How Neolithic humans could have transported so many huge rocks from Wales to Stonehenge is one of archaeology’s most enduring mysteries.
However, a new study of a “lost” rock taken from the Stonehenge site more than 90 years ago suggests that humans may not have moved the stones at all.
Dr. Brian John, retired professor of geology at Durham University, maintains that this bluestone rock has markings that suggest it was moved by glacial ice.
This would undermine the common theory that the bluestone was quarried in the Preseli Hills in south-west Wales and manually transported to Salisbury Plain.
Speaking to MailOnline, Dr John said: “I think it’s hugely significant because it supports the assumption I’ve had for some years that these are not humanely transported.”
A new assessment of a ‘lost’ Stonehenge rock suggests the site’s huge stones may not have been transported by humans
Newall Boulder (pictured) was almost forgotten for more than 90 years, but research now suggests it may have been transported to Stonehenge from Wales by ice.
In addition to the tall Sarsen stones that make up Stonehenge’s distinctive appearance, the site is also home to around 80 smaller blue stones.
It is generally accepted that these stones originate from the Preseli Hills in south-west Wales, but how they arrived at Stonehenge is often debated.
Dr. John’s argument centers on the analysis of a bluestone rock the size of a human skull, known as the Newall rock.
This rock was first excavated in 1924 by geologists Colonel Hawley and Robert Newall.
Hawley originally thought the rock was just a piece of trash and wanted to throw it away rather than analyze it.
However, Newall saved the stone from the rubbish pile and placed it in a cardboard box in his attic along with other finds from the site.
Stonehenge is a prehistoric megalithic structure on Salisbury Plain in Wiltshire, England, two miles (3 km) west of Amesbury.
Dr. Brian John, retired professor of geology at Durham University, maintains that this bluestone rock has markings that suggest it was moved by glacial ice.
The rock remained there until Newall passed it on to Salisbury Museum shortly before his death in 1976.
There was a brief burst of interest in the rock around 1977, but it was then put into storage again and effectively forgotten for another 46 years.
However, in 2022, Dr. John found a reference to the rock and asked museum director Adrian Green if it was still in storage.
Finding this to be the case, he was given permission to examine it and make a careful examination of its superficial features.
Through detailed analysis of the rock surface, Dr. John identified a number of markings that suggest glacial, rather than human, transport.
“Boulders transported by glaciers tend to be faceted,” explains Dr. John.
“That means they have several different faces at angles to each other, which actually indicates where a rock has been eroded or basically sanded down.”
As rocks move with a glacier, they flip from side to side, creating several different flat faces with rounded edges, like Newall Rock.
The findings suggest that Stonehenge’s approximately 80 bluestone boulders may have been transported to the site by ice rather than by Neolithic builders.
Additionally, the boulder features a series of scratches and small fractures, called striae and chattermarks, which are often caused by glacial transport.
And although Newall Boulder is not exactly the same type of rock as the other bluestones, Dr. John says this is exactly what his theory would predict.
He says: “It is often claimed in popular articles that all bluestones are made from spotted dolerite, which is this type of igneous rock that we find in the Preseli Hills, but in reality there are about 30 different types of rock.
“That huge variety of rock types is absolutely typical of the way ice moves across the terrain and picks up rocks from here and everywhere.”
Dr. John says these blue stones (pictured) are too worn and rough to have been mined and transported.
Dr John suggests that this provides compelling evidence that the Newall rock and all the smaller blue rocks at Stonehenge were moved by a glacier.
His claims place him directly at the center of one of the controversial Stonehenge debates.
The idea of the stones being transported to Salisbury Plain came from geologist Herbert Henry Thomas in 1923.
Although Thomas was spectacularly wrong about almost everything, the theory of human transportation remains extremely popular.
The bluestone boulders may have been transported from Wales to Salisbury Plain by a combination of Welsh and Irish ice.
A team of researchers led by Professor Mike Parker Pearson of UCL have been some of the most active proponents of this theory, arguing that the stones moved on land.
Recently, Professor Pearson and his team even claimed to have discovered evidence identifying the Stonehenge bluestone quarry, which dates back to 3000 BC.
However, Dr John now says his discovery should “open up the debate” to consideration of other theories.
He says: ‘Herbert Thomas thought that, since transportation of the glaciers was impossible, they must have been transported by human beings.
‘That’s now part of our national myth because people haven’t seriously questioned it before; it has simply been accepted as the truth.’
This map shows the variety of stones present in South West Wales. Dr. John says the variety of bluestone types matches the way a glacier would pick up stones from many different places.
Instead of the orderly and quite deliberate building project we sometimes imagine Stonehenge to be, Dr John says: “I think it’s always been a bit of chaos.”
He argues that Neolithic builders simply used the stones they had in their immediate vicinity, rearranging and moving the smaller bluestones as necessary.
And, when they finally had to travel too far to collect more stones, the project was simply abandoned in the state it is in now.
“It was a cost-benefit analysis of the Neolithic that ultimately the costs of obtaining the stones were greater than the benefits obtained from them,” he says.
This suggestion could reverse the prevailing theory that the Stonehenge bluestones (pictured and numbered) were transported overland by humans.
However, the ultimate test for their theory would be cosmogenic dating, a test to determine how long rocks have been exposed to the surface by measuring their exposure to cosmic rays.
If Dr. John is right, the deeply eroded rock surface should have been exposed to the elements for hundreds of thousands of years.
Alternatively, if the stones were mined, they should only have been exposed to cosmic radiation for about 3,000 to 5,000 years.
While the debate over the origin of the stones continues, Dr John believes the evidence for erosion will remain strong.
And he concludes: “I am very confident that if one university or another can get their act together and really pull it off, you will see that these stones have been subject to cosmogenic bombardment from the atmosphere for possibly hundreds of thousands of years.
“This would put an end to the idea of quarrying once and for all.”