Topic 4 - Costal Weathering And Erosion (set D)✔️

Question 1

Define mechanical weathering?

Answer 1

The breakdown of rock without changing its chemical composition - main type which affects coasts is salt weathering

Question 2

Explain how salt weathering breaks apart rocks?

Answer 2

1) seawater gets into cracks in the rock
2) when the water evaporates, salt crystals form - which expand and put pressure on the rock
3) repeated evaporation of saltwater and the formation of salt crystals widens the cracks and causes the rock to break up

Question 3

Define chemical weathering?

Answer 3

The breakdown of rocks by changing its chemical composition - carbonation weathering is a type of chemical weathering that happens in warm and wet conditions

Question 4

Define biological weathering? give an example of how it is caused

Answer 4

Breakdown of rock by living things - eg plant roots which break down rocks by getting into cracks on the surface and pushing them apart

Question 5

Explain mass movement?what causes it? What can increase the chance of it?

Answer 5

Is the shifting of rocks and loose material down a slope, eg a cliff - happens when the force of gravity acting on a slope is greater than the force supporting it but is more likley to happen when the material is full of water - which acts as a lubricant

Question 6

Explain how waves erode a coast with hydraulic power?

Answer 6

Waves crash against rock and compress the air in the cracks - this puts pressure on the rock which over time will widen and bits of rock will break off

Question 7

Explain how waves erode the coast through abrasion?

Answer 7

Eroded particles in the water scrape and rub against rock, removing small pieces

Question 8

Explain how waves erode the coast through attrition?

Answer 8

Eroded particles in the water smash into each other and break into smaller fragments, their edges also get rounded off as they rub together

Question 9

give two factors which effect and influence the erosion of landforms?

Answer 9

• rock type - softer rock like clay is less resistant and eroded quickly
• joints and faults are cracks and weaknesses in the rocks - will eroded faster

Question 10

Explain what a discordant coastline is?

Answer 10

Made up of alternating bands of hard and soft rock that are at right angles to the coast - bays and headlands are more common here due to the different rate of erosion

Question 11

Explain what a concordant coastline is?

Answer 11

Made up of alternating bands of hard and soft rock which are parrallel to the coast (horizontal) - will have fewer landforms due to it being eroded at the same rate

Question 12

Two erosional landforms common at discordant coastlines?

Answer 12

• bays
• headlands

Question 13

Explain how uk climate affects coastal erosion?Give three examples

Answer 13

• mild tempertaures increase salt weathering - water evaporates more quickly
• storms are more frequent in winter, which will create strong winds and higher energy, destructive waves
• intense rainfall, saturates cliffs - makes mass movement more likley

Question 14

What are destructive waves?featues of these waves?

Answer 14

The high, steep waves that carry out erosional processes they have a high frequency with a backwash more powerful than their swash - which means material is removed from the coast

Question 15

What is the frequency like for destructive waves?

Answer 15

High frequency - 10-14 waves per minute

Question 16

Explain how destructive waves cause erosion?

Answer 16

Their backwash (movement of water back down the beach) is more powerful than their swash (movment of water up the beach) - so material is removed from the coast

Question 17

Explain how a wave-cut platform is caused through erosion?

Answer 17

1) waves cause more erosion at foot of cliff - forming a wave-cut notch which enlarges as erosion continues
2) rock above notch is unstable and eventually collapses - material is washed away and a new wave-cut notch starts to form
3)repeats, causing the cliff to retreat leaving a platform behind

Question 18

Explain how bays form at discordant coastlines?

Answer 18

Form when there are alternating bands of resistant and less resistant rock along a coast - less resistant rock is eroded quickly which forms bays - which have gentle slopes

Question 19

Explain how headlands form at discordant coastlines?

Answer 19

The resistant rock (eg chalk) is eroded more slowly and its left sticking out, forming a headland - have steep sides

Question 20

Explain how a cave is formed from the erosion of headland?

Answer 20

Headlands made of resistant rock and usually have cracks which are enlarged through hydraulic power and abrasion caused by waves - repeated erosion and enlargement of the cracks causes caves to form

Question 21

Explain how an arch is formed through the erosion of a cave?

Answer 21

Repeated erosion deepens the cave until it breaks through the headland - arch is formed

Question 22

Explain how a stack is formed through the erosion of an arch?

Answer 22

Erosion continues to wear away the rock supporting the arch, until it eventually collapses - forms a stack - which is an isolated rock, seperate from the headland