A new study challenges a 100-year-old theory about the origin of the Altar Stone at Stonehenge, the largest stone in the monument’s inner circle. Stonehenge’s Altar Stone probably wasn’t sourced from the same region as the other bluestones.
The study, published in the Journal of Archaeological Science: Reports, suggests that the stone may have come from northern England or Scotland, rather than western Wales as previously thought.
The Altar Stone is a flat-lying, gray-green slab of stone that measures 16 feet long (4.9 meters). It is one of the so-called bluestones that make up the inner circle of Stonehenge, a prehistoric monument on Salisbury Plain in southern England.
The bluestones were transported over 140 miles (225 kilometers) from the Preseli Hills in western Wales to Stonehenge during an early construction phase, about 4,000 to 5,000 years ago.
The origin of the bluestones was first traced by British geologist Herbert Henry Thomas in his seminal 1923 study on Stonehenge. Thomas included the Altar Stone among the bluestones and claimed that it came from the same region as the others. However, his assessment was based on limited and outdated geological data, according to the new study.
The researchers analyzed thin sections of the Altar Stone under a microscope and compared them with samples from various locations in Britain. They found that the stone’s mineral composition and texture did not match any known outcrop in western Wales.
Instead, they suggested that the stone may have come from an unknown quarry in northern Britain, possibly in Cumbria or even Scotland.
“Initially, we feel it appropriate to investigate areas where there are known ancient monuments of Neolithic ages,” Bevins said. These areas stretch across northern England and Scotland, broadening the horizons of a search that has so far focused exclusively on Wales and allowing for “creative thinking about the source of the Altar Stone,” he said.
Stonehenge was erected during Britain’s Late Neolithic period, roughly 4,000 to 5,000 years ago, on Salisbury Plain in Wiltshire, in southern England. The monument was built, rebuilt and added to over thousands of years, with the bluestones brought to the site during an early construction phase.
The researchers said that their findings open up new possibilities for understanding the archaeological significance of the Altar Stone and its role in Stonehenge. They also said that their study shows the importance of revisiting old assumptions and using modern methods to re-evaluate ancient monuments.