1. PLATE TECTONICS:
A UNIFYING THEORY
Geology
The Walker School

2. Earth’s crust is about 5% of it’s mass.

3. Oceanic Crust
5 to 8 km thick.
Composed mainly of basalt
and gabbro.
Not older than 180 million
years.
Covered with dead organism
and sediment, about 1 km
thick.
Little variability in
composition.

4. Continental Crust
Composed of many
rock types.
Can be as old as 4
billion years.
Varies in thickness
from 20 to 80 km.
Makes up about 41%
of Earth’s surface.

5. Cratons are the oldest parts of the
continents.

6. Crust is made of 10 Major Plates
Fig. 1-11, p. 17

7. Activity Along Plates
 Volcanism
 Earthquakes
 Mountain Building
 Basin Formation

8. Plate Activity
Fig. 1-12, p. 18

9. Composite Satellite Image of
Himalayan Peaks

10. Interactions Between Plates and Climate
Location of Colliding Mountain Ultimately
Movement Continents Plates Shape and Affects
between and Ocean Create Size Affect Global
Plates Basins Mountains Atmospheric Climate
Circulation

11. WHAT IS CONTINENTAL
DRIFT?

12. Alferd Wagner Proposed the Theory
of Continental Drift
Fig. 2-2, p. 35

13. Evidence for Continental Drift
 Shorelines of Continents
 Similar Rock Sequences
 Similar Mountain Ranges
 Matching Glacial Deposits
 Similarity in Extinct Plants and Animals

14. Shorelines of Continents
Fig. 2-3, p. 36

15. Similar Rock Sequences
Fig. 2-4, p. 37

16. Trends of Mountain Ranges

17. Glacial Evidence from Striations
Fig. 2-5, p. 38

18. Fossil Evidence
Fig. 2-6, p. 39

19. TYPES OF PLATE
BOUNDARIES

20. Types of Plate Boundaries
Table 2-1, p. 47

21. DIVERGENT PLATE
BOUNDARIES

22. Mid-Atlantic Ridge
Fig. 2-10, p. 43

23. Earth’s Magnetic Field Recorded in
Oceanic Crust
Fig. 2-11, p. 44

24. Age of the World’s Oceans
Red:
48
MYA
Yello
w: 68
MYA
Green:
155
MYA
Fig. 2-12, p. 45

25. Sediments Increase Away from
Ridges Toward Continents
Fig. 2-13, p. 45

26. Divergent
Plates Form
Oceans
Fig. 2-15, p. 48

27. East African
Rift Valley
Formed from
Divergent
Plates
Fig. 2-16a, p. 49

28. Red Sea: Example of Adv. Rifting
Fig. 2-16b, p. 49

29. Indicators of Rifting
 Faults  Lava Flows
 Dikes (Vertical Intrusions of Magma)  Thick Sedimentary Sequences
 Sills (Horizontal Intrusions of Magma)  Pillow Lava

30. Pillow Lavas
http://www.youtube.com/watch?v=xsJn8izcKtg

31. Example of Paleo-Rifting in the United States
Hudson River Valley: Palisades, NJ
Fig. 2-17, p. 52

32. CONVERGENT PLATE
BOUNDARIES

33. Oceanic Plate Boundaries
Fig. 2-18a, p. 53

34. Oceanic-Continent
Plate Boundaries
Fig. 2-18b, p. 53

35. Continental-Continental
Fig. 2-18c, p. 53

36. Indicators of Convergence
 Melange
 Ophiolites

37. TRANSFORM FAULTS

38. Most transform faults connect two oceanic
ridges.
Fig. 2-20a, p. 56

39. A transform fault can connect a ridge and
a trench.
Fig. 2-20b, p. 56

40. A transform fault can link two ridges.
Fig. 2-20c, p. 56

41. San Andres Fault
Fig. 2-21, p. 57

42. HOT SPOTS: AN
INTRAPLATE FEATURE

43. Mantle Plumb remains stationary while
plates move.
Fig. 2-22, p. 58

44. PLATE MOVEMENT

45. Plates, Zones, and Movements
Fig. 2-14, p. 46

46. Methods for determining movement.
 Measuring age of sediment.
 Dating magnetic anomalies on the seafloor.
 Satellite-Laser ranging techniques.
 Hotspots

47. Supercontinent Cycle

48. DRIVING MECHANISM OF
PLATE TECTONICS

49. Fig. 1-10, p. 16

50. Model I: Thermal convection cells are
restricted to the asthenosphere.
Fig. 2-24a, p. 60

51. Model II: Thermal convection cells involve
the entire mantle.
Fig. 2-24b, p. 60

52. DISTRIBUTION OF NATURAL
RESOURCES

53. Mineral Deposits Associated with
Plate Boundaries
Fig. 2-26, p. 62

54. Fig. 2-25, p. 61

55. Mineral Formation Processes
 Sedimentation (coal)
 Precipitation (salts, metals)
 Crystallization from Magma Plutons (ores)
 Changes in Temperature and Pressure (ores)
 Fluid Inclusions (ores)

56. Greatest Copper Deposits
 The greatest known deposit of copper is in
porphyries formed by volcanic activity in the Chile's
Andean Mountains.
 Chile's copper mines provide over 30% of the
world's mine production of recoverable copper.
 Escondida Copper Mine is today the world's
largest producing mine with 750,000 metric tons of
production which was 5.6% of the world's
production in 2000.

57. Escondida Copper Mine, Chili
 The Escondida copper-
gold-silver mine is
located in the arid,
northern Atacama
Desert of Chile about
160km southeast the
port of Antofagasta, at
an elevation of 3,050m
above sea level.

58. Copper is the Oldest Minded Mineral
 Copper is mankind's oldest metal, dating back more
than 10,000 years.
 A copper pendant discovered in what is now
northern Iraq goes back to about 8700 BC.
 Archeologists have recovered a portion of a water
plumbing system from the Pyramid of Cheops in
Egypt. The copper tubing used was found in
serviceable condition after more than 5,000 years.

59. Copper was mined in Ancient Rome
 Copper was named for
the island of Cyprus,
where the Romans
obtained their supply.

60. Copper in Early America
 When Columbus sailed to the Americas, his ships,
Nina, Pinta and Santa Maria, had copper skins
below the water line. The copper sheathing
extended hull life and protected against barnacles
and other kinds of biofouling.
 Paul Revere, produced the bronze cannon, spikes
and pumps for the famous ship, Old Ironsides.
Revere was one of the earliest American
coppersmiths.