Geochemical proveniencing of the tuff used to build the Temple of Jupiter Optimus Maximus and other Archaic monuments (Rome, Italy)

Abstract

This work presents the results of a geological-geochemical and archaeological study, aimed at determining the origin of blocks of Tufo del Palatino (a pyroclastic flow deposit erupted 534 ka from the Colli Albani volcanic district) used for the construction of the foundations of the Temple of Jupiter and of other important monuments of Archaic Rome (6th-early 5th c. BCE). Through the reconstruction of the underground trend and outcrop areas of Tufo del Palatino, extraction sites mentioned by historical sources and recent literature were recognized and sampled, in order to compare their geochemical signature with that of the cut blocks used by Roman builders. For this purpose, 32 archaeological samples were taken from monuments and analyzed together with 14 geological outcrop samples. By determining the ratios of particular trace elements (Zr/Y, Nb/Y, Zr/TiO2, Nb/TiO2, Th/Ta) it is possible to establish the great compositional homogeneity of all the archaeological samples analyzed and their compatibility only with outcrop samples taken from the Capitoline Hill. The evidence, both of a geological and archaeological nature, of quarry interventions on the hill in Roman times is analyzed and discussed.