Oceans like the Atlantic start to close.By Professor Tanvir Ali Khatana.

The researchers concluded that invasive subduction may be a common way that oceans like the Atlantic start to close, and therefore may be a major factor in how our planet has geologically evolved.Atlantic Ocean May ‘Soon’ Begin to Close

The vast stretch of ocean between the Americas and Europe may be about to close soon — on a geological timescale.

Just before the continents begin to drift back together, an “Atlantic ring of fire” is expected to form, with the area of tectonic activity moving from the Mediterranean into the Atlantic

This is due to begin happening in about 20 million years — just around the corner geologically, but an unfathomably long period of time on a human scale.Image of the tectonic plates making up the Atlantic ocean. The Atlantic may start to close in around 20 million years.

ELLIOT LIM, CIRES & NOAA/NCEI

Tectonic plates are constantly moving, just incredibly slowly. Sometimes, oceans are born as plates move apart, and close again as plates move back together over hundreds of millions of years, in a process called the Wilson Cycle. This is what drove the megacontinent of Pangaea to break up 180 million years ago, forming the Atlantic, and squishing the ancient ocean Tethys into what is now the Mediterranean.

For the Atlantic to close, new subduction zones need to form. These are places where one plate is forced beneath the other into the Earth’s mantle, occurring due to differences in density between the two plates, typically with an oceanic plate being subducted beneath a continental plate or another oceanic plate.

Subduction zones are characterized by intense geological activity, including earthquakes, volcanic eruptions and the formation of deep oceanic trenches.

These zones are hard to form, however, as plates are very strong and a subduction zone would require a plate to break and bend. However, subduction zones that already exist can migrate in a process known as subduction invasion.

According to the paper, which used computational models to predict future plate tectonics, the subduction zone in the Mediterranean underneath the Gibraltar Strait is expected to move further into the Atlantic in about 20 million years, forming an Atlantic ring of fire like the one surrounding the Pacific.

“Subduction invasion is inherently a three-dimensional process that requires advanced modeling tools and supercomputers that were not available a few years ago. We can now simulate the formation of the Gibraltar Arc with great detail and also how it may evolve in the deep future,” paper co-author João Duarte, a researcher at the University of Lisbon’s Instituto Dom Luiz, said in a statement.

Maps from the paper showing the evolution of the Gibraltar subduction zone from 30 million years ago to 50 million years into the future. This subduction invasion may drive the closing of the Atlantic ocean.

JOÃO C. DUARTE / DUARTE ET AL., 2024

The researchers describe how the Gibraltar subduction zone has slowed down over the past few millions of years, with few scientists considering it still active. After the zone enters the Atlantic, however, it is expected to get much more active, driving the closing of the Atlantic Ocean over several more “There are two other subduction zones on the other side of the Atlantic — the Lesser Antilles, in the Caribbean, and the Scotia Arc, near Antarctica. However, these subduction zones invaded the Atlantic several million years ago. Studying Gibraltar is an invaluable opportunity because it allows observing the process in its early stages when it is just happening,” Duarte said.millions of years.The researchers concluded that invasive subduction may be a common way that oceans like the Atlantic start to close, and therefore may be a major factor in how our planet has geologically evolved.

This is due to begin happening in about 20 million years — just around the corner geologically, but an unfathomably long period of time on a human scale.

Image of the tectonic plates making up the Atlantic ocean. The Atlantic may start to close in around 20 million years.