Weathering is the Mechanical breakdown or chemical decay of rocks “in situ” (without movement)
Agents of weathering
these are things that work to cause it:
- gases e.g. CO2,O2
Factors That Influence Weathering
Different areas with different climatic elements experience different types of weathering e.g. block disintegration is experienced in arid areas while frost action is experienced in temperate regions and mountainous regions of tropics.
Weathering is faster on steep slopes than on gentle slopes because weathered material is washed away quickly exposing the rock once again to agents while on gentle slopes materials remain in one position
shielding the rock from weathering agents.
Nature of rocks
Dark-coloured rocks absorb more heat than light coloured ones hence break faster because of excessive expansion and contraction.
A rock with different minerals may disintegrate faster because of differential expansion and contraction of minerals.
A well-jointed rock will break faster because physical and chemical agents can penetrate faster, e.g. by freezing and thawing.
Fine textured rocks have a large surface area on which chemical processes can act, e.g. Limestone.
Bacteria facilitate the rotting of organic matter producing organic acids which react with some minerals causing the rock to break up.
Plant roots and burrowing animals penetrate rocks resulting in cracks providing passage for agents such as water to act on rocks.
People accelerate the rate of weathering by exposing rocks buried deep below by digging, blasting and drilling.