GCSE Coastal Zone Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What factors shape our coastline

A

Waves
Rock type
Land processes
Marine Processes

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2
Q

What are the land processes shaping the coastline

A

Weathering

Mass movement

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3
Q

What are the marine processes shaping the coastline

A

Transportation
Deposition
Erosion

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4
Q

What is the fetch

A

The distance the wind has blown

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5
Q

What depends on the fetch

A

Size and strength of wave

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6
Q

Larger wave means

A

Greater fetch, stronger wind

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7
Q

Waves strongest from

A

South West Britain

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8
Q

Why do waves break

A

Waves slow at beaches because of FRICTION between wave and beach– causes it to break

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9
Q

Define swash

A

Forward movement of a wave UP a beach

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10
Q

Define backwash

A

Movement of a wave back DOWN a beach after the wave broken

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11
Q

Swash/Backwash transfer of energy

A

Transfers energy UP/DOWN a beach

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12
Q

Types of waves

A

Constructive, destructive

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13
Q

Characteristics of constructive

A
  • builds beaches
  • low waves
  • carries material up the beach
  • most common in summer
  • material deposited when backwash soaks into sand/slowly drains away
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14
Q

Characteristics of destructive

A
  • destroys beaches
  • high and frequent waves
  • strong backwash pulls material out to sea
  • most common in winter
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15
Q

What affects height and shape of coastal scenery

A

Resistance, permeability, structure of rock

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16
Q

What is resistance

A

Rocks can be hard (granite) and soft (clay)

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17
Q

What is permeability

A

Rocks can be porous (chalk), permeable (limestone) and impermeable (granite)

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18
Q

What is structure

A

Rocks can have interlocking crystals, joints, faults and bedding planes

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19
Q

Weathering and mass movement are…

A

SUB-AERIAL PROCESSES/land processes

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20
Q

Define mass movement

A

Downhill shifting of rocks and loose material under the influence of GRAVITY which is greater than the force supporting it

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21
Q

What is slumping

A

Common when cliffs are of clay. During heavy rainfall- becomes saturated+heavy and oozes towards sea as part of a MUD or DEBRIS flow
(mudflow, rotational slip)

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22
Q

What is sliding

A

When large chunks of rock slide downslope quickly without warning
(landslide, rockfall)

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23
Q

Rotational slip

A

Rotational movement on a concave slide plane. Weak rock (clay)/soil becomes saturated- in response to GRAVITY simply collapses

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24
Q

Mudflow

A

Weak rock (clay, volcanic ash)/soil becomes saturated and FLOWS downhill. Can be slow/rapid. If mixed with melted snow/ice/ash from volcanoes– become lahars (deadly)

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25
Q

Rockfall

A

On steepest slopes. Rock fragments/slabs suddenly detach and angular debris falls to base as TALUS/SCREE. Gradual processes- freeze thaw weathering OR sudden and dramatic- earthquakes

26
Q

Landslide

A

Flat/planar side plane with impermeable bedding plane is lubricated after rainfall- making slope slippery and landslides RAPID and deadly.

27
Q

Landslide

A

Flat/planar side plane with impermeable bedding plane is lubricated after rainfall- making slope slippery and landslides RAPID and deadly.

28
Q

Define weathering

A

The breakdown or decay or rocks in their original place (in SITU) or close to the earths surface, mainly caused by weather conditions (change in temp+rainfall e.g.)

29
Q

Factors affecting weathering rate

A

Climate, vegetation, animals colonising cliffs

30
Q

Erosion-not in situ- caused by

A

Movement of water, ice and wind

31
Q

Types of weathering

A

Biological, chemical, mechanical

32
Q

Biological weathering (all)

A

PLANTS- tree roots grow into cracks and widen them

ANIMALS- burrow into weak rocks and force apart

33
Q

What is Chemical weathering

A

Breakdown by changing its chemical composition and causing rot and decay. Warm and wet climates
Carbonation, solution

34
Q

What is Mechanical weathering

A

Breakdown of rock w/out changing chemical composition. Common where rock is bare/unprotected from extreme climates.
Exfoliation, freeze thaw

35
Q

Carbonation

A

Rainwater has some CO2 in it making it a weak carbonic acid. It reacts and dissolves rocks e.g. limestone with CACO3. Removed using running water. Forms distinctive landforms

