Ambre protostoriche della Sardegna: indagini archeometriche

A project focused on the study of early vitreous materials and amber from Italy has been developed in cooperation with the Italian Institute of Pre- and Proto-history. The present research reports the analytical investigation and the characterization of Nuragic amber finds in order to investigate the early appearance of this material in Sardinia and the diffusion and use of amber in the island. A set of 90 samples from 11 different Sardinian sites have been selected for the analyses in cooperation with the archaeologists studying the materials (P. Bellintani, A. Usai and M.A. Fadda in this volume). Generally the objects date from the Italian Recent Bronze Age (RBA) to the Iron Age (IA). Although in continental Italy amber objects are known since the Aeneolithic/Early Bronze Age (EBA), in Sardinia amber seem to be present essentially from the RBA. Nevertheless it is only in the Late Bronze Age that a large amount of amber objects may be found in funeral, cultual and settlement contexts. No amber deposits are known from Sardinia, therefore the provenience study may give very important information about the trade routes used for amber exchange, and about the connection of Nuragic people with other Cultures. Interestingly, no amber analyses have been performed on Sardinian finds before this work. Small samples of the selected objects, mainly ornamental beads, have been here analysed by Diffuse-Reflectance Infrared Fourier Transform spectroscopy (DRIFT). For the data interpretation the spectra of the archaeological materials have been compared with a database of Fourier Transform Infrared Spectroscopy (FTIR) and DRIFT spectra of ambers with well known geographic origin, in order to tentatively identify the amber provenience. The majority of the ambers are succinite. Two beads from the grave of Antas (Fluminimaggiore, Cagliari) show complex spectra, similar to the one of succinite, but with a slope inversion in the Baltic shoulder. This characteristic may be present in weathered Baltic amber, as demonstrated by the analyses of different samples cut from the same objects. Moreover similar features are present in the spectrum of non-succinite Baltic ambers, such as gedanite and gedano-succinite. Finally has been showed that in the DRIFT spectra the absorption intensity of this peak may change with respect to the one present in the FTIR spectra. On these bases we can generally identify the two problematic amber from Antas as “possible Baltic amber”. Extremely interesting is the presence in the site of Romanzesu of a different and specific amber type. About the 50% of the analyzed objects are made with a non-Baltic type of amber, whereas the other 50% are succinite. The comparison of the results with our database and with the literature data strongly suggest a similarity of this material with Romanian ambers (rumeniti, schraufite) and Czech ambers (walchovite, neudorfite).