Scientists Rule Out Scotland as Source of Stonehenge’s Altar Stone

Geologists studying Stonehenge have ruled out northeast Scotland as the origin of the six-ton Altar Stone, overturning a prominent theory from 2024 and deepening the mystery of the Neolithic monument, SciTechDaily reported.

The sandstone slab measures 4.9 meters long and lies flat on the ground beneath the collapsed upright of the Great Trilithon, according to research published in the Journal of the Geological Society. Stonehenge itself took shape between around 3000 and 1600 BC.

Researchers examined mineral composition, chemistry, and isotopic characteristics to build a geological fingerprint of the megalith. They traveled across Scotland’s Orcadian Basin to test samples from roughly 70 locations, Smithsonian Magazine reported.

None of those regional samples matched the slab’s profile. That eliminates the Scottish hypothesis that had expanded the search radius to more than 400 miles from the Wiltshire monument.

Testing Scottish Slabs

The latest investigation combined direct examinations of the Altar Stone with rock samples held in museum collections. An international team of scientists from the UK, Canada, Italy, and Sweden took part in the work, The Independent reported.

For nearly a century, the prevailing assumption pointed toward west Wales, mirroring the route of the smaller bluestones that traveled about 225 kilometers to Salisbury Plain. The 2024 study upended that timeline by proposing a northern Scottish source, making it unclear how Neolithic laborers transported a massive stone across hundreds of miles.

Laboratory evaluations of the 70 collected samples dashed that northern hypothesis. The negative result shifts attention away from the Orcadian Basin.

Revising Geological Theories

“This is the most comprehensive geological investigation of the Altar Stone ever undertaken,” said Duncan Pirrie, emeritus professor at the University of South Wales.

Pirrie led the international study team. He said that testing the leading theories established a clearer baseline for future fieldwork.

“By combining a wide range of analytical techniques, we have built the clearest picture yet of the stone’s composition and tested the leading theories about its origins,” Pirrie told SciTechDaily.

“So far, none of the locations examined have the same set of characteristics as the Altar Stone. That tells us the search is not over, but we are now far better equipped to focus on the areas most likely to yield an answer,” he added.

Narrowing Down Next Steps

Richard Bevins explained that dismissing potential locations is a necessary step in the scientific process. The honorary professor works in Aberystwyth University’s Department of Geography and Earth Sciences.

“For almost a century, the prevailing view was that the Altar Stone came from west Wales,” Bevins said to SciTechDaily.

“Our previous research overturned that assumption and pointed instead to Scotland as the most likely source. This latest study significantly refines the search by identifying the specific geological characteristics we need to look for, allowing future investigations to be targeted more effectively,” he said.

Nick Pearce emphasized the value of eliminating candidate sites in a complex geographical puzzle. The emeritus professor of geochemistry also works at Aberystwyth University.

“In a geological detective story such as this, ruling out potential source areas is just as important as identifying new ones,” Pearce told SciTechDaily.

“Every location eliminated narrows the search and brings us closer to discovering where the Altar Stone originated. The stone is unique among those at Stonehenge, and tracing its source would provide valuable new insights into its remarkable journey to Salisbury Plain thousands of years ago,” Pearce said.

Questions About Neolithic Origins

With northeast Scotland and southern Britain ruled out, researchers are turning their attention elsewhere. Potential future search zones include alternative geological formations in northern England, other parts of Scotland, or Ireland, Smithsonian Magazine reported.

Archaeologist Mike Pitts, who was not involved in the new study, said that finding the true quarry remains critical. Identifying the source “would greatly help fit the altar stone into the world of the people who moved it,” Pitts told The Guardian, according to Smithsonian Magazine.

Common Questions Regarding the Altar Stone

Where is the Altar Stone located within Stonehenge?
The six-ton sandstone slab lies flat on the ground, sunk into the grass beneath the collapsed upright of the Great Trilithon and its lintel.

How far did the smaller Stonehenge bluestones travel?
The smaller bluestones originated approximately 225 kilometers away in the Preseli Hills of southwest Wales.

Which academic journals published the new findings?
The research findings appear in the Journal of the Geological Society under the title “Searching for the origin of the Stonehenge Altar Stone: new sedimentological, petrographical, mineralogical, geochemical and isotopic constraints.”

What regions are researchers examining next?
With northeast Scotland eliminated, the search pivots to alternative rock formations in northern England, other parts of Scotland, or Ireland.