Investigation of Roman terra sigillata by atomic absorption and emission spectroscopy and multivariate analysis of data

Twenty-one sherds of Roman terra sigillata from Augusta Praetoria (Aosta, Italy) have been analyzed by atomic absorption and emission spectroscopy. Ca, Ba, Ti, Cr, Mn, Fe, Cu, and Al were determined by atomic absorption spectroscopy with electrothermal atomization in graphite furnaces; Mg and Sr were determined by inductively coupled plasma emission spectroscopy; Na and K by flame emission spectroscopy. The data obtained have been processed by different methods of multivariate analysis, such as cluster analysis, principal component analysis, and nonlinear mapping. The results indicate that at least three compositional groups can be identified among the studied sherds, probably reflecting different geographical provenances.