1. Lesley Monk
Balfron High School
Session 2005/6

2. MARINE DEPOSITION PROCESSES.
The material eroded from the features discussed in slideshow 1 provides a lot of the material for the features in this slideshow!
These slide-shows are all on the Prepwork folder if you wish to copy any notes from them; we will not be stopping in class for you to do this.
Copy the text from the next two slides.

3. BEACHES
Beaches are a buffer zone between the waves and the coast. They usually lie between high and low tide marks, but storms can throw material up beyond high tide marks.

4. The main activity of constructive waves is to deposit pebbles, sand and mud to form a beach.
The sea sorts this material into different sizes according to its weight as it moves it about in the water.

5. LONGSHORE DRIFT
Splash zone
Backwash
direction
Swash direction
High tide mark
Intertidal zone
Low tide mark
On-shore winds make waves approach at an angle ( swash), but they go back down ( backwash) at right angles to the beach. What is the result of this process?

6. Read factzone 5 of the booklet
Read factzone 5 of the booklet. Make sure that you can explain how longshore drift works and draw a labelled diagram.
Answer the questions on the next slide in sentences, as usual.

7. Q1. Define the terms swash and backwash.
A. The swash is the wave motion up the beach away from the sea, and the backwash is the wave motion down to the sea again.
Q2. Why do the waves not travel up and down at the same angle?
A. An off-shore wind or sea current forces the waves onto the beach at an angle. Gravity makes them return at right angles to the sea.

8. Q3.What is the overall result of this action?
A. The material moves along the coastline in the direction of the wind/ current.
Q4.How do people attempt to stop this movement?
A.Structures called groynes are built at intervals along the beach to stop material travelling all along the coast. The material is periodically moved back to where it came from, usually by bulldozers.

9. How do Sand Spits form?
Longshore drift moves large amounts of material along the beach until there is a sudden change in the direction of the coastline. The sand keeps on moving in the original direction, even though there is not a coastline to follow.
The sea has to be relatively shallow and sheltered allowing the accumulation of sand usually beyond a headland.
Sometimes a curve develops if the on- shore wind changes direction.
Spits can become permanent if the prevailing wind picks up sand and blows it inland forming sand dunes.
Copy this text.

10. Hurst Spit in Hampshire is an example that you can quote in the exam.

11. On page 289 of WIDER WORLD there is a diagram to copy; fig 16.25
HURST SPIT, HAMPSHIRE

12. How Do Bars and Lagoons form?
A bar is a barrier of sand stretching right across a sheltered bay.
It usually stretches across the bay due to the absence of any large river that might wash it away.
It can cut off a lagoon to the landward side.
A lagoon is a body of brackish water- part salty, and part fresh. It often supports specialised plants and animals, and is protected as a nature reserve.
Copy this text.

13. This spit will become a bar if it reaches the other side of the estuary. Can you work out the direction of longshore drift?

14. If a bar links up with an off-shore island, it creates a tombolo
If a bar links up with an off-shore island, it creates a tombolo. Chesil Beach- one of the most famous bars in the UK has a tombolo called Portland Bill.
bar
tombolo
Chesil beach from Portland Bill; the shingle is 29kms long.

15. ORDNANCE SURVEY MAPWORK7
You need to be able to recognise coastal deposition landforms from a map.
To practice this skill, take a copy of the question sheet and the two O.S. maps and tackle the questions.
THEY ARE NOT ALL EASY !!

16. As you go through the next revision slide, for each feature mentioned, look back through your textbooks and this presentation. You are looking for named examples of as many features as possible.
Perhaps you could work in pairs to do this task!

17. You have now completed the deposition section .
You should be familiar with the following terms and be able to define and use them in your answers.
BEACH
BAY
BAR
SPIT
TOMBOLO
HEADLAND
SORTING
GROYNE
LONGSHORE DRIFT
LAGOON
SALT MARSH
SHINGLE
SWASH
BACKWASH
ON-SHORE WIND

18. REVISION TIME !
Erosion and deposition features
Now watch the video-
tape 36 number 3;
[stop after the narrator starts to talk about human intervention in coastal features- you will see the rest of the video when we learn about the case studies of coastal management in the Rural Land Resources Application ]