Coastal Landscapes and Change EQ1 Flashcards
1
Q
what are the sections of the littoral zone?
A
backshore, foreshore, nearshore, offshore
2
Q
what is the coast as a system driven by?
A
wave energy
3
Q
what are the categories of inputs into the coast as a system?
A
- Marine
- Atmospheric
- Land
- People
4
Q
what are the marine inputs into the coastal system?
A
waves, tides, storm surges
5
Q
what are the atmospheric inputs into the coastal system?
A
weather/climate, climate change, solar energy
6
Q
what are the land inputs into the coastal system?
A
rock type and structure, tectonic activity
7
Q
what are the people inputs into the coastal system?
A
human activity, coastal management
8
Q
what are the processes of the coastal system?
A
- Weathering
- Mass Movement
- Erosion
- Transport
- Deposition
9
Q
what are the outputs of the coastal system?
A
- Erosional landforms
- Depositional landforms
- Different types of coasts
10
Q
what kind of zone is the littoral zone?
A
‘dynamic zone of rapid change’
11
Q
define offshore
A
The area of deeper water beyond the point at which waves begin to break.
12
Q
what does friction do to wave shape in the offshore zone?
A
Friction between the waves and the sea bed may cause some distortion of the wave shape.
13
Q
define nearshore
A
The area of shallow water beyond the low tide mark
14
Q
what does friction do to wave shape in the nearshore zone?
A
friction between the seabed and waves distorts the wave sufficiently to cause it to break. (breaker zone)
15
Q
what kind of bar may there be between the offshore and nearshore zones?
A
breakpoint bar
16
Q
define foreshore
A
The area between the high tide and the low tide mark.
17
Q
what does the littoral zone vary because of ?
A
short term factors & long term factors
18
Q
define backshore
A
The area above the high tide mark, affected by wave action only during major storm events.
18
Q
what short term factors may cause the littoral zone to vary?
A
individual waves, daily tides and seasonal storms
19
Q
what long term factors may cause the littoral zone to vary?
A
changes to sea level or climate change
20
Q
what are the three types of coastal landscapes (coastlines) the littoral zone forms?
A
rocky, sandy and estuarine
21
Q
describe the relief of rocky, cliffed coastlines
A
- areas of high relief - varying from a few meters to hundreds of meters in height
22
Q
describe the relief of sandy coastlines
A
areas of low relief - with sand dunes and beaches that are mush flatter
23
Q
describe the relief of estuarine coastlines
A
areas of low relief - with salt marshes and mudflats (estuaries)
24
what areas do rocky coastlines typically form in?
- areas with resistant geology, - in a high energy environment,
- where erosion is greater than deposition and big,
- stormy & destructive waves
25
what areas do sandy coastlines typically form in?
- areas with less resistant geology,
- a low energy environment,
- where deposition is greater than erosion,
- usually in areas of less resistant rock
26
what areas do estuarine coastlines typically form in?
- in river mouths,
- where deposition is greater than erosion,
- in a low energy environment,
- usually in areas of less resistant rock
27
what areas of the littoral zone are areas where the greatest human activity occur?
backshore and foreshore
28
why is the littoral zone constantly changing?
because of the dynamic interaction between the processes operating in the seas, oceans and on land
28
what long term criteria can be used of classify coasts?
- geology,
- sea level change
29
what is meant by geology?
all the characteristics of land, including lithology and structure
30
how can geology be used to classify coasts?
- as rocky, sandy or estuarine
- or as concordant and discordant
31
how can sea level change be used to classify coasts?
as emergent or submergent
32
what may sea level change be caused by?
tectonic processes or climate change
33
how can energy inputs be used to classify coasts?
as high or low energy coasts
34
how can sediment inputs be used to classify coasts?
creating either erosional or depositional coasts
35
how do tectonic processes cause sea level change?
can lift land up, causing local sea fall, or lead sections of land to subside - causing local sea rise
36
how does climate change cause sea level change?
- causes sea levels to rise and fall in a 100,000 year cycle due to the change in the Earth's orbit shape.
- sea levels fall for 90,000 years during glacials as ice sheets expand and rise for 10,000 during interglacials
- sea levels rise even more when the Earth emerges from an ice age and all surface ice melts
37
describe sea levels during glacial periods
fall for 90,000 years
38
describe sea levels during interglacial period
- ice sheets expand and rise for 10,000 years
- sea levels rise even more when the Earth emerges from an ice age and all surface ice melts
39
what short term criteria can be used to classify coasts?
- energy inputs,
- sediment inputs
40
when are coastlines classified as advancing or retreating?
long term processes (emergent/submergent) and short term (outbuilding/eroding)
41
complete the sentence
rocky coasts occupy about ____________
1,000 km of UK coastline, mainly in the north and west
42
describe the cliff that can be used as an example of a cliff in a high relief area?
427 m Conachair Cliff on the Isle of Hirta in the Outer Hebrides
43
describe the cliff that can be used as an example of a cliff in a low relief area?
3m cliffs at Chapel Porth in Cornwall
44
what type of areas do rocky coasts usually form in?
- areas of geology that is resistant to the erosive forces of the sea, rain and wind
- their lithology and structure means they erode and weather slowly
45
what environments do rocky coastlines form in?
- high-energy environment where erosion > deposition
- Erosion is continuously moving transported and deposited sediment as well as slowly eroding the cliff.
46
describe a coastal plain landscape
relatively flat, low relief areas adjacent to the sea.
