Natural stones from sacral buildings of the Marzabotto Etruscan site: Petrochemical characterization and hypothesis of provenance.

The Etruscan site of Marzabotto (Bologna Italy) was built and developed between V1 and IV sec b.C. In this site several sacral buildings were erect using various natural stone materials. In this study the attention has been focused on the tufa rocks used in some of the sacral buildings of this archaeological site. The samples were characterized from a petrochemical point of view and compared with lithologies outcropping in the surrounding area in order to recognize the ancient quarries. These tufa called "travertini" in the Italian literature, are very porous and are rich of hacrophyte 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. Hypothesizing that the possible quarry areas of travertine rocks were not far from the site and using the geological ma s of the surrounding of the Etruscan site it was possible to identify few possible supply zones: 1) San Cristoforo di Labante (Castel D'Aiano Bologna) 2) Rio Sponga (Marzabotto, Bologna) and 3) Rio Bucamante (Serramazzoni; Modena). Petrochemical characterization 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 trough a "lizza" way (using rollers along a prepared slope) and then shipped 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.