erosional landforms 0.0 / 5 ? GeographyCoastal environmentsA2/A-levelOCR Created by: beaw18Created on: 23-04-19 13:47 cliffs and shore platforms undercutting occurs when destructive waves break repeatedly on sloping coastlines, erosion causes a wave-cut notch if continued, upper cliff collapsed due to lack of base support - steep profile and a cliff wave cut platform - area of rock at base of cliff boulders or large pieces of rock can accumulate on platform if too large to be removed by waves cliff retreat occurs when this process occurs parallel to the coast cliff profiles vary due to geology wave cut platforms reduce pressure on cliffs, as waves break on platform and not on cliff base, undercutting eventually ceases weathering processes important on platform development - solution, freeze-thaw and salt crystalisation may take place marine organisms such as algae increase chemical weathering - photosynthesis releases CO2, mixes with salt water, more acidic at high and low tide erosion levels are greatest as water levels are more constant 1 of 4 headlands and bays form adjacent to eachother due to bands of rock differing in erosion resistance weaker rocks erode more quickly and cause bays, more resistant rocks slowly and so stick out as headlands causes formation of a discordant coastline width of bay determined by width of weaker rock band rocks which lie parallel to coast produce concordant coastline if more resistant rock faces the sea, it will protect weaker rocks from erosion, resulting in a straight and even coast line bays and headlands may still occur due to the erosion of weaker areas such as fault lines wave refraction takes place at more irregularly shaped coastlines - means that headlands get more wave action erosion than bays 2 of 4 geos and blowholes geo - narrow, steep-sided inle occurs at lines of weakness in coastline, such as joints and faults weak points eroded more rapidly by wave action than more resistant rock surrounding them hydraulic action forces air and water into joints and weakens it when the roof of the cliff above the geo collapses it becomes a blowhole when waves enter, water is pushed out the top violently, causing it to look similar to a whale's blowhole 3 of 4 caves, arches, stacks and stumps erosional sequence which takes place, beginning with a headland cracks/faults in cliffs are eroded by wave action this then becomes widened into a cave when the otherside of cliff is broken through (back of the cave), this then becomes an arch the roof of the arch eventually collapses due to widening nature of erosion, making a stack stack becomes smaller and smaller due to erosion and becomes a stump 4 of 4
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