IB Geography Weathering

Weathering

Gradual disintegration of rocks which lie exposed to the weather in situ

Physical: Temperature Change

Outer layer expands and contracts because of high diurnal temperature range, ‘exfoliation’

Physical: Freeze-Thaw

Frost shattering

Physical: Salt Crystalisation

Salt crystals develop in pore spaces, generating mechanical stress, mostly in coastal locations

Physical: Plants and Animals

• roots crack rocks along joints and bedding planes → root pry

• burrowing animals → land crabs, rabbits, moles, puffins

Chemical: Hydrolysis

Reaction of something with water, dissolves + reacts with minerals

Chemical: Oxidation

Iron reacts with oxygen, happens to mafic rocks

Chemical: Carbonation

CO2 + H20 → carbonic acid, reacts with calcite in CaCO3

Chemical: Acidification

Lichens and moss(cushion plants), water running over it creates weak humic acid, slowly eats away at rock

Kast

Limestone, joints are from drying out, permeable but not porous, water gets through cracks in rock