Question.
Examine various processes of physical weathering. ( UPPSC 2019)
Answer.
Weathering is a process in which rocks and minerals disintegrate or decompose on the surface of the earth, in this process their place of origin does not change.
The process of weathering is also called the process of soil formation.
There are three types of weathering processes – chemical, mechanical (physical), and biological weathering.
Physical weathering:
Physical weathering is also called mechanical weathering in which rock breaks down mechanically or physically without change in its chemical properties.
Following are the processes of physical weathering:
- Exfoliation (onion skin)
- Frost weathering
- Mass fragmentation
- Friction and attrition
- root extension
Exfoliation (onion skin):
In general, rocks are poor conductors of temperature, as a result of which the outer layers of rocks heat up very rapidly when there is extreme heat and expand or contract rapidly on cold days, causing the separation of curved sheets like onions sheets from the main rocks. Peel-like layers fall out. This type of weathering is called exfoliation.
Frost weathering:
As we know that the volume of ice is more than that of water of the same volume. When water repeatedly fills the crevices of rocks and it freezes in winter to become ice, as a result of which the cracks widen and the rocks break. This type of weathering is called frost weathering.
Mass fragmentation :
Where there is a greater difference between day and night temperatures, such as in the desert region, the rock expands due to heat and contracts due to cold. When such action happens again and again, then the rocks break, we call this mass fragmentation weathering.
Friction and Gravity:
When the winds carry the weathered sands on a large scale and transport them to other places, the sand gets abrasive during transportation and the large pieces are converted into small pieces.
Some rocks also break due to gravity. The process of this type of weathering is known as frictional weathering.
Root extension:
Roots of vegetation often penetrate broken rocks, with time the roots widen leading to the disintegration of the rocks.
All the above processes are the process of physical weathering.
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