headlands and bays

Question 1

What type of rocksare found in headlands and bays?

Answer 1

Alternating bands of harder rock which is more resistant to erosion eg limestone, and and softer rock which is less resistant to erosion eg clay

Question 2

What causes the softer rock to be eroded at a faster rate than the harder rock?

Answer 2

The process of differential erosion

Question 3

How is the rock eroded? (Processes)

Answer 3

• hydraulic action- which is when the sheer force of the waves crashing against the rock (cliff) erodes and breaks it down by getting into and widening small cracks in the rock
• corrasion- when the rock (cliff) is eroded by stones and pebbles, picked up by the sea, been thrown against it
• corrosion- the chemical erosion of the rock by acids in the sea water that wash minerals out of the rock, weakening them and eventually breaking them down

Question 4

What does differential erosion do?

Answer 4

Erode the softer rock eg clay which is less resistant to erosion at a faster rate than the harder rock eg limestone which is more resistant to erosion

Question 5

What does the hard rock do?

Answer 5

Juts out into the sea as headlands

Question 6

What does the softer rock do?

Answer 6

Forms bays between the headland in a discordant coastline

Question 7

Once formed, what type of waves are the headlands subject to?

Answer 7

higher energy destructive waves, and so the headlands become more vurnerable to erosion than before

Question 8

Once formed, what type of waves are the bays subject to?

Answer 8

lower energy constructive waves, that deposit rather than erode

Question 9

Why do bays receive lower energy constructive waves?

Answer 9

Because they are sheltered by the headlands

Question 10

Under the right conditions this process can start over and over again so..

Answer 10

coastlines change continuously over time

Question 11

EXPLAIN FULLY THE FORMATION OF HEADLANDS AND BAYS

Answer 11

On a coastline, where there are alternating bands of harder rock, which is more resistant to erosion eg limestone and softer rock which is less resistant to erosion eg clay, the coastline is liable to the process of differential erosion, where softer rock gets eroded at a much faster rate than harder rock.
The rock is eroded in three main ways
-hydraulic action, when the sheer force of the waves hitting off of the rock (cliff) causes it to erode. water is forced into small cracks, or the water forces air into the cracks, which breaks up the rock
-corrasion - when stones and pebbles picked up by the sea are thrown against the cliff causing the rock to erode
-corrosion- the chemical erosion of the rock by naturally occuring acids in the sea water. These acids dissolve the rock, wash away their minerals which weakens them and evetually breaks them down.
The harder, more resistant rock is not eroded as quickly by these processes and so juts out into the sea as headlands.
Once formed, because the headland sticks out it is subject to high energy destructive waves, which makes it more vurnerable to erosion than before
On the other hand, the softer rock is eroded quickly by these processes, and so forms a bay.
Once formed, because the bay is sheltered by the headland, it receives lower energy constructive waves, which deposit rather than erode.
This means, that under the right conditions the process will start over and over again, coastlines continuously change over time.
An example of headlands and bays can be found in Swanage, Dorset

Question 12

An example of headlands and bays

Answer 12

Swanage, Dorset