High impact in the Highlands

The earliest known occurrence of one of Earth’s rarest minerals, reidite, has been found in the North West Highlands Global Geopark, in Scotland.

The reidite mineral, which forms from meteorite impact, has only been discovered in four other crater impacts around the world. The Highland rock samples, which were taken from a layer of rock thought to have been the result of volcanic activity, are believed to be as old as 1.2 billion years.

The discovery, in Stac Fada Member, a large geological area in the North West Highlands, reinforces the theory that the area’s geology was formed by debris from a meteorite impact from the same period.

Pete Harrison, of the North West Highlands Global Geopark, described the new discovery as a “final piece” of evidence it was a meteorite.

Mr. Harrison said:

This looks like proof that the Stac Fada Member was caused by a meteorite impact 1.2 billion years ago. It is amazing that this mineral has survived so long as it was formed at high pressure during the impact”.

A team of geoscientists from Curtin University who found the reidite in a stone called Zircon, are still searching from the meteorite crater, although this may have already disappeared under billions of years of geological change.

This reidite discovery is over double the age of the previous oldest known occurrence at 450 million years and highlights the geological importance of this part of the world.

The North West Highlands Global Geopark was established in 2004 and has recently revalidated its place as a Global Geopark for the next four years.