1
Q
what 2 things work together at a coast
A
lithosphere and hydrosphere
2
Q
what is the lithosphere
A
crust and uppermost mantle continuing the hardened rigid over layer of the Earth
3
Q
what is the hydrosphere
A
Layer of water near the earths surface
4
Q
what is input
A
what arrives in a system
5
Q
what is output
A
what leaves the system and moves across boundaries
6
Q
what do boundaries do
A
separate areas of coastline
7
Q
what’s part of input in costal open system
A
sediment carried by river and waves, wind generated waves, precipitation
8
Q
what takes place an output in open costal system
A
eroded material taken out to sea, ocean currents and evaporation
9
Q
what takes place in transfers in the open coastal system?
A
transportation processes, longshore drift mass movement, wind blow blown sand
10
Q
What takes place in the stores part of the open coastal system?
A
beaches
cliffs
dunes
11
Q
what is dynamic equilibrium
A
State of balance where inputs are equal to outputs in a system that is constantly changing
12
Q
what is feedback?
A
Automatic response to a change with an system
13
Q
what is positive feedback?
A
Leads to further change for example, increasing wave energy could scour the sea bed deepening water allowing more wave energy to enter location increasing wave energy further
14
Q
What is negative feedback?
A
Reduces the effective change for example decrease and wave energy entering the coast zone could lead to deposition of sediment offshore further reducing wave energy as it’s lost a friction
15
Q
What is a landform?
A
Geographic feature on the surface of the Earth
16
Q
what is landscape
A
part of the Earth surface
17
Q
what is the fetch of a wave
A
the distance that the wind blows across water
18
Q
what is the swash of a wave
A
movement of water up the beach
19
Q
what is the backwash of a wave
A
movement of water down the beach
20
Q
what is the crest of a wave
A
top of a wave
21
Q
what is the trough
A
bottom of wave
22
Q
what is wavelength
A
Distance between two crests or two troughs
23
Q
what is velocity
A
The speed that wave is travelling it is influenced by the wind fetch and depth of water
24
Q
wave frequency
A
How many waves there are per minute?
25
What is wave refraction?
the bending of waves as they approach a coastline at an angle, caused by the slowing down of the wave as it enters shallower water, leading to a redistribution of wave energy along the coast
26
what happens when waves diverge
loose power and drop sediment
27
wave energy becomes concentrated on headland causing greater erosion and features
.
28
what are rip currents
Strong, localised underwater currents that occur on some beaches posing danger, swimmers and surfers. They are found in a series of plunging waves cause a temporary buildup water at the top of the beach.
29
What is the current?
The permanent or seasonal movement of surface water in sea is in oceans
30
what is upwelling
is an oceanographic phenomenon where wind-driven motion causes dense, cooler, and nutrient-rich water from deep ocean layers to rise towards the surface, replacing warmer, nutrient-depleted surface water.
31
what is a tide
Periodic rise and fall of the level of sea in repo to the gravitational puddle of the Sun around the moon
32
what are the causes of tides?
moon pulling water
33
What are spring tides?
Twice in a lunar month when the sun moon and earth are in a straight line, the tide raising force is as as lowest point producing highest monthly tide
34
what are neap tides?
twice a month for the Moon and son are positioned at 90° in relation to the Earth. This alignment gives the lowest monthly title ranges called tides gravitational pull is less effective.
