1. Notebook Setup
On pages 28 – 29, glue down the “Physical Geography: Plate Tectonics” worksheets
On pages 30 – 31, glue down the “Oreo Cookies and Plate Tectonics” worksheets

2. Warmup
What is the “truth”? How do you define “truth” and is it debatable? Is your “truth” different from someone else’s “truth”?

3. Physical Geography Plate Tectonics

4. Geologic Time January 1 - Earth and planets formed
Pretend the age of the earth (4.6+ billion years) is compressed into one calendar year.
January 1 - Earth and planets formed
Early March - liquid water stands in pools.
Late March - earliest life
July - oxygen is important part of atmosphere
October 25 – multi-cellular organisms
Late November - plants and animals abundant
December 15 to 25 - dinosaurs arise and disappear
11:20 pm, December 31 - Humans appear
One second before midnight - Automobile invented

5. What is ‘tectonics’?
The word “tectonics” comes from the Greek ‘tektonikus’, meaning “building or construction”
Plate tectonics refers to the process of earth crust formation, movement, and destruction.

6. What is a ‘Plate?’ Lithospheric plate: crust + upper mantle
Asthenosphere: plastic mantle

7. History of Plate Tectonics
‘Fit’ of coastlines was recognized by Sir Francis Bacon in the 1600s
But how did the continents move?

8. 1915 = Alfred Wegener proposed the theory of continental drift.
Supercontinent Pangaea (‘all-earth’) [225mya].
Fragmentation and drift to current positions.

9. Plate Movement History

10. STOP: Answer this question
What would scientists need to find to prove that the continents were once connected?
Check with your neighbor to see what they thought scientists should look at.

11. Wegener’s Evidence Fit of continents
Fossil plants, animals, rock types / geology
matched on opposite shores
deposits inconsistent with current geography

12. Striking Match of Geologic Regions

13. Striking Match of Biological Regions

14. History of Plate Tectonics
Main problem with the theory of plate tectonics:
Couldn’t explain how the continents ‘drift’!
Wegner hypothesized spin of Earth or tides…..

15. History of Plate Tectonics
Arthur Holmes (1930s) came up with a new theory of motion:
Thermal convective cells in the upper mantle (aesthenosphere)
theory is largely ignored

16. History of Plate Tectonics
In the 1960s, Harry Hess and Robert Deitz (geophysicists) proposed sea floor spreading along mid-oceanic ridges for plate motion.

17. Sea Floor Spreading

18. STOP: Answer the question
If the sea floor is spreading in some places, what’s happening in other places? Is Earth getting bigger?
What do your neighbors think about your ideas?

19. Plate Tectonics Theory
Continental Drift + Sea Floor Spreading  Theory of Plate Tectonics

20. Plate Tectonics Theory
Plate boundaries: main location for Earth’s volcanic and earthquake activity. This is the main place where mountains are created.
Type of plate boundary determines activity.
3 types:
diverging (spreading)
converging (colliding)
transform (sliding)

22. Geography of the Plates
7 major plates; several minor plates
Small plates / boundaries still unknown

23. Plate Margins: how do we know?
Marked by volcanic and tectonic activity

24. Convergent Plate Boundaries
Activity:
1) Subduction (heavier plate dives under another)
2) Earthquakes
3) Volcanism
Features:
1) Ocean trench
2) Explosive volcanic mountains

25. Convergent Plate Boundaries
Examples:
Himalaya Mountains
Andes Mountains
Ring of Fire

26. Divergent Plate Boundaries
Landscape features:
Land: rift valleys, volcanic mountains, thinning crust
Ocean/sea: rift valleys, mountain ranges

27. Divergent Plate Boundaries
Examples:
Atlantic Mid-Oceanic Ridge
Red Sea
Rift valleys of eastern Africa

28. Transform Plate Boundary
Activity: Two plates slip past each other; Earthquakes
Features: Faults
Example: San Andreas Fault, California

29. Activity! DON’T EAT THE OREO! I will not give you another one!
Try to keep your Oreo crumbs on the plate
Try to be careful with twisting off the Oreo top so it doesn’t break right away