Plate Tectonics and the History of the Earth.
It is believed that there was
once a very large single
piece of land called Pangaea,
(pronounced "pan-jee-er", from Greek 'all-earth').
Pangaea split up and the separate pieces
of land moved apart as the plates drifted on the mantle.
The evidence for this theory of Alfred Wegener comes from
1) Rocks each side of
the Mid-Atlantic ridge
show identical magnetic orientation, see Sea-floor spreading.
This is the clearest evidence for continental drift.
2) Today's continents
can be pieced together.
South America fits very neatly alongside Africa.
3) Similar fossils of the same
age are found
in different parts of the world,
suggesting that these pieces of land were connected in the past.
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Copyright © 2012 Dr. Colin France. All Rights Reserved.