SECTION 3 DRIFTING CONTINENTS

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Transcript SECTION 3 DRIFTING CONTINENTS

SECTION 3
DRIFTING
CONTINENTS
1. ALFRED
WEGENER
hypothesized that all
of the continents had
once been joined
together in a
SINGLE LANDMASS
and have since
DRIFTED apart.
2. Wegener named this
supercontinent PANGAEA
meaning “all LAND”.
3. Wegener’s idea that the
continents slowly moved over
Earth’s surface became known
as CONTINENTAL DRIFT.
4. Wegener
published all his
evidence for
continental drift in
a book called THE
ORIGIN OF
CONTINENTS
AND OCEANS.
5. Wegener used
evidence from:
Landforms
1. When he pieced
together maps, he
noticed that a
mountain range in
SOUTH AFRICA lines
up with a mountain
range in
ARGENTINA.
Landforms
2. EUROPEAN coal fields
match up with similar coal
fields in NORTH AMERICA.
Fossils
1. FOSSIL – any trace of an
ancient organism that has been
preserved in rock.
Fossils
2. Fossils of the REPTILES
Mesosaurus and Lystrosaurus have
been found in places now
separated by OCEANS.
Fossils
3. Fossils of Glossopteris (a fernlike
PLANT that lived 250 million years ago)
have been found in rocks in AFRICA,
South America, AUSTRALIA, India, and
ANTARCTICA.
Climate
1. The island of SPITSBERGEN lies in the
Arctic Ocean north of Norway. It has a
harsh, POLAR climate. Fossils of
TROPICAL plants are found on Spitsbergen.
This made Wegener think the island was
once located closer to the EQUATOR.
Climate
2. Deep scratches in rocks show that continental
glaciers once covered SOUTH AFRICA. Today, the
climate is too MILD for these thick layers of ice to
form. Wegener concluded that South Africa was
once much closer to the SOUTH POLE.
6. As a continent moves
toward the EQUATOR,
its climate becomes
warmer. As a
continent moves toward
the POLES, its climate
becomes colder.
However, the continent
carries with it the
FOSSILS and ROCKS
that formed at its
previous location.
7. Wegener could not
provide a satisfactory
explanation for the
force that PUSHES or
PULLS the continents.
Therefore, most
geologists REJECTED
his idea of continental
drift.