Coasts (Definitions)

Question 1

What is a coast?

Answer 1

The interface between land and sea, can be viewed as a system, with inputs, processes and outputs.

Question 2

What are the 4 inputs for a coastal system?

Answer 2

Wave energy
Geological structure
Sub-aerial activity
Human activity

Question 3

What is the fetch of a wave?

Answer 3

The distance over which the wind blows in a constant direction across the surface of the water

Question 4

What are the 4 processes at a coastal system?

Answer 4

Wave erosion
Mass movement
Hard/soft engineering
Transport

Question 5

What are the 2 outputs at a coastal system?

Answer 5

• Landforms of erosion
• Landforms of deposition

Question 6

The 7 processes of coastal erosion:

Answer 6

Abrasion - Waves throw loose material at cliffs
Attrition - Movement sandpapers rocks into smoother and rounded rocks
Solution - Carbonic acid in sea water reacts, and spray corrodes rocks, so they disintegrate
Biological activity - Secretions from algae attack rocks, or some molluscs can bore holes in them
Wave pounding - Wave impact can loosen cliff face rock.
Hydraulic pressure -Waves enter tiny crevice/crack and air is trapped
Sub aerial weathering - Rain leading to saturation of cliff material and the failure of cliff by mass movement

Question 7

What determines the amount of energy waves have?

Answer 7

Higher wind speeds impart more energy to the waters surface, creating larger and more powerful waves
A longer fetch allows the wind to transfer more energy to the water, resulting in larger waves

Question 8

What is meant by wave pounding?

Answer 8

The forceful impact of large and powerful waves on a cliff face or coastal structure, pounding or battering effect is pronounced during storms or periods of high winds, with intensified waves.

Question 9

What are two examples of mass movement?

Answer 9

Landslides involve the rapid downslope movement of rock, soil, and debris along a defined surface, triggered by many diff factors or activities that disturb the stability of a slope
Mudflows are fast-moving mixtures of water, mud, rocks, and debris that flow downslope. They are similar to landslides but involve a higher proportion of water, giving them a fluid-like consistency.
Sub aerial activity triggers this movement when soils are more saturated.

Question 10

What do all rocks have and why is this important?

Answer 10

Minerals, are fundamental to the composition, classification, and understanding of rocks

Question 11

What does lithification mean?

Answer 11

The process by which loose sediments are transformed into solid rock, critical in formation of sedimentary rocks

Question 12

What happens to waves in bays?

Answer 12

The behaviour of waves in bays is influenced by the bay’s specific characteristics, including its shape, depth, and the presence of coastal features

Question 13

What is threatening the Holderness Coast?

Answer 13

Rapid coastal erosion due to soft geological formation, lack of coastal defences, high erosion rate due to strong waves from the north sea, and sea level rise.

Question 14

What are the three major inputs influencing cliff formation?

Answer 14

Geological structure - Different types of rocks have varying resistance to weathering and erosion.
Folding and faulting -As a result of earth movements all rocks exhibit some degree of folding which can become weaknesses, creates lines of weakness which can be exploited.
Coastal morphology - On an indented coastline, headland sand the offshore topography concentrate wave attack on the headland by the process of wave refraction.

Question 15

Abandon the line

Answer 15

the strategic withdrawal of human occupation in areas of high risk

Question 16

Accretion

Answer 16

the accumulation of marine sediments

Question 17

Advance the line

Answer 17

Active intervention to produce a defence line that is seaward of the existing line

Question 18

Arch

Answer 18

A raised area when two caves erode back to back on a headland
e.g. Durdle Door

Question 19

Backwash

Answer 19

movement of water back towards the sea after a wave has been broken

Question 20

Bar

Answer 20

Coarse grained deposit of sediment extending across the mouth of the bay

Question 21

Berm

Answer 21

Low hill of sand or gravel that forms at the upper limit of the swash

Question 22

Beach nourishment

Answer 22

sand and shingle brought from elsewhere are added to beaches to maintain depth to protect from erosion in a natural way

Question 23

Char

Answer 23

An island formed from silt deposit in a delta, the land is about at sea level and is very fertile, however easily washed away

Question 24

Constructive waves

Answer 24

Low frequency 6-8 per minute waves with elliptical water motion, powerful swash and weak backwash

Question 25

Concordant geology

Answer 25

The alignment of bands of alternate geology that run parallel to the coastline

Question 26

Corrasion

Answer 26

Erosion by friction in load of contact with banks and bed

Question 27

Deltas

Answer 27

Form when the amount of sediment delivered at the mouth of a river exceeds the amount removed by waves

Question 28

Destructive waves

Answer 28

High frequency 13-15 per minute waves with circular water motion, with weak swash and strong backwash

