Unusual rock formations, long suspected to be an outcome of volcanic activity in the British Isles, were caused by a massive meteorite hit 1.2 billion years ago, spewing debris over a 50 square km area near Scottish town of Ullapool.
A research team from the universities of Oxford and Aberdeen found the evidence buried in a layer of rock they now believe is the material thrown out during the formation of a meteorite crater.
Dubbed as the "most spectacular evidence" for what is believed to be the largest meteorite to hit the British Isles, the discovery could help scientists understand the ancient impacts that shaped the surface of other planets like Mars, said Ken Amor of Oxford University.
Amor, a co-author of the paper, pointed out that 'chemical testing of the rocks found characteristic signature of meteoritic material, which has high levels of the key element iridium, normally only found in low concentrations in surface rocks on Earth.
"We found more evidence when we examined the rocks under a microscope; tell-tale microscopic parallel fractures that also imply a meteorite strike," he added.
The proposed volcanic origin of the rocks has mystified scientists as it was not supported by the presence of volcanic vents or sediments nearby. They took samples from the formations during fieldwork in 2006 and have just had their findings published.
John Parnell of University of Aberdeen, also a co-author, said these rocks are superbly displayed on the west coast of Scotland. "We're very lucky to have them available for study, as they can tell us much about how planetary surfaces, including Mars, become modified by large meteorite strikes.
"Building up the evidence has been painstaking, but has resulted in proof of the largest meteorite strike known in the British Isles."
Since the formation of the solar system leftover space material has collided regularly with the Earth and other planets. Some of these impacts are large enough to leave craters, and there are about 174 known craters or their remnants on Earth.