35
how are waves formed
wind blowing across the water's surface, creating friction that generates ripples which then develop into larger waves
36
properties of destructive waves
- local storms generate them
- high plunging waves
- short wavelength
- weak swash strong backwash
- beach loss destructive
- associated with steep beach profile but over time will flatten it out
37
properties of constructive waves
- distant weather systems generate them
- low plunging waves
- long wavelength
- strong swash weak backwash
- beach gain constructive
- associated with flat beach profile but over time will get steeper
38
what are rip currents
strong localised under water currents that occur on some beaches
39
how are rip currents formed
lots of plunging waves causing a build up of water at the top of the beach met with resistance from breaking waves the backwash is forced bellow the surface
40
what type of environment are rocky coastlines found in
high energy coastlines
41
what is former high energy environment and why
headlands bays wave cut platforms when erosion exceeds deposition
42
what are formed low energy environments and why
beaches dunes etc when deposition exceeds erosion
43
what is wave refraction
distortion of wave fronts as they approach an intended shoreline
44
at a more localised scale in wave refraction what happens
high and low energy environments
45
what does wave refraction cause
energy to be concentrated at headlands and dissipated at bays causing erosive and deposition features
46
what type of feedback can be seen operating due to wave refraction
negative feedback as variations in rock strength cause the wave refraction to encourage eruption and deposition working against original soft rock
47
what is traction
rolling of sediment along sea bed as it’s too heavy to be carried by flow of water
48
what is saltation
sediment bounced along sea bed as its light enough to be picked up but too heavy to remain in the flow of water
49
what is suspension
smaller lighter sediment picked up by flow of water
50
what is solution
chemicals dissolved in water transported and precipitated elsewhere
51
what are the factors that affect transportation
velocity of water and partial size
high/ low energy environments
52
what is longshore drift
movement of sediment along a coastline due to angle of waves
53
how does longshore drift work?
waves approach the beach and angle due to prevailing wind
as waves advance material is carried up the beach
backwash pulls material down the beach at a right angle to the shore
54
what is the importance of longshore drift
is an important flow of mechanism responsible for movement of sediment along a coastline and out to sea
55
what’s the issue with management to prevent LSD
can lead to distortion of natural patterns depriving beaches further along the coast of material meaning they are more vulnerable to erosion
56
what is costal deposition
takes place when water and wind velocity falls bellow a critical value for a size of particular when can no longer be transported
57
exposed parts of the beach will be transported away leaving larger pebbles to form shingle beaches
58
low energy environments impact costal deposition because..
small particles drop to seabed to form things like mudflats and underwater sandbanks
59
what are sed
areas of
60
definition of sediment cell
distinct area of coastline depressed from other areas by well defined boundaries such as headlands and stretches of deep water
61
sources of sediment
streams
ruvers
cliff erosion
estuaries
offshore sand banks
wind
dead organisms
crushed cells
62
sediment sinks
dunes
spits
bars
tombolos
beaches
offshore bars
63
definition of a sediment budget
balance between sediment being added and removed from the costal system being within each individual sediment cell
64
What is a discordant coastline
and what does it form
occurs where bands of rock differ in a cliff and run perpendicular to the coast line
headlands and bays
65
what is a concordant coastline
and what does it form
of course when bands of differing rock run parallel to coastline
causes coves
66
what are the factors effecting erosion
- wave strength
- landforms (e.g wide beach)
- weathering
- human activity
- geology of coastline
- frequency of storms
- concordont discordant coastline
67
how is a wave cut platform formed
- waves crash against base of a cliff eroding the cliff face causing a wave cut notch
- as the notch deepens and widens due to weathering cliff above becomes unstable casing it to collapse
- the collapsed rock and debris is carried away by the backwash and transportation leaving a flat rocky surface
- this process happens repeatedly
68
how is a blowhole formed
roof of cliff collapses due to erosion caused waves splashing upwards from cave
69
process of erosion of a headland
1 - crack opens by hydraulic action and abrasion causing a cave
2 - crack grows
3 - cave breaks through headland forming arch
4 - arch is eroded and collapses via weathering
5 - leaving a stack
6 - stack is eroded by weathering and falls causing a stump
70
what are igneous rocks and examples
formed from solidified lava or magma including granite very hard and strong resistant from erosion
e.g basalt granite
71
what are sedimentary rocks and examples
formed by compaction and cementation of deposited material or sediment very easily eroded
e.g limestone or chalk
72
what are metamorphic rocks and give examples
formed by recrystallisation of sedimentary and igneous rocks through heat and pressure very resistant to erosion
e.g slate
73
what is strata
layers of rock
74
what is horizontal dip
vertical cliff face with notches reflecting weathering and mass movement easily eroded
75
what is seaward dip,
High angle with one rock layer facing the sea vulnerable to rockfall down the slope when strata attacked by weathering profile slopes
76
what landward dip
less erosion less rockfall 70-80 degree angle
77
what is a swash aligned beach
forms when waves break parallel to coastline
78
what is drift aligned beach
formed when LSD moves material along coast
79
how is a spit formed
LSD carries material along the coast in direction of prevailing wind if coastline changes direction sediment is deposited. Moving sediment out to sea. end of spot is curved due to secondary waves approaching from a different direction
