Physical Weathering of Rock Quick Check
Physical weathering refers to the process by which rocks are broken down into smaller fragments without any change in their chemical composition. It occurs primarily through mechanical or physical forces acting on the rocks. Some common examples of physical weathering include:
1. Frost Wedging: This process occurs when water seeps into cracks or joints in rocks and freezes. When water freezes, it expands by about 9%, exerting pressure on the surrounding rock. Over time, repeated freeze-thaw cycles can cause the rock to break apart.
2. Abrasion: Abrasion occurs when rocks and sediment are carried by wind, water, or ice and collide with other rocks. The constant friction and impact gradually wear down the rocks, leading to their breakdown.
3. Exfoliation: Exfoliation is the gradual peeling away of outer layers of rocks due to the release of pressure. When rocks formed under high pressure are exposed to the surface, the outer layers expand and crack, resulting in the formation of curved layers or slabs that peel off.
4. Thermal Expansion and Contraction: Rocks expand when heated and contract when cooled. These expansion and contraction processes cause stress within the rocks, leading to the formation of cracks and fractures.
5. Biological Weathering: Biological activity, such as the growth of plant roots or burrowing of animals, can also contribute to physical weathering. Roots can exert significant pressure on rocks, causing them to crack and disintegrate.
These processes of physical weathering can act individually or in combination to break down rocks into smaller fragments. Over time, repeated cycles of physical weathering, together with chemical weathering, contribute to the further breakdown and alteration of rocks, eventually resulting in soil formation.