Mystery of where Stonehenge's 20-tonne megaliths came from is solved

Researchers have described the discovery as 'a real thrill'

For centuries, archaeologists have puzzled over the origins of Stonehenge, and now, one of its mysteries – the precise source of the site's standing megaliths – has been solved.

Thanks to a scientific breakthrough, researchers have been able to pinpoint for the first time exactly where the prehistoric temple's largest stones came from.

There are two distinct types of stone slabs used at the site, one of which – the smaller bluestones – scientists have been able to trace to a site in Wales. But, until now, researchers did not know where the nine-metre-high sarsen boulders came from.

A new study, published on Wednesday, July 29, in the journal Science Advances, reveals that the monument's builders hauled most of the slabs, which weigh more than 20 tonnes, from a woodland area in Wiltshire, south-west England.

Stonehenge, a Neolithic wonder in Wiltshire, England, has vexed historians and archaeologists for centuries with its many mysteries. AFP

David Nash, the lead author of the study, said that the area, West Woods, is more than 25 kilometres from Stonehenge, “which is insane if you think about it”.

The site originally had some 80 sarsens standing in rectangular archways. However, only 52 remain today. Nash said that 50 of the remaining slabs share a similar chemical make-up.

"Our results suggest that most of the sarsens at Stonehenge share a common chemistry, which is why we're saying they come from the same area."

The research team compared the chemical signature of sarsens from across southern England before they found a sure match in West Woods. They compared the various samples to a metre-long core from inside the prehistoric stone, which was part of a missing piece taken during an excavation in 1958. It was returned by a member of the archaeological team after 60 years.

Nash said that prior to the discovery, archaeologists had speculated that the sarsens came from the nearby Marlborough Downs, since "there were big grey stones at Stonehenge, and the sarsens in Marlborough Downs were big and grey”.

While West Woods is part of that region, researchers overlooked the woodland because most of the sarsens there were concealed under vegetation.

"To be able to pinpoint the area that Stonehenge's builders used to source their materials around 2500 BC is a real thrill," Nash told the BBC.

There are still a number of mysteries surrounding the site, including why the monument’s builders used sarsens from West Woods and how the stone slabs were transported to the site to begin with. The latest finding, pointing to the source of the sarsens, could help solve that puzzle.

Stonehenge’s construction began some 5,000 years ago, in 3000 BC. A thousand years and four long building phases later, the ring of standing stones was complete. In its heyday, it served as a burial ground, a ceremonial site and a destination for religious pilgrimages.