Testing multivariate normality of elemental concentration data obtained by INAA

Abstract

The ceramic provenience studies are important in Archaeology due to its potential to infer the materials source used in the ceramic manufacture, which is an indicative of the socio-cultural interactions among ancient societies. A study of provenience was carried out using the elemental concentrations (Na, Lu, U, Yb, La, Th, Cr, Cs, Sc, Fe, Eu, Ce, Hf, Tb) of 50 ceramic fragment samples obtained by Instrumental Neutron Activation Analysis (INAA), from the Lago Grande archaeological site, in the central Amazon, Brazil. The preliminary multivariate statistical analysis of the ceramics elemental concentration suggested the existence of two distinct groups of different elemental composition. In archaeometric studies, the elemental concentrations are usually logarithmically transformed, based on the assumption that the trace elements have a natural lognormal distribution in nature. The normality is often desirable in multivariate analysis. In this paper, the lognormal distribution of concentrations was tested for multivariate normality, in order to validate the application of some multivariate statistical techniques.