Analytical Sciences

Analytical Aspects of Waterlogged Wood in Historical Shipwrecks

Yvonne FORS,* Farideh JALILEHVAND,** and Magnus SANDSTRÖM***

*Archaeological Research Laboratory, Department of Archaeology and Classical Studies, Stockholm University, SE-106 91 Stockholm, Sweden
**Department of Chemistry, University of Calgary, Calgary, AB, T2N 1N4, Canada
***Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden

Conservation methods applied to historical shipwrecks increasingly rely on combining modern analytical techniques to obtain new insights for specially adapted conservation treatments. Crystalline salts formed on waterlogged wood are identified by powder X-ray diffraction while X-ray fluorescence measurements along wood cores show penetration profiles of contaminating elements. Dedicated synchrotron-based X-ray absorption spectroscopy, especially sulfur and iron K-edge XANES, allows speciation of the large amounts of detrimental sulfur and iron compounds that often are found accumulated within the hull timbers, while high resolution X-ray imaging shows the distribution within the wood microstructure. By fitting spectra of model compounds to high quality sulfur K-edge XANES spectra one can obtain the relative amounts of different types of functional sulfur groups. FT-IR, NMR, ESCA, MALDI-TOF mass spectrometry and size exclusion chromatography are other useful techniques to analyze the status of the wood and of the consolidation agent polyethylene glycol. Examples are given from analyses of famous artifacts.

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