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Geography - Physical - Paper 1 > Coasts - EQ2 - How do characteristic coastal landforms contribute of coastal landscapes? > Flashcards

Coasts - EQ2 - How do characteristic coastal landforms contribute of coastal landscapes? Flashcards

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1
Q

What is the cause of waves

A

friction between wind & the sea surface

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2
Q

Describe the process of wave formation
1.

A
  • wind moves across the surface of the water
  • causing frictional drag
  • which creates small ripples & waves
  • this leads to a circular orbital motion of water particles in the ocean
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3
Q

Describe the process of wave formation
2. ….this leads to a circular orbital motion of water particles in the ocean….

A
  • as the seabed becomes shallower towards the coastline, the orbit of the water particles becomes more elipitical, leading to horizontal movement of waves
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4
Q

Describe the process of wave formation
3. ….the orbit of the water particles becomes more elipitical, leading to horizontal movement of waves so…..

A
  • wave height increases
  • wave length & wave velocity both decrease
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5
Q

Describe the process of wave formation
4. …wave height increases, wave length & wave velocity both decrease….

A
  • this causes water to back up from behind the wave, until the wave breaks (collapses) & surges up the beach
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6
Q

Name 4 factors affecting wave size

A
  • Time of wind blowing
  • Strength of the wind
  • water depth
  • Fetch - distance of open water over which the wind blows
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7
Q

Why are waves generally larger in the South West (e.g Cornwall)

A
  • dominant & prevailing winds come from the South West direction
  • this wind is sustained over a greater distance,
  • which transfers kinetic energy from wind to wave,
  • growing the waves size & strength
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8
Q

Why does Cornwall have such large waves

A
  • Larger fetch from Florida to Cornwall:
  • they are 4000 km apart
  • and as there are no land masses between them,
  • the Waves from the Atlantic Ocean aren’t slowed down before they react the Cornish coast
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9
Q

Name 2 wind types

A

Prevailing
Dominant

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10
Q

Define Prevailing Wind

A

the most frequent type of wind in an area - affecting weather patterns & soil erosion

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11
Q

Define Dominant Wind

A

Strongest winds in an area at a given time

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12
Q

Define Crest

A

the highest point the wave rises to

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13
Q

Define Wavelength

A

distance from one wave crest to another

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14
Q

Define Trough

A

the lowest point the wave sinks to

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15
Q

Define wave height

A

the distance between the trough and crest

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16
Q

How do waves form

A
  • From the transfer of energy from the wind to the sea surface
  • which causes friction
  • & the water begins to move in a circular motion
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17
Q

The amount of energy a wave gains depends on…

A
  • wind speed
  • time the wind has been blowing for
  • distance the wind has been blowing for (fetch)
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18
Q

Friction with the seabed _____ the wave at the base, but the top of the wave doesn’t ________________

A

slows
slow down

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19
Q

Friction with the seabed slows the wave at the base, but the top of the wave doesn’t slow down, therefore….

A

the top becomes higher & steeper until it breaks

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20
Q

Define swash

A

The wave moving up the beach

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21
Q

Define backwash

A

the water slowing back down to the sea, which is due to gravity

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22
Q

What are Constructive Waves associated with

A

Linked to low energy coasts and deposition

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23
Q

Fetch of Constructive Waves

A

short fetch

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24
Q

wave form of Constructive Waves

A

low surging waves - long wavelength

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25
Q

wave break of Constructive Waves

A

strong swash, weak backwash

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26
Q

beach gain/ loss with Constructive Waves

A

gain

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27
Q

frequency of destructive Waves

A

High frequency - 11-16 per minute

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28
Q

Constructive Waves have ______ wavelength in proportion to height

A

low

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29
Q

What are Destructive Waves associated with

A

linked to high energy & storm weather which leads to erosion

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30
Q

Fetch of Destructive Waves

A

long fetch

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31
Q

Wave form of Destructive Waves

A

high plunging waves - short wavelength

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32
Q

Wave break of destructive waves

A

weak swash, strong backwash

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33
Q

beach gain/ loss with destructive Waves

A

loss

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34
Q

frequency of constructive Waves

A

Low frequency - 6-9 per minute

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35
Q

Destructive waves have ______ wavelength in proportion to height

A

high

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36
Q

Define beach morphology

A
  • The shape of a beach including:
  • its width and shape (the beach profile)
  • features (e.g. berms, ridges and runnels)
  • sediment type (shingle, mud & sand)
  • found at different locations on the beach
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37
Q

