While exploring volcanic rocks on Scotland’s Isle of Skye, geologists have found something out-of-this-world instead – materials from a previously unknown, 60 million-year-old meteorite impact. The discovery was made while exploring a metre-thick layer at the base of a lava flow. “We thought it was an ignimbrite (a volcanic flow deposit),” said lead author Simon Drake, Associate Lecturer at Birkbeck University of London.
But when the team analysed the rock using an electron microprobe, they discovered that it contained rare minerals straight from outer space: vanadium-rich and niobium-rich osbornite. These mineral forms have never been reported on Earth. They have, however, been collected by NASA’s Stardust Comet Sample Return Mission as space dust from the Wild 2 comet. What is more, the osbornite is unmelted, suggesting that it was an original piece of the meteorite, said the study published in the journal Geology.
The team also identified reidite, an extremely high-pressure form of zircon which is only ever associated in nature with impacts, along with native iron and other exotic mineralogy linked to impacts such as barringerite. A second site, seven kilometres away, proved to be a two-metre-thick ejecta layer with the same strange mineralogy.