New research suggests the Altar Stone at Stonehenge was transported 500 miles from northern Scotland, not Wales, challenging previous beliefs. Geological fingerprinting indicates the six-tonne stone likely originated from the Orcadian Basin, a rock deposit stretching from Inverness to the Orkney Islands.
Dr Robert Ixer from University College London described the finding as “genuinely shocking”. He posed critical questions about the reasons and methods behind transporting the Altar Stone from northern Scotland to Stonehenge, a journey exceeding 700km.
Archaeologists estimate the Altar Stone was added to Stonehenge during its second construction phase between 2620 and 2480 BCE. Smaller bluestones forming the inner horseshoe and outer circle were quarried from the Preseli Hills in western Wales. For the last century, it was believed the Altar Stone, made of sandstone, was sourced near Swansea en route to Stonehenge.
Geologists, using techniques from the mining industry, analysed mineral crystals within the sandstone. By examining traces of radioactive uranium in the crystals, they established an age-based signature unique to rocks from northeast Scotland. Their findings, published in Nature, show a 95% certainty that the Altar Stone matches rocks from the Orcadian Basin.
Lead author Anthony Clarke from Curtin’s School of Earth and Planetary Sciences in Australia explained that specific mineral grains in the Altar Stone are between 1,000 to 2,000 million years old, while others are around 450 million years old. This distinct chemical fingerprint points to the stone’s origin in the Orcadian Basin.
The research suggests the Altar Stone was deliberately transported, not moved south by glaciers. One theory is it was brought on a raft along Britain’s coast, as overland transport would have been hindered by mountains and dense forests. The reason for transporting the sandstone from northeast Scotland to southern England remains unclear.
Professor Chris Kirkland from Curtin University in Australia highlighted the implications of this discovery. The findings suggest significant societal coordination during the Neolithic period and reveal a sophisticated level of prehistoric organisation. Transporting such a massive stone likely involved marine routes and indicates long-distance trade networks in Neolithic Britain.
The earliest major construction at Stonehenge dates back to around 3000 BCE, featuring a circular ditch and bank, possibly with upright timber posts. The second construction phase around 2500 BCE saw the erection of large sarsen stones, weighing up to 30 tonnes, sourced from the Marlborough Downs, 20 miles away. The smaller bluestones, weighing between two and five tonnes, came from western Wales.
Professor Richard Bevins from Aberystwyth University noted the findings overturn a century of assumptions. He emphasized the significance of identifying the Stone’s Scottish origin and the ongoing efforts to pinpoint its exact source in northeast Scotland.
Frequently Asked Questions
Here are some common questions asked about this news
Where did the Stonehenge Altar Stone come from?
The Altar Stone came from the Orcadian Basin in northern Scotland.
How far was the Altar Stone transported to Stonehenge?
The Altar Stone was transported over 700km from Scotland to Stonehenge.
What method did scientists use to determine the Altar Stone’s origin?
Scientists used geological fingerprinting and radioactive uranium analysis to determine the stone’s origin.
When was the Altar Stone added to Stonehenge?
The Stone was likely added during the second construction phase, between 2620 and 2480 BCE.
Why is the Altar Stone’s origin significant?
It highlights Neolithic societal coordination and suggests long-distance trade networks in prehistoric Britain.