1. LITHOSPHERE CORE COASTLINES 1 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. Origin of sand

2. LITHOSPHERE CORE COASTLINES 2 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.

3. LITHOSPHERE CORE COASTLINES Recap Watch the clip and take notes on longshore drift and the formation of the features shown. BBC - Learning Zone Class Clips - Depositional coastlines - Geography Video

4. LITHOSPHERE CORE COASTLINES 4 LONGSHORE DRIFT 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?Longshore driftLongshore drift Backwash direction Low tide mark Intertidal zone High tide mark Splash zone Swash direction

5. LITHOSPHERE CORE COASTLINES 5 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.

6. LITHOSPHERE CORE COASTLINES 6 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.

7. LITHOSPHERE CORE COASTLINES A beach profile 7

8. LITHOSPHERE CORE COASTLINES Types of beaches Bayhead beach – typically small, crescent shaped and form when sediment (usually sand and/or shingle) accumulates in a bay or cove between two protective headlands. Such protection means little change in input or output of sediment, so the shape remains. Lulworth Cove beach is an example.

9. LITHOSPHERE CORE COASTLINES Lateral beaches are usually longer, develop along straight coastlines and are aligned to the prevailing winds. There has to be a regular input of sediment to sustain these beaches due to longshore drift and erosion during stormy conditions.

10. LITHOSPHERE CORE COASTLINES 10

11. LITHOSPHERE CORE COASTLINES Sand dunes 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 wind blown sand that is initially deposited against an obstruction such as a bush, driftwood or rock. 11

12. LITHOSPHERE CORE COASTLINES BBC Education Scotland : CoastliNE : Physical : Features : Coastlines of Deposition 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. BBC - Learning Zone Class Clips - Sand dune formation and movement - the Dune of Pilat - Geography Video 12

13. LITHOSPHERE CORE COASTLINES Salt marsh Salt marshes occur in sheltered water areas, such as estuaries or behind spits. An estuary is a wide and shallow area of water where a river meets the sea; it contains a mixture of fresh and salt water called brackish, a result of the twice daily flooding by the tide. BBC - Learning Zone Class Clips - Sands of Forvie - marshes and mudflats - Geography Video 13

14. LITHOSPHERE CORE COASTLINES Sand dunes and salt marsh 14

15. LITHOSPHERE CORE COASTLINES Re-cap of coast so far: Q1) define the following terms: Swash Backwash Hydraulic action Attrition Abrasion Longshore drift Q2) explain how a cliff and wave cut platform is formed. 15

16. LITHOSPHERE CORE COASTLINES Re-cap of coast so far: Q3) explain how a spit, bar and tobolo are formed. Q4) explain how a cliff and wave cut platform is formed. 16

17. LITHOSPHERE CORE COASTLINES Re-cap of coast so far: Q5) explain how a cave, arch, stack and stump are formed. Q6) explain how a headlands and bays are formed. 17

18. LITHOSPHERE CORE COASTLINES Re-cap of coast so far: Q5) explain how a blowhole is formed. Q6) explain how a Geo is formed. 18

19. LITHOSPHERE CORE COASTLINES Re-cap of coast so far: Q7) explain how a Saltmarshes are formed. Q8) explain how a Geo is formed. 19

20. LITHOSPHERE CORE COASTLINES 20 ORDNANCE SURVEY MAPWORK 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 !! 7

21. LITHOSPHERE CORE COASTLINES 21 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!

22. LITHOSPHERE CORE COASTLINES 22 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