Scientists may have finally cracked one of Stonehenge’s biggest mysteries

For centuries, the mystery of how one of Stonehenge’s key rocks moved from Scotland to Wiltshire has baffled experts.

The famous monument’s Altar Stone originated in north-east Scotland thousands of years ago, with some arguing that it made the 430 mile (700km) journey to its current place of residence via glaciers.

But now a new study has suggested, based on evidence taken from the stone itself, that humans actually transported it — at least part of the way.

The findings suggest that while ice may have played some sort of part in helping shift it out of Scotland, manpower was most likely responsible for moving the huge stone around 250 miles (400km).

Dr Anthony Clarke, co-leader of the research at Curtin University in Perth, said the findings suggest Stonehenge’s passage to Wiltshire wasn’t easy.

‘Rather than being carried naturally by ice, the evidence points to a deliberate, carefully planned movement across a challenging and varied landscape,’ he explained.

‘Our modelling 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.

‘This means the stone would still have needed to be moved hundreds of kilometers by people.’

The study, which was published in the Journal of Quaternary Science, saw the experts taking mineral grains from the Altar Stone and combining them with ice sheet modelling to pinpoint its origins and see whether it could have been carried south by glaciers.

However, Dr Clarke explained that there were ‘no viable glacial pathways’ it could have taken to Stonehenge, concluding that humans must have played their part too.

He added that the analysis suggests the stone was moved ‘in stages, potentially combining overland hauling with river or coastal transport where possible’.

One possible route could have seen the stone moving across a huge ice sheet which began at Caithness in north-east Scotland and stretched over what is now the North Sea to a region known as Dogger Bank, which connected the east coast to Europe during the last Ice Age.

From there it may well have been recovered by Mesolithic people who transported it by boat, and then over land and along the Berkshire Ridgway – a high ground route from the prehistoric era – before arriving in Salisbury Plain around 2500 BC.

The study reads: ‘Glacial transport to Dogger Bank, bypassing uplands in Scotland and Northern England, could conceivably decrease some of the challenges of transporting the Altar Stone.

‘Nevertheless, human agency would still have been required, which may have included primarily maritime pathways via the southeast coast or overland passage along the Berkshire Ridgeway.’

It would of course have been an arduous task, with some calculations suggesting it would have taken as many as 500 men using leather ropes to pull the single stone and an extra 100 to lay the rollers in front of the sledge to transport it.

However, evidence of the marks any such rollers might have left on it have yet to be unearthed, and the planning for such an endeavour would have been complex.

‘Direct transport from northeast Scotland would have represented a formidable undertaking, requiring sophisticated logistical planning, technological solutions and durable long‐distance social networks,’ the study said.

‘Either scenario therefore implies a society capable not merely of moving stone but also coordinating complex, large‐scale acts of monument construction across extensive geographic ranges.’