1. Coastal Processes and Landforms
Large percentage of world’s population lives near the coast
Insert cover image for Chapter 20 (p. 556)

2. 20.1 The Coastal Zone Shoreline Sea Level Coastal zone
Average position of shoreline
Coastal zone
Nearshore zone
Breaker zone
Surf zone
Swash zone (backwash)
Offshore zone
Insert Figure 20.1

3. 20.2 Origin and Nature of Waves
Wave crests
Wave troughs
Wave height
Wavelength
Wave steepness
Wave period
Tides
Tsunamis
Wind waves
Insert Figure 20.2

4. 20.2 Origin and Nature of Waves
Tides
Gravitational pull of the moon and sun is the force that causes tides
Moon has a stronger pull
Centrifugal force
Tidal range
Difference in sea level between high and low tide
Insert Figure 20.3

5. 20.2 Origin and Nature of Waves
Spring tide
Neap tide
Q: How many spring tides and neap tides occur each month?
Insert Figure 20.4

6. 20.2 Origin and Nature of Waves
Tides
Semidiurnal tide
Diurnal tide
Mixed tide
Q: What is the tidal pattern on the coastal area nearest where you live?
Insert Figure 20.5

7. 20.2 Origin and Nature of Waves
Tidal range varies due to:
Shape of coastline
Water depth
Access to open ocean
Submarine topography
Largest tidal range (Bay of Fundy, Canada)
Insert Figure 20.6

8. 20.2 Origin and Nature of Waves
Tsunamis
Long-wavelength waves that form when a large mass of water displaced upward of downward by:
Earthquakes
Volcanic eruptions
Landslide
December, 2004 Indonesia earthquake and tsunami
Insert Image on p. 563 (Indonesia, 2004)

9. 20.2 Origin and Nature of Waves
Wind Waves
Most waves on surface of standing body of water created by wind
Frictional drag and pressures cause irregularities in the water surface
Waves can travel thousands of miles
3 Factors determine height of wind waves
Wind velocity
Duration of wind
Fetch

10. 20.2 Origin and Nature of Waves
Waves are traveling forms
Deep-water
Wave base
Insert Figure 20.7

11. 20.2 Origin and Nature of Waves
Why don’t the waves break in deeper water?
Insert Figure 20.8

12. True or False Another word for shore is beach.
The backshore is never covered by water.
The foreshore encompasses the mean low tide level.
4. Tides and tsunamis are caused by the same process
5. The top of the wave is called the crest.
6.Wave depth is critical in determining when it breaks.

13. 20.3 Breaking Waves Rip currents
Relatively narrow zones of strong, offshore-flowing water
Q: Why are these currents a hazard to swimmers?
Insert Figure 20.9

14. 20.4 Wave refraction and Littoral drifting
Bending of a wave in map view as it approaches a shoreline
Q: How will this coastline change over a long period of time?
Insert Figure 20.10

15. 20.4 Wave refraction and Littoral drifting
Coastlines tend to straighten over time
Q: What happens to sediment eroded from the headlands?
Insert Figure 20.11

16. 20.4 Wave refraction and Littoral drifting
Not all waves refract completely before they break
Littoral drifting
Incomplete refraction produces sediment transport in the coastal zone
Insert Figure 20.12

17. 20.4 Wave refraction and Littoral drifting
When a wave crest approaches a straight, gently sloping shoreline at a large angle, it interacts with the bottom and starts to slow down
Beach drifting
Longshore current
Longshore drifting
Insert Figure 20.13

18. 20.5 Coastal Erosion Key Terms Coastal Erosional Landforms Corrosion
Hydraulic action
Abrasion
Coastal Erosional Landforms
Coasts of high relief are dominated by erosion
Sea cliffs (or lake cliffs)
Insert Figure and 20.15a

19. 20.5 Coastal Erosion Coastal Erosional Landforms Notch Cobble beach
Sea caves
Insert Figure 20.15b and 20.15c

