'Failed' microcontinent found hiding beneath Greenland and Canada

A failed miniature continent lies hidden beneath the sea between Canada and Greenland, scientists have discovered. 

The Davis Strait, which separates the two landmasses, ranges from about 200 to 400 miles (320 to 640 kilometers) wide on its path connecting the Labrador Sea and Baffin Bay. It's known to have an oddly thick seafloor, and now researchers know why: The crust is actually a crumb of a continent that didn't fully pull away when Greenland and Canada rifted apart. 

The findings, which the team will publish in the September issue of the journal Gondwana Research, is the most detailed look yet at this incomplete rifting process. The researchers also suspect they've discovered an ancient fault, similar to California's San Andreas fault, in the area. This fault may have acted like a guardrail, directing Greenland's initial movement as it started to pull away from Canada around 60 million years ago. 

Related: Scientists finally discover 'lost continent' thought to have vanished without a trace

The two landmasses never fully managed to separate. About 33 million years ago, Greenland stopped pulling away from North America and remains on the North American tectonic plate. But this failed rift zone is an interesting place to study how tectonic plates move and split, said study co-author Jordan Phethean, a geophysicist at Derby University in the U.K. 

"If we can understand why the plates are moving in the directions that they are, it allows us to understand what’s controlling plate tectonics," Phethean told Live Science. 

The researchers called the newfound chunk of continental crust beneath the Davis Strait a proto-microcontinent. Microcontinents are pieces of crust that have broken away from main continents. Many are submerged beneath the oceans, surrounded by denser oceanic crust, but some, like Madagascar, form their own islands. The Davis Strait example didn't quite fully break away; it's a 12- to 15-mile-thick (19 to 24 km) segment of continental crust, surrounded by thinned-out continental crust that is about 9 to 10.5 miles (14 to 17 km) thick on each side. That's why it gets the "proto" moniker, Phethean said.