coastal and glacial landscapes Flashcards
(136 cards)
1
Q
what is a cross section?
A
an imaginary ‘slice’ through a landscape which hells to visualise what we cannot see
2
Q
what is geology
A
the science which deals with the physical structure and rock types of the Earth, their history, and the processes which act on them
3
Q
what is landscape
A
an extensive area whose character is regarded as visually and physically distinct being the result of the action and interaction of natural and human factors
4
Q
what is relief
A
the height of the land and the different landscape features created by changes in height
5
Q
what is metamorphic/resistant rock
A
tough rock eg granite and slate
6
Q
what is a river system
A
the complete river network from its source to mouth
7
Q
what is spot height
A
indication of land height, usually represented on OS maps as black dots with height above sea level written alongside
8
Q
what is the fetch
A
the distance the wind blows across the water
9
Q
what are constructive waves
A
waves that are able to build a beach because the swash is stronger than the backwash
10
Q
what are destructive waves
A
waves that destroy a beach because the backwash is greater than the swash➡️material is taken back to the sea with every wave
11
Q
what is the backwash
A
the part of the wave sweeping back into the sea
12
Q
how are waves formed
A
waves are formed by the wind blowing over the sea
friction with the surface of the water causes ripples to form
13
Q
what does the size of the waves depend on
A
-the strength of the wind
-the length of time the wind blows
-the distance of sea over which the wind has blown
14
Q
what is the UK predominant wind direction
A
south west
15
Q
what is a constructive wave like
A
-low wave height
-long wavelength
-spilling wave
-strong swash
-weak backwash
-gain sediment
-low frequency
16
Q
what are destructive waves like
A
-high wave height
-short wavelength
-plunging wave
-weak swash
-strong backwash
-loss sediment
-high frequency
17
Q
what is the definition of weathering
A
the wearing down or breaking of rocks while they are in place. Can be biological, chemical or physicla
18
Q
give an example of weathering
A
acid rainfall, plants growing into rock
19
Q
give an example of mechanical weathering
A
freeze thaw weathering
20
Q
give an example of chemical weathering
A
carbonation
21
Q
what is mass movement
A
the downward movement or sliding of a material under the influence of gravity
22
Q
what is a rockfall
A
fragments of rock break away from the cliff face, often due to freeze thaw weathering
23
Q
what is a landslide
A
blocks of rock slide downhill
24
Q
what is a mudflow
A
saturated soil and weak rock flows down a slope
25
what is a rotational slip
slump of saturated soil and weak rock along a curved surface
26
what are the main ways particles are transported
-solution
-traction
-saltation
-suspension
27
what is hydraulic action
the force of water crumbles and removes material from cliffs
28
what is abrasion
rocks and pebbles are flung at cliffs by strong waves and break pieces off
29
what is solution
some rocks and minerals are dissolved into the sea water
30
what is attrition
the rocks and pebbles in the sea collide and break into smaller pieces
31
explain longshore drift
-waves approach the beach at a similar angle to the prevailing wind direction
-pulled back into the sea on a vertical line
-material is carried along the beach by longshore drift
32
hard rock makes...
headlands
33
soft rock makes ..
bays and coastlines
34
what is discordant coastline
when the geology alternates between bands of hard and soft rock (vertical bands)
35
what is concordant coastline
alternating bands of hard and soft rock aligning with the coastline (horizontal)
36
how is a wave cut platform created
-sea attacks a weakness in the base of the cliff between the high and low tide level
-wave cut notch is created by erosional processes eg hydraulic action and abrasion
-as the notch becomes larger, the cliff becomes unstable and collapses as the result of gravity -> the cliff retreats inland
- material from the collapsed cliff is eroded and transported away
-> leaves a wave cut platform
➡️this process repeats over time
37
where does coastal deposition occur
beaches, areas where the flow of water slows down,sheltered bays
38
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why does coastal deposition occur
sediment can no longer be carried or moved as the wave has lost energy so is therefore deposited
40
what is a beach
an accumulation of eroded material transported and deposited by the sea
41
what is a beach made of
deposited material eg sand, coral, pebbles and stones
42
how is beach material transported
by longshore drift
43
where does sediment originate from
parts of a cliff face, sea bed, longshore drift, detritus and sediment from rivers
44
where are sandy beaches found
in sheltered bays
45
what is the swash like at sandy beaches
strong
46
what sort of waves do constructive beaches have
low energy constructive waves
47
where are pebble beaches found
non sheltered bays
48
what is the backwash like on a pebble beach
strong
49
what sort of waves do pebble beaches have
high energy constructive and destructive waves
50
how are spits created
deposition and longshore drift
51
how are bars formed
deposition and longshore drift
52
how does a sea wall work
provides a barrier between waves and land
it has a curved face to reflect waves back into the sea
53
how do groynes work
