Download Continental Drift

Warm up


What evidence did Wegner use to
support his theory of Continental
Drift?
What theory did this lay the
groundwork for?
Alfred Wegener

In 1910, Alfred
Wegener
became curious
about the
continents. He
formed a
hypothesis that
the continents
had moved.
Continental Drift

Wegener’s hypothesis
was that all continents
had been joined together
in a single landmass
and have since moved
apart.

He named
this super
continent
Pangaea.
This idea was
known as
Continental
Drift.
Evidence

1. Landforms
• Mountain ranges and other
features on continents provided
evidence. South America and
Africa fit together like puzzle
pieces. A mountain range in
South America lined up with a
mountain range in Africa.
European coal fields matched up
with ones in North America.

2. Fossils
• A fossil is a trace of an organism
preserved in rock. Fossils of the
reptiles Mesosaurus and
Lystrosaurus had been found in
places now separated by oceans.
Another example was the fernlike plant Glossopteris found in
Antarctica, Africa, South
America, Australia and India.
Pangaea had 2 parts


Laurasia: made up of North America,
Europe and Asia
Gondwanaland: made up of South
America, Africa, Antarctica, Australia

3. Climate
•Fossils of tropical plants
were found in Antarctica.
•Glaciers once covered
South Africa. Deep
scratches from the
glaciers were found on
rocks.
Rejection of Wegener’s
Hypothesis

Wegener could not provide
evidence for the forces that push
or pull the continents. Many
geologists in the 1900’s thought
the earth was slowly shrinking
and cooling. Wegener disagreed
with this proposal because
mountains usually appear in
narrow bands along the edge of
continents

Now scientists have new
evidence to support the
theory of Continental
Drift.
New Evidence Today

The Ring of Fire: showing that the
plates once were connected and
convection currents in the mantle
has caused the movement and the
eruption of volcanoes and
earthquakes.