EQ2 - 4.3

Question 1

What is the rock type like on a concordant coastline?

Answer 1

The rock type on a concordant coastline consists of only one rock type (hard) that is parallel to, and consistent throughout the whole of its length.

Question 2

What is the rock type like on a discordant coastline?

Answer 2

The rock type on a discordant coastline consists of differing bands of rock types (hard and soft) that run perpendicular to the coast.

Question 3

What features are found on a discordant coast?

Answer 3

Landforms such as headlands and bays are formed due to the differing resistance to erosion of the varying rock types (hard and soft). The hard rock types create headlands whilst the soft rock types create bays.

Question 4

What is an example of both concordant and discordant coastlines?

Answer 4

The Isle of Purbeck in Dorset. The discordant coastline has been formed into Studland Bay, Ballard Point, Swanage Bay and Durlston Head.

Question 5

What are joints and faults?

Answer 5

Joints and faults are types of natural weaknesses in rocks which influence coastal erosion. Joints are small, usually vertical, cracks found in many rocks. Faults are larger cracks caused by past tectonic movements, where rocks have moved.

Question 6

What is the difference between hard/soft rock?

Answer 6

Hard rocks such as limestone and chalk are more resistant to erosion and recede slower than softer rocks such as sandstone and gravel which are less resistant to erosion and recede faster.

Question 7

What are the characteristics of headlands and bays?

Answer 7

Hard rock types (limestone and chalk) form headlands due to their more resistance to erosion whilst soft rock types (sandstone and gravel) form bays as they have less resistance to erosion and recede more further back. High energy waves crash into the headlands and low energy waves are found in the bays.

Question 8

How are headlands and bays formed?

Answer 8

Headlands and bays are formed when high energy waves attack a discordant coast, which has alternating bands of rock types. Harder rocks like limestone and chalk are more resistant to erosion and so recede less faster than softer rocks like sandstone and gravel which recede further back to create bays, leaving a section of land out to sea called headlands.

Question 9

What are the characteristics of wave-cut platforms?

Answer 9

A sloping rocky platform is left behind at the base of the sea cliff and is exposed at low tide.

Question 10

How are wave-cut platforms formed?

Answer 10

Cliffs are attacked by hydraulic power and corrosion. The powerful waves and the load thrown against the cliff creates a wave-cut notch. Eventually the cliff collapses under gravity. During high tide, the waves crash into the side of the cliff picking up the fallen rock debris and retreat along with it as backwash, eroding the wave-cut platform through abrasion. The swash carries the debris of the fallen rocks advances, eroding the platform through abrasion. This process repeats until the floor is smooth and polished.

Question 11

What three factors affect wave energy?

Answer 11

Wind speed, amount of time the wind blows and fetch (uninterrupted distance over the sea for which the wind blows).

Question 12

What are the characteristics of a destructive wave?

Answer 12

Destructive waves have a strong backwash but weak swash, meaning that sediment is taken away from the beach. The waves are steep and are tall in wave length as well as having a high frequency.

Question 13

How is an arch formed?

Answer 13

Hydraulic action forces its way into cracks of the cliff face, making the crack bigger and eventually into a cave. If the cave is formed into a headland, it may break through to the other side forming an arch?

Question 14

What is freeze-thaw weathering?

Answer 14

Cold weather freezes the water inside cracks. The frozen water increases in size by 9%, putting pressure on the cracks and expanding. When the ice thaws it contracts and releases pressure. This happens over a long period of time, constantly changing pressure.

Question 15

What is chemical weathering?

Answer 15

Rainwater is slightly acidic, containing carbon dioxide, making it a weak carbonic acid. When the rain falls into the side of the cliff the carbonic acid reacts with the rock, which contains calcium carbonate (Carboniferous limestone), dissolving the rock.

Question 16

What is biological weathering?

Answer 16

Vegetation and plants that grow on the cliff side dig their roots down into the rock, wearing the joints within the cliff and its structure. Animals such as rabbits dig burrows and holes within the cliff, also weakening the rock and cracks in the cliff.

Question 17

What is hydraulic action?

Answer 17

Hydraulic action is the power and force of waves and air being forced into cracks in the rock. The pressure increases and expands, causing the rock to chip off and the crack to get bigger.

Question 18

What is abrasion?

Answer 18

Abrasion is when rocks are picked up by waves and thrown or rubbed against the cliff. This action wears away the rock and it is gradually removed.

Question 19

What is solution?

Answer 19

Solution is when the sea becomes slightly acidic, caused by the vegetation near the cliffs. This process dissolves rocks such as limestone and chalk.

Question 20

What is attrition?

Answer 20

Attrition is the process where rocks that are held within waves smash into each other. Gradually, the rocks become smaller through time.

Question 21

What is traction?

Answer 21

Pebbles and larger sediment are rolled along the sea bed.

Question 22

What is saltation?

Answer 22

Load is bounced along the sea bed, eg small pieces of shingle or large sand grains. Currents cannot keep the larger and heavier sediment afloat for long periods.

Question 23

What is suspension?

Answer 23

Small particles are carried in water, eg silts and clays, which can make the water look cloudy.

Question 24

What is solution?

Answer 24

Minerals are dissolved in sea water and carried in solution. The load is not visible. Load can come from cliffs made from chalk or limestone.

Question 25

How does long-shore drift work?

Answer 25

Waves approach the beach at the same angle as the prevailing wind direction. Swash picks up sediment at an angle and moves it along the coastline Kinetic energy in the waves is lost and so backwash carries the sediment down to the shore due to gravity. The next wave picks up the sediment and this process repeats itself.

Question 26

How do spits form?

Answer 26

Longshore drift occurs on a coastline and move along sediment until there is a sudden change of coastline. Large material is dropped off by the headland and the sheltered area has deposition that occurs. Smaller sediment is dropped off and the spit grows. A secondary LSD occurs creating a re-curved end. Waves do not go behind spit and water is low-energy. Deposition creates salt marshes and ecosystems.

Question 27

What are the characteristics of a spit?

Answer 27

A spit is a long and thin landform made up of sand and mud - and where mud has settled, grass grows. The land itself has a curved end and is flat. The waters that surround the spit are shallow. An example is Spurn head.

Question 28

How do beaches form?

Answer 28

Sand is a result from eroded cliffs or headlands caused by high energy waves. Waves will approach the beach at the same angle as the dominant wind direction. When the waves reach the shore, the swash will pick up sediment and will move it along the beach length. The next incoming waves will repeat this process, depositing sediment, forming a beach - this is long-shore drift.