80
what are the different types of erosion
hydraulic action
cavitation
abrasion
attrition
quarrying
solution
81
what is hydraulic action
waves smashing against cliff face and getting into cracks
82
what is cavitation
opening up of cracks in cliff face due to changes in pressure
83
what is abrasion
launching of rocks and pebbles against cliffs by waves breaking off pieces of cliff
84
what is attrition
risks crashing into eachother causing smoothing effect
pebbles - shingle - sand can tell beach via which one more recent
85
what is quarrying
breaking waves trap air as it hits cliff force of water compresses the air into gap creating pressure
86
what is solution
chalk and limestone is dissolved and rock is removed
87
what is weathering
breakdown or disintegration of rocks in situ
88
what is chemical weathering
rain and seawater contain chemicals that reacts with chemical compounds in rock altering structures
89
what is biological weathering
living organisms can contribute to weathering via actions e.g plant roots animals burrowing
90
what is physical weathering
breakdown of rocks via internal pressures exerted on a rock
91
what are groynes and the advantages and disadvantages of it
wooden or rock structures that trap sediment being transported by LSD
Advantages:
works with natural processes to build up beach meaning good tourism
disadvantages:
starves beaches further down coast leaving them more vulnerable to erosion , expensive , ugly
92
what are sea walls and their advantages and disadvantages
stone or concrete walls at foot of cliff or top of beach with a curved face deflecting waves back into the sea
advantages:
- prevents erosion
- provides walking promenade
disadvantages:
- reflecting wave energy rather than absorbing it
- ugly
- expensive
93
what is rock armour and the advantages and disadvantages of it
large rocks places at bottom of cliff or top of beach to allow some water through but breaking waves
advantages:
- cheap
- easy to build
- used for fishing
- looks natural
disadvantages:
- dangerous for walking on or swimming
94
what is offshore breakwater and the advantages and disadvantages of it
submerged rock barrier breaking up waves
advantages:
- effective
disadvantages:
- navigation issues
- ugly
95
what is beach nourishment and the advantages and disadvantages of it
additional of sand or pebbles to add to an existing beach making it higher or wider (sediment used from nearby sea bed)
advantages:
- cheap
- natural
- tourism increase due to beach
disadvantages:
- high maintenance due to costal processes
96
what is cliff regrading and drainage and what are the advantages and disadvantages of it
reducing angle of cliff to help stability and removal of water causing mass movement
advantages:
- effective on clay and sand or loose rock
- cheap
disadvantages:
- cliff retreat
- drainage can cause droughts
97
what is dune stability and what are the advantages and disadvantages of it
maram grass planted to stabilise dunes
advantages:
- natural
- provides habitat
- cheap and sustainable
disadvantages:
- locals may disagree
98
what is marsh creation and what are the advantages and disadvantages of it
form of managed retreat by allowing low lying land (coastal areas) to be flooded by sea creating a marsh
advantages:
cheap
natural
habitat
disadvantages:
agricultural land lost
farmers and landowners need to be compensated
99
what is mass movement
Movement of material down a slope under the influence of gravity, its an input into the littoral zone
100
what is soil creep
slow but continuous movement of soil particals downhill due to wetting and drying it causes shallow terraces
101
what are mud flows
increase in water content in the soil reducing friction leading to earth and water flowing downhill, water can get stuck in between rocks increasing pore water pressure forcing the rock apart and reducing its stability causing quick mud flows
102
what is rockfall
sloped cliff 40 degrees when exposed to physical weathering causing rocks to fall
103
what is a landslide
heavy rainfall between joints and bedding planes in cliffs weakens surface and reduces friction
104
what is slumping
slope is curved in weak areas increasing pore water pressures leading to the land collapsing under its own weight
105
what is runoff
water running down cliff face may erode the land and pick up sediment taking it intro the littoral zone transported via suspension polluting the water
106
what is a swash aligned beach
forms in low energy environments like bays , where sediment moves up and down the beach waves approach at a straight angle
107
what is a drift alined beach
where the waves approach the coast at an angle, LSD moves sediment along the beach causing things like spits
108
how is a spit formed
form on drift alined beaches, prevaling wind and lsd move waves and sediment down the coastline, then a change in land abruptly causes the deposition to continue out to sea away from land causing a spit
109
how is a tombolo formed
when a spit of deposited material, built by longshore drift, extends from the mainland to connect with an offshore island, creating a natural bridge. On swash-aligned coasts, wave refraction around the island creates a calm-water zone where sediment deposition occurs, leading to the connection. The key factors are the continuous supply of sediment, longshore drift to transport it, and the presence of an island to interrupt the drift and facilitate the formation of a depositional bar
110
how are offshore bars formed
form in shallow water from deposited sand or shingle when waves lose energy at their breaking point. Sediment is moved seaward by the backwash of destructive waves or is deposited directly by waves that break early due to declining wave energy in the nearshore zone. The bar creates a submerged or partially exposed ridge parallel to the coast, which can then absorb wave energy and reduce erosion elsewhere
111
how is a barrier beach formed
when a spit or bar extends across a bay to join two headlands
112
how are sand dunes formed
large quantities of avalible sand washed onshore by constructive waves is blown by onshore winds to the back of the beach, repeatedly happening causing vegetation to grow and over time stabilse the dunes.
