Few prehistoric monuments are as fascinating, iconic, and enigmatic as Stonehenge, the magnificent megalithic structure on Salisbury Plain in England. For decades, experts have puzzled over its meaning, why it has such meticulous acoustics, or where the massive rocks that form it came from.

This last was the aim of a study that, in the ironies of archaeology, produced a result that raised more questions than it answered. The reason: he learned that his altar, a massive six-ton ​​boulder, came from none other than Scotland, more than 7,000 kilometers away.

The question, of course, is how he got this far.

Stonehenge dilemmaStonehenge is a huge megalithic monument… And a huge mystery. That’s because, despite how much research has been done in the last few decades and everything we know about it today, studies come along from time to time that reveal more unknowns than they cover.

In 2023, for example, a study was published that revealed that its acoustics were similar to those of a cathedral, raising the question once again of what the monument, generally considered a place for rituals and a great solar calendar, was used for in its time , but there are also theories that question this final use. Now a new study closes one mystery once again at the expense of revealing many: the origin of the altar stone, one of the greatest mysteries.

A rock, a riddle. In a study initiated by experts from the universities of Aberystwyth, Adelaide, Curtin and University College London, the researchers analyzed the stone from the Stonehenge altar. The piece is special for a very simple reason: doubts about its origin. The rock itself is a six-ton, 50cm thick, 5 x 1m block of sandstone, located in the very heart of the stone circle and almost buried.

We don’t know exactly when it was placed there. Construction of Stonehenge began around 5,000 years ago and was expanded over the next two millennia. Exactly when the altar was added remains a mystery, but one possibility archaeologists have is that it was installed during the second phase of construction, around 2620-2480 BC.

Experts assumed that the stone on the altar, like the other stones called the “blue stones” of Stonehenge, came from Wales, although exactly where it came from has not yet been clarified.

So what did they find? We were wrong. If archaeologists have not been able to determine exactly which part of Wales the altar stone came from, it is because its origins lie not in Wales but further north, in Scotland.

To understand this, you must first understand Stonehenge’s structure and its unique ‘mix’ of rocks. The monument is generally thought to be made up of two types of stone: rocks from neighbouring Marlborough, including the large columns that form the outer horseshoe; and the ‘bluestones’ found inside the structure are smaller and come mostly from the Preseli Hills area of ​​West Wales.

Until now, when classifying the Stonehenge stones, the altar block had been catalogued with other “bluestones”. As Aberystwyth University and University College London, both involved in the latest findings on the monument, recall, there was one important question to be solved: the exact origin of the sandstone rock. We now know more precisely. And surprisingly, not in Wales, but much, much further away: in Scotland.

Altar stone under two large stones.

Looking (further) northExperts who analyzed the age and chemical composition of the altar concluded that its origin was not in Wales but in Scotland. Its features point to the red sandstone of the Orkney Basin. “Both the chemical composition of the sandstone and the age of the mineral grains indicate that it is likely to have come from the north-east of Scotland,” the universities involved in the research said in a statement.

The conclusion was reached after a “fingerprint” of the altar rock was created, which overlapped with rocks from the north-east Scottish basin and showed marked differences to minerals from Wales. “It’s exciting to know that our chemical analysis and dating work has unlocked this great mystery. We can now say that this iconic rock is Scottish, not Welsh,” said Professor Richard Bevins, from Aberystwyth, one of the study’s co-authors.

More than 700 kilometers. Moving the stone’s origin from Wales to Scotland has an obvious consequence: it adds several more kilometres to the journey the sandstone block has to make before it is half-buried in the centre of the Stonehenge circle. If the Preseli Hills are already a considerable distance from Wiltshire, where the megalithic monument is located, Scotland is a staggering distance away, considering that we are talking about work that was done several thousand years ago. How much? Over 700 kilometres.

Rethinking travelThe universities explain: “The new discovery shows that one of the most famous stones in the world was transported much further than previously believed, at least 700 km away.” The authors of the study admit that it is still unknown exactly where the altar rock came from in Scotland, and this opens up a fascinating horizon, as archaeologist Mike Pitts recalled a few days ago. Guard“Neolithic inhabitants were said to have brought it from the north-east of Scotland, possibly from the Orkney Islands and even as far afield as Shetland, a journey that could have taken between 450 and 800 miles.”

But… How? The million-dollar question. The latest investigation into Stonehenge leaves many questions. One is the exact origin of the altar. The other is even bigger and more fascinating: How did its creators manage to move a massive six-ton ​​boulder more than 700 kilometres?

There have been those who have pointed out the possibility that the block, believed to have come from Wales, was dislodged by a natural glaciation process, but experts such as Nik Pearce, a geologist from Aberystwyth, question the validity of this theory. “I don’t think the stone from Orkney could have come to Salisbury by passing through half a dozen glaciers in the right order.”

This opens up an even more fascinating horizon: that of ancient logistics. “Given the technological limitations of the Neolithic, our findings raise fascinating questions about how such a large stone was transported over such a long distance,” adds Anthony Clarke, lead author of the study.

By land or by sea? There are hypotheses, although there is no consensus. In fact, experts have been quick to suggest various possibilities. Clarke believes that sea transport is a “viable option”, given the “significant land barriers” on the route between the Highlands and Salisbury, for example. In his analysis, GuardPitts is more apt to transfer by land as part of a slow march that will be loaded with its own meanings and symbolism.

Both theories raise equally interesting new questions: What kind of relationships existed between the Neolithic populations of Great Britain? Did the rock move all at once? How long did it take to complete the journey? “The findings will have huge implications for understanding Neolithic communities, their connectivity and transport systems,” argue Aberystwyth.

One thing is clear: after thousands of years, the Stonehenge complex retains its capacity to surprise and expand human knowledge intact.

Photos | Priyank V (Unsplash)

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