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

A multidisciplinary investigation was carried out in order to study the sculpture materials, state of preservation and provenance of a marble statue representing a Tritone Barbato, together with what is believed to be its base. Both items were recovered during the 1960s from an underwater environment in the Grotta Azzurra, Capri, southern Italy. Together with other statues, these archaeological finds were a decorative element in the nymphaeum (grotto) associated with a maritime imperial villa dating back to the Roman period, attributed to Emperor Tiberius. Diagnostic analysis represents an essential tool for the selection of an appropriate cleaning procedure, since the latter is an irreversible process. For this reason, a study of the nature and extent of degradation was conducted via optical and scanning electron microscopy. In addition, 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, as well as to formulate some hypotheses regarding the marble’s provenance. The results point to Carrara as a potential raw material source and indicate that the two marble items belong to the same artefact.