Notes – Continental Drift
Theory of Continental Drift
Who gave the Theory of Continental Drift?
________________
What is a Continental Drift?
It is the idea or Theory …….. that the continents _________
move over Earth’s surface.
All continents had once been joined together in a ________ land
mass (PANGEA) and later began to drift apart.
Wegener’s 3 main pieces of
evidence
1. LandformsShapes of the Continents – They appeared to ‘fit’ South America
and Africa.
Coal Fields - In North America and Europe match up when pieced
together (also ‘fit’ as well)
Mountains and Rock Layers – In North America and Europe match
up when the continents are pieced together (similar rocks)
2. Fossil Evidence - Fossils of the ________ animals were found
on many different continents, now separated by oceans:
Glossopteris = plant
Cynognathus = land reptile
Lystrosaurus = land reptile
Mesosaurus = freshwater reptile
These organisms had no way to travel across such oceans to
cross that exists today.
Notes – Continental Drift
3. Climate Evidence –
Tropical Plants - Found in areas that are considered
Arctic (frozen) today.
Glaciers - Evidence of glaciers found in areas that have
temperatures far too mild to have glaciers.
Evidence shows that climate must have been much
different in the past
Why didn’t Wegener’s
fellow scientists accept his
theory?
Wegener could not provide an explanation for the force that
pushes or pulls the continents.
Most scientists believed that the Earth was cooling and shrinking,
which created Earth’s mountain ranges. (like the dried up,
wrinkled skin of an apple)
Notes – Continental Drift
Wegener said that if this was true,
Mountains should be found all
over Earth, but they usually occur
in bands along the edges of
continents.
Unfortunately, Wegener died
before his theory was ever
accepted.