1. Theory of Plate Tectonics
1. Continents appear to “drift” with time

2. Continental drift

3. Evidence for continental drift
1. Puzzle like fit of continents

4. Fossils correlation

5. Rock Correlation

6. Glacier Evidence

7. Mountain Belts

8. Buckled Mountains on Continental Margins

9. Theory of Plate Tectonics
Continents appear to “drift” with time
Lithosphere is broken up into rigid “plates”, that are moving

10. Earth’s Plates

11. Plate
Plate
ASTHENOSPHERE

12. To keep the oceans from spilling out And losing all the fish!
The plates can’t curl down
They must curl up
To form a kind of dish
To keep the oceans from spilling out
And losing all the fish!
- King, 1971, Nature

13. Theory of Plate Tectonics
Continents appear to “drift” with time
Lithosphere is broken up into rigid “plates”, that are moving
There are three types of plate boundaries:
Divergent
Convergent
Transform

14. 3 types of plate boundaries:
Divergent – 2 plates move away from each other,
such as a mid ocean ridge where sea floor
spreading occurs
2. Convergent – where 2 plates collide
3. Transform boundary – where 2 plates slide
along side of one another

15. Why do the plates move?

16. Heat – the driving force

17. Mid-Atlantic ridge Sea Floor Spreading!
Did you know that the ocean floor in the Atlantic is growing by 3cm per year?
Which of the following pairs of continents are moving further away from each other?
Europe and Africa
Europe and North America
South America and North America

18. Divergent Plate
Boundary
Creation of
An ocean
Sea Floor Spreading

20. Iceland – a country being split apart
is on the Mid-Atlantic Ridge

21. A new ocean forming?

22. Rift Valley in Africa

24. Magnetic Anomalies Prove Seafloor Spreading

27. The further from
a ridge, the older
the rock
oldest
youngest

28. Divergent plate boundaries
MID OCEAN RIDGE A
Ocean B
Oceanic Crust
Mantle
Where would you find older rocks – at A or at B?