1. Layers of the Earth
Pre Ap - Notes: pg 113

2. Layers of the Earth

3. Layers of the Earth Crust
Crust: a layer of rock that forms Earth’s outer skin
Includes land forms, soil, water, etc..

4. Layers of the Earth Crust
Basalt: Ocean crust made of dark dense rock and is very thin
Granite: Continental crust that is less dense but is thicker (especially where mountains are)

5. Layers of the Earth Mantle Mantle: Layer of hot rock under the crust
Lithosphere: upper most part of the mantle and the crust, solid
About 100 kilometers thick

6. Layers of the Earth Mantle
The temperature and pressure in the mantle increases with depth
This pressure and high temperatures causes the lower part of the mantle to be soft and can flow easily, known as the asthenosphere
The mantle is 3,000 km thick

7. Layers of the Earth Core
Core: inner most part of the earth consisting of 2 parts
Outer core: thick liquid of molten material
Inner core: dense ball of solid metal (iron and nickel)

8. Just the Facts
The mantle makes up about 80% of the Earth’s total volume.
Pressure at the center of the inner core may be more than 1 million times greater than air pressure at sea level.
Crust material is times denser than water, mantel material is times denser than water, core material is times denser than water

9. Fun Fact
Suppose you could drive a car at 100km/hr (62 mi/hr) from Earth’s surface to the center of the core. At that speed the car would take about half an hour to drive through most continental crust, about another 29 hours to drive through the mantle, and about an additional 35 hours to drive to the center of the Earth.

10. Convection Currents and the Mantle

11. Convection Currents and the Mantle
Pre AP: Notes: Pg 114

12. Convection Currents and the Mantle
Heat Transfer
Heat can transfer in 3 ways
1. Radiation
Transfer of
heat energy by
electromagnetic
radiation
Example: waves on
the EMS scale
2. Conduction
Transfer of heat
By direct
Contact
Example: touching
a metal spoon
In a pot of
Boiling water
3. Convection
Heat transfer
By the movement
Of heated liquids
And gasses
Example: Hot
Air rises

13. Heat Transfer

14. Convection Currents and the Mantle
The difference between temperature and density of the fluid changes. This causes:
Hot liquid to be less dense, moving it to the top
Cool liquid to be more dense, moving it to the bottom

15. Convection Currents and the Mantle
Video
The asthenosphere (middle mantle) is a soft liquid and experiences convection currents
As the fluid close to the core heats, it rises to the top (near the lithosphere) and cools, causing it to cycle back down

16. Convection Currents and the Mantle
Convention currents in the mantle, cause the lithosphere (bottom of the crust) to move
This causes the crust of the earth to move around

17. Draw both pictures below in your notes
Heat
Becomes
cool
Heat
rising
Coolness
sinking
Heat
source

18. Pg. 115 Draw both pictures below in your notes
Heat
Becomes
cool
Heat
rising
Coolness
sinking
Heat
source

19. Drifting Continents

20. Drifting Continents
Alfred Wegener
German scientist in early 1900s

21. Drifting Continents Alfred Wegener German scientist in early 1900s
His hypothesis stated that all the continents had once been joined together in a single land mass and have sense drifted apart

22. Drifting Continents Alfred Wegener German scientist in early 1900s
His hypothesis stated that all the continents had once been joined together in a single land mass and have sense drifted apart
He named the
mega continent
Pangea, which
means “all lands”

24. Drifting Continents Alfred Wegener
Pangea existed over 300 million years ago
Pangea took tens of millions of years to move to where the continents are today

25. Drifting Continents Continental Drift and its evidence
Continental Drift: Wegener’s idea that the continents slowly moved over Earth’s surfaces

26. Drifting Continents Continental Drift and its evidence
Evidence from landforms:
Mountain range in Africa matches up with a mountain range in South America
European coal fields match up with North American coal fields

27. Drifting Continents Continental Drift and its evidence
Evidence from Fossils
Fossils of the same animals (mesosaurus and lytrosaurus) have been found on different continents
These reptiles once lived on a single land mass – Pangea

30. Drifting Continents Continental Drift and its evidence
Evidence from Fossils
Glossopteris (fern like plant) fossils have been found in Africa, South America, Australia, India, and Antartica

32. Where do you think South Africa was during Pangaea?
Drifting Continents
Continental Drift and its evidence
Evidence from Climate
Evidence from fossils that the climate in South Africa was once much colder because there is evidence of glaciers
Where do you think South Africa was during Pangaea?

