Living with the physical environmentSection C: Coasts

What you need to know for your examination:Wave types and characteristics.Coastal processes:•• weathering processes – mechanical, chemicalMass movement – sliding, slumping and rock fallsErosion – hydraulic power, abrasion and attritionTransportation – longshore driftDeposition – why sediment is deposited in coastal areas.How geological structure and rock type influence coastal forms.Characteristics and formation of landforms resulting from erosion– headlands and bays, cliffs and wave cut platforms, caves, arches and stacksCharacteristics and formation of landforms resulting from deposition– beaches, sand dunes, spits and bars

Wave types and characteristics.http://www.coolgeography.co.uk/GCSE/AQA/Coastal%20Zone/Processes/waves.htm

Click on the link above: What are waves?

http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/coastal_processes_rev1.shtmlClick on the link above: What 3 things influence the size and energy of a wave?

http://www.coolgeography.co.uk/GCSE/AQA/Coastal%20Zone/Processes/waves.htm

Put this information into the correct order. Use the diagram above to help you. This friction causes the orbit of the wave to become elliptical (egg shaped)

Waves start out at sea and have a circular orbit.

As waves approach the shore friction slows down the base of the wave, changing the shape of the orbit.

The elliptical orbit shape eventually leads to the top of the wave breaking over.

1. 2. 3. 4.

http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/coastal_processes_rev1.shtmlClick on the link above and answer these questions:What is swash?What is backwash?What is a constructive wave? Hint: Is swash or backwash stronger?

What is a destructive wave? Hint: Is swash or backwash stronger?

http://www.coolgeography.co.uk/GCSE/AQA/Coastal%20Zone/Processes/waves.htmClick on the link above and complete this table:Feature of a wave Description/diagramWave crestWave lengthWave heightWave trough

http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/coastal_processes_rev2.shtmlClick on the link above and use the diagrams and written information to complete this table:

Destructive ConstructiveWeather these waves are created in:Power/strength of the wavesAction of the waveSwash or backwash strongest?Description of the wave (wavelength and height)Diagram (copy from the website)

Weathering processes

http://www.bbc.co.uk/bitesize/ks3/science/environment_earth_universe/rock_cycle/revision/6/

Click on the link above and answer these questions:What is weathering?What is physical weathering? Also known as mechanical weathering.What is freeze-thaw weathering? Watch the animation to help you understand it.

Another example of physical (also known as mechanical) weathering is salt weathering. Put the statements into the correct order to explain how salt can wear away rocks:

Salt weathering:1.2.3.4.

In cracks and holes in the cliff, the water evaporates and leaves behind salt crystals.

Seawater contains salt and it gets into cracks in cliffs.

The growing crystals put pressure on the rocks and flakes of rock may eventually break off.

In cracks and holes in the cliff, these salt crystals grow and expand.

http://www.bbc.co.uk/bitesize/ks3/science/environment_earth_universe/rock_cycle/revision/7/

Click on the link above and answer these questions:

What is biological weathering?

http://www.bbc.co.uk/bitesize/ks3/science/environment_earth_universe/rock_cycle/revision/8/Click on the link above and answer these questions:What is chemical weathering?

MASS MOVEMENT

Complete the definition below using these words:gravity Soil downward mud

Mass movement is the ________________ movement of rock, _______ or __________ under the influence of ________________.

ROCK FALLS

Use the link to complete explain how rock falls occur:

http://www.bbc.co.uk/bitesize/higher/geography/physical/lithosphere/revision/8/

Explain how rock falls happen:

SLIDING

Rock slides (also known as landslides if it is land rather than rocks that slip down the slope)

Using the diagram above of a rock fall and the rock slide diagram below, describe the differences between a rockfall and a rock slide.

Hint look at the size of the rock and the angle of the bed rock.

One difference is:

Another difference is:

Rock slide: Rock fall:

Mudslide (also known as a mudflow)

Use this link to explain how a mudslide (or mudflow) occurs:

http://www.bbc.co.uk/bitesize/higher/geography/physical/lithosphere/revision/8/

Diagram of a mudslide (mudflow)

Explanation of how a mudslide (mudflow) happens:

SLUMPING

Using the diagram, organise these statements into the correct order in the table below.

The heavy saturated rock presses down on the cliff causing a curved slip plane to develop.

Rainwater soaks in to the porous sandstone. This rock becomes saturated as it cannot infiltrate the impermeable clay rock beneath it.

A section of the cliff face tears away at the top of the curved slip plane. Gravity pulls the slab of rock down to the beach. Loose material collects at the bottom as a toe.

Waves remove the toe and undercut the cliff’s base so that it becomes unstable so eventually slumps again along the new slip plane.

Repeated rainfall events put pressure on the cliff and a new slip plane develops.

Slumping

Slides take a fairly straight path down a cliff. A slump has a concave slope plane so material is rotated backwards into the cliff as it slips.

Glossary: Porous means water can soak through.Impermeable means water cannot soak through.Infiltrate – water soaking through something.Saturated – something that is soaked

1.2.3.4.5.

Coastal erosion

Use this link to help you match up the erosion process with the correct definition:http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/coastal_processes_rev3.shtml

Type of erosion

Definition

Hydraulic action Bits of rock and sand in waves grind down cliff surfaces like sandpaper.

Abrasion Waves smash rocks and pebbles on the shore into each other, and they break and become smoother.

Attrition Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.

