 
Why would anyone think that the continents
were ever pushed together?
Wegener proposed the idea of continental
drift
  What is continental drift?
 
That the continents have moved slowly to
their current locations
 
Wegener thought that all the continents were
connected as one large landmass that broke
up about 200 million years ago
He called it
Pangaea
 
 
Wegener came up with the idea of continental
drift, but he could not prove it
What clues led him to believe in continental
drift?
The puzzle-like fit of the continents
  Fossils- specifically Mesosaurus
Mesosaurus fossils were found in South
America and Africa
 
Why is this odd?
Mesosaurus could swim but only in fresh
water.
How could it cross an ocean?
 
There were also Glossopteris fossils:
This was a plant found in Africa, Australia,
India, South America and Antarctica.
Most likely all these areas were once connected
and had similar climates
 
Wegener also used continental drift to explain
evidence about changing climates
Fossils of warm-weather plants were found in
the arctic – those land masses must have
drifted from tropical to arctic areas
Evidence of glaciers was found in warm areasthose land masses must have drifted from arctic
to tropical areas
Similar rock structures are found on different
continents
Parts of the Appalachian Mountains of the
eastern US are like mountains in Greenland and
western Europe
 
This supports the idea that the continents were
once connected
Wegener’s ideas were mostly rejected
because he could not scientifically prove
continental drift.
  No one could yet understand how continents
could move through the denser ocean floor.
  We will learn that next!
