Gibraltar: a time bomb under the Atlantic?

A subduction zone currently under the Strait of Gibraltar will spread further into the interior of the Atlantic and contribute to the formation of an Atlantic subduction system: an Atlantic ring of fire, which will cause a slow "closure" or shrinking of the ocean basin, predicts a study carried out by Portuguese scientists and published in the journal Geology. According to the researchers, this phenomenon will occur in about 20 million years. Entire oceans can close if new "subduction zones" form - and this process may have already begun with the Atlantic, they warn. "We have good reason to believe that the Atlantic is starting to close. [...] Subduction zones are the cause of the closure of oceans, by bringing their seabeds back into the mantle, thus bringing the continents closer together," João Duarte, a researcher at the Dom Luiz Institute, Faculty of Sciences, University of Lisbon, who led the study, told MailOnline.

The 16 km long Strait of Gibraltar separates Spain and Morocco (as well as Europe and Africa). It is the meeting point of two major tectonic plates: the Eurasian plate and the African plate. In this subduction zone, the African plate sinks under the Eurasian plate, leading to seismic activity and earthquake risks. Currently, the subduction zone located under the Strait of Gibraltar is "dormant", which means that the speed at which the plate slides into the Earth’s mantle is "very very slow". But in 20 million years, it could reach a length of about 500 miles, predicts Professor Duarte.

For the study, the Portuguese scientists used computer models to simulate the life of the subduction zone since its birth in the Oligocene era (34 million to 23 million years ago). Then they modeled its destiny in the future, which allowed them to discover that it would move westward through the narrow Strait of Gibraltar over the next 20 million years. "There are two other subduction zones on the other side of the Atlantic: the Lesser Antilles, in the Caribbean, and the Scotia Arc (South Antilles), near Antarctica," says João Duarte. However, these subduction zones have invaded the Atlantic several million years ago. Studying Gibraltar is an invaluable opportunity, as it allows observing the process in its early stages, when it has just occurred."