International Journal of Applied Research
Vol. 2, Issue 5, Part G (2016)
Weathering of rocks: A review
Weathering is the alteration of rocks to more stable material from their exposure to the agents of air, water, and organic fluids. No rock is stable or immune to weathering. Many pathways and agents are involved in weathering, but most can be grouped into two main processes: mechanical and chemical weathering.
Mechanical weathering includes processes that fragment and disintegrate rocks into smaller pieces without changing the rock's mineral composition. Chemical weathering is the alteration of the rock into new minerals. Both pathways constitute weathering, but one process may dominate over the other. The two processes can be demonstrated with a piece of paper. It can be torn into smaller pieces, which is analogous to mechanical weathering. It also can be burned into carbon dioxide and water, which is analogous to chemical weathering.
A rock that is weathered into new minerals but still looks somewhat like the parent rock is called a saprolite. If the saprolite fragments are subsequently removed from the site by water, wind, gravity, or ice, erosion has taken place.