1. Geology: Plate Tectonics
By: Ms. Kristin Wilkinson

2. Plate Tectonics Pangea Eurasia North America Africa South America
India
Australia
Plate Tectonics
Antarctica

3. 1-2. Continental Drift (Old Theory)
Alfred Wegener (1900’s) proposed Continents were once a single land mass that drifted apart called- Pangea
Evidence or proof! Fossils of the same plants and animals are found on different continents
Called this supercontinent Pangea, Greek for “all Earth.” Continents fit like a puzzle
245 Million years ago
Split again – Laurasia & Gondwana 180 million years ago

5. 3. What are Plates? 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

6. Tectonic Plates

8. 4. Evidence for Continental Drift
Fossil Clues
Animals
Mesosaurus is a reptile found only in S. America & Africa
Plant
Climate Clues
Glacial deposits
Rock surfaces
Rock Clues
A golden orb-weaver spider from the Middle Jurassic
Inocaulis Silurian Plant Fossil

9. Evidence of Pangea

13. 5. Theory of Plate Tectonics
Due to the mapping of the ocean floor scientists discovered mid-ocean ridges, thus leading towards this new theory.
Seafloor spreading creates new crust along the ridge and older crust is pushed farther away from ridge.

14. CONVECTION CURRENT!!! 6. How Do Plates Move?
Tectonics and Volcanism II

15. 7. Plate Boundaries
Divergent Boundaries – plates move AWAY from each other.
Convergent Boundaries – plates move TOWARD each other.
Transform Boundaries – plates SLIDE past each other.

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

17. Divergent Boundary – Iceland

18. Iceland

19. Divergent Boundary - Oceanic

20. Divergent Boundary - Continental

21. Convergent Boundary – Indian and Eurasian Plates
Indian Plate

22. Convergent Boundary – Oceanic & Continental
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23. Convergent Boundary – Oceanic & Oceanic
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24. Convergent Boundaries - Continental
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25. Transform Boundary – San Andreas Fault

27. Review Name the 3 main layers of the Earth. What is a tectonic plate?
What was Pangea?
Name the three different types of plate boundaries and one location on Earth for each one

28. 11. Dynamic Earth Forces that Shape Earth
Isostasy – the relationship between crust and asthenosphere
Vertical Stress
Subsidence and Uplift
Horizontal Stress
Compression
Tension
Shearing

29. Dynamic Earth… Slow Changes… Rapid Changes to the Earth’s Surface
Earthquakes, Tsunami’s, Volcanic Eruptions
Slow Changes…
Mountain building, Ridge building, island arcs, Volcanic arcs &hot spots

30. 12. Landforms Created by Compression
Mountain ranges
Ocean trenches
Volcanic arcs
Island arcs

31. 13. Landforms Created by Tension
Mid-ocean ridges
Continental rifts

32. 14. Landforms Created by Shearing
Transform Faults