EQ2 - 4.3: Distinctive coastal landscapes are influenced by geology interacting with physical processes

Question 1

What is coastal erosion?

Answer 1

Coastal erosion is the breakdown and removal of sediment at the coastline caused by waves.

Question 2

What are the four types of coastal erosion?

Answer 2

Hydraulic action, abrasion, solution and attrition.

Question 3

What is hydraulic action?

Answer 3

Water is forced into cracks in the rock. The air carried by the wave compresses in the crack. As the wave retreats, the air blasts out. This can force rocks apart.

Question 4

What is abrasion?

Answer 4

Rocks are picked up by the waves and thrown against a cliff face eroding it.

Question 5

What is solution?

Answer 5

This is when the acidic sea water dissolves cliff faces made out of materials like chalk.

Question 6

What is attrition?

Answer 6

Rocks within the waves crash into each other and become smaller and smoother.

Question 7

What are the three factors of the wind that affect waves?

Answer 7

How strong the wind is (strength), how long the wind blows for (duration), and how far the wind travels (fetch)

Question 8

What is the fetch of the UK?

Answer 8

It’s from the Atlantic. It’s very long - 6000km - so the wave has a lot of time to build up.

Question 9

What is the dominant wind direction of the UK?

Answer 9

South West

Question 10

What is the normal wind strength of the UK?

Answer 10

12m/s

Question 11

What is a constructive wave?

Answer 11

A constructive wave is a wave that has long wave lengths, a long wave height and are more common in summer. They have a low wave frequency (6-8 waves per minute) and have a stronger swash than backwash. Also, the waves surge forward instead of crash down and it adds sediment to the beach through deposition.

Question 12

What are destructive waves?

Answer 12

Destructive waves are waves with a shorter wave length, a high wave height and are more common in winter. They have a high wave frequency (10-14 waves per minute) and have a stronger backwash than swash. The waves crash downwards instead of surging forwards and they remove sediment from the beach through erosion.

Question 13

Where do headlands and bays form?

Answer 13

They form on a discordant coastline.

Question 14

How do headlands and bays form?

Answer 14

On a discordant coastline, rocks alternate between hard and soft. Since the hard part takes longer to erode than the soft part, the soft rock erodes faster (hydraulic action and abrasion) forming indents in the coastline. These are called bays and are sheltered from strong waves because their energy is going into the hard rock that sticks out (converging). These are called headlands.

Question 15

What is a wave cut platform?

Answer 15

Where part of a rock falls off into the sea because of a wave cut notch.

Question 16

How are wave cut notches/platforms formed?

Answer 16

The wave erodes a cliff as it projects to sea. The erosion occurs between low tide and high tide, this is inter tidal zone and creates a wave cut notch. Erosion through hydraulic action (power of water and air being forced into cracks) and abrasion (rocks thrown sand scraped against a cliff face) occurs. The rock above the notch is unsupported, the cliff collapses and retreats leaving a gently sloping rocky platform - this is the wave cut platform. The wave now erodes the new cliff line and a wave cut notch is formed. Again this collapses and the wave cut platform increases in width.

Question 17

What is longshore drift?

Answer 17

Longshore drift is when constructive waves wash diagonally across the beach because of a prevailing wind direction and transports sediment up the beach with it’s swash and backwash.

Question 18

What is a spit and how is it formed?

Answer 18

A spit is where sediment forms across the mouth of a river. It is formed when longshore drift pushes sediment out into a river mouth. It can’t form a bar because the erosional force of the river balances the force of longshore drift. Also, behind the spit, salt marshes form because the land is sheltered from the waves.

Question 19

What are bars and how do they form?

Answer 19

A bar is sand that has formed across a cove or a bay. It is formed because longshore drift pushes it in front of the bay/cove and behind the spit, a lagoon is formed.