1. How do geologic processes change the shape of Earth’s surface?

2. What do Earth’s layers consist of?
Crust
Mantle
Core

3. Crust Layer of rock that forms Earth’s “outer skin”
Includes rocks, mountains, soil, water
Thin: 5-40km thick
870◦C

4. 2 Types:
Continental: Dry land (granite)
Oceanic: Ocean (basalt)

5. Mantle
Layer of hot rock
2,900km thick
2,200◦C

6. 2 Sub layers:
Lithosphere
Asthenosphere

7. Lithosphere Rigid Much like the crust 100km thick
Floats on top of the asthenosphere

8. Asthenosphere Plastic like Material can flow slowly like hot tar
Has both solid & liquid qualities

9. Core
Consists of iron & nickel
5,000◦C
Makes up 1/3 of Earth’s mass

10. 2 sub layers:
Outer Core
Inner Core

11. Outer Core Layer of molten material Covers the inner core
2,250km thick

12. Inner Core Dense solid ball of metal
Extreme pressure does not allow Fe & Ni to spread out to form liquid
1,200km thick

13. What are the 3 ways that heat is transferred?
Radiation
Conduction
Convection

14. Radiation Heat transferred by EM waves through space
EX: Sitting by the fire!

15. Conduction Heat transferred through direct contact
EX: Spoon in hot chocolate

16. Convection
Heat transferred through a fluid movement of either a gas or liquid
EX: Chicken noodle soup heating on the stove!

17. Which of these do you think happens in Earth’s mantle?
Convection!
Convection currents flow in the asthenosphere
Heated material rises to the top of the mantle (lithosphere), cools, then sinks back to the bottom

19. What does the Theory of Continental Drift state?
1910
Alfred Wegener hypothesized that all the continents had once been a single landmass
A super continent
called “Pangaea”

21. Scientific Method Problem/Question Research Hypothesis Experiment
Analyze
Conclude

22. Supporting Evidence of Wegener’s theory
Landforms
Fossils
Climate

23. Landforms South America & Africa have similar mountain ranges
Europe & North America have similar coal fields

24. Fossils
Fossil-any trace of an ancient organism that has been preserved in rock
Mesoaurus fossils have been found in places now separated by oceans
Glossopteris (fern like plant) fossils have been in rocks in Africa, South America, Australia, India, & Antarctica

25. Climate
Spitsbergen Island lies in the Arctic Ocean, north of Norway, covered with ice
Fossils of tropical plants have been discovered under the ice!
South Africa-deep scratches in rock indicate glacier movement there!!!

27. REJECTED!!! Scientists rejected Wegener’s theory of continental drift
Most scientists in the 1900’s believed the Earth was cooling & shrinking causing the continents to move & mountains to form

28. Is sea-floor spreading like continental drift?
1960
Harry Hess, when studying the mid-ocean ridge, proposed that the ocean floor moved like a “conveyer belt” moving the continents with them
Sea-floor spreading is the continually adding to the ocean floor

29. Sea-floor Spreading Molten material rises up from the mantle
It spreads out, cools off, & hardens
It pushes the older rock out on both sides of the ridge
New crust forms!

31. Wait a minute…!
Hess’ idea of sea floor spreading caused scientists to revisit Wegener’s idea of continental drift!

32. So where does all of the old crust being pushed out go?
Subduction: It is the process by which the ocean floor sinks beneath a deep ocean trench & back into the mantle

33. Sea Floor Spreading & Subduction…
Can change the shape of the oceans!
The ocean floor is renewed every 200 million years
(That’s the time it takes for new crust to form, move across the ocean floor, & sink into a trench)

34. What is the Theory of Plate Tectonics?
1965
Tuzo Wilson proposed that the cracks in Earth’s surface were broken into section called “plates”
He combined the idea of sea-floor spreading, Earth’s plates, &
continental drift into a single
theory

35. Plate Tectonics Theory
A geological theory that states that pieces of Earth’s lithosphere are in constant, slow motion driven by convection currents in the mantle

36. How does it work?
Lithospheric plates float on top of the asthenosphere
Convection currents rise in the asthenosphere & spread out under the plates
No plate can move without affecting another plate
Plates move extremely slow at 1-10cm per year

37. As the plates move, collide, or pull apart…it produces GREAT changes on Earth’s surface

38. Like volcanoes, earthquakes, mountain ranges, & deep sea trenches

39. 3 types of plate boundaries:
Transform
Divergent
Convergent

40. Transform
Place where 2 plates slip past each other moving in opposite directions
Earthquakes often occur along these boundaries

41. Divergent Place where 2 plates move apart
Most occur at the mid-ocean ridge
Some occur on land creating a “rift valley” which is a deep valley
Great Rift Valley in Africa is 3,000km long

42. Convergent Place where 2 plates come together
Collisions of 2 plates can cause:
Oceanic to oceanic
Oceanic to continental
Continental to continental
When 2 plates collide the more dense plate comes out on top!