90° fences to sea to stop the movement of sediment through longshore drift
54
how does rock armour work
large boulders between sea and land
they reduce wave energy as the waves struggle to get through the rocks
55
how do gabions wotk
when water hits at the gabions, it quickly loses its energy as it falls through the gaps in the rocks
56
how does beach nourishment work
replacement of sand on a beach
there are 2 types
- beach recharge
material is taken from a bay and shifted further down the coast
- beach recycling
sand is moved from one area to another that is down the coastline and not at risk of erosion
57
give one advantage and one disadvantage of sea walls
+ sea walls can last for many years
+ people have a sense of safety
- can look obtrusive and unnatural
-very expensive and high maintenance
58
give one advantage and disadvantage of groynes
+ act as windbreaks
+ relatively cheap
+ can last up to 50 years
- unattractive
- need regular maintaining
59
give one advantage and disadvantage of rock armour
+ relatively cheap
+ often used for fishing
- makes the beach difficult to access
- ugly and doesn't blend in with the local area
60
give one advantage and disadvantage of gabions
+ relatively cheap
+ quick fix solution
- restricted to sandy beaches
- dangerous for animals
61
give one advantage and disadvantage of beach nourishment
+ wider beach means more room for beach users
+ natural environment that blends in with the surrounding
- needs constant maintenance
- access to the beach is restricted due to renourishment
62
give one advantage and disadvantage of beach reprofiling
+ much cheaper than having repairs
+ beach still looks reasonably natural
- bulldozers restrict access to the beach
- a steep high crested beach may look unattractive to tourists
63
give one advantage and disadvantage of sand dune regeneration
+ sand dunes protect the land behind them
+ regeneration helps to develop and maintain habitats for wildlife
- can be damaged by storm waves
- areas have to be zoned off from the public which is unpopular
64
how does beach reprofiling work
artificial reshaping of a beach
in winter the beach is lowered by destructive waves. after the bulldozers move shingle back up the beach
65
how does sand dune regeneration work
artificial creation of sand dunes which is a regeneration of the physical barrier between sea and land that absorbs wave energy and water
66
what is managed retreat
a form of soft engineering where low lying and low value land is allowed to naturally flood so defenses can be improved further inland
67
give one advantage and disadvantage of managed retreat
+ stable coast
+ less upkeep of defense
+ looks natural
+ biodiversity
- loss of land
- cliff instability
- relocation of homes
- loss of tourism
68
where is swanage
south coast in dorset
south of bournemouth
69
what is the coastline like at swanage
located in a sheltered bag, has a broad sandy beach, part of the jurassic coast
70
what is an ice age
a period of long term cooling of the earths atmosphere resulting in an expansion of ice sheets and glaciers
71
describe freeze thaw weathering
- water enters a crack in the rock
- freezes when temperatures drop at night
- this creates a larger crack in the rock
- process repeats until segments of rock begin to break away
72
how do glaciers move
basal slip
73
where is medmerry
near chichester, on the south coast of england
74
how much did the managed retreat at medmerry cost
£28 million
75
why did they decide to use managed retreat in medmerry
- sea wall was in need of repair which would have been expensive
- building a new one would have been even more expensive
- decided that the sea would be allowed to breach the low value land and flood some of the previously protected land
76
what is the hope for medmerry
that it will form a large saltmarsh to form a natural buffer with the sea
77
what is an environmental benefit of the managed retreat at medmerry
it will establish a valuable wildlife habitat to encourage visitors to the area
78
give an economic benefit of managed retreat at medmerry
often cheaper in the long term than to continue to maintain hard engineering defences
79
give a social benefit of managed retreat at medmerry
may take the pressure off areas further down the coast and reduce their risk of flooding
80
give a social cost of managed retreat at medmerry
relocation of people to new homes causes disruption and distress eg north norfolk realignment of 40 sq km will destroy 6 villages
81
give an economic cost of managed retreat at medmerry
short term costs are high - relocation costs
82
give an environmental cost of managed retreat at medmerry
- large areas of agricultural land are lost
- habitats could be lost
83
what is a reason why not managed retreat is that common
- much valuable land is on the coast eg london
- endangered species
- only low lying land can be used
84
name the 4 approaches to coastal management
- no active intervention
- hold the line (maintain current defences)
- advance the line (increase coastal defences to extend the coastline out to sea)
- managed retreat
85
86
describe a glacial environment
- snow and ice covering the landscape
- consistently low temps (barely above freezing)
- development of significant amounts of snow and ice
87
what was the most recent ice age
the Pleistocene
88
what are the cooler periods in ice ages called
glacials
89
what are the warmer periods in ice ages called
interglacials
90
how does abrasion work in glaciation
