1. Plate Tectonics http://www.middleschoolscience.comhttp://www.middleschoolscience.com 2009

2. Earth’s Layers The Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed. This crust is not a solid shell; it is broken up into huge, thick plates that drift atop the soft, underlying mantle.

3. The Crust Outermost layer 5 – 100 km thick Made of Oxygen, Silicon, Aluminum

4. Crust

5. The Mantle Layer of Earth between the crust and the core Contains most of the Earth’s mass Has more magnesium and less aluminum and silicon than the crust Is denser than the crust

6. Mantle

7. The Core Below the mantle and to the center of the Earth Outer Core-layer of molten metal, which behaves like a liquid. Inner Core – is a dense ball of solid metal-b/c the extreme pressure squeezes the atoms of iron and nickel so much that they cannot spread out and become a liquid. Core is believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium “Both the outer & inner core together are just slightly smaller than the moon.”

8. Core

9. Earth’s Magnetic Field A.Currents in the liquid outer core force the solid inner core to spin. B.The inner core inside the Earth, spins at a slightly faster rate than the rest of the planet. C.The spinning movement—creates the Earth’s magnetic field, which is a force that causes the planet to act like a giant bar magnet. 1. Like a magnet, Earth’s magnetic field has north & south poles.

10. Conclusion

11. Plate Tectonics

12. Tectonic Plates

13. Plate Tectonics Greek – “tektonikos” of a builder Pieces of the lithosphere that move around Each plate has a name Fit together like jigsaw puzzles Float on top of mantle similar to ice cubes in a bowl of water

14. Plates

15. Continental Drift http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml Alfred Wegener 1900’s Continents were once a single land mass that drifted apart. Fossils of the same plants and animals are found on different continents Called this supercontinent Pangea, Greek for “all Earth” 245 Million years ago Split again – Laurasia & Gondwana 180 million years ago

16. Continental Drift

17. Evidence of Pangea

18. Ocean Floor

19. Sea Floor Spreading

20. Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins Magma rises to the surface and solidifies and new crust forms Older Crust is pushed farther away from the ridge

21. Clues about Ocean Floors (Expedition)

22. How Plates Move http://pubs.usgs.gov/gip/dynamic/unanswered.html

23. Convection Currents

24. Different Types of Boundaries http://pubs.usgs.gov/gip/dynamic/understanding.html

25. Divergent Boundary – Arabian and African Plates

26. Divergent Boundary – Iceland http://pubs.usgs.gov/gip/dynamic/understanding.html

27. Divergent Boundary - Oceanic http://www.geology.com

28. Divergent Boundary - Continental http://www.geology.com

29. Convergent Boundary – Indian and Eurasian Plates

30. Convergent Boundary – Oceanic & Continental http://pubs.usgs.gov/gip/dynamic/understanding.htmlhttp://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.comhttp://www.geology.com

31. Convergent Boundary – Oceanic & Oceanic http://pubs.usgs.gov/gip/dynamic/understanding.htmlhttp://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.comhttp://www.geology.com

32. Convergent Boundaries - Continental http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.comhttp://www.geology.com

33. Transform Boundary – San Andreas Fault www.geology.com

34. Review

35. Name the 3 main layers of the Earth What is a tectonic plate? What was Pangea? What is Sea-Floor spreading? Name the three different types of plate boundaries and one location on Earth for each one