APPLICATION OF FTIR SPECTROSCOPY TO THE CHARACTERIZATION OF WATERLOGGED ARCHAEOLOGICAL WOODS OF THREE GALLEYS FROM YENİKAPI, İSTANBUL: CONTRIBUTION TO CONSERVATION

Abstract

Thirty-seven shipwrecks, which are dated from 5th to 11th centuries AD, were uncovered under the supervision of the Istanbul Archaeology Museums Directorate in Yenikapı salvage excavations at Yenikapı, İstanbul. The woods of the Yenikapı shipwrecks, which were found during the excavation, were in the waterlogged state. The physical and chemical degradation degree of the waterlogged archaeological wood has been evaluated in detail to establish a successful conservation procedure. The determination of the chemical changes in the structure of the waterlogged archaeological wood provided information about the degradation process. In this study, fourteen untreated wood samples were taken from the three galleys of Yenikapı Shipwrecks (YK 13, YK 16, and YK 25), which are dated between the 7th and 10th centuries AD. In order to determine the chemical characterization of the waterlogged archaeological wood, the ATR-FTIR method was used. With the aim of making a safe comparison, three fresh wood samples (plane, pine, and elm) were also analysed. The spectral comparison all the changes of holocellulose and lignin components in the structure of the waterlogged archaeological wood samples were detected; the lignin degraded but it remained more intact than polysaccharides. New and additional data have been provided regarding the characterization of waterlogged archaeological woods for many ships in the Yenikapı Shipwrecks Project, the variety of the wood types used in the construction of the ships, and the usage of the ships such as galleys.