Coasts Flashcards

1
Q

What makes up a coastal system

A
  • Inputs
  • Sores and components
  • Flows / transfers
  • Outputs
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2
Q

Fetch

A

The distance a wave has travelled

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3
Q

What does larger fetch mean

A

The waves can be acted upon by the wind for a longer time so gain more energy

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4
Q

Inputs

A

Wind, precipitation, sediment

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5
Q

Flows/transfers

A

LSD, mass movement, erosion

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6
Q

Stores and components

A

Beaches, headlands, bays, sand dunes

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7
Q

Outputs

A

Evaporation, ocean currents, rip tides

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8
Q

What might dictate sediment in cell

A
  • Weather = storms
  • Humans = coastal defence
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9
Q

UK sediment cells

A

11 major cells which are subdivided into sub cells local to an area

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10
Q

Subcells

A

Generally bordered by 2 large headlands or deep water

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11
Q

Dynamic equilibrium

A

An ever changing state but in balance

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12
Q

Causes of tides

A

Gravitational pull of the sun and moon

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13
Q

Wave formation

A

Waves form when winds blowing across the water’s surface transfer their energy to the Water

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14
Q

What happens to sediment in the direction of prevailing wind

A

Gets smaller and rounder due to LSD and attrition

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15
Q

High energy coast

A
  • Rough landscape
  • Little deposited material
  • High erosion
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16
Q

Low energy coasts

A
  • Smooth coastline
  • Calm waves
  • Sheltered areas
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17
Q

Constructive waves

A

Add material to the coastline with strong swash

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18
Q

Destructive waves

A

Remove material with strong backwash with high erosion

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19
Q

Why are sediment cells considered closed systems

A
  • Sediment exclusively moves between the stores retained by the two headlands
  • Sediment created through the erosion of cliffs
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20
Q

Why is the coastal orientation key to determining coastal characteristics

A

Winds prevailing direction and magnitude

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21
Q

Coastal weathering

A
  • Biological
  • Chemical
  • Mechanical
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22
Q

Sediment cell example

A

Flanborough head

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23
Q

Biological weathering 2

A
  • Plant roots growing into cracks
  • Animals burrow into weak points
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24
Q

Mechanical weathering 3

A
  • Freeze thaw
  • Salt crystallisation
  • Wetting and drying
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25
Q

Freeze thaw erosion

A

Water enters a fault, freezes and then expands repeatedly

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26
Q

Crystallisation erosion

A

Can grow within cracks and expand

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27
Q

Wetting and drying erosion

A

Rock wetting of certain rocks make them expand and shrink

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28
Q

Positive feedback

A

Feedback that speeds up processes

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29
Q

Negative feedback

A

Feedback that slows processes

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30
Q

Mass movement

A

Downhill movement of sediment under gravity adding sediment

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31
Q

Geomorphical processes

A
  • Erosion
  • Transportation
  • Deposition
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32
Q

Factors that affect erosion 4

A
  • pH
  • Geology
  • Human presence
  • Wind speed/direction
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33
Q

Transportation methods 4

A
  • Traction
  • Suspension
  • Saltation
  • Solution
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34
Q

Traction

A

Large boulders rolled along seabed

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35
Q

Saltation

A

Pebble sized particles bounced along seabed

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36
Q

Suspension

A

Small particles carried along water

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37
Q

Abrasion

A

Eroded material thrown against the rock

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38
Q

Attrition

A

Rocks carried are thrown against each other, smoothing them

39
Q

Solution

A

Soluble materials dissolved in water

40
Q

Factors affecting transportation

A
  • Strength of waves
  • Size of sediment
41
Q

Wave cut platform

A

Flat area of rocks extending from base of cliff

42
Q

Long shore drift alternative name

A

Littoral drift

43
Q

Effect of wave cut platform

A

Waves have further to travel in shallow water and so break earlier, dissipating energy

44
Q

Formation of wave cut platform

A
  • Waves produce a wave cut notch on a cliff
  • As cliff is undercut it collapses and gradually retreats
  • Leaving behind a platform made from the base of the cliff
45
Q

Bedding planes

A

Flat surfaces along which rocks tend to separate or break

46
Q

Cliff profiles are influenced by

A

Geology and tectonic movement dips

47
Q

Vertical bedding planes

A

When rock below is eroded it is on the same plane which means the whole plane stumps

48
Q

Horizontal bedding planes

A

Rock above not affected by erosion below

49
Q

Where can’t wave cut platforms be formed

A
  • Soft rock
  • Steep bedding planes
50
Q

Causes for weaknesses in cliff

A
  • Rock band orientation
  • Bedding plane
  • Layering of sediment
51
Q

Salt marsh formation

A

The area behind a spit will become a salt marsh due to low energy

52
Q

Formation of a spit

A
  • LSD continues in direction of prevailing wind until coastline changes
  • Sediment is taken out to sea until it looses energy and deposits, building up over time
  • Hooks round due to secondary wind direction
53
Q

