Coasts EQ2 Flashcards

how do characteristic coastal land forms contribute to coastal landscapes?

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1
Q

Define wavelength

A

The distance between the creeks of two waves

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2
Q

Define wave crest

A

Top of the wave

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3
Q

Define wave trough

A

Dip between two waves

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4
Q

Define fetch

A

The distance of open water over which they move

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5
Q

Define wave period

A

The time interval from crest to crest in seconds

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6
Q

What are the two types of waves?

A

Constructive / destructive

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7
Q

What is a constructive wave

A

When the swash is larger then the backwash

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8
Q

What is a constructive wave?

A

When the backwash is stronger then the swash

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9
Q

What is the wave frequency for a constructive wave?

A

6-8 per minute

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10
Q

What is the wave frequency for a destructive wave?

A

13-15 per minute

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11
Q

What is the motion of the water for a constructive wave?

A

Elliptical

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12
Q

What is the motion of the water for a destructive wave?

A

Circular

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13
Q

what is differential erosion?

A

erosion that occurs at irregular or varying rates caused by the differences in the resistance and hardness of surface materials

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14
Q

name a cause of differential erosion? (one of the three)

A

permeability of the rock, sub-aerial processes, soluble material

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15
Q

define sub-aerial processes

A

presence or absence of water = may affect weathering and mass movement

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16
Q

name a feature you would see in the upper part of the beach..

A

any from:

  • cliff face
  • storm beach
  • berms
  • beach faces
  • beach cusps
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17
Q

name a feature you would see in the lower part of the beach..

A

any from:

  • ripples
  • runnel with water pool
  • beached ridge
  • runnel
  • ridge
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18
Q

what is a summer beach profile like?

A

beach profiles are steeper

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19
Q

what are the waves like on a summer beach?

A

constructive waves which are more common then destructive waves

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20
Q

what beach profile feature do you see on a summer beach profile?

A

berms at the top of the beach

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21
Q

what is a winter beach profile like?

A

beach profiles are flatter

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22
Q

what are the waves like on a winter beach?

A

destructive waves with strong backwash

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23
Q

what beach profile feature do you see on a winter beach profile?

A

berms eroded away, backwash creates a current called a rip

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24
Q

name the four erosional landforms

A

headlands and bays

wave cut notch/shoreline platform

cliff

cave, arch, stack, stump

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25
Q

how are headlands and bays formed?

A
  1. sea attacks the section of the coast with hard and soft rock
  2. it leaves a section of the land jutting out with had rock called headlands
  3. it also leaves a section of the coast with soft rock and erodes it away creating a section called bays
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26
Q

give an example of an area with headlands and bays

A

isle of purbeck / dorset

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27
Q

how many different types of cliffs are there?

A

5

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28
Q

how are cliffs formed?

A

constant wave action and erosion against the base pf a cliff

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29
Q

how are the 5 cliff formed>

A
  1. horizontal strata
  2. rocks dip into the sea and fall
  3. rocks dip inland
  4. rock slides down towards the sea
  5. joint act as slide planes
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30
Q

give an example of an area with cliffs

A

eastborne

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31
Q

how are wave cut notches and shoreline platforms formed?

A
  1. waves breaks against the foot of the cliff close to the high tide line
  2. creates a wave cut notch which begins to undercut the cliff
  3. as it becomes bigger the rock above becomes unstable and collapses
  4. it is repeated and the notch migrates inland and thee cliff retreats
  5. leaves a shoreline platform which reduces the rate of erosion as it is usually many hundred metres long
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32
Q

give an example of an area with a wave cut notch

A

walton - on - the - naze

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33
Q

how are CCASS’s formed?

A
  1. joints and faults in the cliff are eroded by hydraulic action and abrasion
  2. this erodes more and creates caves
  3. the overlying rock collapses and creates an arch as waves break it apart
  4. the gap is further enlarged by weathering and erosion and the top becomes unstable and collapses into the sea creating a stack
  5. the stack is further eroded by the sea and creates a stump which can be seen at low tides
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34
Q

give an example of an area with a CCASS

A

Old Harry, Bournemouth, south of the UK

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35
Q

what are the 4 erosional processes?

A

abrasion, hydraulic action, attrition, solution

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36
Q

what is abrasion?

A

> waves advance they pick up sand and pebbles from the seabed
transported material is hurled at the cliff hipping away at the rock

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37
Q

what is hydraulic action?

A

> air is trapped and compressed in the joints of the cliff
when the wave retreats the compressed air expands again
weakens the joint and cracks in the cliff causes pieces of rock to break off

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38
Q

what is solution?

A

> when cliffs are formed by alkaline rocks the cement bonds the rock particles together
solution by weak acids in the seawater can dissolve them

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39
Q

what is attrition?

A

> gradual wearing down of rock particles by impact of rocks smashing against each other
the pieces of rock are moves by the waves
reduces particle size and makes rocks rounder and smoother

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40
Q

give 2 ways to transport sediment

A

tides, traction, saltation, currents, angle of wave attack, suspension, solution, longshore drift

41
Q

define suspension

A

lighter sediment is carried

42
Q

define solution

A

dissolved sediment

43
Q

define saltation

A

smaller/ light rocks ‘bounce’

44
Q

define traction

A

large/heavy rocks ‘roll’

45
Q

define tides

A

changes in water level of seas and ocean caused by the gravitational pull of the moon

46
Q

give 2 examples of coastal weathering processes?

A
  • freeze thaw weathering
  • wetting and drying
  • salt weathering
  • carbonation
  • plant roots
  • animals
47
Q

what is freeze thaw weathering?

