The origin of Stonehenge's Altar Stone, a six-tonne sandstone slab, may lie in northern England, according to a new investigation that casts doubt on previous theories pointing to Scotland or Wales. Researchers have spent years attempting to pinpoint where this distinctive stone was sourced before its transport to Salisbury Plain thousands of years ago.
Previously, the prevailing view for much of the last century was that the Altar Stone originated in west Wales. However, more recent studies suggested a link to north-east Scotland. Now, a fresh analysis published in the Journal of the Geological Society indicates that the stone does not come from the Orcadian Basin in north-east Scotland. Instead, the search has narrowed to a broad area encompassing southern Scotland and northern England.
Professor Duncan Pirrie of the University of South Wales, the study's lead author, stated that their investigation is focusing on rocks within a geological unit known as the 'Old Red Sandstone.' Key areas of interest now include the Midland Valley of Scotland, southern Scotland, and northern England. The Altar Stone is unique among Stonehenge's megaliths due to its composition, which includes a distinctive calcite cement and the mineral baryte.
While sandstone is common across Britain, a precise geological match for the Altar Stone has yet to be found. "Our work has suggested that we can rule out Wales," Professor Pirrie noted. "There are still some areas in the far north-east of Scotland that we need to check, so perhaps we cannot entirely rule out this area, although we haven't found anywhere yet in this region. So we are focusing on southern Scotland and northern England."
Identifying the stone's source could offer significant insights into the capabilities of Neolithic people. "I think that we have perhaps rather lost sight of just how capable Neolithic people were," Professor Pirrie added. "Clearly moving a six–tonne stone significant distances is a testament to their engineering and organisational ability."
This latest research provides the most detailed description of the Altar Stone compiled to date, with researchers hopeful of resolving the mystery soon. Professor Richard Bevins of Aberystwyth University commented that the study significantly refines the search by identifying specific geological characteristics, enabling more targeted future investigations. He added, "With each new piece of evidence, we move closer to solving one of Stonehenge's most enduring mysteries."