Coasts: Coastal landscape development - Landforms and Landscapes of Coastal Erosion

Question 1

What are the 2 landforms of coastal erosion?

Answer 1

Cliffs and wave cut platforms

Cliff profile features

Question 2

What are the 3 factors affecting the development of cliffs and wave cut platforms?

Answer 2

Rock type
Wave energy
Coastal morphology

Question 3

Explain how wave cut platforms form.

Answer 3

When destructive waves break at the foot of a cliff their energy is concentrated onto a small area of the rock face between HWM and LWM.
Erosion undercuts the cliff forming a wave cut notch.
The overhanging cliff is subject to weathering and eventually collapses.
After successive collapses the cliff line will begin to retreat, forming a gently sloping wave cut platform at the base of the cliff.

Question 4

Which type of erosion is the most significant in forming wave cut notches?

Answer 4

Abrasion

Question 5

What angle are wave cut platforms at?

Answer 5

Less than 5 degrees

Question 6

Why do wave cut platforms not grow bigger than 500m?

Answer 6

As the platform grows the waves break further out to sea and their energy is dissipated before reaching the cliffs - forming a negative feedback loop

Question 7

How can wave-cut platforms become rough and jagged?

Answer 7

If the platform remains in the tidal zone it will be continually exposed to cycles of marine and sub-aerial processes, exploiting weaknesses in the rock surface.

Question 8

What features may form on wave cut platforms that remain in the tidal zone?

Answer 8

Rock pools and fissures

Question 9

Give an example of a wave cut platform in the UK.

Answer 9

Flamborough Head, North Yorkshire

Question 10

Give an example of a wave cut platform outside of the UK.

Answer 10

Muckross Head, Donegal, Ireland

Question 11

How long can wave-cut platforms take to form?

Answer 11

100s - 1000s of years

Question 12

Name 6 cliff profile features.

Answer 12

Geos
Caves
Blowholes
Arches
Stacks
Stumps

Question 13

How do geos form?

Answer 13

The sea will cut inland along a joint in a cliff, widening the crack to form a geo

Question 14

What is a geo?

Answer 14

A narrow, steep-sided inlet in a cliff

Question 15

How do caves form?

Answer 15

Hydraulic action exploits cracks in a cliffs, opening them up. If the cliff is under cut, the crack will grow into a cave by hydraulic action and abrasion.

Question 16

Where do caves often form and why?

Answer 16

Headlands as erosion is strongest here

Question 17

How do blowholes form?

Answer 17

Oncoming waves applied to the rear of a cave can enlarge joints in the cave roof and weaken the overlying rocks until they collapse.

Question 18

How do arches form?

Answer 18

Refraction around headlands causes caves on either side of the headland to extend backwards until they erode through the headland.

Question 19

How do stacks form?

Answer 19

As the cliff recedes and a wave cut platform develops, the unsupported roof of the arch will eventually collapse due to marine erosion from below and sub-aerial processes weakening the arch.

Question 20

What are stacks?

Answer 20

Isolated portions of rock standing above a wave cut platform.

Question 21

How do stumps form?

Answer 21

Stack bases are in the intertidal zone so are subject to erosion, forming a wave cut notch. Over time the sea will exploit the wave cut notch at the base of a stack eventually leading to its collapse.

Question 22

What will happen to a stump over time?

Answer 22

It will slowly be eroded to the level of the wave-cut platform.

Question 23

Give an example of cliff profile features in the UK.

Answer 23

Old Harry’s Rocks, Dorset

Question 24

Give an example of cliff profile features outside the UK.

Answer 24

The Twelve Apostles, Victoria, Australia

Question 25

What factors affect the development of cliff profile features?

Answer 25

Rock type

Nature of waves

Question 26

How long does the entire process of forming cliff profile features take?

Answer 26

100s - 1000s of years