20. 20.5 Coastal Erosion Coastal Erosional Landforms Sea arches Sea stack
Insert Figure 20.15d and 20.15e

21. 20.5 Coastal Erosion Coastal Erosional Landforms Abrasion platform
Marine terraces
Insert Figure and 20.17

22. 20.6 Coastal Deposition Coastal Deposition
Sediments accumulate where wave energy is low
3 principal sources of coastal sediment:
Streams
Delta
Estuary
Coastal cliff erosion
Offshore sources

23. 20.6 Coastal Deposition Coastal Depositional Landforms Beach
Most common form
Wave-deposited feature
Sandy beach
Cobble beach
Insert Figure 20.18

24. 20.6 Coastal Deposition Coastal Depositional Landforms
Middle latitudes beaches are generally narrower, steeper and composed of coarser material in winter compared to summer
Longshore bar
Insert Figure 20.19

25. 20.6 Coastal Deposition Coastal Depositional Landforms Spits Tombolo
Insert Figure and 20.21a and 20.21b

26. 20.6 Coastal Deposition Coastal Depositional Landforms Barrier beaches
Lagoons
Barrier spit
Barrier islands
Insert Figure 20.21c and 20.22

27. 20.6 Coastal Deposition Coastal Depositional Landforms Barrier Islands
Locations: Atlantic (Cape Hatteras) and gulf coasts
Change drastically with severe storms
Insert Figure 20.23

28. 20.6 Coastal Deposition Coastal Depositional Landforms Beach systems
Equilibrium when input and output of sediment are equal
Groin
Human made obstruction of longshore current (increases size of some beaches)
Insert Figure 20.24

29. 20.7 Types of Coasts
Coastal Classification is based on plate tectonics
Passive-margin
Low relief and broad coastal plain
Continental shelves
e.g. East Coast
Active-margin
Insert Figure and 20.26

30. 20.7 Types of Coasts Coastal Classification Active-margin
High relief and narrow coastal plain
e.g. West Coast of U.S. along Pacific Ocean
Insert Figure 20.27

31. 20.7 Types of Coasts Coastal Classification Regional scale
Coastlines of emergence
Water level has fallen or the land has risen
Best developed along active-margin coasts (e.g. west coast of U.S)
Insert Figure 20.28

32. 20.7 Types of Coasts Coastal Classification Regional scale
Coastlines of submergence
Many features of the former shore are present
2 types of submerged coastlines
Rias coasts
Fjord coasts
Insert Figure 20.29

33. 20.7 Types of Coasts Fjord coasts Highly irregular
Deep, steep sided arms
Locations: Norway, Alaska, Chile, and Canada
Insert Figure 20.30

34. 20.7 Types of Coasts Another Regional classification system of coasts
Primary coastline
Erosion and deposition dominant
Result from rapid changes in coastline
Secondary coastline
Formed by waves and aquatic organisms
Insert Figure and 20.32

35. 20.8 Islands and Coral Reefs
Three basic ocean types of islands
Continental
Geologically apart of continent
Examples: Greenland, Great Britain, New Guinea, and Borneo
Oceanic
Atolls

36. 20.8 Islands and Coral Reefs
Oceanic
Volcanoes that rise from deep ocean floor
Along trenches: Aleutians, Tonga, Marianas
Along mid-ocean ridges: Iceland, Azores
Along chains: Hawaiian islands
Insert Figure 20.33

37. 20.8 Islands and Coral Reefs
Atoll
Island consisting of a ring of coral reefs
Grown up from a subsiding volcanic island
Encircle a central lagoon
Insert Figure 20.34

38. 20.8 Islands and Coral Reefs
Shallow, wave-resistant structures
Remains of tiny sea animals (skeleton of calcium carbonate)
Types of Reefs
Fringing reef
Barrier reef
Challenge for human habitation
Insert Figure 20.35