The application of X-ray absorption spectroscopy in archaeological conservation: Example of an artefact from Henry VIII warship, the Mary Rose

We report a microfocus X-ray absorption (XAS) investigation of a thin film sample from an iron contaminated wooden arrow tip raised from the seabed with the Mary Rose. The XAS studies were combined with optical and scanning electron microscopy measurements. The arrow tip had been treated with polyethylene glycol (PEG) soon after it had been raised and stored in a controlled environment. The measurements revealed a significant concentration of iron sulfide nanoparticles. This indicates that in this sample there was a reduction of the oxidative effects of the normal ambient atmosphere that is usually seen in untreated timbers. The film was treated overnight with an aqueous solution of diethylenetriaminepentaacetic acid (DTPA), which is normally very effective in sequestering iron. This had little effect in terms of removing iron from the film and possible explanations are discussed.