North and South America may be drifting away from Europe and Africa: study

Thirty-nine Ocean Bottom Seismometers were deployed on the ocean floor across the Mid-Atlantic Ridge as part of the PI-LAB experiment. (MAR)

TORONTO — A new study has found that an upsurge of matter from beneath the Earth's crust under the Atlantic Ocean may be pushing the continents of North and South America farther apart from Europe and Africa.

Researchers out of the University of Southampton have found evidence of a "mantle upwelling" from depths of more than 600 kilometres beneath the Mid-Atlantic ridge, causing the distance between continents to increase.

"There is a growing distance between North America and Europe, and it is not driven by political or philosophical differences -- it is caused by mantle convection," one of the study's chief scientists, Nick Harmon, said in a press release.

The findings were published Wednesday in the British weekly scientific journal Nature.

According to the study, the tectonic plates attached to the Americas are moving apart from those attached to Europe and Africa by four centimetres each year. As the plates move, researchers say new plates form to replace them at the central point between the regions, known as the Mid-Atlantic Ridge.

Researchers reported that it is typically believed that the shifting of tectonic plates is driven by forces of gravity or the plates sinking back into the Earth. However, they say the cause behind the separation of the Atlantic plates specifically has "remained a mystery" because the Atlantic Ocean is not surrounded by "dense, sinking plates."

The authors of the study conducted two research cruises over 10 weeks and deployed 39 seismometers to the bottom of the Atlantic Ocean. The data collected showed that an upwelling in the material between the Earth's crust and its core over 600 kilometres beneath the Mid-Atlantic ridge could be pushing the plates from below.

This depth below the mantle is associated with "abrupt changes in mineral phases," according to the study. Researchers say upwellings beneath ridges were typically thought to originate from much shallower depths at around 60 kilometres.

"This work is exciting and that it refutes long-held assumptions that mid-ocean ridges might play a passive role in plate tectonics. It suggests that in places such as the Mid-Atlantic, forces at the ridge play an important role in driving newly formed plates apart," University of Oxford professor Mike Kendall said in the release.

Researchers say the data provides the "first large-scale and high-resolution imaging of the mantle" beneath the Mid-Atlantic Ridge. Researchers said in the study that their findings provide a greater understanding of plate tectonics, which can cause natural disasters, including earthquakes, tsunamis and volcanic eruptions.

"The incredible results shed new light in our understanding of how the Earth interior is connected with plate tectonics, with observations not seen before," lead author Matthew Agius said in the release.

In addition to helping scientists develop better warning systems for natural disasters, chief scientist Kate Rychert said in the release that plate tectonics also have an impact on sea levels, and subsequently affect climate change estimates.

"This was completely unexpected. It has broad implications for our understanding of Earth's evolution and habitability. It also demonstrates how crucial it is to gather new data from the oceans. There is so much more to explore," Rychert said.