Stonehenge’s most mysterious stone was transported hundreds of miles from Scotland by humans, according to a new study.
The monument’s Altar Stone, weighing up to six tonnes, originated in northeast Scotland, some 430 miles (700km) away from where it now resides in Wiltshire.
There has been ongoing debate over how it got there, with some arguing it was transported the whole way by glaciers thousands of years ago.
But a new study suggests that – while glaciers could have played a role in moving it out of Scotland – humans still transported the stone at least 250 miles (400km) across challenging terrain.
Co–lead author Dr Anthony Clarke, from Curtin University in Perth, said the findings suggest the journey was far from simple and likely required careful planning across multiple stages.
‘Rather than being carried naturally by ice, the evidence points to a deliberate, carefully planned movement across a challenging and varied landscape,’ he said.
‘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 kilometres by people.’
The researchers analysed mineral grains from the Altar Stone (pictured) to pinpoint the stone’s origins and test whether glaciers could have carried it south
The Altar Stone (circled) is the largest bluestone at the centre of Stonehenge and originated in northeast Scotland
For the study, published in the Journal of Quaternary Science, the researchers analysed mineral grains from the Altar Stone.
They combined this with ice sheet modelling to pinpoint the stone’s origins and test whether glaciers could have carried it south.
‘The research indicates there were no viable glacial pathways linking the source region directly to Stonehenge, reinforcing the conclusion that human transport was required,’ Dr Clarke said.
‘Instead, this suggests the stone was likely moved in stages, potentially combining overland hauling with river or coastal transport where possible.’
The paper discusses one possible route, which involved the stone being transported by glacier from Caithness, in northeast Scotland, across an enormous ice sheet that covered what is now the North Sea to an area called Dogger Bank.
This prehistoric, habitable landmass connected the east coast of England to Europe during the last Ice Age.
In this scenario, the stone would have been recovered by Mesolithic people before the area flooded, around 7,000 years ago, before eventually being transported further south by boat through sheltered waterways.
After travelling up the Thames river system, the stone could have been carried over land and along the Berkshire Ridgeway – a prehistoric high–ground route.
This map shows one glacial transport scenario, revealing how the stone could have potentially been moved by ice from Caithness in northern Scotland to Dogger Bank
Researchers believe Stonehenge is made of three types of stone. Standing stones made of sarsen (red), smaller bluestones (blue) and a sandstone altar (green)
The monument’s Altar Stone, weighing up to six tonnes, has been found to originate in northeast Scotland, some 430 miles (700km) away from where it now resides in Wiltshire. Pictured: The stone underneath two bigger Sarsen stones
Finally, it was erected as the Altar Stone at Stonehenge on the Salisbury Plain around 2500BC.
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 adds: ‘A Dogger Bank origin requires not a single episode of transport, but a more complicated history.
‘The Stone would first have had to be removed from a landscape undergoing marine transgression, taken to at least one location that remained above sea level for thousands of years, before finally being transported to Stonehenge.
‘Such a scenario requires prolonged cultural significance or multiple‐phase activity, across an exceptionally large temporal gap.’
The team said the need for such a long, multi–stage chain of events challenges the plausibility of this scenario.
However, they added that even if this was the case, transferring the Altar Stone from Dogger Bank would ‘still have required movement over some 400km (250 miles), implying considerable Late Neolithic capacity for organisation, labour mobilisation and overland and marine transport.’
It’s possible the stones were transported by being placed on logs, with a team of people pulling them along via ropes. Pictured: A replica of a stone being transported at Stonehenge
Dr Clarke said the findings reveal a level of organisation and cooperation among Neolithic communities not previously fully appreciated.
‘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,’ he said.
The study reads: ‘Direct transport from northeast Scotland would have represented a formidable undertaking, requiring sophisticated logistical planning, technological solutions and durable long‐distance social networks.
‘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.’
Moving any of Stonehenge’s stones over land would have required a huge and highly coordinated team.
Some early calculations suggested that it would take 500 men using leather ropes to pull one stone, with an extra 100 men needed to lay the rollers in front of the sledge.
However, the hard surfaces and trenches needed when using rollers would have left their mark on the landscape, but none have been found so far.
The Stonehenge monument standing today was the final stage of a four part building project that ended 3,500 years ago
Stonehenge is one of the most prominent prehistoric monuments in Britain. The Stonehenge that can be seen today is the final stage that was completed about 3,500 years ago.
According to the monument’s website, Stonehenge was built in four stages:
First stage: The first version of Stonehenge was a large earthwork or Henge, comprising a ditch, bank and the Aubrey holes, all probably built around 3100 BC.
The Aubrey holes are round pits in the chalk, about one metre (3.3 feet) wide and deep, with steep sides and flat bottoms.
Stonehenge (pictured) is one of the most prominent prehistoric monuments in Britain
They form a circle about 86.6 metres (284 feet) in diameter.
Excavations revealed cremated human bones in some of the chalk filling, but the holes themselves were likely not made to be used as graves, but as part of a religious ceremony.
After this first stage, Stonehenge was abandoned and left untouched for more than 1,000 years.
Second stage: The second and most dramatic stage of Stonehenge started around 2150 years BC, when about 82 bluestones from the Preseli mountains in south-west Wales were transported to the site. It’s thought that the stones, some of which weigh four tonnes each, were dragged on rollers and sledges to the waters at Milford Haven, where they were loaded onto rafts.
They were carried on water along the south coast of Wales and up the rivers Avon and Frome, before being dragged overland again near Warminster and Wiltshire.
The final stage of the journey was mainly by water, down the river Wylye to Salisbury, then the Salisbury Avon to west Amesbury.
The journey spanned nearly 240 miles, and once at the site, the stones were set up in the centre to form an incomplete double circle.
During the same period, the original entrance was widened and a pair of Heel Stones were erected. The nearer part of the Avenue, connecting Stonehenge with the River Avon, was built aligned with the midsummer sunrise.
Third stage: The third stage of Stonehenge, which took place about 2000 years BC, saw the arrival of the sarsen stones (a type of sandstone), which were larger than the bluestones.
They were likely brought from the Marlborough Downs (40 kilometres, or 25 miles, north of Stonehenge).
The largest of the sarsen stones transported to Stonehenge weighs 50 tonnes, and transportation by water would not have been possible, so it’s suspected that they were transported using sledges and ropes.
Calculations have shown that it would have taken 500 men using leather ropes to pull one stone, with an extra 100 men needed to lay the rollers in front of the sledge.
These stones were arranged in an outer circle with a continuous run of lintels – horizontal supports.
Inside the circle, five trilithons – structures consisting of two upright stones and a third across the top as a lintel – were placed in a horseshoe arrangement, which can still be seen today.
Final stage: The fourth and final stage took place just after 1500 years BC, when the smaller bluestones were rearranged in the horseshoe and circle that can be seen today.
The original number of stones in the bluestone circle was probably around 60, but these have since been removed or broken up. Some remain as stumps below ground level.
Source: Stonehenge.co.uk
