1. Plate Tectonics
Liz LaRosa for use with my 5th Grade Science Class

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. Tectonic Plates

7. 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

8. Continental Drift 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

10. Evidence of Pangea

11. Sea Floor Spreading

12. Sea Floor Spreading
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

14. How Plates Move

15. Different Types of Boundaries

17. Divergent Boundary - Oceanic

18. Divergent Boundary - Continental

19. Divergent Boundary – Arabian and African Plates
Arabian Plate
Red Sea
African Plate

20. Divergent Boundary – Iceland

21. Convergent Boundary – Oceanic & Continental
&

22. Convergent Boundary – Oceanic & Oceanic
Note – plates are reversed
&

23. Convergent Boundaries - Continental
&

24. Convergent Boundary – Indian and Eurasian Plates
Indian Plate

25. Progression of Indian Land Mass

26. Transform Boundary – San Andreas Fault

27. Review 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

28. Consequences of Plate Tectonics
Aerial view of the area around Thingvellir, Iceland, showing a fissure zone (in shadow) that is an on-land exposure of the Mid-Atlantic Ridge. Right of the fissure, the North American Plate is pulling westward away from the Eurasian Plate (left of fissure).
The San Andreas Fault – a transform fault

29. Consequences of Plate Tectonics
The Aleutian Islands, an island arc
The 1980 eruption of Mount Saint Helens

30. Consequences of Plate Tectonics
Helicopter view (in February 1994) of the active lava lake within the summit crater of 'Erta 'Ale (Ethiopia), one of the active volcanoes in the East African Rift Zone.
The convergence of the Nazca and South American Plates has deformed and pushed up limestone strata to form towering peaks of the Andes, as seen here in the Pachapaqui mining area in Peru.