Multi-methodological approach from non-invasive to micro-destructive techniques for the characterization of Final Bronze Age vitreous materials: Paduli site (Colli sul Velino, Rieti) in central Italy

Here we present a two-step analytical protocol for the study of vitreous materials from the Middle Bronze Age to the Early Iron Age of the lakeshore settlement of Paduli (Colli sul Velino, RI) in central Italy. The first step was based on non-invasive techniques and, once acquired and evaluated the data, a second step was planned based on the collection of microfragments, from those objects considered representative to be analysed with micro-destructive techniques. In the first step, portable X-Ray Fluorescence (p-XRF), Fibre Optic Reflectance Spectroscopy (FORS) and X-Ray Diffraction (XRD) for acquiring information about elemental composition, chromophoric elements and crystalline phases in the glass matrix, were employed. The results of the first step allowed to address the sampling to the more significant and representative objects, also reducing the size and number of samples. So, five samples (starting from about 20 objects) were selected and analysed (i.e. 2 blue beads, a "star" bead with light and dark blue bands, a vessel fragment bichrome blue and white and a blue barrel bead with white spiral decoration) to obtain microstructure information, chemical composition, colorants and Sr-Nd-Pb isotopes information not otherwise obtainable. All samples were analysed by Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) for morphological and chromophoric investigation. Major and minor elements were analysed by Electron Probe Microanalysis (EPMA), whilst trace elements concentrations were obtained through Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Isotopic fingerprints of Sr, Nd and Pb were determined via Thermal Ionization Mass Spectrometry (TIMS). The data collected by this multidisciplinary approach, carried out for the first time on such materials of this period in central Italy, allowed us to identify the provenance of raw materials and the production technology, confirming the importance of the site into the network of international traffic