Petro-archaeometric characterisation of "cotto ferrarese": Bricks and terracotta elements from historic buildings of ferrara

Petro-archaeometric characterisation of ≪cotto ferrarese≫, i.e., chemicalmineralogical investigation of bricks, tiles and decorative elements from historic buildings in Ferrara (NE Italy) enabled us to constrain the nature of the raw materials employed. These consist of clays closely resembling the present-day fine sediments of the river Po (High-Cr sediments); clays of plausible Apennine provenance (Low-Cr sediments), although outcropping in the area, were not used. Processing of chemical data reveals that, within the High-Cr clays, the most CaO-rich facies were preferred and mixed with minor amounts of the local sands; a Na 2 O-vrich flux component was then probably added. After firing tests on these sediments, the related firing parageneses were compared to those recorded in the studied terracottas, indicating for the latter kiln temperatures between 850-1000°C, with significant variations among samples from different buildings.