Continental drift theory (1)

1. Continental Drift TheoryContinental Drift Theory
No need to take notesNo need to take notes
I have taken them for youI have taken them for you

2. "Doesn't the east coast of South
America fit exactly against the west
coast of Africa, as if they had once
been joined?" wrote Wegener to
his future wife in December 1910.
"This is an idea I'll have to pursue."
Alfred was trying to get his
girlfriend’s father to like him. Her
father was a well-known geologist!!

3. Alfred Wegener (Vegener)Alfred Wegener (Vegener)
•As a young scientist, As a young scientist,
Wegener was curious Wegener was curious
about Earth’s continents.about Earth’s continents.
•In 1910, Mr. Wegener In 1910, Mr. Wegener
formed a hypothesis formed a hypothesis
which stated all the which stated all the
continents were once continents were once
joined together in a giant joined together in a giant
landmass.landmass.
•He named this landmass He named this landmass
PANGAEA.PANGAEA.

4. Wegener used 3 types of evidence Wegener used 3 types of evidence
to prove his theory!to prove his theory!
1.Evidence from landforms1.Evidence from landforms

2.Evidence from fossils2.Evidence from fossils
3.Evidence from climate3.Evidence from climate

5. Evidence from landformsEvidence from landforms
•The shapes of the The shapes of the
continents seemed to continents seemed to
fit together.fit together.
•Mountain ranges and Mountain ranges and
other features also other features also
lined up.lined up.

6. The ‘jig-saw’ puzzle
EvidenceEvidence from landformsfrom landforms

7. The ‘jig-saw’ puzzle
Evidence from landformsEvidence from landforms

8. The ‘jig-saw’ puzzle
Evidence from landformsEvidence from landforms

9. Evidence from FossilsEvidence from Fossils
•Fossils from one Fossils from one
continent matched continent matched
fossils from other fossils from other
continents.continents.
•Wegener used both Wegener used both
plant and animal plant and animal
fossils.fossils.
Glossopteris: a fern
found on the southern
continents
Mesosaurus: a
freshwater swimming
reptile found in Africa
and South America

10. fossil matches
Evidence from Fossils

11. fossil matches
Evidence from Fossils

12. Evidence from ClimateEvidence from Climate
•Wegener looked at Wegener looked at
certain areas on Earth certain areas on Earth
and their climatesand their climates
•He noted that the He noted that the
fossils he found on fossils he found on
certain sections of certain sections of
Earth did not match Earth did not match
the current climate the current climate
•Glacier scratches in Glacier scratches in
S. Africa S. Africa

13. Antarctic ice
Evidence from ClimateEvidence from Climate

14. Ice could not have extended this far.
So...continents MUST have moved..
Evidence from ClimateEvidence from Climate

15. Drift awayDrift away
Continental Drift Theory
At first
nobody
believed
Alfred
Wegener’s
theory…..
WHY YOU
ASK!
He could
not prove
how or
why the
continents
moved.

16. Scientists still do not appear to understand sufficiently that all
earth sciences must contribute evidence toward unveiling the
state of our planet in earlier times, and that the truth of the
matter can only be reached by combing all this evidence. . .
It is only by combing the information furnished by all the
earth sciences that we can hope to determine 'truth' here,
that is to say, to find the picture that sets out all the known
facts in the best arrangement and that therefore has the
highest degree of probability. Further, we have to be
prepared always for the possibility that each new discovery,
no matter what science furnishes it, may modify the
conclusions we draw."
Alfred Wegener.
The Origins of Continents and Oceans (4th edition)