This document discusses coastal landforms and sediment transport along coastlines. It explains that sediments move parallel to the shoreline through processes like longshore currents and longshore drift. Sediments are deposited when waves lose energy, with larger sediments deposited first in sheltered areas. Coastal landforms like cliffs, shore platforms, headlands, and bays form through erosion processes acting on rocks of varying resistance over time. Cliff retreat leads to the formation of shore platforms, while differential erosion of resistant and less resistant rock bands creates alternating headlands and bays along indented coastlines.

1. Chapter 1: Coasts
Chong Boon Secondary School
Pure Geography
Physical Geography

2. Lesson 5

3. Key thinking questions
• What affects the transport of sediments
on a coast?
• How does a piece of sediment move
along the coast?
• What are longshore currents?
• What is longshore drift?

4. Sediment transport
• Refers to the movement of sediments
along the beach
• Beach drift: zigzag movement of
sediments along the beach
• Sediments move up the beach at an
angle as swash
• Sediments move down the beach
perpendicularly as backwash

5. Sediment transport
• Longshore currents: ocean
currents flowing parallel to the
coastline
• Moves sediments along the
shore
• Combine effect of transportation
by longshore currents and
beach drift is longshore drift.

6. Sediment deposition
• Refers to the process where
sediments are let go and no longer
carried by the waves due to loss of
wave energy
• Usually larger sediments get
deposited first (WHY?)
• Sheltered coasts with calmer waters
have fine sediments
• Small bays tend to have coarser
sediments

7. Self
Evaluation
• Complete the timed exercise now.
• You have 10 minutes.

8. Group activity 1
• Using only a diagram, show how a sand
particle is moved along the beach.
• List and explain the four ways in which coastal
erosion can occur.
• With the suitable diagrams, compare
constructive waves and destructive waves
– 30 minutes, discuss and put down what your team
feels is correct.
– Point form.

9. Gallery Walk Time
• Please put up your presentations on the
given space.
• Let’s do a gallery walk.
• You are to award stars to the
presentations that you feel are the best.
• Each person has 2 stars only.
• You should not give both to the same
group.

10. Homework
• Take a detailed look at the
Investigation Task (pg 17)
• Read Pg 17to 29.

11. Lesson 6

12. Key thinking questions
• What are the landforms that are caused
by waves?
• What coastal landforms are linked and
related?
• Besides the force of water, what other
materials are used to form the coast?

13. Sediment deposition
• Refers to the process where sediments
are let go and no longer carried by the
waves due to loss of wave energy
• Usually larger sediments get deposited
first (WHY?)
• Sheltered coasts with calmer waters
have fine sediments
• Small bays tend to have coarser
sediments

14. Coastal features
• Various landforms and
features can be found at
coasts
• The types of features found
tend to be due to factors such
as type of waves, type of
rocks (geology), the location,
and human activities

15. Cliff and shore platforms
• Cliff: A steep or near-vertical
rock face found along coasts
• Shore platform (or wave-cut
platform): gently sloping
platform usually found at the
base of a cliff and submerged
during high tides

16. Cliff and shore platforms
• Due to hydraulic action and abrasion,
a joint or crack in the rocks may be
enlarged to form a notch, usually
found between the high and low tide
mark
• The notch may be further eroded and
enlarged to form a cave
• Further erosion and gravity eventually
causes the roof of the cave to
collapse

17. Cliff and shore platforms
• This results in the formation of a
steep rock face, or cliff
• With further erosion, undercutting
occurs at the base of the new cliff
face
• As the overhang collapses, the cliff
retreats inland
• The gentle slope at the base of the
cliff where previous cliffs used to be
is the shore platform

18. Headlands and bays
• Occurs due to the uneven rates
of erosion of different rock types
• Usually found in locations where
there are bands of alternating
resistant and less resistant
rocks
• What is an example of less
resistant rock?

19. Headlands and bays
• As the less resistant rocks are
more easily eroded, they give
rise to bays
• The resistant rocks will stand out
as headlands
• The formation of headlands and
bays gives an indented coastline

20. Homework
•Revise the entire set of
content we’ve covered so
far.
•Next lesson we will do a
mini test