Name the 3 temporal factors affecting beach morphology

A

daily
seasonal
long-term

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38
Q

Describe the temporal factor (daily) affecting beach morphology

A

Over a day, as a storm passes & destructive waves change to constructive ones as the wind drops

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39
Q

Describe the temporal factor (seasonal) affecting beach morphology

A

between summer & winter

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40
Q

Describe the temporal factor (long-term) affecting beach morphology

A
  • where there are changes to the climate
  • e.g if climate change resulted in the UK climate becoming on average stormier then destructive waves & winter beach profiles would become more common
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41
Q

There are summer & winter beach profiles for each beach due to variations in…

A

wind & wave energy between seasons

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42
Q

Regardless of direction, wind speed is ________ in the winter because of the increased temperature differences between the poles and the equator

A

greater

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43
Q

Why is wind speed greater in the winter

A

Regardless of direction, because of the increased temperature differences between the poles and the equator

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44
Q

How does air movement result in a change in wind speed

A
  • Air movement leads to uneven heating,
  • so the difference between the temperature of the poles & equator increases
  • and so does the pressure differences,
  • resulting in a change in wind speed
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45
Q

Characteristics of a summer beach profile
elevation and width

A
  • gentler summer waves deposit sand from offshore bars onto the beach
  • ultimately widening it & increasing its elevation
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46
Q

Characteristics of a summer beach profile
waves

A

constructive waves which build up berm ridges

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47
Q

Characteristics of a summer beach profile
sands

A

finer & medium grain sands are predominant

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48
Q

Characteristics of a summer beach profile
Vegetation

A

dune plants are green, lots of vegetation

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49
Q

Characteristics of a winter beach profile
width

A
  • stronger winter waves, with more energy
  • pick up those particles deposited in the summer
  • and carry them back offshore in bars,
  • thus narrowing the beach
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50
Q

Characteristics of a winter beach profile
waves

A

offshore ridges / bars are formed by destructive wave erosion

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51
Q

Characteristics of a winter beach profile
sands

A

the sand composition will be much coarser

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52
Q

Characteristics of a winter beach profile
vegetation

A

the plants go dormant, while only the roots remain alive

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53
Q

Material found on a beach ______ in size and type as you move further away from the shoreline

A

varies

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54
Q

The smallest material is deposited near_____

A

the water

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55
Q

the largest material is found nearer to_______

A

the cliffs at the back of the beach

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56
Q

Large material is deposited at the back of the beach in times of…

A

high energy e.g during a storm

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57
Q

Define Hydraulic Action

A
  • water is forced into cracks in the rock
  • this compresses air
  • when the wave retreats, the compressed air blasts out
  • which forces rocks apart
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58
Q

Define Corrosion (solution)

A
  • mildly acidic seawater can cause alkaline rock such as limestone to be dissolved & eroded in a chemical reaction
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59
Q

Define Abrasion

A
  • caused by the waves picking up sand & pebbles
  • hurling them at the cliffs with force
  • wearing the cliffs away
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60
Q

Define Attrition

A

any material carried by the waves will become rounder & smaller over time as it collides with other sediment

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61
Q

How are wave cut notches formed
1. waves

A

At high tide, destructive waves may reach the base of the cliff

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62
Q

How are wave cut notches formed
2. erosion

A

the processes of abrasion & hydraulic action erode the rock at the cliff base

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63
Q

How are wave cut notches formed
3. forms

A

a wave cut notch forms along the length of the cliff

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64
Q

Sea caves may form at ……….. points along the wave cut notch line

A

weaker

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65
Q

How are wave cut platforms formed
1. wave cut notch

A

Above the wave-cut notch, an overhang of unsupported rock is formed

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66
Q

How are wave cut platforms formed
2. recession

A
  • as the overhang is undercut,
  • mass movement of the unsupported rock occurs
  • & the cliff retreats (recession), which is variable according to the lithology
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67
Q

How are wave cut platforms formed
3. post cliff retreat

A
  • as the cliff retreats,
  • it leaves behind a flat or slightly sloping area of rock
  • between the high & low tide levels:
  • a wave cut platform
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68
Q

……………. also contributes to the formation of some wave-cut platforms

A

weathering

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69
Q

How are cliffs eroded

A

constant wave action & erosion against the base of the cliff ensures that it maintains its steep profile as it retreats inland

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70
Q

Rock angle of steeper cliffs

A

rock strata are vertical, horizontal or have almost vertical joints

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71
Q

Rock angle of gentler cliffs

A

where rock dips towards or away from the sea

72
Q

How are headland & bays formed

A

they form on discordant coastlines, where waves erode the softer rock faster than harder rock

