Stonehenge has kept one of its biggest secrets in plain sight. New research says the monument’s six-ton Altar Stone was likely hauled hundreds of kilometres by people, not dropped there by ice.
The study, led by Curtin University researchers, adds to earlier work suggesting the sandstone megalith at the centre of Stonehenge came from northeast Scotland, about 700 kilometres from Salisbury Plain.
To test how it got there, researchers combined mineral grain dating with computer models of ancient ice sheets. They wanted to pin down the stone’s origin and work out if glaciers could have carried it south during the last Ice Age.
The results suggest glaciers may have moved rocks from Scotland part of the way, possibly to Dogger Bank in what is now the North Sea. But the models found no realistic glacial route that could have taken the Altar Stone directly to southern England.
Co-lead author Dr Anthony Clarke, from the Timescales of Minerals Systems Group in Curtin’s School of Earth and Planetary Sciences, said the findings point to deliberate human transport.
“Rather than being carried naturally by ice, the evidence points to a deliberate, carefully planned movement across a challenging and varied landscape,” Dr Clarke said.
“Our modeling shows glaciers may have transported rocks part of the way during the last Ice Age — potentially as far as Dogger Bank in the North Sea — but not into southern England, meaning the stone would still have needed to be moved hundreds of kilometers by people.
“The research indicates there were no viable glacial pathways linking the source region directly to Stonehenge, reinforcing the conclusion that human transport was required.
“Instead, this suggests the stone was likely moved in stages, potentially combining overland hauling with river or coastal transport where possible.”
The researchers said moving a six-ton stone over that distance would have been a major task for Neolithic communities and likely happened in multiple stages with coordination between groups in different regions.
Dr Clarke said, “Transporting a stone of this size over such a long distance would have required planning, coordination and a deep understanding of the landscape — not to mention tremendous determination.
“The study demonstrates how combining geological analysis with computer modeling can help resolve long-standing questions about how Stonehenge was built.”
The team plans to keep investigating by trying to identify the Altar Stone’s precise source location in northeast Scotland and exploring the routes prehistoric people may have used.
The study involved researchers from Curtin University, Sheffield Hallam University, the University of Sheffield, Wessex Archaeology and the University of Bristol.
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