Scientists find largest meteorite impact in the British Isles

Scientists first identified evidence of the impact in 2008, but they were unable to pin down the exact location of the crater. Over the last decade, researchers conducted field studies and analyzed rock samples in the lab. Their findings allowed them to identify the meteorite's exact point of impact.

The ancient crater is positioned roughly 10 miles inland from a remote section of the Scottish coast. Buried beneath layers of new rock and water in Minch Basin, the 25-mile-wide crater has been preserved for 1.2 billion years.

"The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery," Ken Amor, geologist at the University of Oxford, said in a news release. "It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it."

To identify the meteorite's crater, scientists surveyed the pattern of excavated debris, as well as the magnetic alignment of ancient meteorite particles. The direction of the debris helped scientists track down the likely source of molten shrapnel.

"It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area," Amor said.

Amor and his colleagues described their sleuthing efforts in a pair of papers published this week in the Journal of the Geological Society.

Because most ancient impacts are eroded, buried or erased by plate tectonics, scientists don't have a good sense of how often large meteorites impact Earth. But most studies suggest the impact rate was greater when Earth was younger and there was more debris -- leftover from the formation of the solar system -- whizzing around.

Scientists plan to continue surveying the region in order to more precisely characterize the nature of the ancient collision.

"The next step will be a detailed geophysical survey in our target area of the Minch Basin," Amor said.