Coast Processes

Question 1

Define Marine Processes

Answer 1

Processes that operate upon a coastline which are connected to the sea - waves, tides, lsd

Question 2

Define Abrasion/corrasion

Answer 2

Bits of rock & sediment transported by the waves smash/grind against rock
Break bits off & smooth surfaces

Question 3

Define Hydraulic Action

Answer 3

Air in cliff cracks compressed when waves crash
Pressure exerted by compressed air breaks off rock

Question 4

Define Quarrying

Answer 4

Wave energy breaks against cliff - detach bits of rock

Question 5

Define Corrosion/solution

Answer 5

Soluble rocks (limestone, chalk) dissolved by seawater

Question 6

Define Attrition

Answer 6

Bits of rock in H2O smash into each other - break into smaller pieces

Question 7

How does the width of a beach impact the rate of erosion? (width between HWM & LWM)

Answer 7

Beaches slow down waves - wide flat beaches protect cliffs more than steep & narrow

Question 8

How does the breaking point of the waves impact the rate of erosion?

Answer 8

Breaking wave at foot of cliff = most energy transferred - erode more
Waves that hit cliff before breaking = erode less

Question 9

How does the aspect of the coastline impact the rate of erosion?

Answer 9

Coastline faces dominant wind & wave direction - erosion faster

Question 10

How does the fetch of the wave impact the rate of erosion?

Answer 10

Longer fetch -> higher & steeper waves -> more energy -> more erosion

Question 11

How does rock type impact the rate of erosion?

Answer 11

Hard rock like granite much more resistant to erosion unlike soft rock (e.g clay)

Question 12

How does lithology impact the rate of erosion?

Answer 12

Chemical composition - determines resistance to erosion and permeability
Permeability controlled by grain size and joint patterns

Question 13

Structure of rocks impact the rate of erosion?

Answer 13

Physical characteristics:
Strata (layers)
Dip (angle of rocks)
Faults
Alignment of rocks can have an affect on coastline
- Parallel rocks = concordant coastline
- Rocks at right angle = discordant coadtline

Question 14

Define Traction (Marine Transportation)

Answer 14

Large stones & boulders are rolled and slid along the sea bed and beach by moving sea water

Question 15

Define Solution (Marine Transportation)

Answer 15

Small stones bounce or leapfrog along seabed and beach.
Thrusted particles fall again - dislodge other particles upward - more bouncing

Question 16

Define Suspension (Marine Transportation)

Answer 16

Very small particles of sand & silt are carried along by moving H2O turbulence

Question 17

Define Solution (Marine Transportation)

Answer 17

Dissolved materials - transported within mass of moving H2O

Question 18

Define Longshore Drift (Marine Transportation)

Answer 18

Currents move material along the coast
Swash carries up the beach parallel to prevailing wind
Backwash carries sediment down the beach at right angle to shoreline

Question 19

Define Deposition

Answer 19

Deposit of sediment in sheltered areas e.g: bays

Question 20

Define Aeolian Deposition

Answer 20

Refer to the entrainment, transport and deposition of sediment by wind
Normally due to wind from the sea
Large tidal range = sand exposed at low tide - entrained by wind

Question 21

How does sand size sediment impact the deposition on coast

Answer 21

Transported close to the ground over small distances

Question 22

Outline the 2 ways how sand is transported by wind

Answer 22

Surface creep - process similar to traction - wind rolls or slides sand grains along surface

Saltation - wind strong enough can temporary lift grains into the air

Question 23

Define Sub-aerial processes

Answer 23

Processes operating on the land not linked to the action of the sea

Question 24

Define Weathering (sub-aerial process)

Answer 24

Weakens cliffs and makes them more vulnerable to erosion

Question 25

Define Freeze-thaw weathering (sub-aerial process)

Answer 25

Water freezing & melting repeatedly in joints & cracks where temperature is around 0°C Freezing - expanding causes pressure to be exerted

Question 26

Outline Biological weathering (sub-aerial process)

Answer 26

Animals/plants weather rock e.g: Paddock fish drills into rock in chalk areas Seaweed prising rocks away Algae secrete chemicals capable of promoting solution

Question 27

Define Chemical weathering (sub-aerial process)

Answer 27

Decomposition of rocks from chemical change

Question 28

Outline oxidation of chemical weathering (sub-aerial process)

Answer 28

Rocks disintegrate when oxygen dissolved in H2O reacts forming oxides & hydroxides

Question 29

Outline Hydration of chemical weathering (sub-aerial process)

Answer 29

Makes rocks more susceptible to chemical weathering. Physical addition of H2O in rock minerals - causes expansion -> disintegration

Question 30

Outline Hyrolysis of chemical weathering (sub-aerial process)

Answer 30

Mildly acidic H2O reacts or combines with minerals in the rock to create clays & dissolvable salts

Question 31

Outline Carbonation of chemical weathering (sub-aerial process)

Answer 31

CO2 dissolved in rainwater makes a weak carbonic acid Reacts with calcium carbonate in rocks like limestone - creates calcium bicarbonate -> dissolves easily in H2O Better in cooler conditions

Question 32

Define Throughflow (sub-aerial process)

Answer 32

Flow of H2O through the cliffs caused by heavy rainfall can cause cliffs to become more unstable

Question 33

Define Run off (sub-aerial process)

Answer 33

Flow of H2O on land caused by heavy rainfall can cause cliffs to become more unstable

Question 34

Define Mass movement (sub-aerial process)

Answer 34

Movement of material downhill due to gravity - particularly evident in weak rocks Triggered by wave action undermining the base of cliffs

Question 35

Outline rock falls of mass movement (sub-aerial process)

Answer 35

Rock falling from cliffs undercut by the sea

Question 36

Outline landslides of mass movement (sub-aerial process)

Answer 36

Softer rock & deposited material that slips when lubricated

Question 37

Outline mudflows of mass movement (sub-aerial process)

Answer 37

Caused by heavy rain if cliffs are made of fine material

Question 38

Outline slumping of mass movement (sub-aerial process)

Answer 38

Softer material overlies more resistant material causing rotational movement e.g glacial deposit in coastal area Holderness, Norfolk

Question 39

Outline soil creep of mass movement (sub-aerial process)

Answer 39

Slow continuous movement of individual soil particles downslope. Possible cause = presence of soil moisture or weathering