Download Continental Drift

CONTINENTAL
DRIFT
What evidence do scientists have to support the
fact that the Earth’s crust is continuously
moving?
1500S – ABRAHAM ORTELIUS
Saw that the
coastlines of Africa
and the Americas
looked similar
 Concluded they must
have once fit together
 Broke apart due to
floods, earthquakes
and volcanoes

1800S – EDUARD SUESS
Stated that the
southern continents
were once a single
landmass called
Gondwanaland
 Northern continents
called Laurasia

1900S – ALFRED WEGENER
 Continental
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
Drift
Hypothesis that
Earth’s continents
were joined as a
single landmass
that broke apart
about 200 million
years ago (mya)
Known as
Pangaea
Continents slowly
moved to their
present locations
PANGAEA - ALL EARTH
EVIDENCE FROM FOSSILS
Similar fossils of several different plants and
animals that once lived near each other found on
widely separated continents
 Land animals did not swim across ocean, so there
had to be a land connection between continents

EVIDENCE FROM ROCK FORMATIONS
Similarly, rock
formations are similar
on distant continents
 For example, rock
types found in
Appalachian
Mountains similar to
those found in
Greenland and
Europe

CLIMATIC EVIDENCE
Coal deposits in Antarctica indicate that the
climate was much warmer in the past
 Must have been located closer to the equator
before it drifted

FLAWS IN CONTINENTAL DRIFT THEORY
 Wegener’s
theory of continental drift had
some notable flaws:

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Not able to explain what force was large
enough to move such large pieces of earth over
great distances
Not able to explain how the ocean basins were
not shattered, despite solid landmasses
crossing through them
REVIEW QUESTIONS
What does Pangaea mean in Greek?
 What was Ortelius’ contribution to Continental
Drift?
 Who is credited with the theory of Continental
Drift?
 List and describe the three main evidences for
Continental Drift.
 What is one major flaw in the theory of
Continental Drift?
