ORIGIN OF SOILS- Formation And Types

Ø Soils :- It is a loose material consists of solid particales
·       Soil Formation :-There are two type of soil formation
1)       Organic Decomposition
2)     Weathering of Rock (mostly)
·       Organic soil are called as “Cumlose Soil”
·       Soil that formed due to weathering of rock or inorganic soil
Ø Voids;- Voids in the soil get filled with water or air or both
Ø Soil Mechanics:-
                            Mechanics that deal with action of forces on the soil and flow of water in soil.
·       Soil mechanics was coined by “KARL TERZAGHI”


·        Based  On Geological Cycle:-
1)       Residual Soil:-Soils that are deposited at the place of its origin.
2)     Sedimentary/ Transporting :- Soils are deposited away from its origin.
Ø Based on Transported Agents:-
1)       Water
2)     Air
3)    Glacier / Ice
4)     Gravity
1)       Water :-
a)      Alluvial Soil
b)      Lacrustine Soil
c)      Marine Soil
a)      Alluvial Soil :-The soil that are deposited by means of running water.
b)     Lacrustine Soil:- Soil that are formed by means of lake water
c)    Marine Soil :- Soil that formed by sea water
2)     Air:-  Wind Deposit = Aeolian Soil Example:- Sand, Duens,losses    
3)    Glacier :- Soil is formed by melting of Glacier or ice are  called as Glacier. Deposits. Example :-(Taulus )
4)     Gravitational Deposit :- This depostion is based on gravity forces.
Based on Forces :-

Ø Different terminology :-
1)       Varved Clay :- Alternate thin layers of silt and clay
See in lake (Lacrustanine deposit)
2)     Loam :- It is mixture of sand , silt, clay, with each praporation should be less than 50%
3)    Moorum :- Mixture of Red gravel and clay. This is used in construction purpose
4)     Loess (Aeoline soil):- Uniform silty deposit having high compressibility and low shear strength.
5)    Black cotton Soil :- it has high  swelling and shrinkage.
It has high compressibity and low strenghth. Highly expansive soil.
6)    Bentonite clay :- High swelling and shrinkage , formed by volcanic ash , used as Drilling mud
Ø Organic Soils :-
1)       Humus :- Partially decomposed organic matter
2)     Peat :- Full decomposed organic matter and fibres in nature
3)    Muck :- Fully decomposed organic matter and some fine inorganic matter.
By:- Vaibhav Jadhav

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