Coastal Landscape Development Flashcards Preview

A Level Physical Geography > Coastal Landscape Development > Flashcards

Flashcards in Coastal Landscape Development Deck (37)
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1
Q

Define spit

A

A long, narrow ridge of land that joins to the mainland at one end and projects out into the sea / across a river estuary.
Usually on a drift-aligned coast.

2
Q

Which types of coastline do spits usually form at?

A

Drift-aligned coast

3
Q

Describe the formation of a spit

A

LSD carries material along coast -> build up of material in more sheltered water (behind headland) -> storms build up more material above HWM (permanent) -> length of ridge (spit) extends -> wave refraction / 2nd most dominant wind curves end of spit towards mainland

4
Q

What feature may form behind a spit?

A

Salt marsh

5
Q

What factors affect the formation of a spit?

A

Longshore drift - wave energy, fetch.
Prevailing winds.
River current.

6
Q

Name the types of spits

A

Simple

Compound

7
Q

Describe the features of a simple spit

A

Can be straight or recurved.

DO NOT have minor spits / recurved edges along their landward edge.

8
Q

Describe the features of a compound spit

A

Can be straight or recurved.
DOES have minor spits / recurved edges along their landward side -> possibly marking the position where they terminated in the past

9
Q

What might the minor spits / recurved edges on a compound spit show?

A

May mark the position where the spit terminated in the past

10
Q

Define tombolo

A

A spit that joins an island to the mainland

11
Q

Give examples of where spits are found

A

Spurn Head, East Yorkshire

Sandy Hook Spit, New Jersey, USA

12
Q

Give examples of where tombolos are found

A

Chesil Beach, UK

The Angel Road of Shodo Island, Japan

13
Q

Give the factors that affect the formation of tombolos

A

Longshore drift
Prevailing winds
Distance from mainland to island

14
Q

Define offshore bar

A

Where a ridge of beach material that remains semi-submerged accumulates seaward of the breaker zone

15
Q

Define bar

A

When a spit grows across a bay and joins two headlands

16
Q

What feature forms behind a bar

A

Lagoon (former bay)

17
Q

How did some bars form after the last ice age?

A

The result of onshore migration of material from offshore, as sea levels rose after last ice age

18
Q

By how much can bars be submerged by incoming tides?

A

Partially / completely submerged

19
Q

Give examples of where bars are found

A

Slapton Ley, Devon
Chesil Beach - formed by combination of onshore migration + LSD.
Arabat Spit, Sea of Azov - longest spit in the world, joins towns in Ukrain to Crimea.

20
Q

Give the factors affecting the formation of bars

A

LSD - wave energy, fetch
Prevailing wind
Distance from headland to headland

21
Q

How has sea level changed over the past 10,000 years?

A

Sea level has generally been rising over the past 20,00 years.

Sea level appears to be lowering in Scotland (northwest), due to isostatic uplift of land.

22
Q

Name the coastal features that form due to rising sea level

A
Dalmatian coast
Fjords
Rias
Estuaries
Shingle beaches
23
Q

What is a fjord? Give an example

A

Drowned glacial valley.

Eg Sogne fjord, Norway

24
Q

What is a ria? Give an example

A

Drowned river valley.

Eg River Dart, Devon

25
Q

What is an estuary? Give an example

A

Drowned, shallow, lowland river valleys.

Eg Humber estuary

26
Q

How do shingle beaches form?

A

Where sediments previously deposited on the contents shelf were above sea level.
Rising sea levels have swept up the sediment and deposited it on present day coasts.

27
Q

Name the coastal features that form due to falling sea level

A

Raised beaches / relict cliffs

Marine platform

28
Q

What is a raised beach / relict cliff? Give an example

A

Beaches and cliff lines elevated above sea level and exposed following deglaciation -> land height rises.

Eg Isle of Arran, Scotland

29
Q

What is a marine platform? How does it form?

A

Where an expanse of gently sloping, formerly submerged land has been exposed by uplift of land / lowering sea level

30
Q

What is a Dalmatian coastline? How do they form? Give an example

A

Form where valleys (esp glacial valleys) lie parallel to each other.
Valleys are flooded by sea level rise -> tops of valleys remain above sea surface -> appear to be islands that run parallel to the coast.

31
Q

Give the potential impacts of sea level change on coasts

A
  • Increased coastal flooding -> esp during spring tides / strong winds.
  • More erosion -> waves attack areas previously above high tide.
  • Receding coastlines.
  • Zone where seawater mixes with fresh water in rivers may reach further inland.
  • Increased flooding of areas away from coastline -> river flooding.
  • More frequent / intense extreme sea level events eg storm surges.
  • Increased erosion to dunes, salt marshes, mudflats.
  • Increased investment in coastal protection for areas of high economic value.
32
Q

What percentage of the population of England / Wales live within 10km of the coast?

A

30%

33
Q

There is a high proportion of what types of infrastructure in coastal regions?

A

Agricultural land.
Manufacturing industry.
Energy supply.
Transport links.

34
Q

What is the worth of the infrastructure / resources that are at risk from coastal flooding? Coastal erosion?

A

£120 billion - flooding.

£10 billion - erosion.

35
Q

What is the current rate of sea level rise?

A

3mm per year

36
Q

Sea level rise between 1961-2003 was caused by what?

A

40% Thermal expansion of water.

60% melting glaciers, ice caps, ice sheets.

37
Q

What are the main causes of sea level rise? How / by how much?

A
  • Ocean expansion - SLR of 0.5-1.6mm per year.
  • Mountain glaciers - glaciers melt faster than they gain mass through snowfall -> enough water in glaciers to raise sea levels by 50cm.
  • Ice-sheets - Greenland alone is covered by enough ice to raise sea levels by over 7 metres.