36
Q

Solution

A

Minerals (eg rock salt) and rocks DISSOLVE in rainwater

37
Q

Exfoliation

A

Warm climates-
In warm day, rock heats and EXPANDS. In cool night rock cools and CONTRACTS. Repeats, wears rock and it peels like an onion

38
Q

Freezethaw

A

Happens where temp alternates above/below 0C
Rainwater in cracks+joints freezes subzero. Expands by 9%, puts PRESSURE on rock. FORCES cracks to widen. Ice thaws and melts and contracts above 0C, PRESSURE RELEASED. Repeat, causes rock to break apart and form scree

39
Q

Define coastal erosion

A

Wearing away of the land by the action of waves. When a wave smashes down on a beach/against a cliff- it carries out erosion.
(hydraulic action, abrasion, corrasion, attrition, solution)

40
Q

Hydraulic action

A

Sheer power of waves. Waves smash against a cliff- trapped air is compressed and blasted through cracks+holes causing rock to fall apart. Cavitation is the explosive force of trapped air in a cliff

41
Q

Abrasion

A

Sandpapering effect causing rocks to smoothen and become smaller after dragged, scraped and rubbed along a rocky surface

42
Q

Corrasion

A

Sea throws fragments of rock against a cliff face, causing it to scrape+gouge the rock

43
Q

Attrition

A

Rock fragments in the sea bash against each other so become more rounded and smaller as they break into smaller fragments

44
Q

Solution

A

Small, weak and vulnerable rocks e.g. limestone and chalk dissolve in seawater

45
Q

Methods of transportation

A

LSD, traction, saltation, suspension, solution

46
Q

Traction

A

Large heavy rocks ROLLED along the seabed by FORCE of the seawater

47
Q

Saltation

A

Small rocks and pebbles and sand grains BOUNCE along the seabed by FORCE of seawater

48
Q

Suspension

A

Small material (e.g. sand, silt) is CARRIED within the water

49
Q

Solution

A

Small, weak and vulnerable soluble rocks are dissolved and are carried along within the water

50
Q

What is Longshore drift

A

Movement of material along a coast in a zig zag formation

51
Q

Process of LSD

A

Wave approaches in OBLIQUE angle, following direction of prevailing wind. Swash carries material up the beach after wave has broken. Backwash returns material at a right angle down the beach (shortest route under gravity’s influence). Material ZIGZAGS over time across beach.

52
Q

What are the features of erosion?

A

Headland and bays
Cliffs and wave-cut platforms
Caves, arches and stacks

53
Q

Where do headlands and bays form?

A

Discordant coastline- alternating rock types/ erosion resistance is different

54
Q

Define concordant coastline

A

Coastline with the same type of rock along its length

55
Q

Define headland

A

A promontory of land jutting out into the sea

56
Q

Define bay

A

A broad COASTAL INLET often with a beach

57
Q

Formation of Headlands and bays

A

Cliffs rarely erode at an easy pace.
Some types of more rock are more resistant to erosion
At discordant coastlines, destructive waves erode the softer rock quicker to form bays and coves (clay)
Waves cannot wear away resistant rock as easily so harder rock sticks out as HEADLANDS (sandstone, limestone, chalk)

58
Q

Define a wave-cut platform

A

A wide, gently sloping rocky surface at the foot of a cliff

59
Q

Define a wave-cut notch

A

A small indentation cut into a cliff by coastal erosion roughly at the level of high tide

60
Q

How are wave-cut platforms formed?

A

Waves cause most erosion at the foot of a cliff
Concentrated marine erosion causes the waves to undercut the foot of the cliff when wave energy is at its max
Erosion continues and the notch enlarges and widens until the unsupported cliff collapses. This is aided by gravity and SA processes.
Repeated collapsing causes cliff to retreat, increase in height and leave a rocky platform behind.

61
Q

How are caves, arches and stacks formed.

A
  • lines of weaknesses eg faults, cracks occur in headlands (esp vulnerable rock, chalk, limestone)
  • Corrasion, hydraulic action erode, widen fault–cave
  • Cave widened, deepened. Sometimes there’s back to back cave
  • Sea cuts through– arch
  • Marine erosion–notches at base of arch
  • SA processes weaken top+gravity helps towards collapse
  • Isolated stack attacked by marine processes and gravity
  • notches form + are undercut– stump
  • headland retreats, process repeats