EQ1 Flashcards
(91 cards)
1
Q
what does the littoral zone consist of?
A
the backshore, nearshore, and offshore zones
2
Q
coasts can be classified by what longer term criteria?
A
geology and changes to sea levels.
3
Q
coasts can be classified by what shorter term criteria?
A
inputs from rivers, waves, and tides
wave energy
wave type
4
Q
what is geological structure responsible for ?
A
the formation of concordant and discordant coasts.
5
Q
what type of coasts are coastal plain landscapes?
A
sandy and estuarine coasts.
6
Q
what does geological structure influence?
A
coastal morphology
erosion rates
formation of cliff profiles
occurrence of microfeatures eg caves
7
Q
why is vegetation important?
A
vegetation is important in stabilising sandy coastlines through marsh successional development in estuarine areas.
8
Q
What is the zone of breaking waves called ?
A
Breakpoint bar
9
Q
What are the short term factors that cause the littoral zone to vary?
A
Individual waves, daily tides, seasonal storms
10
Q
What are the long term factors that would change the littoral zone?
A
Changes to sea levels, climate change
11
Q
Where do most physical processes operate?
A
Backshore and foreshore
12
Q
What human activities afffect the coast?
A
Rising sea levels Dredging of offshore areas (material for construction) Building of coastal defences Dredging of rivers for navigation Dams
13
Q
How is the coastline divided in England/wales?
A
11 sediment/littoral cells in which processes are closely linked
14
Q
What are the inputs into coastal systems ?
A
1) marine: waves, tides, storm surges
2) atmospheric: weather, climate change
3) land: rock type, structure, tectonics
4) people: human activity, coastal management
15
Q
What processes affect the coast?
A
1) weathering
2) mass movement
3) erosion
4) transport
5) deposition
16
Q
What are the outputs of coastal systems ?
A
Erosional landforms
Depositional landforms
Types of coast
17
Q
What is submergence ?
A
Sea level rise
18
Q
What is emergence ?
A
Tectonic uplift
19
Q
What is coastal morphology?
A
The shape and form of coastal landscapes and their features
20
Q
What is lithology?
A
The physical characteristics of particular rocks
21
Q
How does tectonic uplift link to coastal morphology?
A
Changes angles of different rock layers and their movement and position
22
Q
What is the erosion rate of igneous rocks ?
A
1mm/ year
23
Q
Erosion rate of sedimentary ?
A
2.5cm/ year
24
Q
2 examples of igneous?
A
Granite
Basalt
25
3 examples of sedimentary?
Chalk
Limestone
Slate
26
2 examples of metamorphic?
Marble
| Gneiss
27
Example of unconsolidated material?
Boulder Clay
28
Is metamorphic rock permeable?
Nah
29
Is igneous rock permeable ?
Nope
30
What are strata ?
Layers of rock
31
What are bedding planes ?
(Horizontal cracks ) Natural breaks in the strata, caused by gaps in time during rock formation
32
What are vertical cracks called and how are they caused?
Joints- fractures, caused by either contraction as sediments dry out, or by earth movements during uplift
33
How are folds formed ?
By pressure during tectonic activity, which makes rocks buckle and crumple
34
What's an example of a fold?
Lulworth Crumple
35
How are faults formed ?
When the stress or pressure to which a rock is subjected exceeds its internal strength, causing it to fracture
36
What's a dip?
Refers to the angle at which strata lie ( horizontal, vertical, dipping towards towards sea, dipping inland)
37
What does lithology include ?
- geological structure
- how porous rock is
- grain size, rock structure
- composition
38
What waves are characteristic of low energy coasts?
Less powerful ( constructive) waves , calmer conditions, shorter fetch
39
What processes are characteristic of low energy coasts ?
Deposition, transport, sediments from rivers, longshore drift, nearshore currents
40
What landforms are characteristic of low energy coasts ?
Beaches, spits, salt marshes, sand dunes, bars, mudflats
41
What are examples of low energy coasts ?
Mediterranean Sea
| East Anglian coast
42
What are the general locations of low energy coasts?
Sheltered from large waves
Lowland coasts
Coastal plain landscapes
43
What waves are characteristic of high energy coasts ?
More powerful (destructive) waves, storm conditions, long fetches
44
What is the backshore zone ?
Above high tide level and only affected by waves during major storms and exceptionally high tides.
45
What is the foreshore zone?
Where wave processes occur between the high and low tide marks.
46
What is the nearshore zone?
Shallow water areas close to land and used extensively for fishing, coastal trading, and leisure.
47
What is the offshore zone?
Open sea
48
What are primary coasts ?
Dominated by land based processes
49
What are 2 examples of lad based processes ?
Deposition at the coast from rivers, new coastal land formed from lava flows.
50
What are secondary coasts ?
Dominated by marine erosion or deposition processes.
51
What are the 2 main cliff profile types ?
1) marine erosion dominated
| 2) sub aerial process dominated
52
What do marine erosion dominated cliffs look like ?
Steep face
Active undercutting
Limited cliff base debris
53
What do subaerial process dominated cliff profiles look like?
