The Summary
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THE "altar stone" at the center of Stonehenge likely originated in present-day Scotland, a study has found.
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That’s more than 450 miles away, raising questions about how ancient humans transported the stone such a long distance.
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The study authors suggest they may have used boats.
Scientists say they have unlocked the secret of the 6-ton rock at the center of Stonehenge – a discovery that only deepens the mystery of the site.
The ancient monument’s “altar stone,” a sandstone rock in the center, likely originated in present-day Scotland, according to a study published Wednesday in the journal Nature. This means it was transported more than 720 kilometers to southern England – significantly further than any other stone at Stonehenge with known origins.
The discovery raises profound questions. Researchers suspect the altar stone was installed around 4,500 years ago, meaning Neolithic people were able to move the rock hundreds of kilometers – long before lightweight, spoked wheels were invented.
The revelation also suggests that cultural and social structures were more interconnected in the British Isles at the time than previously thought, and that Neolithic people were capable of carrying out complex projects with relatively simple tools.
The discovery was based on an analysis of the age of mineral grains in the sandstone rock. After profiling the age of the grains, the researchers were able to compare the age “fingerprint” of the altar stone with a database of sandstone samples from across Britain and nearby locations such as Brittany in France.
“With a fairly high degree of statistical certainty, in fact greater than 95% confidence, we can associate the age spectra with a very specific area in northeast Scotland,” said Chris Kirkland, co-author of the study and Professor of Science. of Earth and Planetary Science at Curtin University, Australia.
The region Kirkland was referring to, the Orcadian basin, includes the Orkney Islands, which are themselves known for elaborate stone circles.
“We cannot directly answer the specific reason why this material was transported,” Kirkland said. “All we know is that it is a 6 and a half ton piece of rock that came from 750 kilometers away. This, in itself, tells us a lot about Neolithic society and its connectivity.”
Stonehenge – one UNESCO World Heritage Location and one of the best-preserved prehistoric megalithic monuments – it is surrounded by large sandstone slabs called “sarsens”. These, in turn, support stone lintels – horizontal spans also made of rock, some of which are fitted with joints. Within the outline of the sarsen is an inner circle of “blue stones” with an additional horseshoe shape within that circle.
THE Sarsens are believed to have originated about 15 miles north of the Stonehenge sitewhile the blue stones were sourced from Wales, around 140 miles away.
The new study concerns the altar stone in the middle: a tablet-shaped rock about 5 meters long, which shows evidence of having been shaped by human tools. Other Stonehenge tablets now sit atop the altar rock, apparently toppled by time.
“It’s a special stone for whatever reason,” said David Nash, professor of physical geography at the University of Brighton, who has studied Stonehenge but was not involved in the new research. “It is a very different stone from all the other stones in the monument.”
Kirkland and his fellow researchers examined three ways the altar stone could have traveled from Scotland to Stonehenge. The first is that it was transported by the movement of glacial ice during the Ice Age, but the study authors don’t think this is the correct explanation. The second is that humans moved it overland, but the team suspects the forested terrain would have been too challenging.
The third option, which they consider most likely, is that the stone was transported by boat. There is evidence of maritime navigation during this period – when present-day England had a different coastline.
Nash said the authors reached “solid conclusions” about the origin of the altar stone.
“What they did is really interesting,” he said, adding that their findings reinforce evidence that Neolithic people traveled across the British Isles and were part of a broader social fabric. “There are clearly social structures, there are connections, there is a very clear communication of ideas.”
Stonehenge is one of around 1,300 ancient stone circles in existence, according to the British Museum. Researchers believe the stones at the site were shaped by hand tools and lifted with winch and pulley systems. They are arranged to align with the movements of the sun and the summer and winter solstices.
Experts suspect that Neolithic people used these sites for ceremonies or rituals, but the details have been lost to time. What, in particular, made the altar stone special is unclear.
“Millionaires today adorn their mansions with Carrara marble from Italy, and I’ll never understand why they do that, so it’s just a mystery,” said Anthony Clarke, lead author of the new study and a PhD student at Curtin University. “Humans have always had a fascination with finding the perfect rock, and perhaps the Neolithic Britons were the same, so their motivations were lost to time.”
The researchers said that as a next step, they hope to identify the exact outcrop or region where the rock originated, but the fundamental enigma will likely remain.
“They placed great value on transporting that stone 700, 800, 900 kilometers,” said Nick Pearce, another study co-author and professor of geography and Earth sciences at Aberystwyth University in Wales. “No matter how they brought it, it meant something to them. What does this mean? Why did it mean so much to them? It gives us something to reflect on.”
This article was originally published in NBCNews. with
