Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Geography - B - Coastal Landscapes > Block 8 (Variations In Coastal Processes, Coastal Landforms + Landscapes Over Different Time Scales) > Flashcards

Block 8 (Variations In Coastal Processes, Coastal Landforms + Landscapes Over Different Time Scales) Flashcards

1
Q

What are the three time scales we look at in relation to coasts?

A
  • Seconds
  • Seasons
  • Millennia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the coastal changes over seconds?

A
  • High energy storm events

- Rapid mass movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What causes high energy storm events?

A

Increased wave energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What processes are increased during high energy storm events?

A
  • Erosion (more destructive waves)

- Transportation (more energy to carry larger/more material)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do high energy storm events cause coastal change?

A
  • Change in beach profile (sediment removal, storm beach formed)
  • Destruction or breaching of sand dunes (increased erosion)
  • Coastal flooding (particularly if there is a storm surge)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What conditions facilitate a storm surge to form?

A
  • Storm with strong onshore winds
  • High (spring) tide
  • Low pressure (allows waves to rise)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When pressure decreases by 1mb, how much does wave height increase by?

A

1cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What causes mass movement?

A

Material become unstable, and is moved downslope under influence of gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give an example of change over seconds due to high energy storm events

A

North Sea Storm Surge of 1953

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give an example of change over seconds due to rapid mass movements

A

Hive Beach, Dorset - 2012

  • 50 m high cliffs made of soft sandstone
  • Heavy rain made cliff saturated, heavy - unstable
  • Landslide
  • 400 tonnes rock fell
  • 1 fatality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What changes to coast do rapid mass movements cause?

A
  • Change in cliff face profiles
  • Retreating cliff line
  • Potential damage to cliff top development
  • Change in beach profile (may have sediment on)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the changes over seasons we look at?

A

Seasonal changes to beach profile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What causes the seasonal change to beach profile?

A

Weather differences + how this influences wave type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is typical summer weather + the waves this produces?

A

Anticyclonic weather

  • Dry, with few storms
  • Calm, with low wind speeds
  • Causes low energy waves that are predominantly constructive (spilling)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is typical winter weather + the waves this produces?

A

Depressions

  • Wet, with more storms
  • High wind speeds
  • Causes high energy waves that are predominantly destructive (plunging)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the typical beach profile in summer?

A

Sandy, wide, dissipative beach

  • Sandy: Less energy, so only fine sand can be moved ashore
  • Wide
  • Dissipative: Shallow gradient, formed by constructive waves (spilling)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the typical beach profile in the Winter?

A

Rocky, narrow, reflective beach

  • Rocky: more energy, so large material can be moved ashore
  • Narrow
  • Reflective: steep gradient, formed by destructive waves (plunging)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Give an example of an area where beaches typically undergo seasonal change

A

California, USA

Sandy summer, rocky winter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give an example of a freak seasonal change

A

Dooagh, Ireland

  • Rocky for 34 years
  • Freak tidal event in 2017
  • Became sandy for 2 months
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the changes over millennia?

A
  • Eustatic sea level change

- Isostatic sea level change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the ‘absolute’ sea level?

A

Sea level based on volume of water, regardless of land position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is eustatic change?

A

Global changes to the absolute sea level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the two main causes of eustatic change?

A
  • Glacio-eustatic change

- Thermal expansion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is glacio-eustatic change?