73
Q

How are bay-head beaches formed

A
  • bays have a semi-circular shape once eroded,
  • and the waves entering a bay dissipate & lose energy,
  • and hence deposit a bay-head beach
74
Q

The Cave, Arch, Stack, Stump Sequence
1. weaknesses

A
  • the erosion of rocks like limestone & chalk tend to be exploited at any lines of weakness e.g joints, faults & cracks
75
Q

The Cave, Arch, Stack, Stump Sequence
2. Caves

A

If the joints & faults are eroded by hydraulic action & abrasion, this can then creates caves

76
Q

The Cave, Arch, Stack, Stump Sequence
3. Blowholes

A

If the overlying rock then collapses, a blowhole will develop as the cave opens up at ground level

77
Q

During high tides, seawater can be ……… …… of these blowholes with considerable force

A

blown out

78
Q

The Cave, Arch, Stack, Stump Sequence
4. Arch

A
  • If 2 caves on either side of a headland join up,
  • or a single cave is eroded through a headland,
  • an arch is formed
  • the gap is then further enlarged by erosion & weathering - becoming wider at the base
79
Q

The Cave, Arch, Stack, Stump Sequence
5. Stack

A

Eventually, the top of the arch will become unstable & collapse, leaving an isolated pilar of rock called a stack

80
Q

The Cave, Arch, Stack, Stump Sequence
6. Stump

A
  • The stack itself will continue to be eroded by the sea
  • As it collapses & is eroded further,
  • it may only appear above the surface at low tide,
  • and is now known as a stump
81
Q

Wave move sediments up and down via

A

LSD
Tides and currents

82
Q

Name the 4 methods of transportation

A

traction
saltation
suspension
solution

83
Q

define traction

A

large, heavy pebbles are rolled along the seabed

84
Q

define saltation

A

pebbles are bounced along the sea bed

85
Q

define suspension

A

lighter sediment is suspended (carried) within the water

86
Q

define solution

A

the transport of dissolved chemicals

87
Q

LSD
1. the strongest LSD occurs when waves approach the coast at an angle of ____ to the beach

A

30 degrees

88
Q

LSD
2. the forward movement of each wave, the ______, moves beach sediments…..

A

swash
up the beach at the same angle as the waves approach

89
Q

LSD
3. the _______of each wave then carries the sediment……

A
  • backwash
  • back down the beach at right angles to the shore under the influence of gravity
90
Q

LSD
4. In this way, sediments slowly moves in small ________ steps along the beach until they reach a…… or a……..

A
  • zigzag
  • natural obstacle, such as a bay or an estuary,
  • or an artificial barrier such as groynes
91
Q

LSD
5. The __________ will determine the LSD direction at any section of the coast

A

dominant wind

92
Q

LSD
Name an example of LSD along the UK coastline

A
  • Along the South Coast of England
  • LSD is west to east because the dominant waves come from the Atlantic Ocean
93
Q

What are tides

A

Changes in the water levels of seas & oceans

94
Q

What causes tides

A

the gravitational pull of the moon & to a lesser extent the sun

95
Q

The UK coastline experiences ___high & low ______ in the oceans a day

A

2
bulges

96
Q

Define tidal range

A

the relative difference between high & low tides

97
Q

What does a high tidal range create

A

relatively powerful tidal currents, as tides rise & fall

98
Q

Where can tidal currents become particularly strong and fast

A

in estuaries and narrow channels

99
Q

tidal currents become particularly strong and fast, in estuaries and narrow channels meaning they are important in…..

A

transporting sediment

100
Q

Name 6 depositional landforms

A

Beaches
Cuspate Forelands
Offshore bars
Spits (recurved & double)
Barrier beaches (bars)
Tombolos

101
Q

What is a depositional landform

A

occurs along the coast when waves no longer have enough energy to transport sediment

102
Q

What is a beach

A

a common coastal depositional landform

103
Q

Beaches
___________ creates these low energy environments

A

Wave refraction

104
Q

Beaches are made of ____________ or _______ depending on…

A
  • Beaches are made of rounded sand or shingle depending on factors like the nature of the sediment and the power of the waves
105
Q

What are the 2 types of beaches

A

Drift Aligned
Swash Aligned

106
Q

How are swash aligned beaches built

A

By constructive waves

107
Q

How are drift aligned beaches made

A

LSD - transports sediment down the coast keeping beaches relatively narrow

108
Q

What is a Cuspate Foreland

A

A low lying roughly triangular shaped headland

109
Q

How are cuspate forelands formed

A
  • When significant longshore drift comes from opposite directions along a coast,
  • so that pebbles & sand are deposited across a bay from both directions,
  • forming a spit
110
Q

Where can the largest Cuspate Foreland in Europe be found

A

Dungeness in Kent

111
Q

What is an offshore bar

A
  • A long ridge of sand or pebbles,
  • formed a short distance out to sea,
  • in shallow water
  • where destructive waves break before reaching the beach
112
Q

How is an offshore bar formed

A
  • Destructive waves erode sand from the beach
  • with their strong backwash
  • & deposit it on offshore bars
113
Q

What does an offshore bar look like at high tide

A

The offshore bar is below the sea
A line of breathers reveals its location as waves break on it

114
Q

What does an offshore bar look like at low tide

A

A beach parallel to the coast can be seen, which is an offshore bar

115
Q

What is a spit

A
  • a long narrow depositional feature,
  • made of sand or shingle,
  • which extends from the road into the sea
116
Q

Where do spits form

A
  • On drift-aligned beaches,
  • when there is a dominant main LSD direction,
  • plenty of sediments from mass movement & erosion,
  • & a gap in the coastline such as an estuary or bay
117
Q

How are spits formed

A
  • sand or shingle is moved along the coast by LSD,
  • but if the coastline suddenly changes direction,
  • sediment will be carried for a short way in the same direction until they are deposited on the seabed
  • overtime, so much sediment is deposited that a narrow strip of land (a spit) forms across a bay or estuary
118
Q

What prevents a spit from extending across the estuary mouth

A

the outward flow of the river associated with the estuary

119
Q

How do salt marshes develop once spits are formed

A
  • the shelter provided by the spit
  • means that sediment is deposited behind it to form mudflats,
  • on which a salt marsh may develop
  • & be colonised by salt tolerant plants
120
Q

What is a tombolo

A

a narrow low ridge of sand & pebbles connecting an island to the mainland

121
Q

How do tombolos form

A
  • After longshore drift carries sediment across a gap between the mainland and an island,
  • where the waves lose their energy,
  • so a tombolo builds up
122
Q

What is a barrier beach (bar)

A

a beach that connects two areas of land with a lagoon forming behind

123
Q

In what conditions will a barrier beach form

A
  • a plentiful supply of sand or shingle
  • shallow nearshore or offshore areas
  • waves with enough energy to move the sand or shingle
  • a rising sea level to push the sediment towards the shore
124
Q

How do barrier beaches form

A
  • When rising sea levels cause constructive waves
  • to drive a ridge of sediment onshore to coastlines
  • with a gently sloping shallow sea bed (a barrier beach)
125
Q

Example of a Tombolo

A

St. Ninian’s in the Shetland Islands

126
Q

Where are barrier beaches common

A

Along Dutch coastlines

127
Q

What are subaerial processes

A
  • A combination of weathering & mass movement processes
  • that alter the shape of the coastline,
  • distinct from marine erosion, transport & depositional processes
128
Q

Define weathering

A
  • The breakdown of rocks in situ or near the Earth’s surface,
  • exploiting weaknesses in rocks over a long timescale
129
Q

What does weathering produce

A

Loose sediments that can be moved by gravity or removed by erosion (wind, rivers, waves or ice)

130
Q

What are the 3 types of weathering

A

Chemical
Mechanical
Biological

131
Q

Where does weathering operate

A

Between the low-tide level & the cliffs or land of the backshore

132
Q

Define chemical weathering

A
  • The erosion or disintegration of rocks
  • caused by chemical reactions, chiefly with water & substance’s dissolved in it,
  • rather than by mechanical processes
133
Q

Define mechanical erosion

A
  • Any of the various weathering processes that cause physical disintegration of exposed rock
  • without any change in the chemical composition of the rock,
  • such as collision between rock surfaces
134
Q

Define biological weathering

A
  • The weakening & subsequent disintegration of rock by plants, animals & microbes
  • growing plant roots can exert stress or pressure on the rock
  • although the process is physical, the pressure is exerted by a biological process (growing roots)
135
Q

What type of weathering is freezethaw

A

mechanical

136
Q

where does freeze thaw occur

A

on coasts in a climate where the temperature changes daily above & below zero

137
Q

describe the process of freezethaw

A

water seeps into joints & cracks in the rock, & when it freezes & expands, it exerts pressure & forcing the rocks apart

