Coasts Flashcards
(176 cards)
1
Q
What is enquiry question 1?
A
why are coastal landscapes different and what processes causes these differences?
2
Q
What is the definition of concordant coasts?
A
this is where bands of more resultant and less resistant rocks parallel to the coast
3
Q
What are the key landforms of a concordant coast?
A
Dalmatian coasts- formed as a result of rise in sea level. Valleys and ridges run parallel to each other. When valleys flood ( due to sea levels rising ) the tops of the ridges remain above the sea. Looks like offshore islands.
Example: Dalmatian coasts of Croatia
Haff coasts- consists of concordant features, long spits of sands and lagoons aligned in parallel to the coast
Example: Southern shore of the Baltic sea
4
Q
What is the definition of a discordant coast?
A
the geology alternates between bands of more resistant and less resistant rock which run at right angle to the coast
5
Q
What are the key landforms of a discordant coast?
A
Headlands- force incoming waves to refract or bend concentrating their energy at the headlands. this increases the waves erosive power which leads to steepening of the cliff and their eventual erosion into arches
Bays- waves energy dissipates and reduces in the bay. This leads to deposition of the sediment.
6
Q
What is the definition of deformation?
A
degree to which rock units have been deformed (tilted or folded) by tectonic activity
7
Q
What is the definition of faulting?
A
presence of major fractures that have moved rocks from their original position
8
Q
What is the definition of bedding in terms of rocks?
A
where rock types meet
9
Q
What is a dip?
A
The angle in which rocks lie at an angle usually seen in deformed strata
10
Q
What type of cliff profile is at a low angle with one rock layer facing the sea (usually vunrable to rock slides)?
A
Seaward Dip (high angle)
11
Q
What type of cliff profile is vertical profile with notches reflecting strata that are more easily eroded?
A
Horizontal Dip
12
Q
What type of cliff profile is steep profile of 70-80 degrees producing a very stable cliff with reduced rock fall?
A
Landward Dip
13
Q
What type of cliff profile may exceed 90 degrees producing areas of overhanging rock (very vunrable to rock fall)
A
Seaward Dip (low angle)
14
Q
What is the erosion rate of sedimentary rocks?
A
0.5 - 10 cm per year
15
Q
What is the erosion rate of metamorphic rocks?
A
0.1 - 0.3 cm per year
16
Q
What is the erosion rate of igneous rocks?
A
<0.1 cm per year
17
Q
What are examples of sedimentary rock?
A
chalk, clay, conglomerate
18
Q
What are examples of metamorphic rock?
A
Marble, slate, Gneiss
19
Q
What are examples of igneous rocks?
A
Basalt, Granite, Gabbro
20
Q
What is a psammoseres?
A
Sand dunes
21
Q
What is a haloseres?
A
Salt marshes
22
Q
What rock type and what are the characteristics of gabbro?
A
igneous
course grained and dark coloured
23
Q
What rock type and what are the characteristics of conglomerate?
A
Sedimentary
clasts are well rounded and vary in size
24
Q
What rock type and what are the characteristics of Gneiss?
A
Metamorphic
distinctive banding caused by segregation of mineral grains into layers often alternating between dark and light
25
What is the definition of a high energy environment?
where destructive storm waves breaking on shingle beaches are most typical
26
What is the definition of a low energy environment?
where constructive swell waves breaking upon sandy beaches are most typical
27
What two categories did Valentino use for coasts?
advancing- where marine deposition or the uplift is dominant
Retreating- where marine erosion or the submergence of land is more significant
28
What is the definition of marine erosion?
wearing away of the land surface and removal of materials by river and seawater, ice and wind
29
What is the definition of marine deposition?
Deposition occurs when energy levels decrease in environments such as bays and estuaries. Where deposition occurs on the inside of a spit a salt marsh can form
30
What does the littoral zone consist of?
coast
backshore
foreshore
nearshore
offshore
31
What four types of coast line are formed by the littoral zone?
rocky- resistant rock with high energy environments also destructive waves
sandy- low relief areas, low energy environments with more deposition than erosion
estuarine- salt marshes and mud flats river mounds with more deposition than erosion
32
What is short term classification?
energy inputs (high and low energy coastlines)
sediment inputs (deposition and erosion rates)
advancing and retreating (happens due to erosion and deposition rates)
33
what are the characteristics of a coastal plain?
flat land, low relief, often containing wetlands and salt marshes, low energy environments, high deposition
Mostly south-east UK
34
What are the characteristics of a rocky coast?
