Features of erosion

Open Ended

1. Wassh  (the movement of water up the beach)

2. Nglo erohs rifdt (the movement of sediment along a beach)

3. Rosenio (the wearing away of rock)

4. Brasnioa (sand and pebbles are flung against the rock wearing it away like sandpaper)

5. Dyrhuacil niocta (the wave forces air into the cracks and over time the cracks become weaker)

6. Niotisopde (when the wave doesn’t have the energy to carry the sediment no longer)

7. Noitsoul (when the water dissolves the rock)

8. Porttransnioa (the movement of sediment)

9. Eahbc (an area of sand or shingle)

10. Tchfe (the length of water the wind has travelled)

​Lesson Objectives

​

To know what a landform is.

To explain how headlands and bays are formed.

To understand how differential erosion can be caused by differences in rock type.

To discover What discordant and concordant coastlines are and where they are found

Open Ended

What factors effect the rate of erosion?

​Landforms

​ Landforms are features of the landscape that have been formed or sculpted by the processes of:- erosion, transportation, deposition.

Some rocks are tougher than others. Rocks such as granite, limestone and chalk form impressive cliffs and headlands because they are much more resistant to erosion.  

Erosion

​

Softer rocks are much more easily eroded. They are more prone to collapse and slumping and therefore not as steep as cliffs made of more resistant rocks. Examples of soft rock include sands, clays and shale. This difference in the rate of erosion is known as differential erosion.

​Headland

​

A narrow piece of more resistant rock which projects outwards from the coast. It is surrounded by the sea on three sides.

​Bay

​ A crescent-shaped indentation in the coastline found between two headlands. It usually has a beach, which may be composed of sand or shingle.

​1.What is the name of the feature that juts out to sea?

2.What material is a bay made up of sand?

3.Which coastline do they form on?

4.Why does a headland stick out?

​1.What is the name of the feature that juts out to sea?

•Headland

2.What material is a bay made up of sand?

•Sand

3.Which coastline do they form on?

•Discordant

4.Why does a headland stick out?

•Rock is more resistant

Labelling

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bay

differential erosion

Soft rock e.g clay

hard rock e.g. limestone

headland

Open Ended

Have a look at this coastline. This is an area of the Dorset coast which includes Swanage which we will be looking at in more detail later. Consider the questions

​Here is the same coastline, with the geology (rock types) mapped

Open Ended

Why are these coastlines different?

Match

Match the following

• Rocks are parallel to the wave front and therefore rates of erosion are similar along the coastline.

• Differential erosion may occur, where bands of hard and soft rock outcrop at right angles to the sea.

• Soft rocks are eroded at a faster rate than hard rocks, this forms bays sheltered by headlands

Concordant

Discordant

Differential erosion

• Concordant

• Discordant

• Differential erosion

Labelling

Label the coastlines

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Discordant

Concordant

Categorize

Options (9)

Hard rock such as limestone jutting out into the sea

Near vertical cliff face

High-energy area affected by destructive waves

Crescent shaped indentation on the coastline

• Usually has a beach

Soft rock  such as sand and shingle

Low energy constructive waves

Organise these options into the right categories

Headlands

Bays

​Answers

Open Ended

Explain the formation of headlands and bays (6 marks)

​Mark Scheme

​Example Answer

​Headlands and bays are formed at discordant coastlines where there are alternating bands of hard and soft rock at 90’ to the coast. The waves hit the coastline and erode the softer rock such as clay and sand faster as it is less resistant to erosion. This creates a bay which is an indentation of the land. The headlands are hard rock made from chalk and limestone and they jut out as they are more resistant to erosion and therefore are eroded at a slower rate. This change in the coast line causes the wave to refract (bend) and therefore amplifies this process as the wave energy converges at the headland so when the waves reaches the bay the energy has dissipated and therefore beach material is deposited because the bay has calm waters.

​Lesson Objectives

​

To know what a landform is.

To explain how headlands and bays are formed.

To understand how differential erosion can be caused by differences in rock type.

To discover What discordant and concordant coastlines are and where they are found

​Lesson Objectives

​

To know what a landform is.

To explain how headlands and bays are formed.

To understand how differential erosion can be caused by differences in rock type.

To discover What discordant and concordant coastlines are and where they are found

Open Ended

Look at the photo and try and answer the questions

​Wavecut notch

Open Ended

Describe the features of this coastline

Open Ended

How do you think this feature is formed?

​Wave cut platform

​

A wave cut platform is an area of bedrock visible at the base of some cliffs. It slopes to the sea at a very gentle angle, and is generally only visible at low tide. 

​Wavecut notch and wavecut platform

Formation of a wave-cut (shore) platform

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Labelling

1) Between high and low tide, rocks are hurled at the base of the cliff

2) Sub-aerial processes such as freeze thaw weaken the top of the cliff

3) Erosion cannot occur under the water level so a wave-cut platform is left

4) The top of the cliff becomes unstable

5) This has created an undercut in the cliff, a wave-cut notch.

6)The cliff has now retreated but erosion will continue.

7)The cliff will collapse providing more material for attrition and corrasion at the base of the cliff

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3

1

5

7

2

4

6

Labelling

Explain the formation of a wave cut platform

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5

1

2

4

3

Open Ended

Explain the formation of a wave-cut platform (6 marks)

Structure of answer

1. Describe what a wave-cut platform is

2. Use key terms such as abrasion, hydraulic action (explain what these mean), undercut, cliff retreat, high tide, low tide, unsupported, wave-cut notch

​Example Answer

​

A wave cut platform is an area of bedrock visible at the base of some cliffs. It slopes to the sea at a very gentle angle, and is generally only visible at low tide. 

The cliff line used to protrude out to sea to where the wave-cut platform extends to now. It is created through processes of erosion at the base of the cliff between the areas of high tide and low tide. In this area the waves attack and erode it away through processes of abrasion which is the rubbing of rocks against the cliff and hydraulic action which is the force of water and air into the cracks which increases the pressure and is released in mini explosions. This causes the rock to wear away and form an indentation at the base of the cliff. This is called a wave-cut notch. The process continues and the wave-cut notch widens. The weight of the rock above the wave-cut notch is unsupported and becomes weaker and eventually falls into the sea. This process continues to happen leading to the cliff retreated and leaves a wave-cut platform visible at low tide.

Open Ended

Open Ended

What does this story have to do with coastal landforms?

Open Ended

Describe and explain the formation of caves, arches, stacks and stumps

Labelling

Label the features of erosion

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cave

arch

stack

headland

stump

wavecut platform

​Homework