1. Brigitte Steinmetz John Adams Middle School
Plate Tectonics
Brigitte Steinmetz
John Adams Middle School

2. E-mail: steinmetz@smmusd.org
Disclaimer
The images, maps and diagrams in this presentation were taken from the public domain on the world wide web. Permissions were granted where possible. Any privately owned images not available for this non-commercial, educational project will gladly be removed.

3. Earth’s Interior A. Continental Crust Oceanic Crust Oceanic Crust B.
Lithosphere D. C.
Asthenosphere E.
Mantle
Outer Core
Inner Core

4. http://pubs.usgs.gov/publications/text/inside.html - 12/7/2004
The Mantle
Upper part = hot & rigid (hard)
part of the lithosphere.
Middle part = hotter & soft (asthenosphere)
Lower part = hottest & solid
- 12/7/2004

5. The Earth is HOT Review Heat Transfer Radiation = Conduction =
Energy transferred through an empty space (i.e. sun energy).
Conduction =
Energy transferred directly from one object to another (i.e. burning feet at the beach).
Convection =
Energy transferred through the movement of a heated fluid.

6. Convection inside Earth
- 12/7/2004

7. Convection inside Earth
Convection in the mantle causes the crust’s plates to move!
- 12/7/2004

8. Continental Drift Alfred Wegener: Hypothesis: He named it PANGEA!
About 300 MYA all continents were once joined together forming a SUPER continent!
He named it PANGEA!

9. Continental Drift Theory
Pangaea begins to break apart and continents move to present day locations
Occured tens of millions of years ago
- 12/7/2004

10. Evidence of Drift Continents fit together like a puzzle
Land forms similar on different continents (like mountain ranges)

11. Evidence of Drift Continued
Fossils found in unlikely places
For example:
Reptiles were found in Antarctica.
Tropical plants found in ice covered places.
- November 27, 2005.
What about the FUTURE?

12. Plates on the Move Plates move 1-10cm/year. Moving apart.
Moving plates cause:
Earthquakes
Volcanoes
- December 13, 2004.

13. http://pubs.usgs.gov/publications/text/ridge.html - December 13, 2004.
Plate Boundaries
Place where two plates meet and interact.
Three Types:
Transform
Divergent
Convergent
- December 13, 2004.

14. Convergent Boundaries
Occurs when two plates collide (run into each other).
Two types:
Continental Oceanic
- December 13, 2004.

15. Continental Convergence
Two plates collide and buckle upwards forming mountains and cause earthquakes!

16. Oceanic Convergence
When two plates collide, one goes under the other called subduction!
Causes volcanoes.

17. Divergent Plate Boundaries
When two plates move apart.
Occurs at two places:
Mid-Oceanic Ridge Land – Rift Valley
- December 13, 2004

18. Sea Floor Spreading
Magma comes up forming new rock and pushes old rock to sides.
- December 13, 2004.

19. The older rock is closer to the continents.
Which Rock is Older?
The older rock is closer to the continents.
New rock is at the mid-oceanic ridge.
- December 13, 2004.

20. Where are Mid-Ocean Ridges?

21. Pacific vs. Atlantic Oceans
Pacific Ocean is getting smaller – continents are coming together. Oceanic crust is moving under them.
Atlantic Ocean is getting bigger – USA and Europe are moving apart!
- December 13, 2004.

22. Transform Boundary
Plates slide past each other in opposite directions.
Causes a lot of earthquakes.