Solution Acids contained in sea water will dissolve some types of rock such as chalk or limestone

Coastal transportation

Use the link to describe where material in the sea comes from:http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/coastal_processes_rev4.shtml

1. Eroded from ___________2. Transported by ___________________________ along the coastline.3. Brought inland from offshore by ______________ waves4. Carried to the coastline by ________________.

Longshore drift moves material along a coastline.

http://www.bbc.co.uk/bitesize/ks3/geography/physical_processes/coasts/revision/6/

Swash carries sediment up the beach at an angle.

This creates a zig-zag movement of sediment along the beach.

Waves approach the coast at an angle (the prevailing winds push them that way)

Backwash carries sediment down the beach with gravity – at right angles to the

Glossary: Porous means water can soak through.Impermeable means water cannot soak through.Infiltrate – water soaking through something.Saturated – something that is soaked

beach.

Click on the link above to help you put the statements above into the correct order to show how longshore drift moves material along a coastline.

1.

2.

3.

4.

How geological structure and rock type influence coastal forms

Coastal erosion: Cliffs, wave-cut platforms and notches:

One of the most common features of a coastline is a cliff. Cliffs are shaped through a combination of erosion and weathering - the breakdown of rocks caused by weather conditions.

Use this link to answer these two questions:http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/erosional_landforms_rev1.shtmlWhich types of rocks create gently sloping cliffs?

Why do these types of rocks create gently sloping cliffs?Which type of rock creates steep cliffs?Why does this types of rocks create steep cliffs?

Using the same link as above and the diagram below, organise the statements below into the correct order to explain how cliffs are eroded and moved back:

The notch increases in size causing the cliff to collapse.

Weather weakens the top of the cliff.

The backwash carries the rubble towards the sea forming a wave-cut platform.

The sea attacks the base of the cliff forming a wave-cut notch.

The process repeats and the cliff continues to retreat.

Correct order 1. 2. 3. 4. 5.

Coastal erosion: Headlands and bays:

Use this link to answer these questions:http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/erosional_landforms_rev2.shtml

When are headlands formed? What is a headland?What is a bay? What is a discordant coastline?What is a concordant coastline?

Useful diagram (this shows the land as though you are looking directly down on it from above):

Wave refraction Watch the animation and read the information so you can answer these questions:http://www.wiley.com/college/strahler/0471480533/animations/ch19_animations/animation2.html

1. What does the process of wave refraction to the shape of the wave?

2. What is most of the wave energy concentrated on?

3. What happens to wave energy in a bay? (look up the word in a dictionary if you don’t know what it means).

4. How does wave refraction form sea arches?

5. Why do waves in bays move more slowly?

Coastal erosion: Caves, arches, stacks and stumps: Use the following link to put these diagrams into order to show the formation of a stump:http://www.bbc.co.uk/bitesize/ks3/geography/physical_processes/coasts/revision/5/

Correct order to show how a coastal stump is formed:1. 2. 3. 4. 5.

http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/erosional_landforms_rev3.shtmlUse the link above to explain which erosion process helps to form caves.

Coastal deposition: beaches, spits, tombolos, bars and sand dunesUse following link to answer these questions: http://www.bbc.co.uk/schools/gcsebitesize/geography/coasts/depositional_landforms_rev1.shtmlWhat are beaches made up of?What type of waves help build up beaches?

Use the following link to answer these questions: http://www.bbc.co.uk/bitesize/ks3/geography/physical_processes/coasts/revision/6/

What is a spit?What process forms a spit?

Put these statements about spit formation into the correct order on the diagram below:Over time, the spit grows and develops a hook if wind direction changes further out.

Waves cannot get past a spit, which creates a sheltered area where silt is depostied and mud flats or salt marshes form.

Longshore drift moves material along the coastline.

A spit forms when the material is deposited.

Tombolos

Find slide 7: http://www.slideshare.net/MsGeo/formation-of-spits-tombolos-and-bars-10001053

1. 2.

3. 4.

Use the diagram and the information on slide 8 to explain how a tombolo is formed._________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Find slide 10: http://www.slideshare.net/MsGeo/formation-of-spits-tombolos-and-bars-10001053Use the diagram and the information on slide 11 to explain how a bar is formed._________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Sand dunesRead this information and answer the questions.Sand dunes are small ridges or hills of sand found at the top of a beach, above the usual maximum reach of the waves. They form from windblown sand that is initially deposited against an obstruction such as a bush, driftwood or rock. As more sand particles are deposited the dunes grow in size, forming rows at right angles to the prevailing wind direction. If vegetation, such as Marram Grass and Sand Couch, begins to grow on the dune its roots will help to bind the sand together and stabilise the dunes.Extra reading/pictures: http://www.geography-site.co.uk/pages/physical/coastal/dunes.html

What are sand dunes?How are sand dunes formed?How do sand dunes grow in size?

Sand dune succession

How do sand dunes develop?Use the words in the box below to complete the flow diagram explaining the development of sand dunes.windy vegetation water sandroots fertile obstacles wood

Embryo dunes form around ________________ such as pieces of _____________ or rocks.

These develop and become stabilised by vegetation to form fore dunes and tall yellow dunes. Marram grass is adapted to the __________, exposed conditions and has long _________

to find water. These roots help bind the ______________ together and stabilise the dunes.

In time, rotting ______________ adds organic matter to the sand making it more _______________. A much greater range of plants colonise these ‘back’ dunes.

Wind can form depressions in the sand called dune slacks, in which salty ponds may form if they erode down as far as the ________________ table.