1.2.1 the coast and waves

Question 1

describe an overview of waves on the coast.

Answer 1

• the coast is a narrow contact zone between the land and the sea
• it is a changing landscape
• waves are the primary force causing erosion along the coastline
• a wave is formed by wind blowing across the sea.
• the distance of wind flow is called ‘fetch’
• the larger the wave the more energy it contains

Question 2

name the features of a cliff.

Answer 2

• the cliff
• the wave cut platform
• the wave cut notch. this is at the foot of the cliff and there is more energy (and thus erosion) as there are more waves. eventually the cliff will crumble because of the weight.

Question 3

how are these landforms created?

Answer 3

• the original position of the cliff is eaten away by the low and high water mark
• the cliff retreats, causing the wave-cut platform
• the cliff increases in height as a wave-cut notch is formed

Question 4

describe the process of longshore drift.

Answer 4

position 1:

• prevailing (usual) wind direction is against the start of the beach, with the direction of the waves
• material is carried up the beach

position 2:

• backwash takes material straight down the beach under gravity.
• this repeats in a zig-zag process.
• material is carried along the beach by longshore drift.

Question 5

what is the swash?

Answer 5

the water that rushes up a beach after the wave has broken is called the swash. it picks up material, travelling in the same direction as breaking waves.

Question 6

where is the prevailing wind in britain?

Answer 6

the south-west. material is moved from west to wast along the south coast of england.

Question 7

name a response to longshore drift and what it does.

Answer 7

groynes reduce the force of waves and cause material to pile up on their windward side.

Question 8

what is a vulnerability of groynes?

Answer 8

they leave further down the coast with less sediment and material, therefore there is a smaller barrier between the land and waves.

Question 9

what are spits created from?

Answer 9

deposition.

Question 10

what is a spit?

Answer 10

an extended piece of beach material that projects out to sea and is joined to the mainland at one end.

Question 11

why does longshore drift occur on spits?

Answer 11

because the prevailing wind blows at an angle to the coast.

Question 12

how does a spit form?

Answer 12

• longshore drift moves material
• a spit forms where it is deposited
• the spit grows and develops a hook if wind direction changes
• waves cannot get past which creates a sheltered area silt is deposited
• they commonly form mud flats or salt marshes

Question 13

why do spits form?

Answer 13

• when longshore drift moves a lot of material along a beach to reach it’s end
• where there is a sudden change in direction of the coastline
• is the sea is shallow and sheltered
• second wind direction
• a change in direction like the river mouth or estuary. it loses energy as the waves have nothing to push against

Question 14

what processes occur with longshore drift?

Answer 14

• suspension, saltation and traction

Question 15

why do spits have the characteristics they do?

Answer 15

• they usually have hooked ends as the wind may come from a second direction
• they don’t usually go across the estuary as the river flow is too powerful
• salt marshes often develop behind them

Question 16

how does a headland and bay form?

Answer 16

• cliffs are made up of different bands of rock (less resistant and resistant)
• the softer rock erodes more quickly and material is deposited in the sheltered bay
• more resistant rock erodes slowly and leaves a headland sticking out

Question 17

explain the process of the formation of caves, arches, stacks and stumps.

Answer 17

• the sea attacks the foot of a cliff and erodes the point of weakness with processes such as hydraulic abrasion abrasion and solution
• there is a wave cut notch and the crack gets larger, developing into a small cave. this is predominantly causes by hydraulic action
• there is undercutting and the cave widens and deepens until it cuts through the headland to form an arch
• further undercutting causes the roof of the arch to collapse, leaving part of the cliff detached as a stack. eventually the stack will collapse due to weathering and hydraulic action
• the stack erodes through hydraulic action, attrition and solution at the bade causing it to weaken and collapse into a stump

Question 18

what is a bedding plane?

Answer 18

• a cliff profile has a significant impact on the rate of erosion
• sedimentary rocks form as layers of deposited sediment
• bedding planes are layers of sediment that show when the surface of a cliff was exposed
• these occur between times when rock and sediment has been deposited on the cliff

Question 19

what is the intertidal zone?

Answer 19

the area between the highest and lowest limit of the tides.

Question 20

where are rock pools found?

Answer 20

the inter-tidal zone

Question 21

by which methods of erosion are they formed?

Answer 21

• formed by wave action
• abrasion
• weathering

Question 22

where are small rock pools found?

Answer 22

high inter-tidal zone

Question 23

where are big rock pools found?

Answer 23

the lower inter-tidal zone

Question 24

what things are avoided in rock pools when new water enters the pool?

Answer 24

• avoid temperature stress
• salinity stress
• nutrient stress