Archaeometric analysis of Terra Sigillata pottery from the Roman Cistern at Spoletino,Viterbo,Italy

Abstract

An integrated analytical approach has been performed to characterize terra sigillata ceramics from the archaeological site of Spoletino (Civitella d'Agliano) in Viterbo, Italy, dated between the 1st and the 4th century AD. This thesis aims to examine the production technologies of the ceramic body and the slip and investigate the features and the provenance of the raw materials. Optical microscopy (OM) and Fourier transform infrared spectroscopy (FTIR) results proved that the ceramic body is composed of quartz, K-feldspar and plagioclase, iron oxides, hematite, mica, biotite, carbonates, calcite, dolomite, diopside, and traces of kaolinite clay minerals in the ceramic body. The firing temperature was estimated at 750–850 °C under controlled oxidizing conditions. The mineralogical composition of the ceramic body is consistent either with the Scoppieto production or sigillata wares from Central Italy. Electron microscopy results coupled with energy dispersive X-ray spectroscopy (SEM-EDS) showed that the slips are more enriched in Al2O3, K2O, and Fe2O3 than the matrices, while the matrices are more enriched in CaO. In addition, two samples indicate phosphorous contamination due to post-depositional processes. Results from this study could be utilized to explore trade routes, consumption patterns, and the Roman economy in the middle Tiber Valley.