Question 29

Differential erosion

Answer 29

Varying rates of erosion relating to geology

Question 30

Discordant geology

Answer 30

Coasts which cut across the rock structure

Question 31

Diurnal range

Answer 31

The difference between the lowest temperature and the highest temp in a 24 hour period

Question 32

Eustatic

Answer 32

Changes in sea level caused by variations in water levels in the ocean

Question 33

Fiord

Answer 33

Very deep U shaped estuaries formed by drowning of glaciated valleys

Question 34

Gabion

Answer 34

cages enclosing rocks to defend the coast

Question 35

Geo

Answer 35

Steep sided narrow inlet

Question 36

Groyne

Answer 36

Posts with boards which run at right angles to the coastline which trap sediment drifting along the shore

Question 37

Hard engineering

Answer 37

Structures developed to protect the foot of cliffs and prevent erosion

Question 38

High energy coast

Answer 38

Coasts in which wave power is strong for a significant part of the year

Question 39

Hold the line

Answer 39

taking action to maintain the current defence line

Question 40

Isostatic

Answer 40

Change in sea level resulting from the rise and fall of land masses

Question 41

Isthmus

Answer 41

A narrow piece of land connecting two larger pieces of land

Question 42

Littoral zone

Answer 42

Extends from the high water mark to shoreline areas that are permanently submerged

Question 43

Low energy coasts

Answer 43

coasts in which wave power is weaker, low fetch, few gales enclosed and therefore sheltered

Question 44

Plagioclimax

Answer 44

where succession is stunted by human interference

Question 45

Psammosere

Answer 45

Succession of stages of plant growth forming colonisation of bare sand to climax vegetation

Question 46

Return period

Answer 46

average time between occurrences of a given event

Question 47

Saltation

Answer 47

Sand bounces across the surface of the beach blown by wind

Question 48

Slumping

Answer 48

Triggered by undercutting at the base of cliffs with rotation in the slip plane

Question 49

Spit

Answer 49

Long ridges of sand and shingle attached to land at one end

Question 50

Spring tide

Answer 50

Particularly high or low tides caused when the sun, moon and earth all lie in a straight line, happens twice a month

Question 51

Stack

Answer 51

A residual post of rock resulting from the continued erosion of arches

Question 52

Surges

Answer 52

Changes in water level as a result of meteorological forcing

Question 53

Swell

Answer 53

a circular motion caused by wind in sea as a wave reaches the shore

Question 54

tidal bore

Answer 54

in narrow estuaries the effect of tides can be more pronounced

Question 55

Tombolo

Answer 55

Shingle ridge linking the mainland to an island

Question 56

What can you say about low energy environments and deposition

Answer 56

Deposition occurs when there is insufficent energy to push the sediments further - In low energy environments, factors such as wave and wind direction, the supply of sediment and the depth of water are often significant.

Question 57

What is the maximum tidal range for large depositional landforms?

Answer 57

3 meters

Question 58

What is a "swash aligned" beach? (Deposition)

Answer 58

Forms when waves break parallel to the coast. Creates bay beaches (Dorset coast) and barrier beaches, like Start Bay (Devon)

Question 59

What is a "Drift aligned" beach? (Deposition)

Answer 59

When LSD moves material down the coast producing a range of partly detached features. Such as spits.

Question 60

How are sand dunes formed? (Deposition)

Answer 60

When dry material from flat, open beaches is blown inland. Dunes migrate and a succession of plants colonise and adapt to this environment forming a dune or psammosere ecosystem.

Question 61

How are mudflats and salt marshes formed? (Deposition)

Answer 61

Formed of finer material which flocculates (sticks together) in the shallow water of estuaries. Plants here adapt to salt water and tidal conditions

Question 62

What is beach drift?

Answer 62

Swash processes caused by longshore currents may move material laterally along the shoreline

Question 63

What are beach susps?

Answer 63

Material at the top of the beach is of a larger calibre and supports steeper concave slopes, beach cusps occur where this coarser material is absorbing wave swash.

Question 64

How are bay head beaches developed (Deposition)

Answer 64

They build up in the sheltered, low energy environments of coves.Wave refraction focuses erosion on the surrounding headlands and so encourages deposition in the bay.

Question 65

why are drift aligned beaches more of an open system?

Answer 65

Sediment enters at one end, passes along the length of the beach due to LSD and then leaves the beach at the other end. the predominant angle of wave approach brings with it enough energy to keep the sediment moving

Question 66

What are the 4 criteria for a spit to form?

Answer 66

- Ready supply of sediment, particularly sand and shingle - LSD is active - The coast has an abrupt change in direction, such as at an estruary or bay - Tidal range is limited (<3 metres)