Geologists have uncovered mineral forms never before seen on Earth at the site of a 60 million-year-old meteorite strike on the Isle of Skye in Scotland.
When probing a thick layer of ancient lava flow on the small, picturesque island, Simon Drake and colleague Andy Beard from Birkbeck, University of London, were surprised to find a bizarre-looking rock.
A thin section of the meteoritic rock.
“When we looked at the rock to start off with, it was very, very strange indeed,” Drake tells Newsweek. “It looked completely out of place.… We were staggered.”
Geology published the results of the research, of which Drake is lead author.
Upon further analysis with electron microprobes, the team found minerals that led them to believe the rock was of extra-terrestrial origin.
“The most compelling evidence really is the presence of vanadium-rich and niobium-rich osbornite. Neither of these have ever been found on Earth before. We have these mineral totally enclosed in native iron, which itself is not of this planet,” Drake says.
NASA’s Stardust spacecraft found vanadium-rich osbornite in the path of a comet in 2004. Stardust collected space dust floating in the trail of the 4.5 billion-year-old Wild 2 comet.
The recess where Drake and Beard discovered the unusual rock.
As well as the exotic mineral forms, the team reported the osbornite had not melted, which means that it is probably an original chunk of the meteorite itself.
The discovery of reidite in their samples also suggests the minerals have come from meteorites. “If you have a meteorite impact at extreme pressures, the mineral zircon will convert to a much denser mineral,” Drake explains. “This instantaneous conversion from zircon to reidite has only ever been discovered on Earth at meteor impact sites.”
Four miles away, the research team found the same minerals buried in a two-meter-thick layer of hardened volcanic lava.
The Isle of Skye is of particular interest to geologists because it was created during a period of extreme volcanic activity. The island was formed when magma rose from deep inside the Earth and broke through the crust. The same event is believed to be responsible for modern-day Iceland.
But of particular interest is what caused this event in the first place, Drake says.
“Whilst we can’t say that the volcanological evolution of Skye was started by a meteorite, we think it was definitely a driver for that impact,” Drake told Newsweek.
The first meteorite site explored by Drake and Beard.
Although evidence suggests that at least some volcanic activity took place before the meteorite strike, Drake believes it was minimal. As well as driving the forging we see today, some scientists believe that meteorite activity could have been the trigger for life on Earth.
His research team is now looking beyond the small Isle of Skye to the wider geological area, the North Atlantic Igneous Province, which stretches all the way to Greenland.
This discovery, Drake says, could have implications for the origins of this entire region.