Petrochemical characterisation of natural stones from the Etruscan site of Marzabotto (Bologna-Italy): Preliminary results

The tufa rocks used in sacral buildings in the Etruscan site of Marzabotto (Bologna, Italy) were characterised from a petrochemical point of view and compared with lithologies outcropping in the surrounding area in order to recognise the ancient quarries. These tufa, called “travertine” in the Italian literature, are very porous and are rich of macrophyte moulds revealing an origin by freshwater carbonate deposition (Ford-Pedley, 1996). Facies and thin section analyses show that these rocks were formed in cascade and paludal settings. Hypothesising that the possible quarry areas of travertine rocks were not far from the site and using the geological maps of the surrounding of the Etruscan site it was possible to identify few possible supply zones: 1) San Cristoforo di Labante (Castel DAiano, Bologna), 2) Rio Sponga (Marzabotto, Bologna) and 3) Rio Bucamante (Serramazzoni, Modena). Petrochemical characterisation were complemented with a statistical elaboration using the SPSS 14.0 (Copyright © 2006 SPSS Inc.) method and have highlighted that the San Cristoforo di Labante deposit could be the most suitable quarry area of the travertine used in Marzabotto. The geomorphology of the area suggests that blocks were lowered from the San Cristoforo di Labante deposit through a “lizza” way (using rollers along a prepared slope) and thenshipped along the Reno River to the Etruscan site of Marzabotto.ReferencesT. D. Ford, H. M. Pedley, (1996) A review of tufa and travertine deposits of the world, in: Earth-Science Reviews, 41.