Sasanian glass from Veh Ardašīr investigated by strontium and neodymium isotopic analysis

A collection of 31 glass fragments, dated to the 3rd to 7th century AD and excavated in Veh Ardasir, (modern Iraq), were analysed for their Sr and Nd isotopic compositions with the aim of deepening our knowledge on glass circulating within central Mesopotamia during Sasanian times and to highlight the merits of isotope ratios for the definition of the production scenery. Based on the elemental composition of the samples, two groups related to the exploitation of different plant ashes were previously distinguished, and also a change in the silica source in the course of the 4th century AD emerged. The determination of isotopic distributions of Sr and Nd offers a deeper insight. The Sr-87/Sr-86 isotope ratio, together with the Sr elemental concentration, confirms this use of different plant ashes, and permits one to distinguish distinct glass batches, although the isotopic Sr signature does not allow us to highlight evidences of different provenances for the samples of different composition. Moreover, the Nd-143/Nd-144 isotope ratio suggests the use of sands belonging to a common geological area, and also allows the identification of a set of samples that were possibly produced exploiting a further different sand source. As a whole, Sr and Nd isotope ratio values for the samples considered, i.e. Sr-87/Sr-86 = 0.70833 to 0.70916 and epsilon Nd = -8.69 to -4.98, differ from the published isotopic data on middle Eastern glass samples and can therefore define a characteristic Sr-Nd signature for plant-ash Sasanian glass excavated in Veh Ardasir.