[Rockhounds] The Atlantic Ocean is widening. Here’s why.

[Kreigh Tomaszewski]

The Atlantic Ocean is getting wider, shoving the Americas to one side and
Europe and Africa to the other. But it’s not known exactly how.

A new study suggests that deep beneath the Earth’s crust, in a layer called
the mantle, sizzling-hot rocks are rising up and pushing on tectonic plates
<https://www.livescience.com/37706-what-is-plate-tectonics.html> — those
rocky jigsaw pieces that form Earth's
<https://www.livescience.com/earth.html> crust — that meet beneath the
Atlantic.

Previously, scientists thought that the continents were mostly being pulled
apart as the plates beneath the ocean moved in opposite directions and
crashed into other plates, folding under the force of gravity. But the new
study suggests that’s not the whole picture.

The research began in 2016, when a group of researchers set sail on a
research vessel to the widest part of the Atlantic Ocean between South
America and Africa; in other words, to "the middle of nowhere," said lead
author Matthew Agius, who was a postdoctoral researcher with the University
of Southampton in the U.K. at the time, but is now at the Roma Tre
University in Italy.

The spot is not a particularly popular route for travel, Agius said, noting
that sometimes days would go by without seeing a single other ship or a
plane. Interaction is limited to the occasional whales and dolphins that
swim by and a fleeting signal from the ship's Wi-Fi. Lightless nights
blanket the vast sea in an unobscured view of the galaxy and stars — and
it's very, very quiet, Agius said.

But this vast, empty stretch of ocean rests upon an incredibly important
geological spot: the mid-Atlantic ridge, the planet's largest tectonic
boundary that extends 10,000 miles (16,093 kilometers) from the Arctic
Ocean to to the southern tip of Africa. This is the spot where the South
American and the North American Plates move apart from the Eurasian and
African plates, at a speed of about 1.6 inches (4 centimeters) a year,
extending the Atlantic Ocean.

https://www.livescience.com/atlantic-ocean-widening-mantle-upwelling.html