ABSTRACT
Underwater Cultural Heritage is acquiring more importance in the last years due to the easy access to the submerged ruins and therefore to the looting, destruction or commercial exploitation of them. Most of the pieces that are extracted and recovered from shipwrecks are preserved in museums. However there are still a large number of archaeological pieces that have not been studied, from which there is a lack of information. In order to obtain more information about this type of pieces and in order to study the degradation processes which can affect them, this work is focused on materials extracted from a shipwreck located in Bakio (Basque Country). Concretely, in four iron pieces which are currently preserved in the Archaeological Museum of Bilbao. The conservation state of the pieces is acceptable because they were treated, nevertheless, several chunks have been released from the pieces. To study the raw composition of underwater materials, the degradation processes and to find the better conservation procedure, the applied analytical methodology is based on the application of non-destructive analytical techniques. In this way, in order to obtain molecular and elemental information, Raman spectroscopy and X-Ray fluorescence spectrometer were used. The results obtained showed the presence of expected iron oxides in all the analyzed pieces and lead corrosion products in the lead based pieces. Moreover, the action of sulfate-reducing bacteria has been confirmed due to the presence of elemental sulfur.
