1. Plate Tectonics Liz LaRosa for use with my 5 th Grade Science Class http://www.middleschoolscience.com 2009 http://www.middleschoolscience.com

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. 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

5. The Core Below the mantle and to the center of the Earth Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium

6. 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

7. Evidence of Pangea

8. Sea Floor Spreading

9. 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

10. Tectonic Plates

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

12. How Plates Move Convection Currents: motions in the mantle said to cause sea-floor spreading http://pubs.usgs.gov/gip/dynamic/unanswered.html

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

14. Boundaries – where 2 plates touch Transform – occurs where two plates slip past each other horizontally. (Strike-slip fault)

15. Convergent— occurs where two plates collide or push each other (Reverse fault) Divergent—occurs where two plates pull away from each other (Normal fault)

16. Transform Boundary (all types of crusts) San Andreas Fault www.geology.com

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

18. Convergent Boundary – Indian and Eurasian Plates

19. Himalyas

20. Continental-Oceanic Convergent (subduction) http://pubs.usgs.gov/gip/dynamic/understanding.htmlhttp://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.comhttp://www.geology.com The Andes Mountains

21. Oceanic & Oceanic Convergent Subduction zone – forms a trench (The Mariana Trench is 11 km deep) http://pubs.usgs.gov/gip/dynamic/understanding.htmlhttp://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.comhttp://www.geology.com

22. Continental/Continental Divergent Iceland has a divergent plate boundary running through its middle http://www.geology.com

23. Oceanic/Oceanic Divergent http://www.geology.com