Assessing ceramic compositional data:: A comparison of total reflection x-ray fluorescence and instrumental neutron activation analysis on Late Iron Age Spanish Celtiberian ceramics

A solid-phase, non-chemical processing protocol was recently developed as a means of chemically characterizing archaeological ceramics by total reflection x-ray fluorescence (TRXF). Following this methodology, TXRF can provide semi-quantitative determinations for 18 elements with comparable levels of precision and accuracy for the majority of them in comparison with a clay reference material analysed by instrumental neutron activation (INAA). In order critically to assess the analytical capabilities of TXRF, a large sample set of Late Iron Age Spanish Celtiberian ceramics and modern clays was analysed both by TXRF and INAA. Semi-quantitative chemical data provided by TXRF and quantitative data provided by INAA were subjected to commonly used multivariate statistical methods as a way of evaluating the ability of the new technique to discriminate among different compositional groups. The comparison of the two data sets shows no significant discrepancies, thereby allowing support for the same archaeological interpretation. These results suggest that TXRF has potential applicability for compositional characterization of archaeological ceramics providing data that are useful for provenance studies.