coasts

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inputs of coasts
sediment is brought into the system. energy inputs come from wind, waves, tides and currents
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outputs of coasts
sediment can be washed out to sea or deposited further along the coast
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flows and transfers of coasts
processes such as erosion weathering transportation and deposition
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stores
landforms such as beaches dunes and spits
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negative feedback eg
when change causes other changes that have the opposite effect eg a beach is eroded the cliffs behind it are exposed to wave attack. sediment eroded from the cliffs is disposed on the beach causing it to grow in size again
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positive feedback eg
when a change in the system causes other changes that have a similar effect eg a beach starts to form it slows down waves which cause more sediment to be deposited increasing the size of the beach the new equilibrium is reached when long term growth
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how energy is transfered by air
winds are created by air moving from areas of high pressure to areas of low pressure. during events such as storms, the pressure gradient is high and winds can be very strong. when wind constsantly blows from the same direction this is called prevai
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how energy is tranferred by waves
waves are created by wind blowing over the surface of the sea. the friction between the surface of the sea gives the water a circular motion
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constructive waves
low frequency around 6-8 waves per minute low and long more eleptical cross profile the powerful swash carries material up the beach and deposits it
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destructive waves
high and steep more circular cross profile have higher frequency about 10-14 waves a minute the strong backwash removes material from beach
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sediment sells
coast is divided into sediment cells also called literal cells
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corrasion-erosion
bits of rock and sediment transported by the waves smash and grind against rocks and cliffs breaking bits off and smoothing surfaces
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hydraulic action-erosion
air in cracks in cliffs is compressed when waves crash in the pressure exerted by the compressed air breaks off rock pieces
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cavitation-erosion
as waves recede the compressed air expands violently again exerting pressure on the rock and causing pieces to break off
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wave quarrying-erosion
the energy of a wave as it breaks against a cliff is enough to detach bits of rock
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solution /corrosion-erosion
soluble rocks eg limestone get gradually dissolved by the seawater
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attrition-erosion
bits of rock in the water smash against each other and break into smaller bits
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solution- transportation
substances that can disolve are carried along in the water eg limestone is dissolved into water thats slightly acidic
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suspention-transportation
very fine material such as silt and clay particles is whipped up by turbulance and carried along in the water most eroded material is transpoeted this way
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saltation-transportation
larger particles such as pebbles or gravel are too heavy to be carried in suspension instead the force of the water causes them to bounce along the sea bed.
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traction-transportation
very large particles eg boulders are pushed along the sea bed by the force of the water
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swash
carries sediment up the beach parallel to the prevailing wind
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backwash
carries sediment back down the beach at right angles to the shoreline
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deposition
process of dropping eroded material
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transportation
the process of eroded material being moved
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sub aerial weathering
gradual break down of rock by agents such as ice salt plat rotts and acids
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salt weathering- sub aerial weathering
caused by saline water, enters pores or cracks in rocks at high tide,as tide goes out the rocks dry and the water evaporates forming salt crystals. as the salt crystals form they expand exerting pressure on the rock this causes pieces to fall off
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freeze thaw weathering- sub aerial weathering
occurs in areas where temperatures fluctuate above and below freezing, water enters the joints and crevices in rocks, if the temp is below 0oc the water in the cracks freezes and expands, over time repeated freeze thaw action weakens the rocks
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weathering and drying- sub aerial weathering
some rocks contain clay, when thewet clay gets wet it expands and the pressure caused by this breaks fragments off the rock
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chemical weathering- sub aerial weathering
chemical weathering is the breakdown of rock by changing its chemical composition, eg carbon dioxide in the atmosphere dissolves in rainwater forming a weak carbonic acid
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Other cards in this set

Card 2

Front

sediment can be washed out to sea or deposited further along the coast

Back

outputs of coasts

Card 3

Front

processes such as erosion weathering transportation and deposition

Back

Preview of the back of card 3

Card 4

Front

landforms such as beaches dunes and spits

Back

Preview of the back of card 4

Card 5

Front

when change causes other changes that have the opposite effect eg a beach is eroded the cliffs behind it are exposed to wave attack. sediment eroded from the cliffs is disposed on the beach causing it to grow in size again

Back

Preview of the back of card 5
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