This document discusses different coastal landforms produced by coastal processes. It describes (A) cliffed coasts formed by erosion, including cliff and shore platforms, headlands and bays, and caves, arches and stacks. It also describes (B) depositional coasts, including beaches formed from sediment deposition, and spits and tombolos formed from longshore drift. Key coastal processes that form these landforms include abrasion, hydraulic action, erosion, deposition, wave refraction and longshore drift. The document provides detailed explanations and examples of each landform's formation through the effects of coastal erosion and deposition over time.

1. Landforms Produced by
Coastal Processes
CHAPTER 7: COASTS
Platja D'Aro, Girona, Spain

2. Krabi Province, Thailand

3. Algarve, Portugal

4. Different Coastal Landforms
— (A) Cliffed coasts (Erosion):
— (i) Cliff & shore platforms
— (ii) Headlands and bays
— (iii) Caves, arches and stacks (linked to refraction)
— (B) Depositional coasts:
— (i) Beaches
— (ii) Spits & tombolos (linked to Longshore Drift)

5. Cliffed Coasts (Erosion)
(i) Cliff & shore platforms
(ii) Headlands and bays
(iii) Caves, arches and
stacks

6. Shore Platform
Cliff
(Ai) Cliff & Shore Platform 20

7. (Ai) Cliff & Shore Platform – Formation
— Initially, when waves repeatedly pound against a rocky
coast, it weakens the rocks causing lines of weakness to
form in the rock face.
— (a) Over time, the waves
erode the coast to cut a
notch along the lines of
weakness – HOW?
20

8. Recall: coastal erosional processes
— Corrasion /Abrasion*
— The waves throw rock particles at the coast,
eroding the cliff face away.
— Attrition
— Rocks and pebbles collide with each other.
— Solution / Corrosion
— Acids contained in sea water will slowly dissolve rock
minerals.
— Hydraulic action*
— The force of the waves forces rocks apart.
15

9. (Ai) Cliff & Shore Platform – Formation
— (b)Then, the notch may be further eroded and
deepened to form a cave.
— A cave is a hollow
space that is bigger
than a notch.
20

10. (Ai) Cliff & Shore Platform – Formation
20
— (c)The overhanging part of the notch or cave
eventually collapses with repeated pounding of the
waves.
— The part of the coast
that is left forms a
cliff.

11. (Ai) Cliff & Shore Platform – Formation
— (d)As the cliff continues to be eroded by waves, it
retreats inland.
— Over time, a gently
sloping or flat surface
known as a
shore platform
forms at the base of
the cliff.
20

12. (Ai) Cliff & Shore Platform – Main features

13. (Aii) Headlands and Bays
Navagio Beach, Greece
20

14. INITIAL STAGES:
• Some coasts are made up of alternate bands of rocks with
different resistance to erosion.
• The less resistant rocks (eg. chalk)
erode faster compared to the
more resistant rocks (eg. granite).
(Aii) Headlands and Bays – Formation
22

15. DEVELOPED STAGES:
• The different rates of erosion of the rocks along a coast
produce an uneven coastline.
• Being more susceptible to erosion,
the less resistant areas of rocks
curve inwards as they get eroded
away by the waves à forms bays.
• The areas made up of more
resistant rocks will protrude out
from coastline à forms headlands
which extend into the sea.
(Aii) Headlands and Bays – Formation

16. (Aii) Headlands and Bays
Flamborough Head, on the
Yorkshire Coast of England
20

17. DEVELOPED STAGES:
— When waves approach the coast in a parallel manner, their
energy is concentrated on the headlands because the
waves bend (recall:wave refraction) as they approach the
protruding headlands.
— The bending of the
waves is due to some
waves slowing down
as they reach the
shallower water in
front of the headlands.
(Aii) Headlands and Bays – Formation
22

18. LATER STAGES:
— Over time, with the continuous erosion of the headland
and deposition at the bay, the coastline may straighten.
— Differential rates of erosion between the resistant and
less resistant rocks
will then result in
the formation of
headlands and bays
again.
(Aii) Headlands and Bays – Formation
22

19. (Aii) Headlands and Bays – Main Features
Alternate
bands
Different
rate
of
erosion
Deposition
Refraction

20. Ladram Bay in East Devon, British isles
(Aiii) Caves, Arches and Stacks

21. — Within headlands, some rocks may be less
resistant to erosion than other rocks.
— The less resistant parts will be eroded more
quickly (recall:coastal erosional processes).
(Aiii) Caves, Arches and Stacks 24

22. — (a)Waves attack lines of weaknesses (eg joints
and faults) at the base of the headland and
undercut it.
— This prolonged
undercutting
hollows out
the base area,
forming a cave.
(Aiii) Caves, Arches and Stacks - Formation
24

