coastal landscapes in the UK Flashcards

1
Q

types of weathering

A

mechanical weathering and chemical weathering

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2
Q

what is mechanical weathering

A

breakdown of the rock without altering the rock’s chemical composition.

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3
Q

what is freeze-thaw weathering

A
  1. water gets into rocks and cracks
  2. when the water freezes, it expands, which puts pressure on the rock
  3. when the water thaws, it contracts, which releases the pressure on the rock
  4. repeated freezing and thawing widens the crack, causing the rock to break up
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4
Q

what is chemical weathering

A

breakdown of rock by changing its chemical composition

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5
Q

what is carbonation weathering

A
  1. rainwater has carbon dioxide dissolved in it, which makes it a weak carbonic acid
  2. carbonic acid reacts with rock that contains calcium carbonate, so the rocks are dissolved by rain water
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6
Q

what is mass movement

A

shifting of rocks and loose material down a slope

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7
Q

what are the three types of mass movement?

A

slides, slumps and rockfall

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8
Q

what is slides as a mass movement

A

when material shifts in a straight line

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9
Q

what is slumps as a mass movement

A

when material shifts with a rotation

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10
Q

what is rockfall as a mass movement

A

when material breaks down and falls down slopew

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11
Q

what is erosion

A

the wearing away of rock along the coastline

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12
Q

four types of erosion

A
  • hydraulic action
  • attrition
  • solution
  • abrasion
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13
Q

define hydraulic action

A

hydraulic action is when the force of water crashes across the bottom of the cliff, wearing it down

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14
Q

define solution

A

solution is when weak acids in the water dissolve small rocks like chalk and limestone

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15
Q

define attrition

A

attrition is when eroded particles smash into each other, breaking into smaller, rounder, fragmentd

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16
Q

define abrasion

A

abrasion is when particles in the water scrape and rub against bigger rock, removing smaller pieces

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17
Q

two types of waves

A

destructive and costructive

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18
Q

describe a destructive wave

A
  • DESTRUCTS the beach
  • takes particles away from the beach
  • weak swash
  • strong backwash
  • happens during storm conditions
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19
Q

describe a constructive wave

A
  • CONSTRUCTS the beach
  • drags particles on to the beach
  • strong swash
  • weak backwash
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20
Q

how does a wave cut platform form

A
  1. due to erosion, a crack forms at the bottom of the cliff
  2. this forms a wave-cut-notch, which is enlarged as erosion continues
  3. the rock above the notch becomes unstable and eventually collapses
  4. the collapsed material is washed away and a new wave cut notch starts to form
  5. repeated collapsing results in the cliff retreating
  6. a wave cut platform is the platform that is reft behind as the cliff retreats
21
Q

how do headlands and bays form

A

headlands and rocks form where there are alternating bands of soft and hard rock. the less resistant rock is eroded quickly, and forms a bay. bays have a gentle slope. the more resistant rock is eroded more slowly, and is left jutting out, forming a headland, which have steeper slopes

22
Q

describe how caves, arches, stacks and stumps are formed

A

most cliffs have weaknesses like cracks, that due to hydraulic power, get bigger. the cracks are eroded deeper in the rock, causing a cave to form. overtime, the cave becomes fully eroded through, leaving an arch. due to the bottom of the arch being eroded by abrasion, the arch becomes top heavy, causing it to collapse and leave a stack. a stack eventually erodes to leave a stump

23
Q

examples of caves, arches, stacks and stumps

A

Durdle Door in Dorset

24
Q

how is material transported along coasts (lsd)

A
  1. waves follow the direction of the prevailing wind
  2. they hit the the coast at a oblique angle (anything thats not a right angle)
  3. the swash carries material up the beach, in the same direction as the waves
  4. the backwash then carries the material down the beach at right angles
  5. overtime this creates sediment being deposited as zig zags along the coast
25
Q

other types of transportation

A

traction, solution, saltation, suspension

26
Q

explain traction

A

large boulders are dragged across the bed of the sea bed by the force of water

27
Q

explain saltation

A

pebble sized particles are bounced along the sea bed by the force of water

28
Q

explain suspension

A

small particles are carried along in the water

29
Q

explain solution

A

weak acids dissolve soluble material in the water

30
Q

what is deposition

A

material being carried by the sea water is dropped on the coast

31
Q

how are spits formed

A
  1. spits form at sharp bends in the coastline
  2. longshore drift transports sand and shingle past the bend and deposits it in the sea
  3. strong winds and waves can curve the end of the spit
  4. the sheltered area behind the spit is protected from waves, material is accumulated there - plants can grow
  5. overtime the sheltered area can become a mud flat or salt marsh
32
Q

how are bars formed

A

formed when a spit joins two headlands together. the bar cuts off the bay between bay and spit. a lagoon forms behind the bar

33
Q

what are the conditions for a sand dune to form

A

large supply of sand
large flat beach
an obstacle for the dune to form against, e.g. pebble or driftwood

34
Q

how are sand dunes formed

A

when sand deposited by longshore drift is moved up the beach by wind. obstacles cause wind speed to decrease so sand is deposited here. vegetation stabilises the sand, and encourages more sand to accumulate there.

35
Q

list 4 hard engineering management strategies

A

sea walls, gabions, groynes, rock armour

36
Q

what is a sea wall

A

sea walls are walls placed to reflect the water energy back to the sea, ensuring that the houses behind it do not get ruined

37
Q

what are the advantages of sea walls

A
  • prevents erosion of the coast
  • adds a barrier to prevent flooding
38
Q

what are the disadvantages of sea walls

A
  • expensive to build and maintain
  • creates a strong backwash which erodes under the wall
39
Q

what are gabions

A

gabions are cages of rocks places at the foot of cliffs to absorb the energy of the wave

40
Q

what are the advantages of gabions

A
  • cheap
  • easy to build
  • reduces erosion as they absorb wave energy
41
Q

what are the disadvantages of gabions

A
  • unnatural to look at
  • wire can corrode over time (needs maintenance)
42
Q

what are groynes

A

groynes are wooden fences placed along the coastline to collect material deposited by longshore drift

43
Q

what are the advantages of groynes

A
  • creates wider beaches which slow the waves
  • greater protection from flooding and erosion
  • fairly cheap
44
Q

what are the disadvantages of groynes

A
  • overtime, lots of material gets deposited, it builds up
  • maintenance is required
45
Q

what is rock armour?

A

placing big boulders at the bottom of a cliff. also called rip rap.

46
Q

what are the advantages of rock armour?

A
  • absorbs wave energy, reducing the direct impact to the cliff
  • fairly cheap
47
Q

what are the disadvantages of rock armour?

A
  • may need to be replaced
  • doesn’t look natural
48
Q
A