33. South Africa at the Pole

34. Where do you think Splisbergen was during Pangaea?
Drifting Continents
Continental Drift and its evidence
Evidence from Climate
Spitsbergen: island up by Norway which is covered in ice, but where fossils of tropical plants have been discovered
Where do you think Splisbergen was during Pangaea?

35. Drifting Continents Theory was not accepted by scientists…why?
Continental Drift and its evidence
Theory was not accepted by scientists…why?
Because Wegener could not identify the cause of continental drift

36. Sea Floor Spreading

37. In order to get sea floor spreading…
We have to go back and remind ourselves about what convection currents are…
What are convection currents?

38. Heat
Becomes
cool
Heat
rising
Coolness
sinking
Heat
source

39. The lithosphere is broken into different plates

40. Sea Floor Spreading
Mid Ocean Ridge
Mid Ocean Ridge: longest chain of mountains in the world under the oceans.
Mountain range curves around the world like the seams on a baseball
Video:

41. Mid-Ocean Ridge

42. Sea Floor Spreading Mid Ocean Ridge
Video: Sonar video:
Sonar: device that bounces sound waves off under water objects to see their location and depth
Sonar mapped the mid ocean ridge

43. Sea Floor Spreading Harry Hess
An American geologist who studied mid-ocean ridges.
He suggested that the ocean floors move like conveyor belts, carrying the continents along with them.
He came up with the idea of sea-floor spreading

44. Sea Floor Spreading

45. Sea Floor Spreading Sea Floor Spreading
At the mid-ocean ridge, molten material rises from the mantle and erupts.
Molten material then spreads out, pushing older rock away on both sides of the ridge

46. Sea Floor Spreading Sea Floor Spreading
3. As the molten material cools, it forms a strip of solid rock in the center of the ridge.
4. Eventually, more molten material will erupt and the cycle will begin again

47. Sea Floor Spreading Sea Floor Spreading
This process continually adds new material to the sea floor

48. Question???
Video:

49. Sea Floor Spreading Sea Floor Spreading
Deep-Ocean Trench: under water canyon where deep oceanic crust bend downward into the mantle
Subduction: Process by which the ocean floor sinks beneath a deep-ocean trench into the mantle
Video:

50. Sea Floor Spreading Sea Floor Spreading Evidence molten material
magnetic stripes (video:
drilling samples: drilling sample show younger rocks on the ridge

51. The Theory of Plate Tectonics

52. The Theory of Plate Tectonics
Plate tectonics: Theory that explains the formation, movement, and subduction of Earth’s plates

53. The Theory of Plate Tectonics
The lithosphere is broken into separate sections called plates
The plates fit closely together along cracks in the lithosphere

54. The Theory of Plate Tectonics
How do the plates move?
As the convection currents under the lithosphere move, they cause the plates to move
One plate cannot move without effecting another plate

55. The Theory of Plate Tectonics
Plate Boundaries
Faults: breaks in the earth’s crust
Faults are formed along plate boundaries

56. The Theory of Plate Tectonics
Plate Boundaries
There are three types of plate boundaries
Transform Boundaries
Divergent Boundaries
Convergent Boundaries

57. The Theory of Plate Tectonics
Transform
Boundary
Motion
Sliding past one another
Effect
Shallow Earthquakes
Topography
Fault
Volcanic Activity
Yes, Ring of Fire

58. The Theory of Plate Tectonics
Divergent Boundary
Motion
Move away from one another
Effect
Oceanic Lithosphere created
Topo-graphy
Ridge or Rift valley
(Mid ocean ridge or African Rift Zone)
Volcanic Activity
Yes – formed from magma in the mantle, Ring of Fire

59. The Theory of Plate Tectonics
Convergent Boundary
Motion
Move together or collide
Effect
Oceanic Lithosphere destroyed, deep earthquakes
Topography
Trench, mountains, Island arcs
Volcanic Activity
Yes – as the plate submerges, it melts and can rise back up to the surface as lava

60. The Theory of Plate Tectonics
Plate Boundaries
Convergent Boundaries
When plates converge, their density will depend on what happens

61. The Theory of Plate Tectonics
Plate Boundaries
Oceanic – Continental Convergent Boundary
Oceanic crust is more dense, so it will go under the continental crust forming trenches and volcanoes

62. The Theory of Plate Tectonics
Plate Boundaries
Oceanic – Oceanic Convergent Boundary
The more dense oceanic crust will go under the less dense oceanic crust forming trenches and volcanoes

63. The Theory of Plate Tectonics
Plate Boundaries
Continental – Continental Convergent Boundary
Plate collide up, folding together to create mountains