Stonehenge, a 5,000-year-old monument in the United Kingdom, was erected with two types of stones.
Archaeologists traced one type of stone, the smallest blue stones, to a site in Wales. But the origins of Stonehenge’s huge sandstone rocks, called sarsens, remained a mystery.
A new study shows that most 25-ton sarsens come from a forest area 15 miles (25 km) away.
The find offers more information on how Stonehenge was built. An expert suggested that the 80 sarsens be transported at the same time.
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Stonehenge’s origin story has puzzled archaeologists for centuries.
Erected in two waves of hectic construction 5,000 and 4,500 years ago, the mysterious monument on the Salisbury Plain of the United Kingdom features two distinct types of stone slabs in concentric semicircles.
The researchers traced one type of stone, the smallest blue stones, to a site in Wales. But the origin of Stonehenge’s 30-foot (9-meter) sandstone boulders, called sarsens, remained an unsolved puzzle until now.
According to a study published Wednesday in the journal Science Advances, Stonehenge builders hauled most of these 50,000-pound (22,700-kilogram) sundsns out of a forest area in Wiltshire.
The area, called West Woods, is more than 15 miles (25 kilometers) from the monument, “which is really crazy if you think about it,” David Nash, the study’s lead author, told Business Insider.
He added that “our results suggest that most of the sarsens at Stonehenge share a common chemistry, so we are saying that they come from the same area.”
The findings could help archaeologists discover how the builders transported the giant stones south.
Stonehenge sarsens came from woods 15 miles away
Stonehenge originally had 80 sarsens erected in square arches, but only 52 remain.
According to Nash’s team’s analysis of the elements present in the rocks, 50 of those 52 sarsen share the same chemical composition.
Researcher Jake Ciborowski analyzes a sarsen stone at Stonehenge using a portable X-ray fluorescence spectrometer.
David Nash / University of Brighton
Armed with that chemical signature, the team searched for other sarsens in the southern UK and compared those rocks to those at Stonehenge. They found their partner in West Woods, about 15 miles north of the monument.
Prior to this discovery, archaeologists had speculated that the sarsens came from a nearby region called the Marlborough Downs, as “there were large gray stones at Stonehenge, and the sarsens at Marlborough Downs were large and gray,” Nash said.
West Woods is part of that region, but researchers had never searched for clues at that particular location since most of the sarsens were hidden underneath the vegetation.
A large sarsen stone in West Woods, the area where most sarsens used to build Stonehenge probably came from.
Katy Whitaker / Historic England / University of Reading
Furthermore, Nash said, the distant origin of the Bluestone from Stonehenge offered evidence that the builders did not necessarily sacrifice rocks from the most convenient areas.
“Since the builders bothered to bring Welsh blue stones to Stonehenge, why would they bother to bring sarsens from the closest location?” Nash said. At least four dozen 2-5 ton blue stones came from the Preseli Hills of Wales, about 150 miles away.
“The people who built Stonehenge would not have cared about the distance,” added Nash.
The reason the builders used West Woods sarsens is not yet clear, but the study authors suggest it likely has to do with “the size and quality of the stones present there.”
All sarsens may have been moved at the same time
The new finding does not yet confirm what Stonehenge was actually used for: Nash said theories range from a burial and cremation site to an ancient healing site. But knowing where the sarsens come from can at least help experts figure out how the monument’s builders erected it and the route they took to transport their building materials.
David Nash analyzes a sarsen nucleus extracted from Stonehenge.
Sam Frost / English Heritage
Nash said Stonehenge’s builders are likely to have used some kind of roller or dragged the sarsens over a slippery surface such as vegetation or icy ground.
“There is no evidence that they used animals to do it, but we don’t know,” he said.
The new study also supports the idea that the builders carved and raised all the sarsens in their standing positions in the Stonehenge rock circle at the same time, around 2,500 BC. C., after transporting them en masse.
Stonehenge is seen against the Wiltshire landscape.
Andre Pattenden / English Heritage
“For me, it confirms the idea that all the stones moved at once, at the same time,” Nash said. “It’s an amazing thought: how many people would need to be involved dragging huge rocks as part of a big project.”
