1. Earth’s Interior Structure

2. Earth’s Origins
4.6 billion years ago Earth was a planetesimal developing into a planetoid. The only gasses present were Hydrogen and Helium No magnetic field Meteorite bombardment continued for over 500 million years aided Earth’s growth.

3. Earth’s Origins
Meteorites contained rock-forming elements (Mg, Si, Fe, Al, Ca, Na, Ni) non-condensable elements (H, He, O, C, Ne, N, S, Ar, P).

4. Earth’s Origins
Meteorite impact with Earth, some non-condensable elements evaporated on impact. Others have volatilized over time outgassed through, fumaroles, steam wells geysers.
Volatilized = evaporated

5. Earth’s Origins
Formation of the Earth’s Crust bya, Earth’s core hotter. mechanism of energy escape - conduction conduction is slow Internal energy could not Dissipate entire Earth became molten surface was magma ocean.
Volatilized = evaporated

6. Earth’s Origins
Formation of the Earth’s Crust Convection all0wed more Energy to be released. This permitted Cooling of the surface Forming Earth’s crust 3.8 – 4.3 bya
Volatilized = evaporated

9. Earth’s Interior Structure
1. Crust
Thin outer layer
B. Varies in thickness
1. 70 km in some mountainous regions
2. Less than in oceanic regions

10. Earth’s Interior Structure
2. Crust is made of two main parts A. Continental Crust Light granitic rocks granitic – Quartz Potassium Feldspar

11. Earth’s Interior Structure
2. Crust is made of two main parts B. Oceanic Crust- Heavier basaltic composition Plagioclase feldspar pyroxene

12. Earth’s Interior Structure
3. Lithosphere A. Crust and upper mantle (about 100 km thick) B. Cool, Rigid, Solid

13. Earth’s Interior Structure
4. Mohorovicic Discontinuity (The Moho) A. Separates the crust from the mantle 1. "discontinuity" is used for a surface at which seismic waves change velocity. B. exists at an average depth of 8 km beneath the ocean basin and 32 km beneath the continents. C. seismic waves accelerate

14. Earth’s Interior Structure
5. Mantle A. below crust B km thick C. Composition similar to the rock peridotite

15. Earth’s Interior Structure
6. Asthenosphere A. Upper Mantle B. Depth of 100 to 350 Km C. Hot, weak rock D. Easily deformed E. Up to 10% is molten F. Key to the explanation of plate movement

16. Earth’s Interior Structure
7. Outer Core A. Below mantle B km thick C. Mobile liquid D. Does not transmit S waves from Earthquakes E. Mainly iron and nickel composition F. Related to Earth’s magnetic field

17. Earth’s Interior Structure
8. Inner Core A km Radius B. Solid C. Iron and Nickel composition D. High Density

18. Consequences of Core Formation
Increase in gravity
Increasing pressure in the center creating solid metallic inner core
Release of pressure moving out from the center
allows for a molten outer core
Generates the magnetic field
Less dense materials “floated” to the top (crust)

20. Earth’s Interior Structure

21. Physical Structure of the Earth (5 Layers)
Lithosphere- rigid outer layer (crust)
Asthenosphere- solid rock that flows slowly (like hot asphalt)
Mesosphere- middle layer
Outer Core- liquid layer
Inner Core- solid, very dense

22. Earth’s Interior Structure

23. Quiz

24. 1.The crust is ____ km thick in oceanic regions70 5 75 57

25. 2.Continental crust is made mostly of ________ rocks
granitic
basaltic
granular
crushed

26. 3. The lithosphere includes the ______ and _______
Mantle and inner core
Crust and lower mantle
Mantle and atmosphere
Crust and upper mantle

27. 4. At the Mohorovicic Discontinuity, seismic waves ________
accelerate
decelerate
stop
Reflect upwards

28. 5.The mantle has a composition similar to ________
granite
basalt
peridotite
quartz

29. 6. The movement of the Earth’s plates is partly explained by the __________
Sauronsphere
Atmosphere
Lithosphere
Asthenosphere

30. 7.The outer core is a _______
Liquid
Solid
Gas
Plasma

31. 8. The inner core is composed of ______ and ______
Iron & Basalt
Granite & Nickel
Iron & Nickel
Basalt & Granite

32. Earth’s Interior Structure