Weathering

The term weathering is used for disintegration and decomposition of rocks without any significant transportation of resulting product.

Weathering is of two types
1.Mechanical weathering:In this case rocks are disintegrated by physical breaking down.
2.Chemical weathering:In this case decomposition of rocks are formed by chemical reaction.Most of the reaction occurs with presence of water with different dissolving materials.

Chief weathering agents
Followings are the chief agencies responsible for weathering of rocks.
1.Atmospheric gases:The atmosphere contains CO2,O2,N2 and other gases.When these dissolve in water react with rock.
2Water:Water is an important agency.Pure water has little effect.But water with dissolved materials bring about massive changes in rocks.
3Frost:In cold regions water enter into the pores of rocks.When water becomes ice its volume expands causing disintegration of rocks.
4Heat:In hot regions rocks expand in day because of heat of sun and in night when temperature drops rocks get contracted.This develops stress causing disintegration of rocks.
5Organic agencies:Organic agencies cause both mechanical and chemical weathering.many animals dig holes in rocks for living,roots of plants forming on rocks give stress on rocks,different bacteria cause chemical reactions on rock surface etc.