Analysis of Organic Artefacts from the Mary Rose

The Mary Rose is a Tudor warship, commissioned by Henry VIII in 1510, which sank in 1545 off the south coast of England. It was raised in 1982 with over 19,000 artefacts. Research into conservation of marine archaeological artefacts has expanded since then but research into organic-based marine archaeological materials is relatively sparse. There is an increased likelihood of these materials surviving in a near anoxic, marine environment but degradation can still occur through mechanical, chemical, and biological processes. This can create complicated pathways of degradation, which need to be explored further. In marine archaeological wood, one of the major degradation pathways is through sulfur species, where reduced sulfur compounds oxidise upon raising the ship to form sulfate salts and sulfuric acid. This hydrolyses cellulose, leading to its breakdown. Iron from ship fixtures and other artefacts catalyse this process.1 A conservation treatment that neutralises sulfuric acid and removes iron sulfate is essential to prevent further degradation of organic-based artefacts from the ship. In this thesis, SrCO3-cellulose patches were applied to iron sulfate soaked model wood. After removal, the patches and the wood were analysed by S and Fe K-edge X-ray Absorption Near Edge Structure (XANES) spectroscopy, FTIR, Raman, and portable XRF spectroscopy. The results indicate that sulfur and iron species can be removed by the patch, demonstrating its potential as a useful spot treatment for marine archaeological wood. Other organic artefacts of sail cloth, anchor rope, wool, and leather from the Mary Rose were characterised using optical microscopy, SEM, and FTIR spectroscopy leading to a greater understanding of the organic artefacts from the ship through investigating fibre identification, and extent of degradation. This will influence the development of specific conservation treatments and has further reaching implications for the conservation of marine archaeological organic materials in general. 1 K. M. Wetherall, R. M. Moss, A. M. Jones, A. D. Smith, T. Skinner, D. M. Pickup, S. W. Goatham, A. V. Chadwick and R. J. Newport, J. Archaeol. Sci., 2008, 35, 1317–1328.