Non Destructive Investigations of the Ag distribution in the late roman folles from about 309 to 333 AD

The archaeological investigation of the finds within the votive deposit of Alaimo in Lentini (Sicily, Italy) showed the presence of three reference classes of pottery. Nevertheless, some artefacts were difficult to classify both for their stylistic typology and for the colour and consistence of the clay pastes Among these samples, a group of Rhodian-like aryballoi has been evidenced. In order to group the finds and to identify the doubtful artefacts, the content of some trace elements (Rb, Sr, Y, Zr and Nb) has been determined in 28 well preserved samples of different pottery shapes. Measurements have been performed by using a portable non destructive XRF spectrometer at the Archaeological Museum of Lentini. Compositional data of trace elements have been determined by using a new method based on a multilinear regression approach. A best relative fit and a multivariate cluster analysis have been performed; analytical results allowed for the verification of the presence of groups of membership among the analysed objects and the classification of some artefacts of doubtful archaeological categorization.