47
what do coastal plain landscapes typically contain?
freshwater wetlands and marshes due to the poor drainage of the flat landscape
48
what is the littoral zone of a coastal plain landscape composed of?
sand dunes, beaches, mud flats and salt marshes
49
what environments do coastal plain landscapes form in?
- low-energy environments where deposition > erosion,
- so they experience a net accumulation of sediment.
50
what could coastal plain landscapes form through?
- typically coastal accretion
- also by sea level change
51
what is coastal accretion?
a continuous net deposition of sediment
52
what does coastal accretion (a continuous net deposition of sediment) come from?
- offshore sources (transported by waves, tides or current)
- terrestrial sources (transported by rivers, glaciers, wind or mass movement)
53
what may coastal plains be?
1. sandy coasts, composed of sands, shingles and cobbles.
2. estuarine (alluvial) coasts composed of mud (clays and silts)
54
where along the UKs coastline do coastal plains form most of?
the UK's south and east coastline.
55
how do coastal plains form through coastal accretion?
- where continuous net deposition causes the coastline to extend seawards
- This is often extended biologically as plants colonise shallow water, trapping sediment and forming organic deposits when they die.
56
how do coastal plains form through sea level change?
when the falling sea level exposes a flat continental shelf
57
name an example of a coastal plain formed by sea level change
e.g. the Atlantic coastline of the USA.
58
rocky coasts are generally found in high energy environments, where in the UK do these tend to be?
stretches of the Atlantic-facing coast, where waves are powerful for much of the year
eg Cornwall or north-western Scotland
59
sandy an estuarine coasts are generally found in low energy environments, where in the UK do these tend to be?
stretches of the coast where the waves are less powerful or where the coast is sheltered from large waves
eg Lincolnshire and Northumberland
60
complete the sentence:
______________________ is responsible for the formation of concordant and discordant coast
geological structure
61
where do concordant coasts usually form?
where rock strata or folds run parallel to the coast
62
where do discordant coasts usually form?
where rock strata or structures are aligned at an angle to the coastline
63
describe features of concordant coastlines
Some concordant coasts have long, narrow islands running parallel to the coastline.
64
describe features of discordant coastlines
Discordant coasts have a crenellated pattern of projecting headlands and indented bays
65
what are concordant coastlines also known as?
Dalmatian coasts
66
what are discordant coastlines also known as?
Atlantic coasts
67
what is geological structure?
the characteristics and arrangement of rock units
68
what are strata?
layers of rock
69
what is a bedding plane?
the interface between two sedimentary strata. Bonding between rocks either side of the plane is weaker than bonding within strata.
70
what is deformation?
the degree of tilting of folding of rock.
71
what is dip?
the angle at which strata lie
72
what is faulting?
the fracturing of rock with movement from its original position.
73
what is a joint?
a fracture of rock without movement from the original position
74
what is morphology?
the shape of landscape features
75
what is morphology influenced by?
geological structure (headlands and bays for discordant, Dalmatian and Haff for concordant).
76
what are the case studies for concordant coastlines?
- the dalmatian coast of Croatia
- the South Dorset Coast
- Haff Coastline
77
what is the case study for discordant coastlines?
- Swanage bay
- Bantry bay
78
describe the south Dorset coast
- A concordant coastline with resistant Portland Limestone forming a protective stratum parallel to the sea.
- Less resistant Purbeck limestone and Wealden Clay lie behind the Portland, with resistant chalk further north.
79
describe the erosion that takes place on the South Dorset Coast
- Portland limestone erodes very slowly, retreating landwards by marine undercutting and collapse to form a straight W-E coastline.
- At points where the Portland is weaker, erosion has broken through and then rapidly eroded out the softer strata laterally, creating a series of coves, e.g. Lulworth Cove and Stair Hole, with narrow openings, widening laterally parallel to the coast.
80
what has happened in places such as Worbarrow Bay and St Oswald's Bay, as a result of erosion on the South Dorset Coast?
- lateral widening of coves led to them joining into a single bay, with remnants of the outer Portland left as a line of stumps parallel to the coast,
- e.g. Bull's Head in St Oswald's Bay.
81
what is the ultimate stage of the erosion on the South Dorset Coast?
straight coastline now formed by a concordant band of constant chalk
82
where is the Dalmatian Coast of Croatia located?
on the Adriatic sea
83
describe the Dalmatian Coast of Croatia
A concordant coastline produced by the geological structure of folds parallel to the coast.
84
Explain how tectonic forces shaped the Dalmatian Coat of Croatia
- Tectonic forces produced by the collision of African and Eurasian plates compressed Carboniferous Limestone during the Alpine Orogeny 50 million years ago.
- Created up folded ridges (anticlines) and down folded valleys (synclines) aligned parallel to the coast.
85
when did the tectonic forces compress Carboniferous Limestone?
during the Alpine Orogeny 50 million years ago
86
What are anticlines?
up folded ridges
87
what are synclines?
down folded valleys
88
what did Sea level rise at the end of the Devensian Glacial do?
overtopped the low points of the anticlines and the sea flooded synclines.
89
on the Dalmatioan Coast of Croatia, sea levels rose at the end of the Devensian Glacial, what did this produce?
- lines of narrow islands parallel to the coast formed by projecting sections of anticlines.
- Lines of islands separated by narrow sea channels parallel to the coast
90
where do haff coastlines form?
where deposition produces unconsolidated geological structures parallel to the coastline.
91
describe sea levels during the Devensian glacial
about 100 m lower than today as water was retained in huge ice sheets.
92
