1. Mr. Russo Beaumont High School
Ch 9 Notes
Mr. Russo
Beaumont High School

2. Ch 9 Vocab Matrix (Pg 45) Divergent boundary Subduction Zone
Convergent boundary
Trench
Transform fault boundary
Continental Volcanic Arc
Oceanic Ridge
Volcanic Island Arc
Rift Valley
Paleomagnetism
Seafloor Spreading
Hot Spot

3. Objective: Ch 9.1 Pg 47
We will be able to describe the 4 pieces of evidence for the theory of continental drift.

4. Continental Drift
Continental Drift – The continents had once been joined to form a single supercontinent
Proposed by Alfred Wegner

5. Pangaea Continents broke apart and drifted to their current position
Pangaea – The supercontinent (All Land)
Continents broke apart and drifted to their current position

6. What evidence supports continental Drift?
Continental Puzzle – Continents appear to form a puzzle that can be put together

8. What evidence supports continental Drift?
Matching Fossils – Several of the same types of fossils on different landmasses

9. What evidence supports continental Drift?
Rock Types and Structures – Mountain belts that end on one coastline seem to reappear on a landmass across the ocean

10. What evidence supports continental Drift?
Ancient Climates – Found evidence of glacial ice in countries that shouldn’t have any glaciers

12. Objective

13. Ch 9.2 What is the theory of plate tectonics?
The upper mantle and the crust act like a strong rigid layer.
This layer is called the lithosphere

14. The lithosphere lies on top of the weaker mantle called the ASTHENOSPHERE

15. Plates Plate – Plates are sections of the lithosphere 7 Major plates
Largest – Pacific Plate
Plates move 5cm/yr

16. What are the 3 types of plate boundaries?
Convergent
Divergent
Transform

17. Divergent Boundary
Divergent Boundary – Occur when two plates move apart
Example – East African Rift Valley

18. Example – East African Rift Valley

19. Convergent Boundary
Convergent boundary – Occur when two plates move together

20. Transform Boundary
Transform Boundary – When two plates grind past each other
Example – San Andreas

21. Every Plate contains all 3 types of boundaries

22. Ch 9.3 Oceanic Ridge
Oceanic Ridge – Elevated area in the ocean, found along divergent boundaries

23. Rift Valley
Rift Valley – Deep faults found along divergent boundaries

24. Seafloor Spreading
Seafloor Spreading – The process by which plate tectonics produce new lithosphere
Oldest part of the ocean floor is 180 million years old.

25. Subduction Zone
Subduction Zone – When one plate is forced down beneath another plate. (Convergent Boundary)

26. Trench
Trench – Surface Feature produced during a subduction zone.

27. Continental Volcanic Arc
Continental Volcanic Arc – When a continental and ocean plate collide, they produce volcanoes on the land.

28. Volcanic Island Arc
Volcanic Island Arc – When 2 ocean plates collide, they produce volcanoes in the middle of an ocean, forming islands

29. Mountains Mountains are formed when two continent plates collide.
Example – Himalayas in South Asia

30. Transform Fault - Earthquakes
Transform Fault – Earthquakes – At Transform faults, plates grind past without destroying the lithosphere and produce earthquakes.
Example – San Andreas Fault , CA

31. Notice Convergent Boundaries – Lithosphere is destroyed
Divergent Boundaries – Lithosphere is created
Transform Boundaries– Lithosphere is neither created nor destroyed.

32. Ch 9.4 Paleomagnetism
Paleomagnetism – Study of changes in Earth’s magnetic field

33. Normal Polarity
Normal Polarity – Same magnetism as present day magnetic field

34. Reverse Polarity
Reverse Polarity – Rocks that show opposite magnetism then present day

35. What evidence supports theory of plate tectonics?
The discovery of strips of rocks of alternating polarity across the ocean ridges.

36. How old is the seafloor?
The youngest crust (Seafloor) is at the ridge crest, the oldest crust is further away
Youngest
Oldest

37. Hot spot
Hot Spot – A rising plume of mantle that creates a volcanic area (Hawaii)
Hot spot supports idea that the plates move over Earth’s surface

38. Shaded Region – Reverse Polarity
White Region – Normal Polarity