ice scours the valley floor (sandpaper effect) which creates a smooth polished surface but@
91
explain plucking
- meltwater beneath a glacier freezes
- bonds the base of the glacier to the rocky surface below like glue
- as the glacier moves any loose fragments of rock are plucked away
92
how does basal slip work
meltwater acts as a lubricant to the glacier, enabling it to move downhill
93
how does rotational slip work
ice moved along a curved surface to enlarge and develop hollows
94
what is a hummock
a small amount of sediment
95
what is glacial till
deposited material that was eroded and weathered from the uplands
96
what is till
poorly sorted debris carried by the ice and then dumped when the ice melts
97
what is outwash
debris carried by meltwater streams
98
what is moraine
deposited material from a glacier
99
100
what are striations
sharp straight lines found in the valley where sharp rocks have grinded their way along
101
what are crevasses
a deep open crack found in a glacier
102
what is erosion
the gradual wearing away of something
103
where is lyme regis
- small coastal town on the south coast of england
-popular tourist destination
- in summer the population increases from 4000 to 15000
104
why does lyme regis need coastal management
- unstable cliffs
- most rapidly eroding coastline in europe
- popular tourist destination
- powerful waves from the south west
- sea wall has been breached many times
- many properties have already been damaged due to erosion
105
how do glaciers form and move
-snowflakes fall and accumulate in a hollow in the mountainside
-with more snowfalls, the weight compresses the snow together to form firn
-as more snow falls and more weight is added the firn turns into ice
- the ice appears blue because all of the air is squeezed out under the pressure
-if ice doesnt melt and snow continues to fall the glacier gets bigger and heavier
-gravity causes the glacier to move downhill
-as the glacier moves it erodes the valley on either side and underneath it, altering the landscape
106
107
what is a corrie
a deep depression found on a hill side in the upper course of the glacier
108
give a characteristic of a corrie
-steep back wall and sides
-usually contains a lake (tarn)
-raised lip at front to keep water from tarn inside
109
what is an arête
a knife edged ridge formed when 2 corries develop side to side or back to back
110
give an example of an arête
Striding Edge, Lake District
111
what is a pyramidal peak
a peak formed when 3 or more corries develop on all sides of a mountain which erode towards each other
112
give an example of a pyramidal peak
Stob Dearg, Scotland
113
what is a hanging valley
a tributary valley that is higher than the valley of the main glacier
its formed when a smaller tributary glacier flows from the valley sides towards the main glacial valley
114
give an example of a hanging valley
Nant Ciliau, Snowdonia
115
what are truncated spurs
blunt ended, sloping ridge which descends from the flank of a valley
formed by the force of a glacier bulldozing through a valley which removes large portions of the valley sides
116
give an example of truncated spurs
Devil's Point, Scotland
117
how is a glacial trough (U shaped valley formed
- before glaciation - V shaped
- during glaciation - rock in valley sides removed through plucking and abrasion
- results in a U shaped valley
118
give an example of a U shaped valley
Glen Coe, Scotland
119
what is a ribbon lake
a long narrow lake in a glacial trough
120
give an example of a ribbon lake
Windermere or Ullswater both in the Lake District
121
what is a drumlin
a small egg shaped hill often found on the floor of a glacial trough
122
how large are drumlins
1km+ in length
500m+ in width
50m+ in height
123
what are erratics
rocks that have been transported by ice and deposited elsewhere
124
what is important about erratics
the type of rock that the erratic is made from is different to the type of rock where the erratic is deposited
125
name the 4 types of moraine
-ground
-lateral
-medial
-terminal
126
where does lateral moraine form
on the side of a glacier
127
where does ground moraine form
dragged underneath the glacier and left behind when the ice melts
128
where does terminal moraine form
at the end of glaciers
129
where does medial moraine form
when a tributary glacier joins a smaller one, two lateral moraines merge into one
when the ice melts, it forms a ridge in the middle
130
why does sheep farming take place in previously glaciated areas
-marshy
-upland farms or hills are good for rearing sheep
131
why does arable farming happen in previously glaciated areas
-sloping land
-fertile soil
-open areas
-open sunny locations
-ribbon lakes are a good source of water
132
why does tourism take place in previously glaciated areas
-mountains are good for hiking , walking, biking
-coastline and lakes can offer beaches, harbours and watersports
133
why does forestry take place in previously glaciated areas
-lower slopes of U shaped valley are ideal for forestry
-coniferous and evergreen forests can survive harsh conditions
134
why does quarrying take place in previously glaciated areas
-valuable sources of rocks and minerals
-U shaped valleys are easy for machinery to access them / other quarries
135
give an example of conflict from a previously glaciated area
Glenridding zip wire 2014
-treetop trek put forward a proposal to construct 4 parallel 1 mile long zip wires
-strong local opposition to it
-provides economic opportunities
136