Cliffs that vary in height, high resistant rock, low relief, little deposition with high erosion
Mostly north-west UK
35
What are faults?
major fractures caused by tectonic processes
36
What are joints?
fractures created by rocks being moved
37
What are fissures?
more open than fractures
38
What is folding?
bends in rock due to sedimentary rock layering
39
What is anticline and syncline?
anticline-top of curve
syncline-bottom of curve
40
What is enquiry question 2?
how do characteristics of coastal landforms contribute to coastal landscapes?
41
What causes waves to be stronger and higher?
strength of wind
water depth
duration of wind blowing
distance of sea travelled (fetch)
42
What is an example of a long fetch?
Cornwall (longest prevailing wind of 4000km)
43
What are the characteristics of a constructive wave?
long wavelength
low surging waves
strong swash
weak backwash
beach gain
44
What are the characteristics of a destructive wave?
short wavelength
high plunge waves
weak swash
strong backwash
beach loss
45
What are the four erosional processes?
abrasion
hydraulic action
attrition
solution
46
what is marine processes?
action of waves
46
define erosion
wearing away of land surface and removal of material by river
47
what is abrasion
when waves advance they pick up sand and pebbles from sea bed and throw them at cliff face
48
what is hydraulic action
when wave advances air can become trapped and compressed in faults then the wave retreats air expands. This continuous process weakens the faults
49
what is attrition
gradual wearing down of rock particles by impacts and abrasion as [pieces of rock are moved by waves and tides
50
what is solution
when a cliff is formed by alkaline rock or cement bonds the rock particles together, solution by weak acids in salt water dissolve them eroding them down
51
define geomorphic
relates to the formation and shaping of landforms and landscapes by natural processes such as weathering, mass movement transportation and erosion
52
define weathering
breakdown or disintegration of rock in situ (original place) as a process it leads to the transfer (flow) of material
53
define mass movement
downhill movement of material under the influence of gravity
54
define marine process
includes erosion, transportation and deposition. Caused by power of wind which transfers energy to waves
55
what is an example of bay beaches
dorset coast
56
what is an example of bay bars
looe cornwall
57
what is an example of barrier beaches
start bay, Devon
58
what is an example of spits
Orford Ness Sufolk
59
what is an example of recurved spits
Hurst castle spit Hampshire
60
what is an example of cuspate forelands
Carolina USA
61
what is an example of tombolo's
loch Eriboll Scotland
62
what is an example of a sediment cell
Portland bill
63
How many sediment cells are there in England and Wales?
11
64
What three components make up a sediment cell?
sinks, transfers and sources
65
What isa sediment cell
it is a closed system which is in dynamic equilibrium meaning no sediment is transferred between each cell
66
What are sources
places where sediment generated
67
What are transfer zones
place where sediment moving alongshore
68
What are sinks
locations where dominant process is deposition
69
What are examples of sources
erosion on cliff
onshore currents supply sediment to shore
land sediment eroded by rivers
wind-blown sediment from land
subaerial processes such as weathering and mass movement
shells and remains of marine organisms
70
What are examples of transfers
longshore drift
wave transport through swash and backwash
tides moving sediment in and out
currents- localised or large scale
wind alongshore and off shore
71
What are examples of sinks
backshore depositional landforms
foreshore depositional landforms
nearshore depositional landforms
offshore sediment deposition to deep offshore waters
72
What is negative feedback
maintains balance e.g. wave erosion causes rock fall which protects the base from further erosion
73
What is positive feedback?
changes the balance until a new equilibrium is reached e.g. sand dunes are damaged during storm causing 'blow out' (depressions/hollows) allowing wind to move sand away , preventing marram grass from re-growing = more erosion
74
What is mass movement?
movement of material downslope as result of gravity can be slow or fast. Water commonly acts as lubricant
75
What is soil creep?
slow downhill movement of soil and debris under the influence of gravity
76
What are mudflows?
fast movement of mass of water saturated soil, rock and debris that move downhill due to gravity.
Often occur after lots of heavy rainfall causing excessive friction between particles
77
What is solifluction?
is the slow downslope movement of water logged soil and sediment caused by upper layer thawing during summer while permafrost still remains
78
What is rock fall and talus slopes?
larger bits of rock fall down the cliff face, usually due to freeze thaw weathering
this creates talus slope, when the rock falls almost vertically, down the side of the cliff face
The coastline loses in shape and becomes more like a slope
79
What are translational slides?
a translational or planar landslides is downslope movement of material that occurs along a distinctive planar surface of weakness such as a fault, joint or bedding plane
80
What is rotational slumping?
occurs when a slump block, composed of sediment or rock, slides along a concave-upward slip surface with rotation around the axis parallel to the slope
81
What are plant roots?