A

Continental ice melts, releasing water into sea

Floating ice melting does not contribute - as vol ice lost = vol water gained

25
What is thermal expansion?
As temp rises, water particles take up more volume
26
What is the greatest cause of eustatic change to sea levels? Give figures to exemplify
Glacio-eustatic change - Est all Antarctica + Greenland’s ice melting would cause rise of 90m - Thermal expansion only makes difference of approx 10m
27
What is isostatic change?
Regional changes to sea level caused by localised uplift/sinking land
28
What are the three causes of isostatic change?
- Isostatic rebound/readjustment - Glacio-isostasy - Hydro-isostasy
29
What is isostatic rebound/readjustment?
Melting of ice removes weight from the crust in that area, causing that area to rise - Happens after glacio-isostasy - Sea level LOWERS relative to land
30
What is glacio-isostasy?
Glaciated areas are depressed by the weight of the ice | - Sea level RISES relative to land
31
What is hydro-isostasy?
Increased volume of water in ocean basins weighs down ocean floor, depressing it - Sea level FALLS relative to land
32
How much of the 90m eustatic rise is thought to be cancelled out in Antarctica + Greenland areas due to hydro-isostasy?
60m
33
What impact does rising/falling sea levels have on the coastline?
- Rising sea levels cause SUBMERGENT COASTLINES | - Falling sea levels cause EMERGENT COASTLINES
34
What are emergent coastlines?
Coastlines building out, as a result of MARINE REGRESSION (relative fall of sea levels)
35
What 3 scenarios can cause the formation of emergent coastlines?
- Sea levels fall faster than land falls/stays same/rises - Sea levels stay same + land rises - Sea levels rise but land rises faster
36
What are the emergent landforms?
- Raised beaches | Often accompanied by: old landforms, relic/fossil cliffs, marine terrace
37
What are raised beaches?
Beaches left stranded above the new sea level, no longer affected by waves
38
What 3 features often accompany raised beaches?
- Old landforms (e.g. old CASS sequence) - Relict/fossil cliffs (old, steep cliffs, now weathered but not eroded) - Marine terrace (old wave cut platform, often used for agriculture)
39
Give an example of a raised beach
Raised beaches in Western Scotland - Beaches have been raised up to 30m above sea level - Isostatic rebound is happening at approx 2mm/yr there - Raised beach backed by relict cliffs can be seen at Gruinard Bay
40
What is a submergent coastline?
Coastline drowned, as a result of MARINE TRANSGRESSION (relative rise in sea levels)
41
What 3 scenarios cause formation of submergent coastlines?
- Sea level falls + land falls faster - Sea level stays same + land falls - Sea level rises + land falls/stays same/rises slower
42
What are the submergent landforms?
- Rias - Fjords - Fjards - Dalmatian coasts
43
What is a ria?
Flooded river channel
44
What are the characteristics of a ria?
- Form on discordant coastlines - V-shaped (with gentle sides) - Widest at sea, getting narrower inland - Maintain dendritic drainage system (tributaries)
45
Give an example of a ria
Kingsbridge estuary, Devon
46
What is a fjord?
Flooded glacial valley
47
What are the characteristics of a fjord?
- U-shaped (steep sides) - Narrow (get narrower moving inland) (never wider than they are long) - Deep (deepest in middle) Often accompanied by: - Hanging valleys + waterfalls - Skerries (small rocky islands at the shallow fjord entrance - threshold)
48
Give an example of a fjord
Sognefjord, Norway - 204km long - 1308 km deep
49
What is a fjard?
Flooded inlet (geo) rather than a whole valley - Very similar to fjords
50
Give an example of a fjard
Hjortsholm, Denmark
51
What is a Dalmatian coast?
Group of small islands parallel to the coast, formed by flooded valleys called ‘sounds’
52
Where are Dalmatian coasts found?
On concordant coastlines, where valleys lie parallel to coast
53
Give an example of a Dalmatian coast
Dalmatian Coast, Croatia - Originally folded into synclines + anticlines - After Ice Age, low synclines + low points on anticlines flooded, leaving ridges
54
What eustatic + isostatic sea level changes occur during a glacial period?
Eustatic - Ice freezes, temps fall - eustatic absolute fall in sea levels Isostatic - Ice weighs down land - localised relative sea level rise (glacio-isostasy)
55
What eustatic + isostatic sea level changes occur during an interglacial period?
Eustatic - Ice melts, temps rise - eustatic absolute rise in sea levels Isostatic - Weight of ice removed from land and seabed weighed down- localised relative fall in sea levels (isostatic rebound) (hydro-isostasy)
56
What was the last Ice Age called + when did it end?
The Devensian, ended 10,000 yrs ago
57
What period are we in now + what is happening?
The Holocene, interglacial period where temps + eustatic sea levels have risen, rate accelerated by humans
58
What is the risk of the current eustatic sea level rise?
Over 600 million people live less than 10m above sea level Could face... - Settlement loss - Coastal flooding - Increased insurance/management costs - Salt + fresh water mixing in underground stores, reducing potable water - Environmental damage, e.g habitat loss

Geography - B - Coastal Landscapes (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions