Geology and geophysics at the archeological park of Vulci

Abstract

The Vulci archeological site was object of interest by the Soprinten- denza ai beni culturali dell’Etruria meridionale (Italian government department responsible for southern Etruria’s cultural heritage) since the beginning of the 20th century. In 2001, the Ministero dei Beni Cul- turali (Italian ministry of cultural heritage) along with the local au- thorities, opened a natural-archeological park. In this area, it lies most of the ancient Etruscan city of Velch (today known by its Latin name, Vulci) including the Osteria Necropolis that is the object of this study. Recently, new archaeological excavations were made and the local au- thorities needed major geological information about the volcanic litho- types where the Etruscans used to build their necropolis. The aim of this study is to define the geological and geophysical characteristics of the rock lithotypes present in the Vulci park. For this purpose, a geo- logical map of the area (1:10000) has been realized. Moreover, two dif- ferent geophysical methods were applied: measurements of magnetic susceptibility and electrical resistivity tomography. Magnetic suscep- tibility analyses clearly identify magnetic contrasts between different lithotypes; the characteristics of the pyroclastic flow that originated the Sorano unit 2 and its vertical facies variations are well recorded by this parameter that along with lithostratigraphic observations provides information about the depositional conditions. Two electrical resistiv- ity tomographies were performed, which show the Sorano unit 2 thick- ness to be of c. 7 m with resistivity values ranging from 200 to 400 Ω·m. This kind of multidisciplinary approach resulted to be suitable to study this type of archaeological sites, revealing that areas charac- terized by a relevant thickness and wide areal extension of volcanic lithotypes can be a potential site where Etruscans might have excavated their necropolis.