Source Provenance of Andesite Artefacts Using Non-Destructive XRF Analysis

X-ray fluorescence spectrometry is a common technique in determining the elemental composition of lithic materials. With the exception of glassy volcanic rocks like obsidian, most rock types are prepared for analysis by conversion of specimens to powder or glass in order to reduce the effects of irregular surface topography and internal inhomogeneity. Concern for artefact conservation necessitates a less destructive preparation technique, which has not been widely investigated except with respect to obsidian artefacts. A series of analyses of andesitic and dacitic rocks explore the degree of influence of surface topography and inhomogeneity to determine if less destructive procedures can distinguish effectively between different geological sources. Focusing primarily on major elements, results suggest that source discrimination can be achieved using data produced by any of the three sample preparation procedures investigated: quantitative chemical data from glass beads; semi-quantitative chemical data from polished rock billets; or X-ray intensity ratios from unmodified flakes or polished billets.