1. Sitges, Barcelona

2. What's expected for today
By the end of this lesson, you should be able to:
Explain how headlands and bays are formed with the help of well-labelled diagrams
Draw clear diagrams in boxes with:
Labels
Title

3. v a r y ing r e s i s t a n c e to erosion.
Textbook p. 144
Headlands and bays
Headlands and bays form along a coast that is made up of bands of rock with
v a r y ing r e s i s t a n c e to erosion.
This means that, the rate at which a coast is eroded depends partly on rock resistance.

4. Less resistant rock → the faster/slower it takes for waves to erode it
Textbook p. 144
Headlands and bays
More resistance rock → the faster/slower it takes for waves to erode it
Less resistant rock → the faster/slower it takes for waves to erode it

5. 1.3 Formation
Wave energy is concentrated at the headlands because the waves bend as they approach the protruding headlands.
This is due to the waves slowing down as they reach the shallower waters in front of the headlands while other waves not affected by the headlands continue ahead at the same speed. [1]

6. 1.3 Formation
different rate of erosion of rocks along the coast produces an uneven coastline
- less resistant rocks curve inwards, forming bays (Y)
- while the more resistant rocks will protrude out from the coastline, forming headlands (X)

7. Textbook p. 144
1.1 Some specifics
Granite and basalt are examples of more resistant rock.

8. Textbook p. 144
1.1 Some specifics
Chalk, sandstone, and shale examples of less resistant rocks.

9. Textbook p. 144
1.1 Some specifics
What are some of the places where headlands and bays can be found?
This is Homework Part 1: due tomorrow (April 3, Tuesday).

10. Textbook p. 145
1.2 Wave refraction
Wave refraction refers to the bending of waves because of differences in wave speeds.

11. Textbook p. 145
1.2 Wave refraction
Waves bend and slow down as they approach the protruding headlands.
Because they encounter friction with the increasingly shallow seabeds in front of these headlands

12. Textbook p. 145
1.2 Wave refraction
Wave refraction causes headlands to be the focus of wave energy and thus the focus of erosion.
Wave energy is weakened along the wider stretches in the bays, so waves deposit sediments at bays.

13. Textbook p. 144
1.3 Formation
Bay
Less resistant rock
At a coast where resistant rocks alternate with less resistant rocks,
the less resistant rocks are eroded at a faster rate than the resistant rocks.
More resistant rock
Headland
More resistant rock
Headland
Figure 1: Formation of headlands and bays

14. Textbook p. 144
1.3 Formation
The different rates of erosion along the coast produces an uneven coastline.

15. 1.3 Formation The less resistant rocks curve inwards, forming bays,
Textbook p. 144
1.3 Formation
The less resistant rocks curve inwards, forming bays,
while the more resistant rocks protrude from the coastline, forming headlands.

16. Homework
Part 1
Complete asterisked (*) question under 1.2 Some specifics
Part 2
Read textbook pages for tomorrow's lesson on beaches, spits and tombolos.

17. Looking back and ahead... 1. Coastal processes Erosion ✔ Deposition ✔
Longshore drift ✔
2. Coastal landforms
Cliff & shore platform ✔
Headland and bay ✔
Beach
Spit
Tombolo
3. Coastal engineering

18. What's expected for today
By the end of this lesson, you should be able to:
Explain how a coastal SPIT is form with the help of well-labelled diagrams
Predict what a spit would turn into if there is an offshore island nearby - TOMBOLO
Draw clear diagrams in boxes with:
Labels
Title

19. Depositional Landforms
In addition to shore platforms there are three other types of depositional landforms.
Beach
Tombolo
Spit

20. Beach
A beach is the result of constructive waves depositing material on the coast.
Swash is stronger than backwash
Waves have energy to bring material upshore but not back into the sea

21. The coarser the sediment, the steeper the beach gradient
Pebble Beach, California

22. The finer the sediment, the gentler the beach gradient
Moonlight Cove, California

23. Tombolo

24. Homework
Complete Worksheet _____ in the Workbook.