1. Overview of Plate Tectonics Processes
But NO PROOF!!!

2. To sustain such topography the earth must be dynamic

3. Earth’s primary
Layered structure

4. What is the “shallow” structure?
Shallow = ~ 200 km
Note the names of the layers and thicknesses.
Not labelled: Inner core begins at
~ 5,150 km depth

5. CRUST and UPPER MANTLE

6. Note: image not extended to full lithosphere depth

7. Typical Numbers for “crustal thickness”
Continental: Average ~ 35 km
Continental: Range: 20 – 75 km
Oceanic: Average ~ 7 km
Oceanic: Range ~ 5 – 10 km
Lithosphere: (fill in yourself!)
Asthenosphere: (fill in yourself!)

8. Cross section of the earth

9. EARTH’S DENSITY AS A FUNCTION OF DEPTH
APPROXIMATE COMPOSITION OF MAJOR LAYERS

10. DENSITY vs
DEPTH

11. Composition in the
major layers of the
Earth

12. Generating New (Oceanic) Crust
Seafloor Spreading (Divergent Plate Boundary)

18. A Research Article (Just to point out that EAR is an active research area)
History of the development of the East African Rift System: A series of interpreted maps through time

19. What happens to all this new oceanic crust?
Subduction Zones (Convergent Boundary)

20. Generate
continental
Crust
(subduction zone)

21. Generate
Oceanic
Crust
(subduction zone)

22. What happens when trailing continental crust collides?
(convergent boundary)

26.
India/Asia:

27. What’s happening on the ocean floor during all this?!?!
Transform Plate Boundaries
(and Divergent, again)

29. Marie Tharp produced the first maps of mid-oceanic ridge system and the axial valleys between the ridges

31. Note the three types of plate boundaries and types of locations.

32. How did we get to our present configuration of oceanic and continental crust?

35. Plate Tectonics
Is an excellent unifying model of earth dynamics as a whole
Context for understanding earth processes
Create testable hypotheses, predictions
“Exceptions” exist

36. No “proof” has been provided for any of the ideas presented above
Evidence for these processes will be noted and discussed as the class goes on.
Processes have been stated to give context for our study of geologic processes
No “proof” has been provided for any of the ideas presented above
IMPORTANT CLASS THEME

37. Plate Tectonics Is Still Not Fully Understood
Simplest possible question: When did Plate Tectonics begin?

38. Advice
When reading and thinking about geology, have scratch paper handy – sketching processes will really help you learn and internalize the ideas.
Often, an exam/quiz question I write will say Use an annotated sketch to explain …