23. — (b)As caves develop on each side of the
headland, erosion may eventually join caves
together,
forming an
opening at the
base of the
headland called
arch.
(Aiii) Caves, Arches and Stacks - Formation
24

24. (Aiii) Caves, Arches and Stacks - Formation
Punta de Arucas
Arch Cave
Cave

25. — (c) Over time, the roof of the arch may
collapse to form a stack (a pillar of rock in
the sea after the arch collapses).
(Aiii) Caves, Arches and Stacks - Formation
24

26. Krabi, Thailand
(Aiii) Caves, Arches and Stacks

27. (Aiii) Caves, Arches and Stacks - Formation
24
— (d)The stack may be further eroded by waves,
causing some portions of it to collapse,
forming stumps.

28. (A) Cliffed Coasts – Recap
Putting all the features and landforms caused by erosion:
(Arch)
(Shore
pla.orm)
Undercut
Collapse
Hollow
out
Wave
erosion
Lines
of
weakness

29. Depositional
Coasts
(i) Beaches
(ii) Spits &
tombolos
Whitehaven Beach, Australia

30. — A beach is a zone of sediment deposition.
— Composition and size of beach materials vary greatly:
— Beaches are usually formed from loose sand, gravel, pebbles,
broken shells and corals, or a mixture of these materials.
— Source of beach materials affects the composition of beach
materials:
— Beach material may come from eroded cliffs, river deposits
and sediments carried by waves.
— The slope of the beach:
— Determined by grain size (finer grain size à gentle gradient;
coarser grains à steeper gradient.)
(Bi) Beaches 25

31. (Bi) Beaches
Horseshoe Bay, Bermuda

32. (Bi) Beaches
Glass Beach, Fort Bragg, California

33. (Bi) Beaches
One’uli Beach, Maui, Hawaii, USA

34. — Beaches are constantly changing as their shapes
and sizes are affected daily by waves, tides and
currents.
— During calm weather, constructive waves can
help to deposit materials on the beach and build it
up further.
— During coastal storms, strong waves
(destructive waves) will remove materials from
the beach, eroding it away.
25(Bi) Beaches

35. (Bii) Spits and Tombolo 28

36. (Bii) Spits
Farewell Spit, New Zealand (16 miles long!)

37. (Bii) Spits 28
— A spit is a long, narrow ridge of sand or pebbles
with one end attached to the land.
— It is formed by
longshore
drift.
Golden Horn or Zlatni Rat Beach,
Bol, Brac Island, Croatia

38. Recap: SedimentTransport – Longshore Drift
16

39. (Bii) Spits – Formation 28
1
1. Direction of prevailing
winds blowing at an
angle to the coastline.

40. (Bii) Spits – Formation 28
2
2. Longshore drift moves
materials along the
coastline.

41. (Bii) Spits – Formation 28
3
3. Longshore drift transports
beach materials in same
direction as prevailing
winds.

42. (Bii) Spits – Formation 28
4
4. This deposition will cause
a sand bank to build up,
called a spit.

43. (Bii) Spits – Formation 28
4
4. Overtime, a long, narrow
ridge of sand with one end
attached to main land and
the other extending to the
open sea will be formed.

44. (Bii) Spits – Formation 28
5
5. This leads to further
deposition and causes the
marshland to form.

45. (Bii) Spits
Błękitna
Laguna

46. (Bii) Spits – Formation 28
6
6. Wave refraction or
changes in wind direction
for a prolonged time

47. (Bii) Spits – Formation 28
7
7. can cause the free end
of the spit to curve,
forming a hooked spit.

48. (Bii) Spits – Formation
Fraser Island, Australia
(largest sand island in the world)
Lagoon

49. (Bii) Tombolo – Formation 28
Spit grown out from the
mainland and joined to an
island creating a tombolo.

50. (Bii) Tombolo 28
Tombolo, California

51. (Bii) Spits and Tombolo – Recap 28
Wave
refraction
Hooked
Change
in
wind
direction
Deposition
Longshore
drift
Prevailing
winds
Extend
from
land

52. Krabi Island, Thailand

53. Algarve, Portugal

54. Activity Time!
1. Choose your favorite COASTAL FEATURE / LANDFORM.
2. With your partner, draw a sketch of its formation process.
• What are they key features?
• What might it look like before?
• What coastal processes operated on it?
• What might it look like in the future?
3. After sketching, explain how and why did the landform
transform into what it looks like today.
• Remember the key geographical terms that are used to
explain its formation.
• What other key features/concepts can you bring in?