Denudation is the process of wearing away the Earth's surface by various agents such as water, wind, and ice. It involves the removal and transportation of rocks, sediments, and soil. The correct sequence in which denudation occurs is:
Weathering → Erosion → Deposition
1. Weathering: This is the first step in denudation. Weathering refers to the breakdown and decomposition of rocks and minerals at or near the Earth's surface. It can occur through physical, chemical, or biological processes. Physical weathering involves the mechanical breakdown of rocks into smaller fragments due to factors like temperature changes, frost action, or plant roots. Chemical weathering involves the alteration of rock composition through processes like dissolution, oxidation, or hydrolysis. Biological weathering refers to the breakdown of rocks by living organisms such as plants and animals.
2. Erosion: Once weathering has broken down the rocks, erosion takes place. Erosion is the process of removing and transporting the weathered materials from their original location to a new location. This is often done by agents such as water, wind, glaciers, or gravity. For example, water erosion occurs when rainfall or flowing water carries away sediments, creating channels, gullies, and valleys. Wind erosion happens when strong winds pick up and transport loose particles, leading to the formation of sand dunes and desert landscapes.
3. Deposition: After weathered materials have been eroded and transported, they are eventually deposited. Deposition occurs when the eroded particles and sediments settle down and come to rest in a new location. This can happen when the transporting agent loses energy, such as when a river slows down or when wind speed decreases. Deposited materials can form various landforms such as deltas, alluvial plains, or beaches.
In summary, denudation starts with weathering, where rocks are broken down. Then erosion takes place, transporting the weathered materials. Finally, the eroded materials are deposited in a new location.