Printed from The Discovery of Hydrothermal Vents - 25th Anniversary
CD-ROM ©2002 Woods Hole Oceanographic Institution
EARLY CLUES: Evidence
Ophiolites: A Bit of Seafloor Thrust
Up Onto Continents
One of the best clues that hydrothermal vents might
exist was right on land. People had known about them for thousands of
years, though they didnt realize what they were.
As early as 3,000 B.C., people mined copper from massive ore deposits on
the island of Cyprus. It was the Roman Empires main source of the
precious metal, which they originally called Cyprium. (Later it became
cuprium, the root of the English word copper.)
In the early 1970s, scientists began to recognize that massive metal-rich
ore deposits like the ones on Cyprus were actually within pieces of the seafloor
that literally had been left high and dry. These slivers of seafloor,
called ophiolites, were pieces of ancient mid-ocean ridges that had been
thrust up onto continents by the movements and collisions of Earths
tectonic plates. They are found in many places around the world.
Ophiolites became a convenient place to examine the results of chemical
and geological processes that took place at and beneath ancient mid-ocean
ridges. With new eyes, scientists closely investigated ophiolites. The
mineral deposits in ophiolites pointed to the existence of seafloor hydrothermal
vents.
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