Weathering and erosion

weathering and its types
erosion and its agents

1. Weathering and Erosion

2. Weathering Weathering is the breaking down of rocks, soil, and minerals as well as wood and artificial materials through contact with the Earth's atmosphere, water, and biological organisms. Weathering occurs in situ (on site), that is, in the same place, with little or no movement.

3. Weathering

4. Types of weathering Physical weathering : also called mechanical weathering or disaggregation, is the class of processes that causes the disintegration of rocks without chemical change. The primary process in physical weathering is abrasion (the process by which clasts and other particles are reduced in size). However, chemical and physical weathering often go hand in hand. Physical weathering can occur due to temperature, pressure, frost etc. For example, cracks exploited by physical weathering will increase the surface area exposed to chemical action, thus amplifying the rate of disintegration. Chemical weathering: changes the composition of rocks, often transforming them when water interacts with minerals to create various chemical reactions. Chemical weathering is a gradual and ongoing process as the mineralogy of the rock adjusts to the near surface environment. New or secondary minerals develop from the original minerals of the rock. In this the processes of oxidation and hydrolysis are most important. Chemical weathering is enhanced by such geological agents as the presence of water and oxygen, as well as by such biological agents as the acids produced by microbial and plant-root metabolism. Biological weathering: is the weakening and subsequent disintegration of rock by plants, animals and microbes. Growing plant roots can exert stress or pressure on rock. Although the process is physical, the pressure is exerted by a biological process (i.e., growing roots).

5. Physical weathering

6. Chemical weathering

7. Biological weathering

8. Erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, animals, and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (Aeolic) erosion, zoogenic erosion, and anthropogenic erosion. The particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion; this contrasts with chemical erosion, where soil or rock material is removed from an area by its dissolving into a solvent (typically water), followed by the flow away of that solution. Eroded sediment or solutes may be transported just a few millimeters, or for thousands of kilometers.

9. Agents of Erosion Wind erosion: is a major geomorphological force, especially in arid and semi-arid regions. It is also a major source of land degradation, evaporation, desertification, harmful airborne dust, and crop damage especially after being increased far above natural rates by human activities such as deforestation, urbanization, and agriculture. Running Water: Causes Erosion. Of all of the agents of erosion, running water is the most powerful For our purposes running water includes everything from precipitation like rain and snow, streams, and rivers. When rain falls on the Earth's surface it will always move to the lowest elevation possible. Sea Waves : erosion caused by sea waves dominates along coast lines. The continuous pounding of waves weaken and break down rocks along the coast. Moreover, rock particles and sand carried by waves gradually wear down the rocks to form coastal physical features such as cliffs, stacks and arches.

10. Erosion

11. Wind Erosion

12. Flowing water Erosion

13. Sea waves Erosion