coasts

Question 1

draw diagram of the formation of a headland/bay

Answer 1

draw diagram.

Question 2

Explain the formation of a headland/bay

Answer 2

1st) Headland and Bays are formed when bands of rocks are perpendicular to the coastline (this is called a discordant setting.)
2nd) Alternating bands of harder rocks (e.g. sandstone), and softer rocks (e.g. clay) leading to differential erosion.
3rd) This will be Hydraulic action (when parts of the cliff face break away when air is compressed into the cracks by incoming waves)
4th) and by Corrasion (when pebbles and rocks are hurled against the cliff face causing damage.)
5th) Deposition will take place in more ‘sheltered bays’ leading to the formation of beaches
6th) A named example is Swanage Bay.

Question 3

draw a diagram of the formation of a stack

Answer 3

draw diagram.

Question 4

explain the formation of a stack

Answer 4

1st) The initial setting is a headland of resistent rock (e.g. chalk or limestone.)
2nd) A natural point of weakness in the headland (a crack or vertical join) is widened by erosion.
3rd) This will be Hydraulic Action (where parts of the cliff face break away due to the air being compressed into the cracks by incoming waves.
4th) and by Corrasion (when pebbles and rocks are picked up by the waves and hurled against the cliff face causing damage.)
5th) A wave-cut notch develops at the base of the cliff (in the tidal zone) which through erosion develops into a cave due to continued erosion.
6th) Where erosion progresses through the headland completely, or when two caves back-to-back join to form an arch.
7th) Erosion and weathering (biological and freeze-thaw) make the roof of the arch unstable and it collapses due to the gravity pulling it down. The wasted debris is removed by the waves.
8th) Finally a stack or pillar is left to remain (e.g. Old Harry)

Question 5

draw a diagram of a cliff/wave-cut platform

Answer 5

draw diagram.

Question 6

Explain the formation of a cliff/wave-cut platform

Answer 6

1st) The original position of the coastline has a gently slopping shape.
2nd) Waves erode at the base of the developing cliff (in the tidal zone) creating a wave-cut notch.
3rd & 4th) This erosion will be caused by Hydraulic Action (when parts of the cliff face break away due to air being compressed into the cracks by incoming waves.)
5th & 6th) and by Corrasion (when pebbles and boulders are picked up by waves and hurled against the cliff face causing damage.
7th) The land being undercut, the rock above becomes unstable and collapses into the sea due to gravity
8th) Continued erosion in the land backwards causes a steeper cliff to develop.
9th) The flat area of rock in front of the cliff is called the ‘wave-cut platform’. Waves lose power and energy in this shallow area so slower retreat will occur as cliff becomes static.