Curved slope profile
Lower angle face
Accumulated debris (not actively eroded at the base by waves)
54
What are 3 ways coastal plains are formed ? And examples of each
1) sea level falls exposing seabed of what was once a shallow continental shelf sea, e.g. Atlantic coastal plain, USA
2) sediment brought from land by river systems is deposited causing coastal accretion so coastlines gradually move seaward-e.g. River deltas
3) sediment moves from offshore sources (sand bars) towards the coast by ocean currents.
55
What are the 3 elements to geological structure that influence micro features?
1) strata
2) deformation
3) faulting
56
What are strata ?
Different layers of rock exposed on a cliff
57
What is deformation ?
Tilting and folding by tectonic activity.
58
What is faulting ?
Major fractures that have moved rocks from their original positions.
59
What is an example of a discordant coastline ?
West Cork, Ireland
60
What is the effect of wave refraction?
1) To concentrate powerful waves at headlands, creating more erosion
2) creating lower, diverging wave crests on bays, reducing erosion.
61
What are the layers of rock at lulworth cove ?
Outside: hard Portland limestone, resistant purbecks
Inside: sedimentary Wealden beds
At the back there's chalk to stop the cove from eroding back any further.
62
What is the geology at the Adriatic Sea Dalmatian coast?
Limestone, which has been folded by tectonic activity into a series of anticlines and synclines that run parallel to the coastline.
63
What are anticlines and synclines ?
Types of geological fold caused by tectonic compression:
anticline-crest
syncline-trough
64
What are the 4 kinds of cliff profile ?
Horizontal dip
Seaward sip high angle
Seaward dip low angle
Landward dip
65
Horizontal dip cliff profile ?
Vertical profile w notches reflecting strata that are more easily eroded.
66
Seaward dip cliff profile ?
Sloping, low angle profile w 1 rock layer facing the sea, vulnerable to rock slides down the dip slope.
67
Seaward dip low angle cliff profile ?
May exceed 90 degrees--> areas of overhanging rock
| V vulnerable to rock falls
68
Landward dip cliff
| Profile ?
Steep profiles 70-80 degrees producing v stable cliff w reduced rock falls.
69
What other geological features influence cliff profiles and rates of erosion?
1) faults- either side of a fault line rocks are often heavily fractured- weaknesses exploited by marine erosion.
2) joints
3) fissures- much smaller cracks in the rock, represent weaknesses erosion can exploit.
4) folded rocks- often heavily fissured- more easily eroded.
70
What are micro features ?
Small scale coastal features eg caves, wave cut notches- form part of cliff profile.
71
What is the difference between clastic and crystalline rocks ?
Clastic- sediment particles cemented together
| Crystalline- made of interlocking mineral crystals.
72
Why is permeability of rock important in cliffs ?
Groundwater flow through rock layers can:
1) weaken rocks by removing the cement that binds sediments together
2) create high pore water presses within cliffs which affects their stability.
Water emerging from below ground into a cliff face at a spring can run down the cliff face and cause surface run off erosion, weakening the cliff.
73
what kind of coastlines are protected by plants?
coastal sand dunes
salt marshes
mangrove swamps
74
how does vegetation stabilise coastal sediment?
1) roots bind sediment particles together making them harder to erode.
2) when submerged plants provide a protective layer so the sediment surface is not directly exposed to moving water and erosion.
3) plants reduce wind speed at the surface because of friction with the vegetation, protecting sediment from erosion by wind.
75
what are halophytes?
salt tolerant plants
76
what are xerophytes?
drought tolerant plants
77
what forms the first stage of plant succession?
when pioneer plant species begin to grow in bare sand or mud.
78
what is plant succession?
the changing structure of a plant community over time as an are of initially bare sediment is colonised.
79
what is each step in plant succession called?
a seral stage
80
what is the end result of plant succession?
a climatic climax community
81
what are 2 examples of coastal climatic climax communities?
sand dune ecosystems
| salt marsh ecosystems
82
what is a climatic climax community?
biological community of plants, animals, and fungi which, through the process of ecological succession in the development of vegetation in an area over time, have reached a steady state.
83
what do embryo dune pioneer plants do?
- stabilise the mobile sand by their root systems
- reduce wind speeds at the sand surface allowing more sand to be deposited
- add dead organic matter to the sand, beginning the process of soil formation
84
going from the sea to the land, what kind of plants would you expect to see on the dunes?
saltwort, sea rocket
marram grass
heather, creeping willow
bramble, pine
85
what do rocky coasts result from?
resistant geology to erosive forces of sea, rain, and wind
high and low relief
high energy environment
86
what do coastal plain landscapes result from?
supply of sediment from different terrestrial and
offshore sources, often in a low-energy environment.
low relief
87
what is geological structure responsible for?
CONCORDANT AND DISCORDANT COASTS which in turn influence coastal morphology (bays, headlands etc) and jointing, dip, faulting, folding
88
what is a haff coastline?
a long shallow lagoon separated from the open sea by a narrow sandbar or barrier beach (that booky thing where you're on a barrier beach in the open sea)
89
what is an example of a haff coastline?
the whole baltic sea tbh
| eg curonian lagoon, lithuania
90
how do wave types influence beaches?
they influence:
beach morphology
beach sediment profiles
91
what landforms does erosion create?
wave cut notches, wave cut platforms, cliffs, the cave-arch-stack stump sequence
