Coasts 2 - Coastal processes

Question 1

What are the 6 types of erosion

Answer 1

• Corrasion (Abrasion)
• Hydraulic action
• Cavitation
• Wave quarrying
• Solution (Corrosion)
• Attrition

Question 2

What is corrosion (Abrasion)

Answer 2

Bits of sediment transported by the waves, small and grind against rocks and cliffs, breaking bits off and smoothing surfaces

Question 3

What is hydraulic action

Answer 3

Air in cracks in cliffs are compressed when waves crash. The pressure exerted by the compressed air breaks off rock pieces

Question 4

What is cavitation?

Answer 4

As waves recede the compressed air expands exerting pressure on the rock and causing bits to break off

Question 5

What is wave quarrying

Answer 5

The energy of a wave as it breaks against a cliff enough to attack bits of rock222222

Question 6

What is solution (Corrosion)?

Answer 6

Soluble rocks gradually dissolve In seawater

Question 7

What is attrition?

Answer 7

Bits of rock in the water smash against each other and break into smaller pieces

Question 8

What Is transportation

Answer 8

The process of eroded material being moved

Question 9

What are 4 transportation processes?

Answer 9

• Solution
• Suspension
• Saltation
• Traction

Question 10

What is solution?

Answer 10

Substances that dissolve are carried along the water eg.- limestone is dissolved into slightly acidic water

Question 11

What is suspension>

Answer 11

Very fine material, like slit and clay particles is whipped up by turbulence and carried along the water causing them to BOUNCE along the seas bed

Question 12

What is saltation?

Answer 12

Larger particles like gravel and pebbles are too heavy to be carried along in water. Most eroded material is transported like this

Question 13

What is traction?

Answer 13

Very large particles like boulders are pushed along the seabed by the force of water

Question 14

How does longshore drift work?

Answer 14

Swash carries sediment up the beach, parallel to the prevailing wind. Backwash carries sediment back down the beach at right angles to the shoreline.
When there’s an angle between the prevailing wind and shoreline, a few rounds of swash and backwash move the sediment along shoreline

Question 15

What is deposition

Answer 15

The material Being transported and dropped at the coast

Question 16

What are the 2 types of deposition

Answer 16

• Marine
• Aeolian

Question 17

What’s marine deposition?

Answer 17

Sediment carried by seawater that’s deposited

Question 18

What is aeolian deposition?

Answer 18

Sediment carried by wind is deposited

Question 19

When does deposition occur?

Answer 19

When sediment load exceeds the ability of wind or water to carry it

Question 20

Why does this happen?

Answer 20

Because sediment load increases or wind or water flow slows down

Question 21

Why do wind and water slow down?

Answer 21

Friction increases and flow becomes turbulent

Question 22

How does friction increase?

Answer 22

Waves enter shallow water or wind reaches land, friction between water / wind and the ground increases, slowingg down the water or wind

Question 23

How do flows become turbulent

Answer 23

If water or wind encounters an obstacle the flows become rougher and overall speed decreases

Question 24

What happens if the wind drops?

Answer 24

Wave height, speed and energy absorption decrease

Question 25

What is sub-aerial weathering?

Answer 25

The gradual breakdown of rocks by agents like ice, salt, roots and acids

Question 26

What does weathering do?

Answer 26

Weakens cliffs and makes them more vulnerable to erosion

Question 27

What 4 types of weathering affect the coast

Answer 27

- Salt Weathering - Freeze - thaw weathering - Wetting and drying - Chemical weathering

Question 28

What is salt weathering caused by?

Answer 28

Saline (salty) water

Question 29

How does saline water enter the rocks?

Answer 29

Through pores or cracks at high tide

Question 30

What happens as the tide goes out?

Answer 30

Rocks dry and water evaporates forming salt crystals/ As they form, they expand, exerting pressure on rocks causing pieces to fall off

Question 31

When does freeze-thaw weathering occur?

Answer 31

In areas where temperature fluctuates above and below freezing

Question 32

How does water enter the rocks?

Answer 32

In the joints and crevices

Question 33

What happens as the temperature freezes?

Answer 33

Water in cracks freeze and expand. Over time, repeated freeze-thaw weakens the rocks meaning pieces fall off

Question 34

What happens when rock containing clay gets wet?

Answer 34

Expand and the pressure caused by this breaks off fragments of the rock

Question 35

What is chemical weathering?

Answer 35

The breakdown of rock by changing its chemical composition

Question 36

Give an example of chemical weathering

Answer 36

CO2 in the atmosphere dissolves in rainwater, forming weak carbonic acid. The acid reacts with rock that contains calcium carbonate

Question 37

what is mass movement

Answer 37

The shifting of material downhill due to gravity

Question 38

When is mass movement more likely in coast areas

Answer 38

When cliffs are undercut by wave action - causing an unsupported overhang which is likely to collapse

Question 39

What are the 4 types of mass movement

Answer 39

- Landslides - Slumping - Rockfalls - Mudflows

Question 40

How can material move gradually downwards?

Answer 40

By soil creep

Question 41

What are slides?

Answer 41

Material shifts in a straight line

Question 42

What are slumps?

Answer 42

material shifts with a rotation

Question 43

What are rockfalls?

Answer 43

Material breaks up and falls

Question 44

What are mudflows

Answer 44

Material flows downslope

Question 45

What's an example of an unconsolidated rock?

Answer 45

clay

Question 46

What's likely to happen to unconsolidated rock?

Answer 46

They're prone to collapse as there's little friction between particles to hold them together

Question 47

What happens when there's heavy rain on unconsolidated rock?

Answer 47

It can saturate the rock and reduces the friction making it more likely to collapse

Question 48

What is runoff

Answer 48

The flow of water over the land

Question 49

What can runoff do?

Answer 49

Erodes fine particles and transport them downslope