Contrasting Coastlines

Question 1

What are discordant coastlines?

Answer 1

When the rock layers are at right angles to the coastline

Question 2

What are concordant coastlines?

Answer 2

When the rock layers are parallel to the coastline

Question 3

What are joints

Answer 3

Small usually vertical cracks found in many rocks

Question 4

What are faults

Answer 4

Larger cracks caused by past tectonic movements

Question 5

What are constructive waves

Answer 5

Waves that build a beach (have a strong swash and weak backwash)

Question 6

What are destructive waves

Answer 6

Waves that erode the beach (weak swath and strong backwash)

Question 7

What is a headland

Answer 7

piece of land jutting out into the sea

Question 8

What is a bay

Answer 8

Broad coastal inlet often with a beach

Question 9

What is the formation of headlands and bays

Answer 9

• Headlands and bays happen at discordant coastlines
• soft rock is eroded away more quickly by hydraulic action than hard rock forming a bay
• the harder rock juts out to sea forming a headland
• eroded rock is deposited at bays making water there shallower
• the water near a headland is deeper

Question 10

What is the formation of a cove (Lulworth cove)

Answer 10

• water begins to erode the hard rock due to crack
• the hard rock doesn’t erode much because it’s resistant
• when water reaches soft rock it’s eroded faster across a larger area forming a cove

Question 11

What causes waves?

Answer 11

Wave energy depends on the fetch (distance over which the wind has blown), the strength of the wind and the length of time over which the wind has blown

Question 12

How is Old Harry’s Rock formed?

Answer 12

• The sea attacks lines of weakness (joints) causing the rock to expand
• As the crack erodes further a sea cave is formed
• if the cave is eroded right through the headland an arch is formed
• the arch will widen as the sea attacks it and weather wears it away leaving a stack
• the weather and sea continue to attack the stack leaving a stump

Question 13

Why is the erosion of cliffs greater in winter than in summer? (Exam question)

Answer 13

During winter there are more storms. This means that waves are likely to be destructive and cause the most erosion. This is because destructive waves have a strong backwash, which removes material from the beach. This along with its higher frequency means greater hydraulic action occurs, eroding the cliffs at a faster rate