CINCINNATI, Ohio -- Most people have heard about the mythical lost continent of Atlantis, but University of Cincinnati geologist Warren Huff is more interested in the disappearance of the ancient Iapetus Ocean, an ocean some believe may never have existed at all.
During a presentation Wednesday, Oct. 22 at the annual meeting of the Geological Society of America in Salt Lake City, Huff will present evidence from ancient volcanic ash beds which he believes demonstrates a narrow Iapetus Ocean did exist during the Ordovician but closed off and disappeared by the Silurian 420 million years ago.
"If you look at the younger beds 420 million years ago there is no more Iapetus Ocean," said Huff. "The question is whether there ever was one."
The best way to determine whether the ocean existed is to look at the land masses which would have surrounded it. If large land masses were locked together, there would have been no room for an Iapetus Ocean to exist. If they were spread farther apart, the ocean would have filled the gap between ancient continents.
There are three basic tools geologists have to determine how the ancient continents were spread out over the globe: paleo- magnetic data, the fossil record, and the ash beds left by massive, explosive volcanism.
Paleo-magnetic data is difficult to interpret during the time period in question. The fossil record indicates strong similarities between what is now Texas and the southern Applachians and a portion of Argentina known as the Precordillera. Those similarities have led some geologists to argue that ancient North and South America were smashed together side by side. That would leave no room for the Iapetus Ocean.
Huff and his collaborators have examined dozens of ancient volcanic ash beds, including 30 in the Argentine Precordillera. They find no similarities between ash beds in North and South America.