It is an ppt for weathering and its type, with diagram. And in this ppt we use easy language so it help you for better understand.

1. WEATHERING

2. CONTENT
◦ Defination
◦ Controlling factors of weathering
◦ Agents of Weathering
◦ Types of weathering
◦ Physical or Mechanical weathering
◦ Chemical weathering
◦ Biotic weathering

3. 1. Defination: The physical and chemical processes ( like Air, Water, Temperature) which
decompose rocks & convert them to loose gravel, sand, clay, & soil it’s called
weathering.
According to B.B.Polynov(1937) “ The change of rock from the massive to the clastic state”.
According to Arthur Holmes “ Weathering is the total effect of all the various sub aerial
processes that cooperate the bringing about the decay and disintegration of rock provide
no large scale transport of the loosened products is involved “.

4. CONTROLLING FACTORS OF WEATHERING
1. Composition and structure of rocks
2. Nature of ground slope
3. Climatic variation
4. Floral Effects

5. AGENTS OF WEATHERING
◦ There are three types of agents which determine the all types of weathering. Such as..
1. Physical and Mechanical weathering
◦ Moisture and water
◦ Frost
◦ Temperatures
◦ Wind
2. Chemical weathering agents
◦ Oxygen
◦ Carbon dioxide
◦ Hydrogen
3. Biological weathering agents
◦ Vegetation
◦ Animals, micro organisms

6. Types of weathering
◦ On the basis of weathering agents, weathering are divided into 3 major types. Like..
1. Physical or Mechanical weathering:
The disintegration of rocks due to temperature variations, frost action, wind action and unloading of
confining superincumbent pressure then it’s called Physical weathering.
◦ Types of physical weathering:
◦ Exfoliation
◦ Frost Wedging
◦ Block Disintegration
◦ Granular disintegration
◦ Shattering
◦ Abrasion

7. Exfoliation
Exfoliation is a mechanical weathering process in
which pressure in a rock is released (unloading)
along parallel alignments (sheet joints) near the
surface of the bedrock and layers or slabs of the
rock along these alignments break off from the
bedrock and move downhill by gravity.
Shattering
◦ It’s occurred in hot climatic regions mainly in hot
deserts area,when light drizzles suddenly strike the
Rocks.

8. Frost Wedging
Frost wedging is a mechanical weathering
process caused by the freeze-thaw action of
water that is trapped between cracks in the
rock.
Abrasion
◦ Abrasion occurs when rocks collide against
each other while they are transported by
water, glacial ice.

9. Block disintegration
◦ It is mainly occurs when the temperature
changed through day and night.
Granular disintegration
◦ When the rocks are coarse grained and
also different colours, they absorb
insulation differently. So the differential
expansion and contraction created stresses
which break down the rocks it’s called
granular disintegration.

10. Chemical Weathering
◦ Decomposition and disintegration of rocks due to chemical reactions is called Chemical
Weathering.
◦ Types of Chemical weathering
◦ Carbonation
◦ Hydrolysis
◦ Hydration
◦ Oxidation
◦ Solution
◦ Chelation

11. Solutions
◦ Solution occurs when minerals in rock
dissolve directly into water.
◦ Solution most commonly occurs on rocks
containing carbonates , also affects rocks
with large amount of halite, or rock salt.
Oxidation
◦ Oxidation occurs when an ion in a mineral
structure loses an electron to an oxygen
ion.
◦ 4FeO (Ferrous oxide) + O2 → 2Fe2O3 (Ferric
oxide)

12. Carbonation
◦ Carbonation is a process by which carbon
dioxide and water chemically react to
produce carbonic acid, a weak acid, that
reacts with carbonate minerals in the rock.
◦ The first step in the reaction: formation of
carbonic acid by the reaction of water and
carbon dioxide.
◦ CO2 + H2O → H2CO3
Hydration
◦ Hydration is a process where mineral
structure in the rock forms a weak bond
with H20
◦ Mineral grains expand, increased stress
promotes the disintegration of the rock.
◦ 2Fe2O3 (hematite) + 3H2O → 2Fe2O3.3H2O
(limonite)

13. Hydrolysis
◦ Hydrolysis is a chemical reaction between
H+ and OH- ions in water and the
minerals in the rock. The H+ ions in the
water react with the minerals to produce
weak acids.
◦ Mg2SiO4 + 4 CO2 + 4 H2O ⇌ 2 Mg2+ + 4
HCO3
− + H4SiO4
Cheletion
◦ Chelation is a complex organic process by
which metallic cations are incorporated
into hydrocarbons molecules.

14. All types of weathering:

15. Biological weathering :
Biological weathering is the disintegration or decay of
rocks and minerals caused by chemical or physical agents
of organisms.
Faunal Weathering
◦ When the Animals like gophers,prairie
dogs,foxes,Rabbits etc are breakdowns tha
rocks, then it’s call Faunal weathering.
Floral weathering
◦ Plant roots penetrate into cracks and
crevices of rocks and cause the rock to
split or break into smaller particles
through mechanical weathering.

16. THANK YOU
DEBASISHBISWAS