EQ2: How do characteristic coastal landforms contribute to coastal landscapes?

Question 1

What factors does wave size depend on?

Answer 1

The strength of the wind

The duration the wind blows for

Water depth

Wave fetch

Question 2

When do waves break?

Answer 2

Waves break as the water depth shallows towards a coastline - at a water depth of approximately half the wavelength.

Question 3

What happens as waves approach the shore?

Answer 3

As waves approach the shore, wavelength decreases and wave height increases, so waves ‘bunch’ together.

The wave crest begins to move forward much faster than the wave trough.

Question 4

Where are constructive waves usually found?

Answer 4

Constructive waves are generally found where nearshore depths are shallow and there are gently sloping sandy beaches.

Question 5

What are the four main processes that cause erosion?

Answer 5

Hydraulic action

Abrasion

Attrition

Corrosion

Question 6

What is another word for hydraulic action?

Answer 6

Wave quarrying

Question 7

What is the effectiveness of wave erosion processes determined by?

Answer 7

The type of wave (destructive or constructive)

The size of wave (linked to energy)

The tide level

The shape of the coastline

The lithology (characteristics of the rocks).

Question 8

What is hydraulic action (wave quarrying)?

Answer 8

When a large destructive wave breaks on a cliff for one/two seconds the force of water exerts considerable pressure, around 50kg/cm2. This pressure may loosen pieces of rock. Air may also be trapped in the circular shape of the breaking wave and compressed into cracks and joints in the rock. Pressure released - rock shatters.

Question 9

What factors in relation to structural geology influence the location of fault lines and fissures?

Answer 9

The location of fault lines and major fissures influences the location of caves and therefore arches.

Question 10

Name the four ways in which transport of sediment happens.

Answer 10

Traction

Saltation

Suspension

Solution

Question 11

Explain the process of longshore drift.

Answer 11

When wave crests approach a coast at an angle (rather than at 90 degrees to the coast) the swash from the breaking waves, and the subsequent backwash, follow different angles up and down the beach in a zig-zag pattern.

Question 12

Where do rip currents take sediments from and to?

Answer 12

Rip currents take sediments from the foreshore to nearshore areas.

Question 13

When does the strongest longshore drift occur?

Answer 13

The strongest longshore drift occurs when waves approach the coast at an angle of 30 degrees to the beach.

Question 14

When is sediment deposited?

Answer 14

Sediment is deposited when the force transporting sediment drops.

Question 15

Name the two ways in which deposition can occur.

Answer 15

Gravity settling

Flocculation

Question 16

Name the process that transports sediment along the coastline and contributes to many depositional landforms.

Answer 16

Longshore drift

Question 17

Why do sandy beaches have a gentle angle, while pebble beaches are steeper?

Answer 17

Because of the angle of rest of the particles and the wave energy shaping them.

Question 18

What happens to the longshore drift current in the process of spit formation?

Answer 18

The longshore drift current spreads out and loses energy, leading to deposition.

Question 19

Summarise the processes contributing to the formation of a bay head beach.

Answer 19

Waves break at 90 degrees to the shoreline and move sediment into a bay, where a beach forms. Through wave refraction, erosion is concentrated at headlands and the bay is an area of deposition.

Question 20

What is a tombolo?

Answer 20

A sand or shingle bar that links the coastline to an offshore island.

Question 21

Why is wave refraction key to how tombolos are formed?

Answer 21

Tombolos form as a result of wave refraction around an offshore island which creates an area of calm water and deposition between the island and the coast.

Question 22

What two processes are the formation of tombolos determined by?

Answer 22

Wave refraction

Opposing longshore currents

Question 23

Explain how a barrier beach/bar is formed.

Answer 23

A spit grows so long that it extends across a bay, closing it off.

Question 24

What is the definition for a hooked/recurved spit?

Answer 24

A spit whose end is curved landward, into a bay or inlet.

Question 25

Why does vegetation play a very important role in stabilising depositional landforms?

Answer 25

Vegetation binds the loose sediment together and encourages further deposition.

Question 26

When do spits form?

Answer 26

Spits form when:

There is a dominant main longshore drift direction

There are plenty of sediments from mass movement and erosion

There is a gap in a coastline, such as an estuary or bay.

Question 27

Name the three interlinked components that the sediment cell consists of.

Answer 27

Sources

Transfer zones

Sinks

Question 28

What is the difference between negative feedback and positive feedback?

Answer 28

Negative feedback usually helps to maintain a balance within a system. Positive feedback tends to change the balance until a new equilibrium is reached.

Question 29

What are the three types of weathering?

Answer 29

Mechanical weathering

Chemical weathering

Biological weathering

Question 30

What are the three types of weathering?

Answer 30

Mechanical weathering

Chemical weathering

Biological weathering

Question 31

Which type of weathering often speeds up mechanical or chemical weathering?

Answer 31

Biological weathering

Question 32

Name the two types of mechanical weathering.

Answer 32

Freeze-thaw

Salt crystallisation

Question 33

Name the three types of chemical weathering.

Answer 33

Carbonation

Hydrolysis

Oxidation

Question 34

Name the two types of biological weathering.

Answer 34

Plant roots

Rock boring

Question 35

Name the four types of mass movement processes.

Answer 35

Fall

Topple

Rotational slide/slumping

Flow