Stonehenge is among the most iconic locations in England, but it may have a wee bit of Scottish ancestry.
Previous analysis of the rocks that comprise Stonehenge indicate they had been sourced from several places. The larger stones, known as sarsens, weigh up to 30 tons, and originated from a quarry around 16 miles (25 kilometers) from the site. The smaller rocks, called bluestones, weigh between two and five tons, and originated in Wales, around 140 miles (225 kilometers) away, though whether they were transported by humans or glaciers remains contested.
Now, a new study, published in the journal Nature may have solved one of the remaining Stonehenge mysteries: the origin of the megalithic structure’s Altar Stone.
The Altar Stone, or Stone 80, as it’s known in academic circles, is the largest of Stonehenge’s non-sarsen rocks. It lies partially submerged in the ground, stuck beneath two of the bluestones. A previous geological study of the Altar Stone confirmed that, unlike the surrounding stones, it did not originate from Wales.
To figure out where it had come from, a team of geologists led by Anthony Clark, a PhD student at Australia’s Curtin University, looked at the age and chemistry of zircon, apatite, and rutile grains taken from two fragments. The zircon, they found, dated back around 1 billion years, while the apatite and rutile were relatively younger at 470 million years old. That composition doesn’t match any of the other Stonehenge rocks. What it does match is rocks in northern Scotland’s Orcadian Basin, about 466 miles (750 kilometers) away from Stonehenge on Salisbury Plain, which is 85 miles (137 kilometers) west of London.
“These findings are truly remarkable—they overturn what had been thought for the past century,” said Richard Bevins, an honorary professor at Aberystwyth University, who worked on the study, in a statement. “We have succeeded in working out, if you like, the age and chemical fingerprints of perhaps one of the most famous of stones in the world-renowned ancient monument.”
The researchers noted that the purpose of their study was only to determine the origins of the 6-ton Altar Stone, and not how it was transported. However, they observed that, given the distances and weights involved, there would be obvious difficulties in bringing it by land. They also ruled out glaciers as a transport vehicle, observing that ice sheets in that area had drifted north, not south. Instead, it’s more likely that the Altar Stone was moved by humans via the sea. That conclusion indicates that Neolithic societies in the region may have been more complex than previously thought.
“Transporting such massive cargo overland from Scotland to southern England would have been extremely challenging, indicating a likely marine shipping route along the coast of Britain,” said Chris Kirkland, a geochronology professor at Curtin University, who also worked on the study. “This implies long-distance trade networks and a higher level of societal organization than is widely understood to have existed during the Neolithic period in Britain.”
Stonehenge has long been an object of fascination for archaeologists. Its history stretches back as far as 8500 BCE, and work on its famous monuments began around 5,000 years ago. Its purpose remains a subject of debate, though some scholars believe it was meant to be a memorial site.
While the paper casts new light on Stonehenge’s origins, its future appears to be secure. In July, the British government nixed a planned highway expansion that would have included a tunnel under part of the site. Critics had long criticized the plan, arguing it would pose a threat to Stonehenge’s geology, and to any unfound archaeological treasures.
