What is Mechanical Weathering?

Weathering is the gradual wearing and tearing of rocks on the surface of the Earth. The main agents of weathering are temperature, humidity, and precipitation. Weathering is of three types— mechanical, chemical, and biological Weathering. Here we have discussed Mechanical Weathering only.


Main characteristics of weathering

  • Weathering is the wearing away or the disintegration of rocks.
  • This process includes the breaking down and not the removal of rocks from the surface of the Earth.
  • One of the most important results of weathering is soil formation.
  • Rocks break into stones, pebbles and eventually fine particles, which get transported by the agents of gradation such as wind and water.
  • It depends on climatic conditions. For example, in dry climate, mechanical weathering is very common.
  • The nature of rock (texture, composition and hardness) also affects the process of weathering.

Mechanical Weathering


It is also known as physical weathering. The disintegration of rocks without any change in their chemical composition is known as mechanical weathering. Moisture, changes in temperature, frost action, and winds are the main actors of this weathering. This kind of weathering usually occurs in hot deserts because of the wide ranges of temperature. There are four types of mechanical weathering:

Block Disintegration: Rocks disintegrate because of repeated expansion (due to high temperature) and contraction (due to extremely low temperature).

Granular Disintegration: Agents of weathering reduce the rocks made of different minerals to small pieces and fragments.

Exfoliation: Sudden change in temperature may cause cracks and fissures in rocks. Weathering occurs when water percolates in these fissures. The sudden expansion and contraction of rocks result in the peeling of their outer layers or exfoliation.

Frost Action: In regions of a dry climate, the cracks in rocks get filled with water. During the night, the water freezes and expands. When this process is repeated several times, the rock eventually breaks.


Also, Read Weathering