A

when water entres a crack or join in the rock when it rains > it freezes in the cold weather and expands in volume > repeated freezing exerts pressure on the rock which forces the crack to widen and fragments of rock to break away

48
Q

what is the effect of freeze thaw weathering?

A

rock fragments are picked up by the sea and used as tools in marine erosion

49
Q

what is wetting and drying (weathering process)?

A

rocks rich in clay expand when they get wet ad contract when they dry

50
Q

what is the effect of wetting and drying?

A

cracks and breaks up rock

51
Q

what is salt weathering?

A

salt water evaporation = leaves salt crystals behind

52
Q

what is the effect of salt weathering?

A

exerts stresses in the rock causing it to break up and corrode the rock

53
Q

what is carbonation (weathering process)?

A

rainwater absorbs carbon dioxide from the air to form a weal carbonic acid = causes it to be easily dissolved

54
Q

what is the effect of carbonation?

A

creates easily dissolved rocks

55
Q

what Is plant root weathering?

A

vegetation grows in the small cracks in the cliff face and widen as the roots grow thicker therefore breaking the rock

56
Q

what is an effect of plant root weathering?

A

breaks rock apart and any decaying roots increase chemical weathering

57
Q

what is animal weathering?

A

birds and animals dig burrows into cliffs

58
Q

what is an example of chemical weathering ?

A

carbonation

59
Q

what is an example of mechanical weathering?

A

freeze thaw weathering, wetting and drying, salt weathering

60
Q

what is an example of biological weathering?

A

plant roots, animals

61
Q

give 2 examples of coastal depositional landforms?

A
  • spits
  • beaches
  • bars
  • offshore bars
  • tombolo’s
  • cuspate foreland
62
Q

what are the stages for the formation of a spit?

A
  1. sand shingle is moved along a coast by longshore drift
  2. coastline changes direction due to a river estuary, sediment begins to build across the estuary
  3. a hook is formed by prevailing wind changing direction
63
Q

what is a spit?

A

long narrow feature made of sand or shingle which extends from land to sea

64
Q

what is a recurved spit?

A

sand continues to move down and curve

65
Q

what is a double spit?

A

two spits extending from ends of the bay

66
Q

give an example of an area which has a spit?

A

Poole Harbour

67
Q

what are the stages in forming a beach?

A

wave refraction crates a low- energy environment leading to deposition

68
Q

what is a swash-aligned beach?

A

moves up and down the beach with little transfer

69
Q

what is a drift-aligned beach?

A

transferred along the coast by longshore drift

70
Q

what are the stages in forming a bar?

A
  1. sediment carried across a headland by waves

2. traps water behind to form a lagoon

71
Q

give an example of an area which has a bar?

A

cornwall

72
Q

what are the stages in forming a offshore bar?

A

destructive waves erode sand from the beach with the strong backwash and deposit it offshore creating a ridge

73
Q

what are the stages in forming a tombolo?

A
  1. deposition occurs where waves lose their energy and the tombolo builds up
  2. carry’s on until it reaches the island
74
Q

what is a tombolo?

A

beach that has formed between a small island and the mainland

75
Q

give an example of an area with a tombolo?

A

northumberland

76
Q

what is a cuspate foreland?

A

triangular -shaped headlands that extends out from the mainlands coastline

77
Q

what are the stages in forming a cuspate foreland?

A
  1. longshore drift from opposite directions
  2. sediment deposited at the point where the two meet
  3. vegetation begins to grow on deposited sediment
78
Q

give an example of an area with a cuspate foreland?

A

kent

79
Q

what is a sediment budget?

A

Amount of sediment available within a cell

80
Q

What is negative feedback to a coastline?

A

Prevents erosion and helps to maintain a balance within the system

81
Q

What is positive feedback to a coastline?

A

helps erosion by changing the balance of the coastline will a new equilibrium is reached

82
Q

name 2 coastline sources?

A
  • erosion of cliffs
  • onshore currents
  • land sediments
  • wind blown sediments
  • subaerial processes
83
Q

name 2 coastline transfers?

A
  • wave transport through swash and backwash
  • longshoremen drift
  • tides moving sediment
  • currents
  • wind alone shore
84
Q

Name 2 coastline deposits?

A
  • backshore
  • foreshore
  • nearshore
  • offshore sediments
85
Q

name 3 examples of coastal mass movement..

A
  • solidification
  • flows
  • rock falls
  • land slides
  • slumps
  • soil creep
86
Q

name the 3 groups of coastal mass movement..

A

flow, slide, slump

87
Q

what is solidification?

A

top layer of the soil thaws in summer but the layer below is frozen
the surface layer becomes saturated and flows over the frozen subsoil and rock

88
Q

where does solidification occur?

A

in the tundra areas where the ground is frozen

89
Q

what are flows?

A

increase in the amount of water causing earth and mud to flow over bedrock

90
Q

where do flows occur?

A

areas with heavy rain

91
Q

what are rock falls?

A

material once broken away either bounces or falls vertically to form scree at the foots of the cliff

92
Q

where do rock falls occur?

A

steep rock faces/ cliffs which are exposed to mechanical weathering

93
Q

what are land slides?

A

an increase in the amount of water causing sliding

slabs of rocks slide over underlying rocks

94
Q

where do land slides occur?

A

in rocks that are jointed, have bedding planes parallel to the slope or cliff

95
Q

what are slumps?

A

rotational movement causing rotational scars

96
Q

where do slumps occur?

A

saturated conditions, moderate to steep slopes

97
Q

what is soil creep

A

the slowest form of mass movement, slow downhill movement of individual soil particles

98
Q

name a factor affecting mass movement?

A
  • angle of the slope or cliff
  • rock type and its structure
  • vegetation cover
  • how wet the ground is
99
Q

what are dispersion diagrams?

A

scatter graphs