A multidisciplinary approach for the study of underwater artefacts: the case of Tritone Barbato marble statue (Grotta Azzurra, Island of Capri, Naples)

Abstract

A multidisciplinary investigation has been carried out in order to study sculpture materials, the state of preservation and provenance of a marble statue representing a Tritone Barbato, together with that is believed to be its base. Both items were recovered from underwater environment in the 60s from the Grotta Azzurra, Capri, Italy. Together with other statues, these archaeological finds were a decorating element of the nymphaeum (grotto) of a maritime imperial villa dating back to the Roman period, attributed to Emperor Tiberius. Diagnostic analysis represents an essential tool for the choice of the proper cleaning procedure, since it is an irreversible process. For this reason, a study of the nature and the extension of degradation forms has been conducted by means of optical microscopy and scanning electron microscopy. Moreover, petrographic analysis, oxygen and strontium isotopic ratios, evaluation of maximum grain size (MGS) and determination of Mn content made it possible to determine textural characteristics, and formulate some hypotheses about the marble’s provenance. Results suggest Carrara as raw material source and provide an indication that the two marble items belong to the same artefact.