1. Development of the Theory of PLATE TECTONICS

2. Continental Drift
1912 – Alfred Wegener (German) suggested that the continents were once joined together forming a super- continent called Pangaea.
Pangaea – all land
Panthalassa – all ocean
Laurasia – Northern section of Pangaea
Gondwanaland – Southern section of Pangaea

3. Evidence for Continental Drift
By 1912 the maps of the continents were accurate enough to use scientifically…
1) THE COASTLINES OF CONTINENTS FIT LIKE A PUZZLE!

4. Evidence for Continental Drift
Fossil evidence
2) MESOSAURUS (ancient alligator) – fossils found in South America and Africa
3) GLOSSOPTERIS (ancient fern tree) – fossils found in Antarctica, India, Australia, Africa, and South America

5. Other Fossils
) Lystrosaurus- Land reptile found in south Africa, Antarctica, and India.
Cynognathus- Land mammal-like reptile found in central South America
and Africa.

6. Evidence for Continental Drift
Rock Types
4) The Appalachian Mountains have the same composition and age as the mountains found in Africa and Northern Europe

7. Evidence for Continental Drift
Climate Change
5) Glacial erosion (striations and erratics) are found in tropical and sub- tropical locations in Africa, South America, India, and Australia

8. EVERYONE LAUGHED AT HIM!!!
ALFRED WEGENER COULD NOT EXPLAIN HOW OR WHY THE CONTINENTS MOVED. IT JUST SEEMED TOO IMPOSSIBLE FOR PEOPLE TO BELIEVE.

9. Sea-Floor Spreading 1960s – Harry Hess (American), Glomar Challenger
Used modern day SONAR to map the ocean floor.
He discovered the Mid-Ocean Ridges AND suggested that the sea-floor is actually growing

10. Evidence for Sea-Floor Spreading
6) Age of Rocks on Sea-Floor
Hess found that the rocks were
youngest near the mid-ocean ridge
and
oldest near coastlines of continents.

11. Evidence For Sea-Floor Spreading
7) Paleomagnetism
The magnetic poles of Earth have shifted several times throughout the course of Earth’s History.
When a rock forms it takes on the magnetic orientation of the Earth at that time
The magnetic orientation is mirrored on the ocean floor

12. The Final Piece of Evidence
Earthquake Data proves that pieces of the earth’s crust (plates) MOVE!!!!!!!
Do Now: see handout

14. Complete the Plate Map Activity

15. 1.Put your name and a title on front of puzzle.
Plate Tectonic Puzzle
-Using your notes, and pgs of your textbook, complete the following.
1.Put your name and a title on front of puzzle.
2. Complete a key to indicate the 3 ways plates interact. -Divergent
-Convergent
-Transform
3. Like the examples show, identify all plates by name.
4. Label the location of all 8 of the following,
-Himalayan Mtns Appalachian Mtns
-Mid-Atlantic Ridge -African Rift Valley
-Andes Mtns -San Andreas Fault
-Japan -Mariana Trench
5. Using the colors from your key, identify which type of plate interaction exists at each boundary for the items from #5.

16. PLATE TECTONICS
The theory of Plate Tectonics suggests that the crust and upper mantle (lithosphere) is broken into sections called plates. The plates move and float on the liquidy part of the mantle called the Aesthenosphere.

17. PLATE TECTONICS
The plates grow, shrink, and move due to CONVECTION CURRENTS IN THE MANTLE

18. How do the plates interact?
3 types of plate boundaries:
Convergent Boundary – move toward one another
Divergent Boundary – move away from one another
Transform Fault Boundary – slide past one another

19. Convergent Boundaries (type 1)
Oceanic Crust – Continental Crust
Subduction Occurring – creates trenches, coastal mountains and volcanoes
Examples: Andes Mountains, Appalachian Mountains

20. Convergent Boundaries (type 2)
Continental Crust – Continental Crust
Creates large mountain ranges
Examples: Himalaya Mountains

21. Convergent Boundaries (type 3)
Oceanic Crust – Oceanic Crust
Subduction Occurring – creates trenches, island arcs and volcanoes
Examples: Japan Island Arc, Mariana Trench

22. Divergent Boundaries (type 1)
Mid-ocean ridges (Mid-Atlantic Ridge)

23. Divergent Boundaries (type 2)
Rift Valleys (African Rift Valley)

24. Transform Fault Boundaries
Creates Earthquakes (San Andreas Fault)

25. Practice