Weathering & it types

Weathering & it types By Sardar Hashim Abbas

1. Presented by Sardar Hashim Abbas Roll # 02 BS-Geology 1 st semester Presented to Mr. Aamir Asghar Sabz Ali Khan & Malli Khan Institute Of Earthsciences

2. What Is Weathering ?

3. What Is Rock? Aggregate of minerals is known as rock. Rock is naturally occurring in the earth. Which have different physical & chemical properties.

4. What Is Weathering ? Defination : The Physical, Chemical & biological Break Down Of Rocks Is Called Weathering. The Rock Break and Undergo Decay Under The Influence Of Atmosphere Agencies Like Wind,Water, And Glaciers. Disintigration Of Rock Known As Weathering .

5. Types Of Weathering There Are Three Types Of Weathering :- Physical Or Mechanical Weathering: Chemical Weathering: Biological Weathering:

6. Physical Weathering Rock break into pieces. Changing size and shape. But not their composition. Example: Breaking of a rock cliff into boulders and pebbles.

7. Types of Physical weathering Following are the agents or types of physical weathring frost wedging: Wetting and drying: Exfoliation: Plant Growth: Thermal expansion: Abrasion: Burrowing of animals: Temperature changes:

8. Frost wedging Water enter the small cracks in the rock. When it freezes,it expand and forces the crack to open more. The process repeat over again untill the rock break apart.

9. Frost wedging

10. Freeze-thaw weathering in action

11. Wetting and drying breaks up rocks that are made from clay. When they are wet they expand, and they shrink as they dry. As this repeats over and over, the clay becomes weak and cracks.

12. The top rock layers are removed releasing pressure. The underlying rocks then crack and fall apart. Exfoliation

13. Granite exfoliation:-

14. Plant Growth:- As plants such as trees send out root systems, the fine roots find their way into cracks in the rocks. As the roots increase in size, they force the rock sections apart, increasing the separation and weathering.

15. Root wedging:-

16. Thermal expansion Daily cycle of temperature change weakens rock. Rock expand when they are heated and contract when they cool. The repeated expansion and contraction tends to develop cracks in rocks. It is most common in deserts.

17. Abrasion Many rocks along on the beach or stream or river are rounded. They have been rounded by collision during down stream movement with silt and sand carried by water. Abrasion is also done by wind.

18. Chemical Weathering When agents of weathering chemically change the composition of rock. The process that break down the rock through chemical change.

19. Agents of chemical weathering:- Oxidation: Hydration: Carbonation: Acid rain: Living organisms:

20. Oxidation:- oxygen reacts with some minerals, especially those containing iron to form rust (called iron oxide) Oxygen combines with minerals to form oxides. (iron + oxygen = Rust)

21. Hydration:- Minerals absorb water and chemically change the composition of the material.

22. Carbonation:- When pollutants like Carbon Dioxide, Nitrogen & Sulfuric Oxides mix with rain water creating acid rain, which can dissolve limestone and harm the living environment. 1:- 2:-

23. Karst Topography A type of landscape in rainy regions where there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams. Created by chemical weathering of limestone

24. Acid rain:- Compounds from burning coal, oil and gas react chemically with water forming acids. Acid rain causes very rapid chemical weathering.

25. Living organisms:- Lichens that grow on rocks produce weak acids that chemically weather rock.

26. They wedge their tiny roots into spores and crevices. When the roots grow, the rock splits. Lichens:-

27. Soil Formation:- Over many years, weathering and erosion will cause the formation of soil. Soil is the loose, weathered material on the Earth’s surface in which plants can grow. Soil forms as rock is broken down by weathering and mixes with other materials on the surface.

28. Factors affecting soil formation:- Parent material: Slope: Living organism: Climate: Time:

29. Thanks