a seed from a plant lands in crack of a rock and as it grows the roots grow into the crack causes it to widen
this is a mechanical process that creates more surface area for other weathering processes to act upon
82
What is rock boring?
rock boring acts as a catalyst within subaerial processes by initiating and enhancing the breakdown of rock material through biological means
Molluscs and sponges bore into cliffs and rocks along shorelines, weakening them and contributing to erosion
83
What are seaweeds acids?
kelps contains pockets of sulphuric acids, when cells break, sulphuric acids attacks nearby rocks minerals like calcium carbonate, this leads to a chemical reaction similar to carbonation, increasing ocean acidity
84
How does seaweed acids affect the landscape?
increases the oceans acidity means that erosion is quicker because the acid in water attacks the rocks
The increase in erosion makes the coastline more rocky
85
What is freeze thaw weathering ?
is the continuous ongoing expansion of rock faults.
86
What is salt crystallisation?
disintegration of rocks when saline solution seeps into cracks or faults of rocks then evaporates leaving salt crystals
87
What is oxidation?
chemical process of oxidation is the reaction of a substance with oxygen
88
What is hydrolysis?
affects the coast by causing weathering especially on softer rock types. Occurs when a mineral within a rock reacts with water to produce a new substance which can usually be eroded faster.
89
what causes sea level change daily?
high and low tides
atmosphere pressure
winds
90
What are the two types of sea level change?
isostatic
eustatic
91
what is isostatic change?
local rise or fall in land level, relative to sea level (e.g. snow on Scotland causing tilt in UK)
92
What is Eustatic change?
rise or fall in water level caused by change in volume of water, global change (e.g. thermal expansion)
93
What is Kiribati a case study for?
climate change
94
What problems does Kiribati face?
salt water contamination
sea level rise causing increased erosion and retreating land
lack of money for good defences
95
How high is Kiribati above sea level
1M
96
By 2100 how much will sea levels rise for Kiribati?
30cm - 1 M higher
97
What is the case study for tectonic sea level rise
Aceh
98
What is 'great Britain slowly pivoting upwards in north and downwards in south' an example of
isostatic change
99
What is 'Scotland still rebounding upwards, in some places up to 1.5mm a year' an example of
isostatic change
100
What is 'England and Wales are subsiding up to 1mm per year' an example of
isostatic change
101
What is 'global change affecting all the world's connected sea's and ocean's' an example of
eustatic change
102
Define an emergent coast
result of a relative fall in sea level
103
define a submergent coast
post glacial sea level was very rapid and would have drowned many coastlines
104
What is 'raised beaches and fossil cliffs' an example of
emergent coastline
105
What is 'fjords-drowned river valley' an example of
Submergent coastline
106
What is 'Ria-a drowned river valley in an unglaciated area caused by sea level rise' an example of
submergent
107
What is 'Barrier islands-offshore sediment bars, usually sand dune covered' an example of
submergent coastline
108
how long is the plate in Aceh?
1600 km fault line
109
What are the issues caused by the plate in Aceh?
sea bed rose by 7m displacing 30km^3 of water
(permanent sea level rise of 0.1mm)
110
What percent of Egypt's population live near the Nile Delta?
95%
111
How much land has already been lost due to the erosion of offshore bars in the Nile Delta?
3.3%
112
How much fertile land will be lost if the sea level rises by 1m in the Nile Delta?
2 million hectares
113
What percent of the Nile Delta is high vulnerability?
32.4%
114
How much the sediment volume fall in the Nile Delta?
130 million tons to 15 million tons
115
How does dredging increase erosion and what is it?
dredging is digging out the bottom of a river to improve shipping capacity but it reduces the amount of energy dissipated from incoming waves and so increases erosion
116
What are the physical vulnerabilities that effect bangladesh?
low lying
three major rivers
storm surges increased by funnelling effect
117
What are the human vulnerabilities that effect bangladesh?
climate change
urbanisation
dredging
vegetation removal (mangroves)
subsidence
118
How much does the mangroves retreat in Bangladesh per year?
200m
119
What was the economic loses in Bangladesh due to storm surges?
$3 billion in loses
120
How high is the land in Bangladesh above sea level?
5m
121
How many major floodplains are there in Bangladesh
3
122
How many people will be displaced by 2050 in Bangladesh due to storm surges and seal level rise?
1 in 7
123
How much of Bangladesh's land will be submerged by sea level rise of 1.5m
22,000km^2
124
How many people in Bangladesh will be affected by sea level rise and storm surges ?
