Weathering of rocks

2. Weathering of Rocks
The process by which rocks are broken down and decomposed by
action of external agencies such as wind, rivers, rain, temperature,
changes is called Weathering.
● Mechanical Weathering
● Chemical Weathering
● Biological Weathering

3. Mechanical Weathering
● When the forces of weathering break rocks into smaller pieces
but do not change the chemical makeup of the rocks, the
process is called mechanical weathering.
● During mechanical weathering, rocks are broken into different
shapes and smaller pieces. At the beginning the edges are
jagged, as weathering continues, they become round.
Causes of Mechanical Weathering
1.Temperature
2.Frost action
3.Organic activity
4.Gravity
5.abrasion

4. Mechanical Weathering
Temperature (Expansion and contraction)

5. Weathering by Froast action

6. Mechanical Weathering
Effect of vegetation

7. Chemical weathering
● When the chemical compositions of the rocks is changed
it is called chemical weathering.
● During chemical weathering, changes occur in the
mineral composition of rocks. Minerals can be added,
removed or broken down (decomposed).Many substances
react chemically with rocks to break them down.
● There are several causes of chemical weathering.
1.Water
2.Oxidation
3.Carbonation
4.Sulfuric acid
5.Plant acids

8. Chemical Weathering
Dissolution

9. Chemical Weathering
Leaching

11. Weathering of Rocks
Biological Weathering

12. Thank you