43. Continental – Continental: mtns form
Oceanic – Continental: Oceanic dives under the continent
Oceanic – Oceanic: the less dense of the 2 sinks into the trench

44. What is an earthquake?
Shaking & trembling that results from the movements of rock beneath Earth’s surface
The movement of Earth’s plates creates stress that squeezes/pulls the rock in the crust

45. Stress A force that acts on rock to change its shape & volume
3 types of stress
Shearing
Tension
Compression

47. Shearing
Stress that pushes a mass of rock in opposite directions

48. Tension
Stress that pulls on the crust stretching the rock so it becomes thinner in the middle

49. Compression
Stress that squeezes rock until it folds or breaks

50. What is a fault?
A break in the crust where slabs of rock slip past each other
Faults usually occur along plate boundaries
3 types:
Strike-slip
Normal
Reverse

51. Strike-Slip Fault
Rocks on either side of the fault slip past each other sideways
Ex: San Andres Fault

52. Normal Fault The fault is at an angle
One block is above the fault & the other is below it
Ex: Rio Grande Rift Valley in New Mexico

53. Reverse Fault
Same structure as a normal fault, but the blocks move in opposite directions
Ex: Appalachian Mts

54. Where do earthquakes begin?
Earthquakes occur in the lithosphere 100km below Earth’s surface
The focus is point beneath the surface where the rock broke causing the earthquake
The epicenter is the point on the surface right above the focus

56. Seismic Waves
During an earthquake seismic waves race out from the focus in all directions
The seismic waves are greatest at the epicenter
Seismograph is the instrument used to record ground movement caused by seismic waves
3 types:
P waves
S waves
Surface waves

58. P waves Primary Waves 1st to arrive
Compress & expand the ground like an accordion

59. S waves
Secondary Waves
2nd to arrive
Vibrate the ground back & forth

60. Surface Waves Come from P/S waves Move slowly
Can cause the ground to roll like ocean waves

61. How do they measure the size of the quake?
Magnitude is the measurement of earthquake strength based on seismic waves & movement along faults
3 ways to measure magnitude:
Mercalli Scale
Richter Scale
Moment Magnitude Scale

62. Mercalli Scale
Measures the intensity
Not precise

63. Richter Scale
Rates the size of seismic waves using a particular seismograph
Accurate measurements for nearby earthquakes

64. Moment Magnitude Scale
Rates the total energy released by an earthquake near or far

65. What types of damage can a quake cause?
Damage/destroy buildings
Topple power lines
Break water & gas lines
Cause landslides
Can cause aftershocks days/months later
Can cause tsunamis

71. Tsunamis
Large wave that occurs when an earthquake displaces water in the ocean

73. What causes volcanoes?
A volcano is a weak spot in Earth’s crust where magma comes to the surface
They form at:
Divergent boundaries
Convergent boundaries
Hot spots

74. Divergent Boundaries Most volcanoes occur here Ex: Mid-ocean ridge
•Volcanic belts occur along plate boundaries where lithospheric plates are weak
Ex: Ring of Fire

75. Ring of Fire
Major volcanic belt formed by volcanoes that rim the Pacific Ocean

76. Convergent Boundaries
•Island Arc-when 2 oceanic plates collide creating an arc of islands
Ex: Japan, New Zealand, Caribbean Islands

77. Hot Spots Where magma rises up from the mantle melting Earth’s crust
Often occur in the middle of a plate
Ex: Hawaiian Islands, Yellowstone National Park

78. How do volcanoes erupt? Magma is under extreme pressure in the mantle
It bubbles up through cracks in Earth’s crust
Pressure decreases as magma nears Earth’s surface
Lava bubbles out of the volcano

79. What does the inside of a volcano look like?

80. Magma Chamber
Where magma is stored under the volcano

81. Pipe
Magma moves through this long pipe that connects the magma chamber to Earth’s surface

82. Vent
Opening where gas and lava leave the volcano

83. Crater
Hollowed-out area at the top of a volcano

84. Volcanic Neck
Magma that hardens inside the pipe

85. Dike
Magma that forces itself “across” rock

86. Sill
Magma that squeezes between layers of rock

87. Batholith
A mass of rock formed when a large body of magma cools inside the crust

88. What are the different types of volcanoes?
Shield Cone
Cinder Cone
Composite

89. Shield Cone Volcano

90. Cinder Cone Volcano

91. Composite Volcano

92. Volcanoes in the US
Mt. Hood

93. Mt. St Helens

94. Mt. Kilauea

95. What are the stages a volcano goes through?
Active→Dormant→Extinct

96. Active
It’s alive!
It is erupting or shows signs of erupting

97. Dormant It’s sleeping…
It is expected to become active in the near future

98. Extinct
Dead as a door nail.
Unlikely to erupt again

99. The End!!!

100. Sike…this is the end!