For more than a century, archaeologists have known that some of the stones at Stonehenge came from Wales and was – somehow – transported some 200 km (125 miles) to the site of the Neolithic monument on Salisbury Plain.
Now, a “handbag” study has revealed that one of Stonehenge’s central megaliths isn’t Welsh at all – it’s actually Scottish.
In a discovery described as “truly shocking” by one of the scientists involved, new analysis has found that the largest “bluestone” at Stonehenge was dragged or drifted into the site from the very north-east corner of the site. Scotland – a distance of at least 466 miles (about 750 km).
The astonishing discovery that the megalith, known as the “altar stone”, was transported by prehistoric people from at least as far away as present-day Inverness, and possibly from the Orkney Islands, “not only changes what we think about Stonehenge . , it changes what we think about the whole Late Neolithic”, said Rob Ixer, an honorary senior research fellow at University College London (UCL) and one of the experts behind the study, who was published in Nature on Wednesday.
“It completely rewrites the relationships between the Neolithic populations of the whole of the British Isles,” he told the Guardian. “The science is beautiful and it’s remarkable, and it’s going to be discussed for decades to come… It’s fascinating.”
The altar stone is not one of Stonehenge’s famous trilithons – the enormous lintel-topped sarsen stones that come from just 16 miles (25 km) away, and which today form its outer circle. Instead, the huge block of sandstone, 5 meters long and weighing 6 tons, lies flat and semi-buried in the heart of the monument, trapped under two fallen sarsens and barely visible to visitors.
Made of a sedimentary rock called old red sandstone, the altar stone is classed as a non-local bluestone and has long been suspected to have been brought from somewhere in Wales, as are a separate group of Stonehenge’s bluestones. now known to be dug in the Preseli Hills in Pembrokeshire.
However, the altar stone was an outlier and research the past years has led archaeologists, including Ixer, to question whether its origins were Welsh at all.
The new study, which involved experts from Curtin University in Perth, Australia; the University of Adelaide; Aberystwyth University; and UCL, aimed to find out more by examining the stone’s chemical composition and the age of minerals within it.
Taken together, this gives the sandstone a distinctive “age fingerprint”, said Nick Pearce, a professor of geography and earth sciences at Aberystwyth, who is another of the report’s co-authors.
“With that age fingerprint you can match it to the same kind of rocks in the UK – and the match for the age fingerprint was a dead ringer for the Orcadian Basin in north-east Scotland,” he said. “It was completely unexpected for us.”
While identifying the exact site will require further work, the experts have narrowed down the potential source area to include Orkney; a triangle of land around the present John o’Groats in Caithness; and a narrow coastal strip extending south to the Moray Firth around Inverness and east to present-day Elgin. Small areas of old red sandstone on Shetland are also theoretically possible sources, but were considered unlikely, Ixer said.
The finding may be surprising, but the science is not controversial, Pearce said. “This is very, very well-established science. It’s not something people can look at and say, ‘Oh no, that can’t be right.'”
The chance of the stone coming from elsewhere is “fractions of a percent”, he said.
For many, the biggest question will be one not explored in detail in the scientific paper: how on earth did Stonehenge’s builders transport the giant stone from Scotland to Wiltshire?
“Given major land barriers en route from north-east Scotland to Salisbury Plain, marine transport is one viable option,” said lead author Anthony Clarke of Curtin University.
But archaeologist and author Mike Pitts, who was not involved in the research but whose work on Neolithic monuments includes the book How to build Stonehengesaid he believed it was more likely that the stone was dragged overland than drifted by sea.
He said: “If you put a stone on a boat out of the sea, you not only run the risk of losing the stone – but also no one can see it.” Instead, an overland journey, which may take many years, will involve people along the way, with the stone “becoming more and more precious … as it travels south”, he added. Impossible as it may seem today, overland travel “was easily within the reach of Neolithic technology”.
“[The study] is exciting and it’s so meaningful,” Pitts said. “The bluestones have long been known to come from Wales, but they identify links with a very different part of Britain, and considerably further away from Stonehenge. So it suggests that the site was not only known to people in the south, but over a much wider area – and it makes suggestions for the whole way we think about Neolithic Britain.”
