Archaeometric analysis of wall coatings from the Chalcolithic site of Su Coddu (Sardinia, Italy)

This paper addresses the archaeometric analysis of several wall coatings applied to diverse architectural structures (wells, silos and domestic spaces) from the Chalcolithic site of Su Coddu/Canelles (Sardinia, Italy; c. 3400-2850 BC). The study of the samples was carried out by means of optical microscopy by thin-section analysis, micro X-Ray Diffraction and Scanning Electron Microscopy combined with Energy Dispersive XRay Spectroscopy. The study showed the application of successive layers of different thickness and granulometry to isolate the architectural structures. On the one hand, up to two layers made with a Tertiary fossiliferous marly clay as plaster are documented. On the other hand, the application of a very thin final layer very rich in calcite is observed in the majority of the samples studied. The analyses conducted evidence certain variability in the technological choices made by the craftpeople. However, it is also observed a clear adaptation of the properties of the studied materials to the insulating and waterproofing function that they played in such architectural structures.