138
Q

what are the effects of freeze thaw

A

angular rock fragments

139
Q

what type of weathering is salt crystallisation

A

mechanical

140
Q

what is salt crystallisation

A

when waves break or splash cliffs on coastal rocks, the water evaporates, leaving behind sodium & magnesium

141
Q

What is the effects of salt crystallisation

A

Angular rock fragments are loosened and fall to create scree slopes at the base of the cliff or rock faces crumble away

142
Q

What type of weathering is oxidation

A

Chemical

143
Q

Describe what is meant by oxidation

A
  • Oxygen combines with iron-based minerals in a rock
  • causing a chemical breakdown of the minerals,
  • as shown by a red-orange rusty colour on a rock face
144
Q

What is the effects of oxidation

A

The rock minerals will no longer be bonded together and so the rock will crumble, making erosion easier

145
Q

What type of weathering is seaweed acids

A

Biological

146
Q

Describe what seaweed acids is

A

Some seaweed (eg kelp) cells contain pockets of sulphuric acid, so when these cells break in contact with rock, the acid will dissolve some rock minerals

147
Q

What is the effects of seaweed acids

A

Rock minerals will no longer be bonded together and so parts of a rock will crumble, and these become points of greater erosion

148
Q

What type of weathering is boring molluscs

A

Biological

149
Q

Describe what boring molluscs are

A
  • Many marine molluscs live on coastal rocks, scraping away at the rock surface to get food or boring a hole in the rock to make a home
  • One example is the Piddock, which has a shell with serrated cutting edges.
150
Q

What are the effects of boring molluscs

A
  • Pebbles and rocks with holes bored into them are more easily moved around by the waves.
  • The holes also provide weak points for other weathering processes to act.
151
Q

What is mass movement

A

Downslope movement of rocks, sand, glacial till or soil

152
Q

What causes mass movement

A
  • By gravity once a slope has become unstable
  • & it is common at the coasts due to the constant undercutting of the cliffs
153
Q

The _____ content also determines the type of mass movement

A

Water

154
Q

How does water content determine the type of mass movement

A

The sheer weight of rainwater and weak geology will lead to cliff collapse

155
Q

What are the 6 mass movement types

A

Soil Creep
Solifluction
Mud flows
Rock falls
Landslides
Slump/ rotational slip

156
Q

Soil creep is the ______ form of mass movement & is almost a ______ process

A

Slowest
Continuous

157
Q

Where does soil creep occur

A

On very gentle slopes because of the way soil particles repeatedly expand & contract in wet & dry periods

158
Q

How can soil creep be identified

A

By terracettes

159
Q

Solifluction’s movement averages between…

A

5cm & 1m per annum

160
Q

How does solifluction occur

A
  • when the top layer of soil thaws in the summer,
  • but the layer below remains frozen as permafrost
  • the surface layer becomes saturated and flows over the frozen subsoil & rock
161
Q

Where does solifluction occur

A

Occurs mainly in tundra areas, where the ground is frozen

162
Q

What is a mud flow

A
  • An increase in the amount of water can reduce friction
  • causing earth & mud to flow over underlying bedrock
  • typically, a torrential rainfall or very rapid snow melt run off is the initiating factor
163
Q

What is the difference between a slide & a flow

A

Is that in a slide the material remains intact wheras in a flow, material is jumbled up

164
Q

How can you identify a mud flows

A

A lobe ( material at the bottom )

165
Q

Where do rock falls occur

A
  • On slopes over 40 degrees
  • Most likely to occur when strong joined and steep rock faces/cliffs are exposed to mechanical weathering
166
Q

What is a rock fall

A

The material once broken down from the source by mechanical weathering, either bounces or falls vertically

167
Q

What is a block fall

A

Similar to rock falls
A large block of rock falls away from the cliff as a single piece, due to the jointing of the rock

168
Q

How can rock falls be identified

A

By scree/ talus

169
Q

Where can landslides occur

A

Rocks that are jointed or have bedding planes are susceptible to landslides

170
Q

How do landslides occur

A

An increase in the amount of water can reduce friction - causing sliding
In a landslide, slabs of rock can slide over underlying rocks along a slide or slip plane

171
Q

Where do slumps/rotational slips occur

A

In saturated (raining) conditions on moderate to steep slopes

172
Q

When do slumps/ rotational slips occur

A

Common when softer materials overlie more resistant or impermeable rock

173
Q

What is the difference between sliding and slumping

A

There is a rotational movement in slumping

174
Q

How can slumps be identified

A

Rotational scars

175
Q

What does repeated slumping create

A

A terrace cliff profile

Geography - Physical - Paper 1 (13 decks)

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