The production cycle of lime based plasters in the Late Roman settlement of Scauri, Island of Pantelleria (Italy)

This paper deals with the archaeometric study and analysis of lime based plasters recently found in the archaeological settlement of Scauri, located in the homonymous bay at the island of Pantelleria (central Mediterranean, Strait of Sicily). The Bay of Scauri is sited in the south-west part of the island. It can be considered a natural harbour overlooking the coast of Cape Bon in Tunisia. Since the 1999, the archaeological importance of place was reconsidered thanks to the recovering of huge remains of a Late Roman settlement dating back to the 4th-5th century AD. A production quarter, a residential area, a necropolis and a religious area were brought to light. The economy of the settlement was based on fishing, as well as on the production of peculiar class of pottery, well known as Pantellerian ware, exported all over the western Mediterranean (Montana et al., 2007). The study of the production cycle of lime mortars and plasters having different end-use at the site of Scauri is the object of this paper. It is well acknowledged that the island of Pantelleria is entirely composed of volcanic rocks (pyroclastic deposits and lava flows). Accordingly, for lime production it is essentially required the import of calcareous raw material from elsewhere. Also the selection criteria of the sandy aggregate are relevant and equally interesting in order to evaluate the technological level locally reached. Within this frame, a detailed mineralogical and petrographic characterization of the mortars was carried out by thin section petrography, for the complete compositional classification of the sand aggregate and the stratigraphy. Moreover, X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS) were carried out with the purpose to investigate the composition of the lime-based binder. The analytical results allowed to highlight the pozzolanic reactions in the binder, to identify the provenance of the calcareous raw material and to individuate different categories of mortar recipes in terms of intended use.