Scientists say they have unlocked the secrets of Stonehenge’s six-tonne rock, a discovery that adds even more mystery to the site.

A study published Wednesday in the journal Nature suggests that the ancient site’s central sandstone “altar stone” was likely created in what is now Scotland, meaning it was transported more than 450 miles to southern England — farther than any of Stonehenge’s other stones of known origin.

The discovery raises important questions: Researchers estimate that the altar stone was placed about 4,500 years ago, meaning Neolithic people could have moved it hundreds of miles, long before the invention of the lightweight spoked wheel.

The find also suggests that culture and social structure in the British Isles at this time was more intertwined than previously thought, and that Neolithic people were capable of carrying out complex projects with relatively simple tools.

The discovery was made based on the dating analysis of mineral grains within the sandstone. After profiling the age of the grains, the researchers were able to compare the altar stone’s age “fingerprint” with a database of sandstone samples from across the UK and nearby areas, such as Brittany in France.

“We can link the age spectrum with a fairly high degree of statistical certainty – in fact more than 95% confidence – to a very specific region in northeast Scotland,” said study co-author Chris Kirkland, professor of earth and planetary sciences at Curtin University in Australia.

The area Kirkland refers to, the Orkney Basin, includes the Orkney Islands themselves; Known for its elaborate stone circles.

“We can’t directly answer the question of why this rock was transported,” Kirkland said, “all we know is that this 6.5-ton rock was transported from 750 kilometers away, and that alone tells us an awful lot about Neolithic societies and their connections.”

Stonehenge — UNESCO World Heritage Site One of the best-preserved prehistoric megalithic monuments, the site is surrounded by large sandstone slabs called “sarsens”, which support stone lintels (also horizontal spans of rock, some held together by joints). Inside the outline of the sarsens is an inner circle of “bluestones”, which in turn is a horseshoe shape.

of The sarsens are thought to have originated approximately 15 miles north of Stonehenge.Meanwhile, bluestone comes from Wales, about 140 miles away.

The new study concerns the central Altar Stone, a roughly 16-foot-long slab of stone that shows evidence of being shaped by human tools. Stonehenge’s other slabs currently rest on top of the Altar Stone but have apparently been toppled over time.

“Whatever the reason, this is a special stone,” said David Nash, a professor of physical geography at the University of Brighton who has studied Stonehenge but was not involved in the new study. “It’s totally different to the other stones on the site.”

Kirkland and his colleagues looked at three possible routes the altar stones could have taken from Scotland to Stonehenge: They could have been transported by shifting glacial ice during the Ice Age, but the study authors don’t think that’s a good explanation, or they could have been transported overland by humans, but the team thinks that would be too difficult in the wooded area.

The third possibility, which they consider to be the most likely, is that the stones were transported by ship, and there is evidence of seaborne transport during this period, when England’s coastline was different to what it is today.

Nash said the authors had reached a “sound conclusion” about the altar stone’s origins.

“Their work is really fascinating,” he said, adding that their findings add to the evidence that Neolithic people travelled throughout the British Isles and were part of wider social structures. “There was clearly a social structure, there were connections and there was a very clear transmission of ideas.”

Stonehenge is one of approximately 1,300 surviving ancient stone circles. According to the British MuseumResearchers believe the site’s stones were shaped with hand tools and assembled using a winch and pulley system, with the stones aligned to coincide with the movement of the sun and the summer and winter solstices.

Experts speculate that Neolithic people may have used these sites for rituals and ceremonies, but details have been lost to time — especially what was so special about the altar stones.

“Today’s billionaires decorate their mansions with Italian Carrara marble, but I don’t understand why they do it. It’s a mystery,” said Anthony Clark, lead author of the new study and a doctoral student at Curtin University. “Humans have always been fascinated by finding the perfect stone, and perhaps Neolithic Britons were too, so their motivations have been forgotten over time.”

As a next step, the researchers hope to pinpoint the exact outcrop or region where the rocks originated, but said fundamental mysteries are likely to remain.

“They placed a lot of value in transporting that stone 700, 800, 900 kilometres,” said Nick Pearce, a professor of geography and geosciences at Aberystwyth University in Wales and another co-author of the study. “However they transported it, it meant something to them. What did it mean? Why did it mean so much to them? It gives us all something to think about.”