4.3 Landforms and Processes Impacting Coasts

Question 1

What are the more resistant rocks in rock types?

Answer 1

Igneous-granite and resistant semdimentry

Question 2

What are the less resistant rocks in rock types?

Answer 2

Clays and shales which are more easily eroded

Question 3

What are joints ?

Answer 3

Joints are small usually vertical cracks formed in many rocks

Question 4

What are faults?

Answer 4

Faults are larger cracks formed by past tectonic movements, where rocks have moved.

Question 5

What is the rock alignment of discordant coastlines?

Answer 5

Strata at a right angle to the coastline

Question 6

What is the rock alignment of concordant coastlines?

Answer 6

Strata is parallel to the coastline

Question 7

What is an example of a discordant coastline?

Answer 7

Studland to Durlston

Question 8

What is an example of a concordant coastline?

Answer 8

Durlston Head to Kimmeridge

Question 9

What are the features and landforms of discordant coastlines?

Answer 9

• Arch
• Stack
• Stump
• Headlands

Question 10

What are the features and landforms of concordant coastlines?

Answer 10

• Cone
• Cliffs

Question 11

What are the erosion and/or deposition landforms of discordant coastlines?

Answer 11

• Coastal erosion
• Deposition landforms

Question 12

What are the erosion and/or deposition landforms of concordant coastlines?

Answer 12

• Usually just coastal landforms

Question 13

How are headlands and bays formed?

Answer 13

1. The less resistant rock is quickly eroded and this forms a bay which had a gentle slop.
2. The resistant rock is eroded more slowly and so its left jutting out, forming a headland with steepsides

Question 14

Why are headlands and bays formed?

Answer 14

Headlands and bays are formed because there are alternating bands of resistant and less resistant rocks along a coast.

Question 15

How are arches, stacks and stumps formed?

Answer 15

1. Caves can form at the base of the cliff where the cracks are enlarged by erosion.
2. Caves can form on opposite sides of the headland, eventually they will meet and form a natural arch.
3. Further weathering and erosion will cause the arch to become unstable and collapse, leaving a pillar called a stack.
4. The base of the stack is weathered and eroded until the top falls off leaving a stump.

Question 16

Why are arches, stacks and stumps formed?

Answer 16

Waves are very strong where headlands jut far into the sea which allows them to attack any faults or cracks in the rock

Question 17

Why are wave-cut notch’s and platforms formed?

Answer 17

Waves cause most erosion at the foot of the cliff.

Question 18

How are wave-cut notch’s and platforms formed?

Answer 18

1. Waves cause most erosion at the foot of the cliff, so this forms a wave cut-notch which is enlarged by further erosion.
2. The rock above becomes unstable and eventually collapses.
3. The collapsed material is washed away and new wave-cut notch starts to form.
4. Repeated collapsing results in the cliff receding.
5. A wave-cut platform is the platform left behind as the cliff retreats.

Question 19

What is the seasonality of the UK climate?

Answer 19

January had the highest wind speeds in the UK

Question 20

What is the storm frequency of the UK climate?

Answer 20

Gale force winds from the North East

Question 21

What is the prevailing wind and fetch of the UK climate?

Answer 21

Prevailing wind from the south west.
Large fetch over the Atlantic to reach the UK.

Question 22

Describe the process of rotational slumping.

Answer 22

Rain falls and it accumulates at the boundary between sand and clay which lubricates the boundary. The sand becomes saturated and will dramatically slump rotationally.

Question 23

What is the process of rock slides?

Answer 23

When rocks move down cliffs and slopes due to gravity and other factors such as saturation.

Question 24

What is the process of weathering?

Answer 24

This is the break down of rocks near the surface. There are 3 ways this can occur - mechanical, chemical and biological weathering.

Question 25

Describe the process of abrasion.

Answer 25

Eroded particles in the water scrape and rub against rock removing small bits.

Question 26

Describe the process of hydraulic action.

Answer 26

Waves crash against the rock and compresses the air into the cracks, putting pressure on the rocks. This happens over and over until the rock breaks off.

Question 27

Describe the process of attrition.

Answer 27

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 28

Describe the process of solution.

Answer 28

Minerals in the rock dissolve

Question 29

What are the 2 kinds of waves?

Answer 29

Destructive and constructive

Question 30

What are the characteristics of destructive waves?

Answer 30

Weak swash and strong backwash - likely to erode and shift big rocks

Question 31

What are the characteristics of constructive waves?

Answer 31

Strong swash and weak backwash - likely to shift small rocks

Question 32

What is deposition?

Answer 32

Deposition is when material is deposited by constructive waves and forms landscapes such as: beaches, spits and bars.

Question 33

What is solution?

Answer 33

Dissolved chemicals often derived from limestone or chalk.

Question 34

What is suspension?

Answer 34

Small particles carried within the water.

Question 35

What is saltation?

Answer 35

A hopping or bouncing motion of particles too heavy to be suspended.

Question 36

What is traction?

Answer 36

Large pebbles are rolled along the seabed.

Question 37

How are spits formed?

Answer 37

Longshore drift moves sediment along the coastline and a sudden change in the coastline causes a spit. The heaviest and largest materials are dropped first by the headland. Gradually smaller sediment is dropped and the spit grows.

Question 38

How does a spit form into a bar?

Answer 38

A bar is formed when a spit joins 2 headlands together. The bar cuts off the bay forming a lagoon.

Question 39

Describe how longshore drift moves sediment.

Answer 39

Backwash moves sediment down the beach at a right angle because of gravity. Swash moves sediment up the beach in the same direction as the wind. The sediment moves across the coastline.