All those centuries of wishing that Europeans had never come to Turtle Island may well be rendered moot—at least, in a couple of million years.
A group of scientists in Melbourne, Australia, have found that North America is inexorably being pulled toward the Iberian Peninsula by the clashing of two tectonic plates that are showing signs of increased activity. In time—lots and lots of time—the Atlantic Ocean will be no more, said the researchers at the Monash University School of Geosciences in a statement announcing their results on June 16.
“The fault system may herald the start of a cycle that will eventually see the Atlantic Ocean close up as North America is pulled towards the Iberian Peninsula,” ABC of Australia described it.
Mother Earth is covered in tectonic plates that float on the liquid rock magma just beneath the planet’s crust. Over the past four billion years the plates have moved around quite a bit, breaking up and re-forming at lest three times, the university’s statement said.
A subduction zone is a plate containing an ocean dives under a landmass, as National Geographic explains it. The overlying plate lifts up, forming mountain ranges, while the one being shoved underneath melts and spurts out from volcanoes elsewhere, in the form of lava, forming volcanic mountain ranges.
Using a devastating 1755 earthquake in Lisbon as a starting point—it killed 100,000 people—university researcher João Duarte and his team mapped out the ocean floor using sonar imaging and precise measurements of seismic activity to create a three-dimensional model of what’s going on at the floor of the Atlantic Ocean. They found that it is beginning to fracture, which told the team there is tectonic activity around the boundaries of the South West Iberian plate, they said in their statement. That means the Eurasian plate, pressured by the African plate, is “fracturing and folding in on itself," ABC explained, and the information provided the evidence they needed that there is a new subduction zone.
"What we have detected is the very beginnings of an active margin—it's like an embryonic subduction zone," Duarte said in the university statement. "Significant earthquake activity, including the 1755 quake which devastated Lisbon, indicated that there might be convergent tectonic movement in the area. For the first time, we have been able to provide not only evidences that this is indeed the case, but also a consistent driving mechanism."
The findings could help scientists better understand and predict seismic activity, Duarte said. Understanding the Earth's long-term evolution is another bonus.
"Understanding these processes will certainly provide new insights on how subduction zones may have initiated in the past and how oceans start to close," Duarte said of the research, which was published in the journal Geology.