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Monday, October 15, 2018

Summary on Karst Topography


Short Notes on Karst Topography


Topography
Karst Topography





Areas of karst topography



·        In India --Bihar,Himachal, Chhattisgarh  and Jammu Kashmir
·        Florida, carlsbad area of USA, Chalk area of England ,some part of Alps and Apennines






Type of cast topography
·        On the surface
Sinkhole
Spring
Natural Bridge
·        Below the surface
Cave



Erosional landforms
Lapies
Sinkhole
Doline
Karst window
Uvalas
Poljes
Caves
Natural Bridge



Depositional  landform
Stalagmite
Stalactite
Cave pillars
Helictites
Heligmite


Speleothem

All types of deposit of calcite in limestone Caves collectively called speleothom


Drip stone

The calcareous deposits from dripping of water in dry limestone Caves are called drip stone


Environment


Humid region

 

Karst Topograpgy Part 2







Erosional landform


Lapies

The highly rough surface of limestone lithology characterized by low ridge and pinnacles, narrow clefts  and numerous solution holes is called lapies. lapies are variously named in different part of the world that are; Clint in North England, Karren in  Germany, bogar in Earstwhile Yugoslavia etc.  lapies are generally formed due to corrosion of limestone along their joints when limestone are well exposed at the ground surface

Sinkholes

Chemically active rainwater charged with atmosphere carbon dioxide dissolved limestone and other carbonate Rock along their joints and thus various type of solution hole developed at the ground surface when limestone are directly exposed to the atmospheric process.

Smaller holes are called sinkholes while are generally of two types that are

  •  Funnel shaped sinkhole
  •  Cylindrical sinkhole



Some Shallow holes are further enlarge due to continuous solution into large depression which are called Dolines in the karst region and doline in Serbia. a feature almost similar to doline in appearance but with Shallow depth and large area extent is called solution pan. When the water cannot percolate downward and the doline is filled with water Sach doline full of water are called karst lakes.

Uvalas

Extensive depression are called uvalas which are up to one km across. They are formed in a number of ways e. g

  • Due to coalescence(fuse)  of several doline due to containers    solution and enlargement of doline.
  • Due To collapse of upper roof of a large cavities form underground.
  • Due to coalescence of various sinkhole


Poijes

Most extensive large then do line depression are called poljes. it is a closed basin of elliptical shape they are found in karst region of Earstwhile Yugoslavia and in Jamaica.They are formed due to downfolding and downfaulting of limestone area due to Earth movement. The resultant grabens are then modified by solution work of water.

Caves

Cave are void of the large dimension below the ground surface in fact they were the most significant landforms produced by erosional work of groundwater in limestone lithology. Carlsbad cave of USA are the example of very expensive cave. Limestone cave are found in India near Dehradun in Uttar Pradesh (Sahastradhara ,Robert cave) ,in Bihar Gupta Dham cave Bastar district of Chhattisgarh Kutumbsar cave and in Madhya Pradesh Gupt Godavari cave.



Formation of cave

Caves are formed due to collision (aberasion) of limestone why groundwater in the vadose zone above the water table of groundwater.
some scientist believe that cave are formed by phreatic (zone of saturation,)  water under hydrostatic pressure below water table.
some geomorphologist suggested that caves are not formed by fratta quarter water under hydrostatic pressure but are formed by the lateral flow of watervadose zone.

Features of Caves

  •  Ponores
  •  Natural Bridge


 Depositional landform

All type of deposits in the cave are collectively called speleothems. The landform are

  • Stalagmite
  • Cave pillars ( formed when stalactite and stalagmite meet together )
  • Helictite and Heligmite ( dripstone growing side word from stalactite and stalagmite )


Stalactite


Stalactite


Image result for stalactite

The formation of stalactite, stalagmites common in cavesit's a type of formation that hangs from the ceiling of caves , Stalactites may be composed of lave minerals mud peatand sands, A stalactite is not necessarily a speleothems though speleothems are the most common form of stalactite because of the abundance of limestone caves.




The corresponding formation on the floor of the cave
 is known as a speleothems.This rainwater plays a very
 important role in forming stalactite. When the water trickles
 through the rocks, inside the cave, minerals from the limestone 
as well as carbon dioxide in the air is picked up by the water.
CaCO3 + H2OCO2 → Ca(HCO3)2

CaCO3 + H2O + CO2 → Ca(HCO3)

Type of Stalactite
Lava stalactite 


Ice stalactite
Image result for stalactite
Concrete stalactite