1. Main Points: Geodynamics
Earth is a system of systems (“spheres”)
Earth’s layering is driven by gravity
Pressure and temperature increase with depth
#3 causes some strange conflicts in material behavior
Heat within Earth flows by conduction, convection, and radiation; differently within different layers
Earth’s internal motions are driven by the 2nd law of thermodynamics (heat flows from hot to cold regions)

2. Question: What percentage of the volume of Earth’s crustal rock is made up of oxygen?
b) 4.9%
c) 9.4%
d) 49%
e) 94%
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3. Geosphere Composition of Crust (%):
Weight Moles Volume
Oxygen
Silicon
Aluminum
Iron
Composition of Whole Earth (weight %):
Iron 35
Oxygen 30
Silicon 15
Magnesium 13
Nickel

4. Hydrosphere: 96.5% in Oceans
3.5% in glaciers, groundwater
~0% in streams, lakes, atmosphere, biosphere
71% of Earth’s surface is currently covered with water.
If Earth were a perfect sphere, it would be covered with 2.25 km of water.

5. Atmosphere: Composition (by volume): N2 - 78.1%
Ar %
H2O %
CO %
(increasing)
Ne %

6. Earth's magnetic field LOOKS LIKE there is a tilted, offset, wandering, bar magnet in its core. (But there isn’t!!)
Fluid flow (convection) of liquid iron in Earth’s outer core creates the magnetic field.  Magnetohydrogeodynamo

7. The magnetosphere protects us from ionized particles of solar wind.

8. Biosphere: Extends from the seafloor and deep crust, to the tops of mountains and the atmosphere.
million species; ~1.5 million identified
VERY significant geological agent (Ex: atmosphere, weathering)

9. Temperature 10ºC ?
? bar
Pressure

10. Temperature 10ºC
~3500ºC
~5500ºC
3.62 Megabars bar
Pressure

11. A Planet’s History is Dominated by the Flow of Heat Outward:
Occurs through
Radiation
Conduction
Convection

12. Major “players” in the story of Earth’s evolution:
(1) 1st Law of Geology: Rocks Fall Downhill (Gravity)
- Controls LAYERING, MINERAL PHASES

13. Major “players” in the story of Earth’s evolution:
(2) 1st Law of Geophysics - Heat “rises” (Thermodynamics, thermal expansion, gravity)
Heat flows from hot regions to cold regions (therefore up and out of the Earth).
(1) 1st Law of Geology: Rocks Fall Downhill (Gravity)
- Controls LAYERING, MINERAL PHASES

15. Hypsometric Curve:

18. “Plate” Tectonics

19. “Plate” Tectonics

20. “Plate” Tectonics

21. “Plate” Tectonics

22. “Plate” Tectonics

23. “Plate” Tectonics
? ?

24. Geologic “Action” mostly happens at plate boundaries (Earthquakes, Volcanoes, Mountain Building, etc.)

26. “World’s Geologic Wonders:” Example/ Erta Ale Volcano, Ethiopia
Aerial view of Erta Ale summit caldera from S during February 2002 overflight. The active pit crater is in the center of the picture.

27. Erta Ale, 2011 (used in “Clash of the Titans”)

29. Erta Ale

30. Erta Ale, fountaining

31. Erta Ale, pseudo-subduction zone

32. Erta Ale, looking like mid-ocean ridges

33. Erta Ale, looking like Mid-Atlantic ridge, with transforms too!:

34. Erta Ale

35. Erta Ale, looking like a plate boundary triple-junction

36. Erta Ale, 2010 flow
Extent of Nov lava flows viewed from SW of crater on rim

37. Dallol hot springs, Ethiopia

38. Dallol hot springs, Ethiopia

39. Dallol hot springs, Ethiopia

40. Nyiragongo, DR Congo

41. Nyiragongo

42. Pu’o O’o, Hawaii

43. Marum crater, Ambrym island, Vanuatu

44. Mt. Erebus Lava Lake, Antarctica

45. Earliest Earth?

48. Rifting:

49. Rifting:

50. Rifting:

51. Subduction:

52. Subduction:

53. Mountain
Building:

54. Mountain Building:

55. Transform Faulting:

57. There are other geodynamic processes besides plate tectonics
What causes the volcanism at Hawaii?

59. Hot Spot Mantle Plume Volcanism

61. Map of Ocean Bathymetry (how do we get this?)