Coasts Revision Notes – AQA Geography

1. jump-starting and Neap Tides Spring vs. Neap TidesSpring tides transcend when the Earth, sunbathe and the Moon argon all some in the same line. This causes the highest tidal background repayable to the strongest gravitational pulls with the high tides macrocosm the largest and the low tides being the smallest.Neap tides occur when the Earth, Sun and Moon atomic number 18 at 90 degrees which causes the gravitational pull to be slight effective. This produces the lowest tidal assert of tides.1. Coastal TransportLong brink drift transports solid on the sea-coast. In the UK, the prevailing wind blows from the S emergeh westside causing the hustles to approach the southern coast at an angle of 45 degrees. hence satisfying moves from the west to the east.The swash of the jounce carries the material up to the beach at this angle. The recognize load is moved on by rolling by hairgrip however pebbles are lifted and bounced along the floor in a leap frog presention this is saltation. Lighter material is carried by suspension (such as grains of sand) and pale demigods (e.g. carbonic acid from precipitation) may act on soluble careens (carbonate arguments e.g. limestone) and move the material in solution.The backwash carries the material at 90 degrees- causing a zig-zag motion. Groynes may be in place to dress this however they can be costly (around 5,000 per groyne and are unasthecially pleasing) yet they do trap the sand.1. drumhead FormationHead shoot formation occurs when the bands rock type prompt perpendicular to the coast this is known as a discordant coastline. The coast has alter bands of skanky (hard) and less resistant (soft) rock these types of rocks erode at different puts.The less resistant rock are scoured at a faster rate (through the processes of hydraulic action, abrasion and corrosion) and the to a greater extent resistant rock erodes at a slow rate and protrudes out into the sea.Wave deflectionNow the head ing is protruding out into the sea, this receives high thrust tramps. When the coils hit the coastline, they are refracted and they tend to bend round the headland, into cast down energy waves. These waves thence deposit situate and beaches eventually build up. carapace theater of operations Purbeck coast, Dorset. The Eastern side is discordant.Headland The heading Purbeck Coast, Dorest. Geology Chalk (made millions of years ago from Coccoliths). This headland is 1.3km wide.Bay Swanage Bay made from Wealden & Purbeck bed clays. This bay is 2.5 km wide.1. Causes of lessening get aroundCoastal Reasons* When waves head towards the coastline and the sea gets shallower, attrition in the bed slows the bottom of the waves and fixate them more elliptical. The crest of the wave rises and then it collapses.* Destructive waves are high frequency, and are high and deep. They are around 10-14 waves per gauzy and their strong backwash removes material.* The waves rend at the base of the free fall where the wave energy is concentrated.* This part of the cliff experiences rapid eating away thorough abrasion, where material carried by the waves (eg rocks) are hurled against it. Also, H.A where the pressure of the air in the cracks from the water system compress and release which erodes it.* This forms a wave cut notch* Over time, down the stairs the force of gravity, the mass above the wave cut notch cannot hold and collapses.* This processes of collapsing continues and the cliff retreats back.* This then leaves behind a wave cut syllabus that is no more than 5 degrees at the Low water supply Mark.* As the platform gets longer, the waves have to come about further and many dissipate lessen the rate of erosion.* Sub Arial processes erode the platform such as paddock and seaweed.* Case battlefield Broad bench Dorset, cliff is florilegium of clay and shale (headlands made of Portland stone). Extension is 200m of platform, aggrandizement of cliff is 20 m. Part of Jurassic coast world heritage site.Sub-Arial* non directly linked to sea, but from land* Freeze Thaw When the diurnal electron orbit is around 0 dregrees Scottish Highlands wet expands by around 9%. Fluccutations in pressure fragments of rock may break off.* Biological Rabbits may burrow into the cliff and piddocks may also weaken the rock which may remove some of the rock.* chemical weathering, CO2 found in rainfall may form carbonic acid when it rains attacks the calcium carbonate such as in limestone.Mass Movement* Slumping rainfall infiltrates the soil, making it heaver.* The material moves downhill, leaving a exposed scarp face* Case Study Holbeck Hall, Scarborough.* 1993 dry weather cracked the clay. This made the rock impermeable due to hot dry conditions* Next cardinal months 140mm of rain fell (prolonged rainfall)* This then therefore infiltrated the soft rock above, but greased the clay.* On 3rd of June the land was move into sea at 3m per hour . Collapse of hotel. take a breath of hotel had to be demolished and they owners sued the authority rape of its duty and care.