Processes of erosion and landforms Flashcards
What is attrition?
Where rocks collide against each other and break into smaller particles
What is hydraulic action?
Parcel of air gets trapped, the pressure builds and the rock gets broken off
What is abrasion?
Where cliffs are worn away by rocks, sand and shingle that are hurled against it
What is corrosion?
Rocks can be eroded by salt in the sea e.g. Limestone
Sub-aerial
Non-marine processes which cause mass movement e.g. Land slides
Wave pounding
Steep waves with lots of energy, generating shock waves of up to 30 tonnes per metre squared
What are some of the factors affecting the rate of erosion?
Steepness and energy of waves
Beach material
Type of rock
Human activity
Headlands and bays
Areas of alternating resistant and less resistant rock
Less resistant rock is eroded, developing a bay, and leaving the more resistant rock as a headland
Later, the headlands receive the highest energy waves and become more vulnerable to erosion than the sheltered bays
Wave-cut platforms
High, steep waves break at the foot of a cliff leaving a wave cut notch
Continual undercutting results in the cliff collapsing, the cliff retreats leaving a wave-cut platform
Process from headland to stump
Headland Cave Arch Stack Stump
Chemical weathering
Hydrolosis - acid rain reacts with minerals that are removed in solution
Solution/carbonation - carbon dioxide dissolves in rainwater and forms a weak carbonic acid. This can dissolve limestone
Physical weathering
Freezethaw - water seeps into cracks in rocks, freezes and expands, eventually breaking the rock apart
Insolation - expansion and contraction of the rock due to temperature
Salt crystallisation - saline solution gets into the rock, it crystallises and expands, fracturing the rock. Mostly happens at Coastal and marine areas
Biological weathering
Animals - tiny bacteria, algae and lichen produce chemicals that help break down rocks. Some animals bore into the rock for protection
Root structure - roots move into cracks to find moisture. As the roots grow, the roots gradually prise the rock apart
