The tectonic plates under the Americas, Europe, and Africa are being pushed apart as the Atlantic Ocean widens year by year.
New research reveals what’s pushing the plates apart: Material from deep within the Earth is bursting upward at an undersea ridge in the middle of the Atlantic.

The Atlantic Ocean grows 4 centimetres wider every year.

That’s because the tectonic plates under girding the Americas are separating from those beneath Europe and Africa. But precisely how and why that is happening has been a mystery to scientists, since the geological forces that typically push plates apart aren’t prevalent in the Atlantic.

A study released Wednesday finally answers that question. The research, published in the journal Nature, suggests the key to the Atlantic’s expansion lies beneath a large underwater mountain range in the middle of the ocean.

This set of undersea peaks is known as the the Mid-Atlantic Ridge, and it separates the North American plate from the Eurasian plate, and the South American plate from the African plate. The researchers behind the study found that material from deep within the Earth is rising to the surface under the Mid-Atlantic Ridge, thereby pushing the plates on either side of the divide apart.