A Scottish altar at Stonehenge

One of the main stones of the Stonehenge megalithic complex in England comes from northern Scotland, a new study shows. The discovery raises many questions about prehistoric society.

“It’s amazing”

101 years ago, a Welsh geologist discovered that the famous megaliths of Stonehenge came from the Preseli Hills in Wales, 200 km from the famous English prehistoric site.

But since the turn of the millennium, the Welsh origin of one of Stonehenge’s most important stones, a six-tonne half-buried altar, has been called into question. Last year, researchers at Aberystwyth University confirmed those suspicions. On Wednesday, they determined in Nature “with 95% certainty” that this altar comes from the north of Scotland, perhaps even from an island.

“When we got the results, it was a shock,” the study’s lead author said in a teleconference Tuesday. Naturegeologist Nick Pearce of Aberystwyth University. “It’s mind-boggling. We never thought this rock had travelled over 700km.”

The study was carried out by geologists who examined the chemical characteristics of the altar and compared them to rock formations in the UK.

This type of “geoarchaeological” analysis is becoming more common, according to Adrian Burke, an archaeologist at the University of Montreal. “I do a lot of geoarchaeology myself,” says Burke. The study of Nature is very well done. My partner, who is a geologist, is of the same opinion.

New puzzles

The discovery opens up a new perspective on prehistoric populations. “We didn’t think there was trade over such long distances,” said Richard Bevins, another Aberystwyth geologist, on Tuesday.

Mr Burke believes that transporting them from Scotland or Wales does not involve radically different technological capabilities. “The hypothesis is that the Stonehenge megaliths were transported by sea and then by river from Wales. Going a few hundred kilometres by sea, or a greater distance, still following the coast, does not seem very different to me. But that is not my speciality.”

The ABCs of Stonehenge

The Stonehenge site was built over nearly two millennia, starting 5,000 years ago. Initially, it consisted of earthen mounds with wooden structures, but soon megaliths were erected there. The altar is believed to date back 4,500 years.

The site was frequented, sometimes for periods of several weeks, by peoples meeting according to the lunar and solar calendars.

“It is thought that people carried stones to represent their ancestors,” Mr Bevins said. “There are people from the north of Scotland who would have carried the altar to commemorate their dead.”

Uranium

The analysis was done with Curtin University in Perth, on Australia’s west coast. “We do a lot of chemical analysis for the mining industry,” the study’s lead author, Anthony Clarke, explained Tuesday from Perth.

The analysis was carried out in particular on the uranium and lead present in the altar, which constitute a “geological clock”.

The only area in the UK of similar age to the stone was in northern Scotland and Orkney.

Other megaliths

Transporting a six-ton ​​stone over such a long distance is a European record, according to Mr Bevins.

Burke also doesn’t know of any megaliths being transported such great distances in the Americas. But megaliths were transported from island to island in Hawaii before Europeans arrived, in similar societies, he points out. The Pacific archipelago was settled by Polynesians 800 years ago.

“We don’t use the term prehistory for the Americas,” Burke said. “But we do think that at the time of Stonehenge, there was a culture of chieftaincy, charismatic leaders who didn’t pass on their power through inheritance. Similar chieftaincies existed in North America millennia ago, and these people built very large mounds, which required social coordination similar to that of Stonehenge.”

The best known of these mounds is the Great Serpent Mound in Ohio, erected 1,000 years ago.

Mr Burke further believes that if geoarchaeological analyses were carried out on the thousands of prehistoric megaliths erected in Western Europe, for example the Breton menhirs, journeys of several hundred kilometres could also be revealed.

Ramah Chert

Trade and cultural exchanges over 1,000 km also took place in the Americas. One of the most famous cases is that of Ramah chert, a translucent stone from Labrador. Tools made from this stone have been found as far away as Ontario and New York.