Weathering Flashcards
What is weathering?
The breakdown or disintegration of rock in situ at or close to the ground surface.
What type of weather is wetting and drying? Explain this process.
Physical- rock in the intertidal zone alternates between wet and dry and these rocks expand when wet and contract when they are dry, forming small cracks and fissures overtime.
What type of weathering is exfoliation? What is exfoliation?
Physical - dry rock heated by the sun is cooled when it comes in contact with the sea, the rock then fractures as it expands and contracts.
What type of weathering is salt crystallisation? What is salt crystallisation?
Physical - The evaporation of water from rock surfaces leads to the crystallisation of salts, this exerts pressure on the surrounding rock, causing it to fracture.
What type of weathering is freeze thaw weathering? What is freeze thaw weathering?
Physical - water enters cracks in the rocks and expands as it freezes, placing pressure on the surrounding rock.
What type of weathering is carbonation? What is carbonation?
Chemical - rainwater combines with carbon dioxide in the atmosphere and makes a weak carbonic acid which dissolves chalk and limestone rock.
What type of weathering is oxidation? What is oxidation?
Chemical - Iron minerals are exposed to the air by cracks and fissures in the rock, these minerals become oxidised and increase in volume. This puts pressure on the surrounding rock, causing it to fracture.
What type of weathering is hydrolysis? What is hydrolysis?
Chemical - water reacts with minerals in the rock causing the chemical composition of the rock to change and become more unstable.
What type of weathering is plant root weathering? What is plant root weathering?
Biological - Roots grow into the cracks of rocks, exerting pressure between the rocks and causing them to split, weakening the cliff. Also, seeds may fall into cracks in the rocks and can germinate, expand or thicken.
What type of weathering is seaweed acid weathering? What is seaweed weathering?
Biological - Seaweed contain pockets of sulphuric acid, if these come in contact with the rock then the acid will dissolve some of the rock minerals.
What type of weathering is rock boring? What is rock boring?
Biological - Shellfish can drill and bore into rock, piddocks drill depressions into the rock, clams secrete chemicals which dissolve the rock.
What is an example of positive feedback in weathering?
Cracks form in the cliff face which increase the likelihood of rock slumping, this is called pressure release.
What is an example of negative feedback in weathering?
A build up of debris (scree) occurs at the cliff foot due to weathering, this protects the original cliff face from erosion by reducing the erosion rate.
