coasts

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describe the coastal system
inputs- energy from waves, tides, winds and sediment. components - landforms/landscapes. outputs- dissipation of wave energy, sediment removed/build up of sediment.
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what do all coasts try to maintain?
dynamic equilibrium
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describe coastal zones
backshore - changes only occur due to storm activity. foreshore - between HWM and LWM where marine processes occur and storms influence it. inshore - between LWM and area where waves cease to have influence on land under offshore - limited
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what is winds effect on costal environments?
erosion and transport. prevailing wind for longshore drift. fetch which determines what type of wave.
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wave height
crest and neighbouring trough
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wavelength
one crest to another
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wave frequencyy
time for one wave to travel distance of one wave length
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destructive
high frequency, powerful backwash, little material moved, long fetch, higher crests,
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constructive
low frequency, powerful swash, materials constantly moved, short wavelength, short fetch, shorter crests.
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wave refraction
waves approach at not a regular shape, refract and become parallel. ONLY where headlands are. Waves approach coast and creates friction and causes it to bend. creates a longshore current.
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longshore current
parallel to shore and generates a flow parallel. this transports sediment parallel to shoreline
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rip currents
strong currents that seawater is piled up by every wave and this means that it runs to breaker zone which can be hazardous.
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upwelling
cold denser water rises and replaces the warm water on surface. This creates a rich cold nutrient ocean current.
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Whats a tide?
periodic rise and fall in the level of the sea
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Spring tide
Sun moon and earth are all in line and this causes gravitational pull to be at its highest which creates a bulge and upwelling of sea water
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neap tide
The moon is at a right angle to the sun and the moon. This creates a small bulge.
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whats the coriolis effect?
spinning force of the earth
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what does tidal ranges affect?
it determines the upper and lower limits of erosion and deposition and how long each day to can occur.
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tidal/storm surges
strong winds result in a higher than normal high tide. has a pulling up effect on the coast.
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coastal sediment budget
balance between sediment added and sediment removed in each sediment cell
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sediment cell
distinct area of coastline which is separated by distinct features such as headlands and deep stretches of water. It only transports sediment within its own cell and the sediment income is from estuarys and erosion. Inputs and outputs are balanced.
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high energy coastline
high energy waves higher rate of erosion wave cut platforms
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low energy coastline
low energy waves higher rate of deposition beaches and spits
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sub aerial processes
operate on land but affects the shape of the coastline e.g., mass movement.
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erosional processes
hydraulic action - pure force of water. attrition- rocks are rounded and become smaller abrasion - breaking of rocks against each other. wave quarrying - breaking wave trap air which builds up and releases explosive energy.
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transportation processes
traction - large boulders moving saltation- pebbles being brought by currents over each other solution - dissolved material suspension - small particles suspended by moving water.
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discordant coastlines
right angles to coast . forms headlands and bays
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concordant coastlines
parallel to coasts. forms caves. lulworth cove.
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marine deposition
low energy waves deposit sediment. e.g. during braking, water pausing at top of swash, sand and shingle accumulating faster than being removed
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aeolian deposition
transport and deposition of sediment by wind. large tidal range= large amounts of sand exposed and more sediment picked up by wind.
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aeolian deposition- two ways
surface creep- wind rolls sand grains along surface. saltation- wind brings sand particles up and then back down.
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physical weathering
freeze thaw - water enters and gets cold and expands causing cracks before unfreezing and shrinking in size. pressure release - overlying mass of rocks can cause pressure and form cracks.
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biological weathering
processes by organisms. seaweed moving with movement of sea can dislodge rocks on the sea bed. some dig into cliff for habitats.
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chemical weathering
oxidation - o2 dissolved in water reacts with rock minerals. carbonation - weak carbolic acid from rain and dissolves chalk. hydrolysis - acidic water reacts with rock to from salts. hydration - can seek into rocks and cause to expand when froze
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mass movement - slow
soil creep - continuous movement of soil particles due to soil moisture, soil fluction - saturated top soil runs off in bleak areas as top soil is permafrost, run off - lots of load during floods. creating v shape groove.
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mass movement - fast
rock falls - cliffs undercut by wave cut platforms. rotational slumping - softer overlies resistant with excessive lubrication causing concave sides and move whole sections of cliff.
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Other cards in this set

Card 2

Front

what do all coasts try to maintain?

Back

dynamic equilibrium

Card 3

Front

describe coastal zones

Back

Preview of the front of card 3

Card 4

Front

what is winds effect on costal environments?

Back

Preview of the front of card 4

Card 5

Front

wave height

Back

Preview of the front of card 5
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