Ever wonder who's buried at Stonehenge? Maybe not, but some of them apparently came from a ways off—which adds to our understanding of Stonehenge and shows how 5,000-year-old cremated remains can still be analyzed, the Guardian reports. A new study finds that 10 out of 25 remains buried at Stonehenge came from over 100 miles away in West Wales, near the Preseli Mountains where the site's stones were quarried. The remains' dates are "tantalizingly" close to when those bluestones were used to form the site's initial stone circle, researchers say. Conclusion: "People from the Preseli Mountains not only supplied the bluestones used to build the stone circle but moved with the stones and were buried there too," study co-author John Pouncett tells NPR.
All scientists had were cremated skull-bits buried in holes around the site. Team leader Christophe Snoeck calls that "the perfect challenge," because cremation destroys organic matter while leaving inorganic matter behind. As he explains, heavier elements like strontium are "about seven times heavier than carbon" and remain unaltered. So they extracted two strontium isotopes from cremated bone—a process considered impossible until recently—to find remnants that had passed from eaten plants into the people's teeth and bones, per the Los Angeles Times. Then they compared the finding to a map of strontium isotope ratios from the surrounding area. "We expected to see some people that were not local, but so many was a surprise," says Snoeck.