Mechanical weathering is the physical breakdown of rocks into smaller pieces without a change in their chemical composition. It is caused by physical forces such as temperature changes, pressure, and the actions of wind, water, and ice. The processes of mechanical weathering include:
- Exfoliation: This is a process in which the outer layers of a rock are stripped away due to the release of pressure. This can occur in rocks that were once buried deep beneath the earth’s surface and have since been exposed through uplift and erosion. The pressure release causes the outer layers of the rock to expand and flake off, resulting in a rounded rock surface.
- Frost weathering: This is a process in which water seeps into the cracks and crevices in rocks and freezes, expanding and pushing the rock apart. When the ice melts, the water drains away, leaving the rock weakened and susceptible to further weathering. This process is common in regions with freeze-thaw cycles, such as mountainous regions.
- Granular disintegration: This is a process in which rocks break down into smaller pieces due to the actions of wind and water. Over time, wind-blown sand and dust can erode rocks, causing them to break down into smaller pieces. Similarly, water can cause rocks to break down due to the abrasive action of waterborne sediments.
