Ancient rocks from the Isle of Rùm, UK, are playing an important role in discovering more about Mars. An international team of scientists collected martian-like samples on Rùm island off the west coast of Scotland as part of the Mars Sample Return campaign last July.

The field expedition targeted rocks that best match the characteristics of some of the samples collected by NASA’s Perseverance rover during the exploration of a crater on Mars. A series of ESA and NASA missions will be the first attempt to return scientifically selected samples from another planet.

An intensive study of the rocks from Rùm will give scientists a good head-start to learn the best analysis techniques to analyse martian rocks brought to Earth. The pristine Mars rocks would be a unique opportunity to reveal clues about the early evolution of the Red Planet, including the potential for past life.

The complex geology of the largely uninhabited island, where less than 50 people live today, has had generations of geologists flocking to the site to study its volcanic rocks. Millions of years of erosion have scoured away the surface rocks to reveal the inner plumbing system of a volcano that erupted over 60 million years ago.

Following clues discovered by other geologists, the science team scouted the island. The international crew of six found rocks with a very similar mineral and chemical content to the martian samples found in the Séítah formation, an area within the Jezero crater where Perseverance has collected 20 sample tubes so far. The scientists could strike the rocks with their hammers, feel their heft, and scan their surface with a lens.

Hundreds of samples are now on their way to the University of Oslo in Norway for further preparation and analysis.

Read more about how the European science community is getting ready for the precious martian samples, the Rùm martian adventure and an account by expedition leader Lydia Hallis on the To Mars and Back blog.