Vitrious Mosaic from Tyana (Cappadocia)

The archaeological research of the Italian Mission at Tyana revealed a mosaic fragment at the extreme southern end of the arcade which overlooked the entrance to the Baptistery. This religious building which can be dated to the 5th-6th c. A.D. and the mosaic are considered a unicum in Cappadocia, where no other churches or tessellated pavements of such an early date are known so far. The archaeometric study, carried out on a representative set of loose glass tesserae, specifically aimed to define the glass matrix as well as the colorant and opacifying agents. This allowed us to obtain a detailed analysis of the materials and prodution technology (useful also for the definition of the chronological context of the mosaic), and to identify distinctive features of the six different colour types that have been identified. The glass matrix of the majority of the tesserae from Tyana is made of soda-lime, with the remaining Tyana tesserae composed of soda-lime-lead and leaded glass. The identification of chronological markers, such as the natron as flux, manganese as the decolorizer, and the tin-based phase and hydroxyapatite as opacifiers, allowed us to hypothesize that these tesserae could not have been created before the 4th-5th c. A.D. In addition, the identification of obsidian samples from Göllü Dağ in the Tyana mosaic is an important discovery for archeaological research in Central Anatolia, since it is clear evidence of the exploitation of Göllü Dağ sources, previously unattested since the Prehistoric period. (D’après le résumé de l'auteur.)