Searching for the origin of the Stonehenge Altar Stone: new sedimentological, petrographical, mineralogical, geochemical and isotopic constraints
Duncan Pirrie, R. E. Bevins, Rob A. Ixer, Nicholas J.G. Pearce, Peter Turner, Matthew R. Power, Stephen Hillier, Andrew C. Morton, Ian Saunders, Sergio Andò, Marta Barbarano, Andrew Horbury, Gregory D. Price
Figshare · 2026
Accurately constraining the provenance of geological materials from archaeological contexts is critical for the subsequent interpretation of their significance. In fact, it can be argued that no provenance is better than the wrong provenance. Stonehenge, the iconic Neolithic monument on Salisbury Plain, is significant in terms of well-documented long-distance transport of geological materials used in its construction, with many of the bluestones transported c.
225 km from west Wales. One stone at Stonehenge, the Altar Stone, is distinctive in terms of its composition, being composed of a well-sorted fine- to very fine-grained calcite-cemented sandstone. Its purpose at the monument, and when it was transported to the site, is unknown.
Early interpretations of a provenance from west Wales have previously been discounted based on both geochemical and mineralogical data. More recently, the age of detrital zircon, rutile and apatite grains in the Altar Stone were used to infer a provenance from the Orcadian Basin of northeast Scotland.