underground water percolates through the joints into the tunnel enlarging it forming a phreatic cave i.e. cave below
the water table.
- The water flows out at the vauclusian spring lowering the water table causing the phreatic cave to become a limestone cave.
- Continued solution from water percolating through the caves roof widens and lowers its floor to form a larger cave called limestone cavern e.g.
Carls band cave in New Mexico U.S.A.