Neutron-based techniques for archaeometry: characterization of a Sardinian boat model

A Depalmas,F Grazzi,A Fedrigo,A Canu,W Kockelmann,A Scherillo,A Brunetti,F Di Gennaro,M Cataldo

doi:10.1007/s12520-021-01345-w

Abstract

Sardinian metallurgy produced samples of high artistic and historical value. In particular, ship models are rare and unmatched examples of the mastery reached by Sardinian metallurgists and their production process deserves an in-depth analysis of all the phases involved in the making. In this work, we examined a Sardinian boat model to obtain information about its composition, microstructure and manufacturing technique. The object is a small bronze ship model that was found near the Nuraghe Colovros, located in north-east Sardinia (Italy). It was analysed by means of neutron imaging and neutron diffraction experiments at the ISIS Pulsed Neutron and Muon Source laboratory (Harwell, UK). Neutron techniques are relatively new in the field of archaeometry, but they are a very effective tool for the study of archaeological objects: they permit to survey complete artefacts, determine compositions and structures, assess the conservation status and address questions of effective use and casting techniques. This type of data can add new and different insights to existing archaeological information, especially where sampling is not permitted. The outcome of the study reveals a peculiar approach to the manufacturing of the boat model.

Highlights

Sardinian bronze artefacts constitute a rich historical archive providing key information about the metal production and casting techniques concerning the development of metallurgy in the Mediterranean area
Boat/ship models, in particular, are the miniature representation of their larger siblings and represent a very specific type of objects that testify the special bond between the Sardinian Iron Age culture and the sea
Since boat models were generally found in religious contexts, the accepted theory among the archaeological community is that they probably served as votive lamps (Depalmas 2014)

Summary

Introduction

Sardinian bronze artefacts constitute a rich historical archive providing key information about the metal production and casting techniques concerning the development of metallurgy in the Mediterranean area. One of the main issues concerns the connection between the different elements of the boat, since it is assumed that metallurgists of the first Iron Age were not able to make soldering (Lechtman and Steinberg 1980) This assumption leads to hypothesize that complex shapes as animal figurines and other decorations might have been added at a second stage, on top of a first casting of the hull and the protome, by using the casting-on technique (Brunetti and Al 2018). Following this procedure, the joint was made by putting the wax model of decorative elements directly on the precasted hull and by building up the mould around it. This work aims to characterize the elemental and phase compositions of the Colovros boat and to establish whether it was made in a single casting or, as in the case of more complex examples, it was made using the casting-on technique

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Results