How the Atlantic Ocean Could Disappear
This one came in a University of Alberta dispatch about research on the role of subduction — that is, the sinking of one tectonic plate beneath another as they collide — in the disappearance of the ancient Iapetus Ocean some 420 million years ago.
The closing of the Iapetus, which occupied roughly the same spot as today’s North Atlantic Ocean is the subject of a just-published article in the journal Geology by earth and atmospheric sciences professor John Waldron and colleagues.
That’s all pretty interesting, but the kicker comes at the end, in which the release notes: “The modern Atlantic may be similarly doomed to close, in the distant future. If subduction zones like those around the Caribbean Plate continue to consume the floor of the Atlantic Ocean, eventually the continents around the Atlantic may collide to form a mountain range and a new supercontinent.”
That idea may give a momentary shock to everyone who owns beachfront real estate in North Carolina or Florida, but not to worry. According to the release, Waldron says that the process is likely to take another 100 million years to occur, though other sources see it taking several times longer.
And you’ll have to forgive all the scientists who respond to this revelation with a yawn, since the rise of a supercontinent isn’t actually big news in a geologic sense. As Yale University geophysicist Ross Mitchell explained to Science magazine back in 2012, the Earth has seen the rise and disappearance of three supercontinents over the past two billion years or so. The oldest one, Nuna, came together about 1.8 billion years ago, and was followed 800 million years later by Rodinia. The most recent, Pangea — alternatively spelled Pangaea — was fully assembled by the Permian Period, 270 million years ago, and began to break apart about 70 million years later.
Scientists, who’ve deduced the movements of those land masses in part by analyzing the mineral content of rock deposits, have constructed models for where they’ll go in the future. In one model, the motions of tectonic plates will cause the Arctic Ocean eventually will result in a supercontinent called Amasia.
If geological history is any guide, that supercontinent will last for no more than 100 million years, before it begins to break up.