18 million
125
What are storm surges
temporary rise in sea level caused by atmospheric pressure changes and strong winds during storms
126
What are the primary cases of storm surges?
low atmospheric pressure and strong winds
127
What contributes to the strength of storm surges?
wind strength, coastal topography
tide levels
climate change
land use
coastal development
funnelling effect
sea beds shallow towards coast
128
What were the environmental impacts of Cyclone Sidr?
685 528 hectares of damaged crops
many fresh water sources contaminated
server coastal flooding
129
What were the economic impacts of cyclone Sidr
cost of $1.7 billion
1,500,000 houses damaged
$29.6 in damage to roads
703 KM of electricity lines damaged
130
What were the social impacts of Cyclone Sidr?
4234 dead/missing
55 000 injured
16000 educational institutes damaged
sanitiation+infastructure
131
What were the causes of the impacts of cyclone sidr?
river embankments had been lowered to pave roads
low lying country
removal of mangroves
funnelling effect
developing country
132
What are the causes of storm surges in the UK
intense low pressure
sea shape and coastline
sea depth
high seasonal tides
strong northernly winds pushed surge further south
133
What are the social impacts of the storm surge in Uk between 2013-14
forced evacuation
bridges shut
two people died
134
What were the environmental impacts of the storm surge in the UK between 2013-14
strong winds (over 200 km/hr in scotland)
135
What were the economic impacts from the storm surge in the UK between 2013-14?
1400 homes flooded
cliff erosion led to properties falling into sea
cost of £100 million
136
what causes increased flooding risk?
more storms due to warmer oceans
more flooding due to climate change decreasing height above sea level
137
How can we prepare for flooding in the future?
adaptation (making changes to lessen the impacts of flooding)
Mitigation (making efforts to reduce emissions of greenhouse and so reduce impacts of climate change)
138
What is enquiry question 3?
How do coastal erosion and sea level change alter the physical characteristics of coastlines and increase risk?
139
What is an example of dalmatian coast
dalmatian coast of croatia
140
What is an example of haff coast
Southern shore of baltic sea
141
What is an example of headlands
Dorset Coastline
142
What is an example of bays
Lulworth cove
143
What is an example of High energy environment
Lulworth cove
144
What is an example of sedimentary rocks
chalk or clay
145
What is an example of metamorphic rocks
marble or slate
146
What is an example of igneous rock
Basalt or Granite
147
What is an example of Coasts that need protecting (livelihood)
fairbourne
148
What is an example of vary geology in area effecting defences
New Biggin
149
What is an example of tombolos
Chesil Beach Cornwall
150
What is an example of wave cut platforms
Flamborough, Holderness coast
151
What is an example of low energy coastal environment
Nile Delta
152
What is an example of long fetch
Cornwall
153
What is an example of bay beaches
Dorset coast
154
What is an example of bay bars
Looe, Cornwall
155
What is an example of spits
Orford Ness Suffolk
156
What is an example of cuspate forelands
Carolina USA
157
What is an example of sediment cell
Portland Bill
158
What is an example of sources
erosion on cliffs
159
What is an example of tranfers
longshore drift
160
What is an example of sinks
backshore depositional landforms
161
What is an example of climate change
Kiribati
162
What is an example of tectonic sea level rise
Aceh
163
What is an example of Storm surges (developing)
Cyclone Sidr
164
What is an example of storm surges (developed)
UK storm surges
165
What is an example of human and physical vulnerability to do with flooding
Bangladesh
166
What kind of coastal landscapes do headlands and cliffs belong to?
high energy with resistant geology
Rocky coastline
167
What kind of coastal landscapes do beaches and psammosere's belong to?
low energy environments
Sandy coastline
168
What kind of coastal landscapes do mudflats and halosere's belong to?
low energy environments
Estuarine coastlines
169
How does permeability effect the coast?
Water drainage and erosion (more permeability=less surface run off=less erosion)
Mass movement (permeable rocks on top of impermeable leads to water accumulation=more weight and lubrication)
Formation (influences formation of stacks, etc)
170
What three distinctive landforms form as a result of mass movement
rotational scars
talus scree slopes
terraced cliff profiles
171
How do rotational scars form
form when section of a cliff slump due to rotational movement, exposing fresh curved untethered rock surface
172
How do talus scree slopes form
develops when rock fragments accumulate at base of cliff following blockfall event
173
How does terraced cliff profiles form
result of repeated slumping where detached slope sections settle into a stepped formation
174
How are emergent coastlines formed
formed when land rises faster than sea levels revealing raised beaches and fossil cliffs
175
How are submergent coastlines formed
created when rising in sea levels flood coastal areas forming rias (drowned river valleys) and fjords
