1. Chapter 4: Section 1: Inside the Earth

2. The Earth is made of different layers which are described by their Composition and Physical properties

3. The Earth is divided into
Composition
The Earth is divided into
3 main layers:
Crust
Mantle
Core

4. The Crust
The crust is the outermost layer of the Earth with a thickness of 5 to 100 km

5. 2 Types of Crust
Continental crust: - land bodies, usually 30 km thick! (Mostly granite)
Oceanic crust: - bottom of water bodies, 5-8 km thick. (Mostly basalt)

6. Two types of crust

7. The Mantle thickness of 2,900 km.
It is so deep that… no one has ever seen what it looks like.
Contains most of the Earth’s mass

8. The Core
Is the center of the Earth and is made of Iron with smaller amounts of Sulfur, Aluminum and Magnesium, and silicon and oxygen

9. Physical Properties
of Earths Layers

10. Based upon structure, there are 5 physical layers:
) Lithosphere
) Asthenosphere
) Mesosphere
) Outer core
) Inner core

12. 1.) The Lithosphere Outermost layer
made up of the crust and the rigid upper part of the mantle.
Divided into pieces called tectonic plates.

13. 2.) The Asthenosphere
This is the soft layer of the mantle on which pieces of the lithosphere move.

14. 3.) Mesosphere
Lower part of the mantle

15. 4.) The Outer Core
Outer liquid layer of the core

16. Solid inner layer of the core
5. Inner Core
Solid inner layer of the core

17. Tectonic Plates
Pieces of the lithosphere that move around on the asthenosphere.
Made of continental crust, oceanic crust or both

18. Depths of the Earth
Scientists cannot visit the depths of the Earth like the mantle and the core but use seismic waves recorded during earthquake activity.

19. Seismic Waves
The device that measures seismic waves is a seismograph.

20. Section 1 Recap Questions
What are the 3 main layers of the Earth?
Crust, Mantle, Core
What are the 2 components of the crust? Continental and Oceanic
What is the largest layer of Earth?
The Mantle
According to their characteristics, what are the 5 layers Earth can be broken into?
Lithosphere, Asthenosphere, Mesosphere, Outer core, Inner core

21. Alfred Wegener
1911
Developed a Theory called the Theory of Plate Tectonics which states that the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere. The continents once formed a single landmass, broke up, and drifted to their present locations

22. Wegener’s Theory explains some observations:
 The continents seem to fit together

23. 2. Fossils of the same plant and animal species are found on continents that are on different sides of the Atlantic Ocean.

24. 3. Similar types of rock were found on several continents.

25. 4. Evidence of the same ancient climatic conditions were found on several continents.

26. Wegener proposed that all of the separate continents that we see today were once connected in a giant landmass called Pangaea which broke up about 180 M years ago and formed 2 big pieces called Laurasia and Gondwanaland. Then, about 65 MYA, these broke up and formed the continents that we know today.

33. Sea Floor Spreading
As the tectonic plates move away from each other, the sea floor spreads apart and magma fills in the gap.

34. Sea floor spreading is proven by the ages of the rocks
As this new crust forms, the older crust gets pushed away from the mid-ocean ridge.
The older crust is farther away from the mid-ocean ridge than the younger crust is.

35. Magnetic Reversal
Throughout Earth’s history, the north and south magnetic poles have changed places many times.

36. How does Magnetic Reversal Prove Sea Floor Spreading?

37. Plate Tectonics
Theory of Plate Tectonics states that the Earth’s lithosphere is divided into tectonic plates that move around on top of the asthenosphere. The continents once formed a single landmass, broke up, and drifted to their present locations

38. Boundary Boundary - is a place where tectonic plates touch.
3 types of boundaries (depending on how the plates are moving relative to one another):
1.) Convergent
2.) Divergent
3.) Transform

39. Convergent Boundary Type of Crust  O-O, C-C, or O-C
Type of Movement - 2 plates move together often, 1 oceanic plate moves under another oceanic or continental plate in a process called subduction
Arrows - 

40. Divergent Boundaries Type of Crust  O-O or C-C
Type of Movement - 2 plates move apart
Arrows -

41. Stress
Stress is: the amount of force that is applied on a given material.

42. Deformation - when rock changes shape due to stress

43. Pd 2 starts here

44. There are two main types of stress that can act on a rock.
Compression
Tension

45. Compression Rock is squeezed & will fold Convergent Motion that Occurs
What type of boundary?
Convergent

46. Tension Rock is stretched and can break Divergent Motion that Occurs
What type of boundary?
Divergent

47. Folding
Folding occurs when rock layers bend due to stress in the Earth’s crust.

48. 3 Types of folding:
Anticline
Syncline
Monocline

49. Anticline
Description: rock folds downward (like a hill)
Picture:

50. Syncline
Description: rock folds upwards (like a “u”)
Picture:

51. Monocline
Description: layers of rock are stacked but remain horizontal.
Picture:

52. Pd 1, 9 starts here

53. Fault
A crack in the Earth’s crust along which rocks move.

54. Fault Blocks
The blocks of crust on either side of the fault

55. If a fault is cut diagonally, it usually has two specific sides.
a)Hanging wall: the upper side of the cut, the upper portion sticks out.
b)Footwall: the lower side of the cut, the bottom portion sticks out

56. Hanging wall & Footwall

57. 3 Types of Faults
Normal
Reverse
Strike-slip

58. Pd 7,8 starts here

59. Normal Faults
Description: Stress at a divergent boundary pulls Hanging wall down relative to the footwall
Picture:

60. Reverse Fault
Description: Compression pushes Hanging wall moves up relative to the footwall at a convergent boundary
Picture:

61. Description: Rock breaks & moves horizontally (transform boundary)
Strike-Slip Fault
Description: Rock breaks & moves horizontally (transform boundary)
Picture:

62. Mountains
Mountains are formed when tectonic plates undergo compression or tension.

63. 3 Types of Mountains
Folded
Fault-block
volcanic

64. Folded mountains
Description: Rock layers are squeezed together & pushed upwards

65. Fault-Block Mountains
Description: when there is enough tension, a large number of normal faults can result. Mountains are tilted upwards by faulting & will have sharp, jagged peaks.

66. Volcanic Mountains
Description-When molten rock erupts into the Earths surface, magma pushes the surface of the Earth upwards