Did central part of Stonehenge come from Caithness?
Archaeology experts are asking themselves why a key element of Stonehenge, one of the world’s most famous prehistoric monuments, might have been brought all the way from Caithness.
Geochemical analysis of the Altar Stone – a six-tonne block of sandstone at the centre of the circle near Salisbury in Wiltshire – suggests that it came from the far north of Scotland rather than from Wales as previously thought.
The findings, published in the international science journal Nature, trace the source of the Altar Stone to Old Red Sandstone formations in the Orcadian Basin, which takes in Caithness as well as Orkney.
The journal notes that some components of Orcadian Basin samples from Spittal, as well as from Cruaday in Orkney, “match those from the Altar Stone”.
It also says: “Whether the people of Neolithic Britain moved it by land or by sea is an open question.”
It is a distance of at least 750 kilometres, or more than 460 miles.
The study was led by Anthony Clarke, of Curtin University in Western Australia, who grew up in Wales.
The researchers studied the age and chemistry of mineral grains within fragments of the Altar Stone, a 50cm thick sandstone block measuring five metres by one metre.
Mr Clarke described the results of the analysis as “like finding a fingerprint”.
He said: “Our analysis found that specific mineral grains in the Altar Stone are mostly between 1000 to 2000 million years old, while other minerals are around 450 million years old.
“This provides a distinct chemical fingerprint suggesting the stone came from rocks in the Orcadian Basin, at least 750 kilometres away from Stonehenge.
“Given its Scottish origins, the findings raise fascinating questions, considering the technological constraints of the Neolithic era, as to how such a massive stone was transported over vast distances around 2600 BC.
“This discovery also holds personal significance for me. I grew up in the Mynydd Preseli, Wales, where some of Stonehenge’s stones came from. I first visited Stonehenge when I was one year old and now, at 25, I returned from Australia to help make this scientific discovery – you could say I’ve come full circle at the stone circle.”
The study was conducted in collaboration with Aberystwyth University, the University of Adelaide and University College London (UCL).
Dr Robert Ixer, of UCL’s Institute of Archaeology, said: “The work prompts two important questions: why and exactly how was the Altar Stone transported from the very north of Scotland, a distance of more than 700 kilometres, to Stonehenge?”
Stonehenge, part of a World Heritage Site, was built in several stages from around 5000 years ago. The Camster Cairns in Caithness and the Ring of Brodgar in Orkney were built around the same time.
