Weathering: as endogenic processes .pptx

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1. by Airo Gumban Weathering is a natural process that breaks down rocks and minerals on Earth's surface into smaller particles. This process is essential in the formation of soil and provides necessary nutrients for plant life. WEATHERING

2. THREE TYPES OF WEATHERING Biotic weathering

3. 1. Also known as mechanical weathering, this process involves the breakdown of rocks without a change in their chemical composition. The rocks are fractured, cracked, or fragmented into smaller pieces.

4. Processes that can cause Physical Weathering: 1 Abrasion As rocks are subjected to the relentless forces of wind, water, and ice, their surfaces become worn down through a process called abrasion. This mechanical weathering causes the rock to gradually erode and break apart into smaller fragments. 2 Exfoliation Extreme temperature fluctuations can cause the outer layers of a rock to expand and contract at different rates, leading to the formation of thin, flaky sheets that peel away from the surface, a process known as exfoliation. 3 Freeze-Thaw Cycles When water seeps into cracks and crevices and then freezes, it expands and exerts immense pressure on the surrounding rock, causing it to crack and break apart. This cycle of freezing and thawing is a powerful agent of physical weathering. 4 Temperature Changes Changes in temperature cause rock to expand (with heat) and contract (with cold). As this happens over and over again, the structure of the rock weakens.

5. 2. This type of weathering involves the decomposition of rocks due to chemical reactions between the minerals in the rocks and the environment. Chemical weathering transforms rocks and minerals exposed to water and gases in the atmosphere into new chemical compounds, thus forming different rocks and minerals.

6. Hydration/ Hydrolysis Processes that bring about Chemical Weathering: Water reacts with minerals, particularly silicates, causing them to decompose and form new minerals like clay, altering the rock’s structure.

7. Processes that bring about Chemical Weathering: 2. Carbonation

8. 3. Oxidation Processes that bring about Chemical Weathering:

9. 4. Solution Processes that bring about Chemical Weathering:

10. Biotic weathering 3. This type of weathering involves both mechanical and chemical processes. The roots of plants penetrate into the joints of the rocks, growing longer and thicker over time. This exerts pressure on the rocks, causing them to break into smaller fragments.

11. 1 Lichen, Algae and Decaying Plants These symbiotic organisms secrete acids that can dissolve and chemically weather the surfaces of rocks, contributing to the overall process of rock breakdown and soil formation. Factors C ontributing to Biotic W eathering

12. Plant Roots The relentless growth of plant roots can penetrate deep into the cracks and crevices of rocks, exerting physical pressure that causes the rock to gradually break apart and disintegrate. Factors C ontributing to Biotic W eathering 2

13. Burrowing Animals Numerous small animals, such as insects, worms, and rodents, burrow into the soil and rock, creating intricate networks of tunnels and cavities that contribute to the mechanical breakdown of the underlying material. 3 Factors C ontributing to Biotic W eathering

14. Factors C ontributing to Biotic W eathering 3 Human

15. Weathering and Erosion: A Continuous Cycle Weathering The physical, chemical, and biotic processes of weathering gradually break down and transform rocks, minerals, and other materials on the Earth's surface. Erosion The weathered materials are then transported and carried away by wind, water, ice, and gravity, a process known as erosion, which shapes the landscape over time. Deposition The eroded materials are ultimately deposited in new locations, where they can form new rock formations or contribute to the development of soils and sedimentary environments.

16. Factors Affecting Transportation of Sediments: Transport by Water - Running water is the primary agent of erosion on Earth -Most running water is found in streams and rivers Transport by wind - wind continuously blows loose particle of rocks and soil from place to place. Many factors affect the movement of sediments in a stream: - Gradient (slope), discharge, and channel shape influence a stream’s velocity and the erosion and deposition of sediments. - Sediments carried by a stream are almost always rounded due to the grinding action of the water on the rocks, a process called abrasion. Factors Affecting Transportation of Sediments: