Download Sea-floor Spreading

Sea-floor Spreading
It’s tearing me apart!
The Idea
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Sea-floor spreading is the process in
which the ocean floor is pulled outwards
when two plates move apart. As the
plates move apart, the rocks break and
form a crack between the plates.
Magma rises through the cracks and
seeps out onto the ocean floor.
The Man
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Born in 1906
Became a professor
of geology at
Princeton in 1932
He commanded a
submarine base
during World War II
In 1960 he hypothesized that the sea-floor was
spreading from vents (underwater holes) in a
rift found in the Atlantic Ocean
The Evidence
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During WWII, his
mission was to study
the deepest parts of
the ocean floor
•
Until this time,
scientists believed the
sea-floor was
completely flat!
The Evidence
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Hundreds of flat
topped mountains in
the Pacific Ocean
Great Global Rift in
the Atlantic Ocean
In his own words.
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It was possible that molten magma from
beneath the earth's crust could ooze up
between the plates in the Great Global Rift.
As this hot magma cooled in the ocean water,
it would expand and push the plates on either
side of it -- North and South America to the
west and Eurasia and Africa to the east.
This way, the Atlantic Ocean would get wider
but the coastlines of the landmasses would not
change dramatically.