113
what plants help stabilise the dunes and what are their adaptations
pioneer species that develop adaptations such as ability to cope with dry salty conditions, when they die they add important organic matter to the dunes helping develop soil
114
what are low sand dunes called
fore dunes
115
what grass grows on fore dunes
marram grass and its extremely, well adapted by having long lateral roots, so they can stay hydrated
116
what is evidence for long term sea level change
during quaternary period several alternating cold and hot periods
117
what is isostatic sea level change
when the land rises or falls relative to the sea
118
what is eustatic sea level change
when the sea itself rises or falls
119
more about isostatic change
occurs locally, during glacial periods the weight of the ice sheets makes the land sink, as the ice begins to melt the land starts to rise back up, due to reduced weight
120
more about eustatic sea level change
change is global, precipitation falls in cold periods, forming huge ice sheets that store water usually held in the oceans, as temps rise the ice melts the stores water then flows into rivers and oceans. causing the sea levels to rise
121
how has past tectonic activity caused sea level change
- uplift of mountain ranges
- local tilting of land at destructive margins
122
what are the landforms caused by changing sea level
fall in sea level = emergent coast lines
increase in sea level = creates submerging coast line
123
what are emergent costal landforms
raised beaches, former wave cut platforms,
124
what are submergent
rias , fjords
125
how are rias formed
when a rise in sea level floods the lower parts of river valleys, creating a funnel-shaped estuary. The process results from either a global eustatic sea level rise, where ocean water volume increases, or isostatic change, where the land level falls. Rias are common in south-west England and retain the V-shaped cross-section and dendritic drainage pattern of the original river valley
126
how are fjords formed
when deep glacial troughs are flooded by a rise in sea level, long steep sided with a U shaped cross section and hanging valleys, fjords deep inland
127
what is a shoreline management plan
a long-term strategy for managing coastal flooding and erosion risk in a specific stretch of coastline, outlining how to protect people and the environment
128
what is hold the line
maintaining current position of the coastline (usually hard engendering methods)
129
what is advance the line
extending out the coastline to sea encouraging build up of a beach.
130
what is managed retreat
allowing the coastline to retreat in a managed way,
131
what is the do nothing approach
letting nature take course and allowing natural processes to occur
132
what is an integrated coastal zone management scheme (ICZM)
holistic and collaborative process that aims to achieve sustainable development in coastal zones by balancing economic needs, social well-being, and environmental protection
Physical geography
flashcards
Decks in class (17)
# Cards
-
Hazards96
-
Hazards case studies (Haiti)10
-
Hazards case studies (Tohoku, Japan)11
-
Hazards case studies (Iceland)10
-
Hazards case studies (Monsterat)9
-
hazards Case Study ( typhoon haiyan)15
-
hazards Case Study (hurricane harvey)15
-
hazarss case study (austrailia black summer)7
-
hazards Case Study (storm desmond)8
-
MHE Phillupines Case study14
-
coasts132
-
holderness coastline case study13
-
Odisha case study15
-
Coasts case studies (The Holderness coastline)10
-
Water and Carbon cycles102
-
River exe case study22
-
Amazon rainforest carbon cycle case study37