Depositional landforms

A
  • Beaches
  • Spits
  • Tombolos
  • Offshore bars
54
Q

Tombolo

A

Spit that connects an island to the mainland

55
Q

What causes the hook on a spit

A
  • Wave refraction curves sediment
  • Second dominant wind direction
56
Q

Wave refraction

A

The bending of waves due to reduction in velocity so they move nearly parallel to the shoreline

57
Q

Neep tide

A

Sun and moon fight against each other, pulling in opposite planes, spreading water evenly

58
Q

Spring tide

A

Sun and moon pull in the same plane, highest tides

59
Q

Sand dune

A

Accumulation of mounds of sand blown by the wind (aeolian)

60
Q

Stack formation 4

A
  1. Weakness in headland
  2. Carves out cave, punching through, forming an arch
  3. Erosion attacks base, weathering attacks roof, roof cannot hold itself up and collapses
  4. Forming a stack until it topples and leaves behind a stump
61
Q

Tidal range

A

Difference in height between the high and low tide lines

62
Q

Tidal range influences on processes

A

Dictates how long a process can act on a cliff face, small range focuses on the same area for longer

63
Q

Sand dune formation

A
  1. Sediment accumulates on beach with large tidal range to dry
  2. At low tide, wind carries sand by creep or suspension
  3. And obstacle that causes the sand to lose momentum and settle, forming an embryo
64
Q

Pioneer species

A

First species to populate an area

65
Q

Flocculation

A

Particles come out of suspension and lump to form something larger

66
Q

Halophytes

A

Salt tolerant plants

67
Q

Conditions for mudflats 4

A
  • Sheltered low energy environment
  • large tidal range
  • Supply of sediment
  • Prevailing wind
68
Q

Succession of salt marshes

A
  • Pioneer plants first move
  • Builds up land allowing other plants to move in
  • makes area an extension of land
69
Q

Isostatic change

A

A LOCAL rise or fall in land level causing RELATIVE sea level change

70
Q

Eustatic change

A

An ACTUAL change in sea level

71
Q

Emergent landforms

A

Raised beaches, abandoned cliffs, marine terraces

72
Q

Submergent landforms

A

Rias, fjords

73
Q

Effects of climate change on coastline 4

A
  • Major infrastructure nearby
  • Disrupt fresh water supplies
  • Damage environments
  • Urban environments at risk
74
Q

What is a sediment cell

A

Areas that encompass the intertidal and nearshore moment of sediment

75
Q

Sediment cell advantages

A

Allows for a sediment budget to be established to understand coastal changes

76
Q

Sediment cell disadvantages

A

Fine sediment is not confined by boundaries and so model is not entirely closed

77
Q

Swash aligned beach 3

A
  • Smooth curved beach
  • Waves aligned with beach
  • Likely a closed sediment cell
78
Q

What is a swash aligned beach

A
  • The deposited sediment moves up and down the beach
  • Shaped by waves arriving parallel to the shore
79
Q

Drift aligned beach 4

A
  • Angle of beach based on prevailing wind
  • Backwash at 90°
  • Material is moved and becomes smaller over time
  • Sediment moves to another beach
80
Q

What is a drift aligned beach

A

Drift aligned beaches are produced where waves break at an angle to the the coast

81
Q

Wave quarrying

A

Waves breaking against cliffs traps air which compresses it into gaps which creates explosive effect

82
Q

Sea level rise facts

A
  • only 2/3 of ice sheets have potential to melt
  • can cause 72 meters of sea level rise
83
Q

Offshore bar formation

A
  • Destructive waves remove sediment parallel from the beach and form the offshore bar
  • constructive do the opposite
84
Q

Sources of energy

A
  • wind
  • waves
  • currents
  • tides
85
Q

Why do areas receive variable wave energy

A
  • Direction of prevailing wind
  • Larger fetch
  • Wind circulation (Gulf Stream)
86
Q

Sources of sediment

A
  • river estuaries
  • cliff erosion
  • offshore sediment
  • wind
87
Q

Factors that affect rate of erosion 5

A
  • geology
  • wind
  • pH
  • landscapes
  • coastal defences
88
Q

Required conditions for mudflats 5

A
  • Sheltered low energy environment
  • Larger inter tidal range
  • Dominant wind direction
  • sediment supply
  • Occasional flooding
89
Q

Threats to salt marshes 3

A
  • SLR
  • Wave energy increase
  • Higher rates of flooding
90
Q

What is the difference between weathering and erosion

A
  • Weathering = land based
  • Erosion = water
91
Q

Weathering and processes

A
  • Land based processes above water line
  • Weathering
  • Mass movement
92
Q

Erosional processes 5

A
  • Hydraulic action
  • Abrasion
  • Attrition
  • Solution
  • Wave quarrying
93
Q

Causes for joints in bedding planes

A
  • Igneous rock cooling
  • Compression/stretching sedimentary
94
Q

Joint

A

Fractures in rocks created without displacement increasing erosion rates by creating cracks