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Chapter 4 - 2
Restless Continents
Continental Drift Theory
 Alfred Wegener
 Continents can drift apart from one another and have
done so in the past
Pangea
 Greek word meaning “All Earth”
 Name for the single land mass that is the separate
continents of today
Panthelassa
 Name for the single ocean of the world that is the
separate oceans of the world today.
Sea-Floor Spreading
 Process by which new oceanic lithosphere is created as older
materials are pulled away
o Tectonic plates move apart causing the sea floor to
spread apart
o Magma rises to fill in the gap
o New oceanic crust is created
o This takes place at the Mid-Ocean Ridges
Mid-Ocean Ridges
 Underwater mountain chain that runs through the Earth’s
oceans