1. Evidence for Continental Drift
Unit 12.1

3. continental drift theory
These observations lead him to come up with the ___________________________
A very long time ago (~200 million years) the continents were joined together in a ___________________ called ______________.
Continents _________ around the world
continental drift theory
supercontinent
Pangaea
move

4. 1. The shape of the continents
The shape of the continents fit together like jigsaw pieces.
the continents fit together even better if we include the ___________________________
continental shelf

5. 1. The shape of the continents

6. 1. The shape of the continents

7. Pangaea

8. 2. Matching geological features

9. 3. Matching fossils

10. 3. Matching fossils

11. 4. Paleoglaciation

12. 4. Paleoglaciation

13. 4. Paleoglaciation

14. that the Earth is too young
Some scientists opposed Wegner’s theory of continental drift
The age of the Earth is debated. Continental drift takes a VERY long time and many scientists believe ___________________________
Wegener could not explain how continental drift occurs. How can huge pieces of land move?
that the Earth is too young

15. The Earth
Unit 12.2

19. Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on magma
there are ______ major tectonic plates and many smaller ones
continents are _________ to the tectonic plates
tectonic plates are always ______________

20. floating
Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on magma
there are ______ major tectonic plates and many smaller ones
continents are _________ to the tectonic plates
tectonic plates are always ______________
molten

21. floating molten 12 attached moving
Tectonic plates are like giant pieces of rock ____________ on top of the ___________ asthenosphere. They float on magma
there are ______ major tectonic plates and many smaller ones
continents are _________ to the tectonic plates
tectonic plates are always ______________
molten 12
attached
moving

23. Why do the tectonic plates move?

25. rises
sinks
Convection is a process where hot material _________ and cool material _________. Tectonic plates are always moving due to convection. They move at a rate of ______________!
2 cm/year