5. Coastal Processes

Question 1

What are the key sub-aerial processes?

Answer 1

Runoff
Sub-aerial weathering (mechanical, biological and chemical)
Mass movement

Question 2

What are the key coastal marine processes?

Answer 2

Marine erosion
Marine deposition
Marine transportation

Question 3

What are the factors affecting erosion?

Answer 3

Shape of coastline
Beach presence
Human activity 
Geology
Sea depth
Fetch
Wave characteristics

Question 4

What are the main types of marine erosion?

Answer 4

Hydraulic action
Wave quarrying
Abrasion (corrasion)
Attrition
Solution (corrosion)
Cavitation

Question 5

What are the main types of marine transportation?

Answer 5

Traction
Saltation
Suspension 
Solution
Longshaw drift

Question 6

What are the main types of marine deposition?

Answer 6

Accumulation of sediment faster than removal
Slow waves after breaking
Powerful swash

Question 7

What are the main types of mechanical sub-aerial weathering?

Answer 7

Freeze-thaw

Pressure release

Question 8

What are the main types of chemical sub-aerial weathering?

Answer 8

Oxidation
Hydration
Hydrolysis
Carbonation

Question 9

What are the main types of mass movement?

Answer 9

Landslide
Rockfall
Mudflows
Rational slip (slumping)
Soil creep

Question 10

What are mass movements dependant on?

Answer 10

Slope angle
Grain size
Temperature
Saturation

Question 11

What is hydraulic action?

Answer 11

The force of the water on rocks (wave pounding)

Question 12

What is wave quarrying?

Answer 12

Breaking wave traps air in crack in a cliff surface
As the water pulls back, air is released under a pressure
This weakens the rock face over time

Question 13

What is abrasion (corrasion)?

Answer 13

Sand, shingle and boulders picked up by the sea and hurled against a cliff

Question 14

What is attrition?

Answer 14

The wearing down of rocks and pebbles as they rub against each other
This makes them smaller and rounder

Question 15

What is solution (corrosion)?

Answer 15

Where fresh water mixes with salt water, acidity may increase
This breaks down carbon-based rocks

Question 16

What is traction?

Answer 16

Large boulders roll along the seabed

Question 17

What is saltation?

Answer 17

Small stones bounce along the seabed

Question 18

What is suspension?

Answer 18

Very small particles carried in moving water

Question 19

What is solution?

Answer 19

Dissolving material

Question 20

What is longshaw drift?

Answer 20

Waves approach the shore at an angle
Swash moves material il the beach in the same direction as the wave
Backwash moves material back down the steepest gradient, perpendicular to the shoreline
This is picked up by the next wave, carrying sediment down the coast

Question 21

Where does marine and aeolian deposition occur?

Answer 21

On low-energy coastlines
OR
Where there is an abundance of erosional material

Question 22

What is mechanical weathering?

Answer 22

Climate related
Eg freeze-thaw weathering/ pressure release of underlying rock where overlying material is removed by erosion, weathering or mass movement

Question 23

What is biological weathering?

Answer 23

Breakdown by the action of vegetation and other coastal organisms and

Question 24

What is oxidation?

Answer 24

Oxygen dissolved in water reacts with some rock minerals

Question 25

What is hydration?

Answer 25

Physical addition of water to minerals in rocks makes them more susceptible to chemical weathering

Question 26

What is hydrolysis?

Answer 26

Mildly acidic water reacts with minerals

Question 27

What is carbonation?

Answer 27

Carbon dioxide dissolved in rain water makers a weak carbonic acid which reacts with calcium carbonate in limestone and chalk

Question 28

What are landslides?

Answer 28

Cliffs made of softer rocks slip when lubricated by rainfall

Question 29

What are rockfalls?

Answer 29

Rocks undercut by the sea or slopes affected by mechanical weathering

Question 30

What are mud flows?

Answer 30

Heavy rain causes fine material to move downhill

Question 31

What is rational slip/slumping?

Answer 31

Where soft material overlies resistant material and excessive lubrication takes place

Question 32

What is soil creep?

Answer 32

Very slow movement of soil particles down slope

Question 33

What is run-off?

Answer 33

The movement of water across a hard surface, carrying debris

Question 34

In what situations would deposition occur?

Answer 34

When sediment accumulates faster than it is removed As waves slow down after breaking When water pauses at the top of swash and before backwash When water percolates into the beach material as backwash takes in back down the beach

Question 35

Define aeolian processes.

Answer 35

The entrainment, transport and deposition of sediment by wind

Question 36

What is surface creep?

Answer 36

Where wind rolls or slices sand grains along the surface

Question 37

By which two processes is sand transported by wind?

Answer 37

Surface creep | Saltation

Question 38

What is freeze-thaw weathering?

Answer 38

``` Water enters cracks in rocks It freezes when temps are low It expands by 10% on freezing This exerts pressure on the surrounding rocks This repeats The crack widens Rock breaks off ```

Question 39

What does underlying rock experience when processes remove overlying material?

Answer 39

Pressure release

Question 40

What is the effect of gases other than carbon dioxide?

Answer 40

Sulphur dioxide/ nitric oxides Creates acid rain Weakens/dissolved rocks