Stonehenge, an iconic prehistoric monument in England, continues to intrigue archaeologists and historians. While much is known about its construction and the origins of its massive stones, some mysteries remain. A recent study published in Nature sheds light on one such enigma: the provenance of the Altar Stone.
The stones of Stonehenge are broadly categorized into sarsens and bluestones. Sarsens, the larger stones weighing up to 30 tons, were sourced locally, approximately 16 miles (25 kilometers) from the site. Bluestones, smaller rocks ranging from two to five tons, originated in Wales, some 140 miles (225 kilometers) away. The debate continues as to whether these bluestones were transported by humans or glaciers. However, the Altar Stone, also known as Stone 80, stands apart. This largest non-sarsen rock lies partially buried beneath two bluestones, its origin a puzzle until now. Previous geological analysis confirmed that, unlike its surrounding counterparts, the Altar Stone did not originate in Wales.
To pinpoint its origin, a team of geologists led by Anthony Clark, a PhD student at Curtin University, Australia, analyzed the age and chemical composition of zircon, apatite, and rutile grains extracted from two fragments of the Altar Stone. Their findings revealed that the zircon dated back approximately 1 billion years, while the apatite and rutile were considerably younger at 470 million years old. This unique composition differed from all other Stonehenge rocks. However, it matched rocks found in the Orcadian Basin of northern Scotland, a staggering 466 miles (750 kilometers) from Stonehenge, which itself lies 85 miles (137 kilometers) west of London.
This discovery challenges long-held assumptions about the Altar Stone’s origin. “These findings are truly remarkable—they overturn what had been thought for the past century,” stated Richard Bevins, an honorary professor at Aberystwyth University and a contributor to the study. “We have succeeded in working out, if you like, the age and chemical fingerprints of perhaps one of the most famous of stones in the world-renowned ancient monument.”
The researchers emphasized that their study focused solely on determining the origin of the 6-ton Altar Stone, not its method of transportation. Nevertheless, they acknowledged the logistical challenges of transporting such a massive stone overland from Scotland to southern England. They also ruled out glacial transport, as ice sheets in the region moved north, not south. The most plausible explanation points to human transport via sea routes. This suggests a more complex Neolithic society than previously imagined, capable of long-distance trade and sophisticated organization.
“Transporting such massive cargo overland from Scotland to southern England would have been extremely challenging, indicating a likely marine shipping route along the coast of Britain,” explained Chris Kirkland, a geochronology professor at Curtin University and a member of the research team. “This implies long-distance trade networks and a higher level of societal organization than is widely understood to have existed during the Neolithic period in Britain.”
Stonehenge, with its history dating back to 8500 BCE and monument construction beginning around 5,000 years ago, remains a source of enduring fascination. Its purpose continues to be debated, with some scholars suggesting it served as a memorial site.
While this study unveils a crucial piece of the Stonehenge puzzle, the future of the site seems more secure. Recent government decisions have halted planned highway expansions that threatened Stonehenge’s geological integrity and potential undiscovered archaeological treasures. This ensures that future generations can continue to marvel at this ancient wonder and the stories it holds.
