weathering is the decay/disintegration of rocks in situ. doesn’t transport materials
away. eolith are weathered materials and the surface cover of loose
unconsolidated materials.
Factors influencing weathering
climate: temp and rainfall have greatest effect. cold areas, fluctuate around 0
degrees physical W is in the form of freeze thaw is dominant. hot areas (desert)
large diurnal temp ranges, exfoliation and heating and cooling is dominant. hot and
wet areas (savannah and rainforest) chemical W takes place, aided by the easily
available moisture and high temps which favour chemical reactions. in rainforests
the decomposition of humus creates humid acid leading to organic W. indirect
affect W by affecting the amount of vegetation and presence of organisms that
lead to chemical W.
relief: mountains have steep slopes that means in rain they drain fast leaving them
dry. physical W dominant as a result. moisture accumulates at base so aids chemical W. granite regions lead to development of vleis (marshy ground) which
are water logged as granite is impermeable so chemical W in favour in moist
conditions.
Vegetation: trees roots penetrate into rocks, widen cracks, release CO2 during
respiration, results in biological W. dominant in areas with more trees. when tree
roots decay humic acids are produced, causing biological W, happens into areas
with dense vegetation cover and moisture.
rock type: limestone is soft and porous, more easily affected by carbonation.
granite is hard and non-porous so less chemical W processes which need certain
moisture amount in order to occur. chemicals in limestone readily react with weak
acids while granite rocks are more resistant.
Exposure: rocks exposed to surface tend to be weathered faster than bedrock
which is covered.
