Linking derived debitage to the Stonehenge Altar Stone using portable X-ray fluorescence analysis

Abstract The Altar Stone at Stonehenge in Wiltshire, UK, is enigmatic that it differs markedly from the other bluestones. It a grey–green, micaceous sandstone and has been considered to be derived Old Red Sandstone sequences of South Wales. Previous studies, however, have based on presumed fragments (debitage) identified visually as coming Stone. Portable X-ray fluorescence (pXRF) analyses were conducted these ( ex situ ) well ). Light elements Z <37) analyses, performed after night heavy rain, affected by surface pore water attenuate low energy X-rays, however dry debitage produced data for full suite elements. High elements, including Zr, Nb, Sr, Pb, Th U, all occupy same compositional space fragments, are statistically indistinguishable, indicating Barium compares very closely between Stone, with differences being related variable baryte distribution limited accessibility its analysis, probably weathering. A notable feature presence (up 0.8 modal%), manifest relatively high Ba both These contents marked contrast those small set field samples, analysed alongside raising possibility may not sourced This ‘fingerprint’, baryte, provide rapid test using pXRF search source