New x-ray technique gives insights into the Mary Rose

The vessel was sunk during a battle in 1545 but raised from the Solent in 1982 along with 19,000 Tudor artefacts. Since then, conservationists have kept the remains intact but new threats from within the boat’s structure could jeopardise the remains of the vessel, which are on display in a purpose-built museum at Portsmouth Historic Dockyard.

Now, researchers led by Professor Serena Cussen from Sheffield University have used a new x-ray technique available at the European Synchrotron Radiation Facility (ESRF) to discover the presence, location and structure of nanostructured bacterial by-products lodged within the ship’s wood that could contribute to its degradation.

The remains of the Tudor flagship are vulnerable to degradation after spending over 400 years at the bottom of the sea where harmful deposits have collected inside the ship’s wooden hull. These deposits originate from degradation of metal fixtures and artefacts after centuries spent under the seabed and the activity of anaerobic sulphur-reducing bacteria can lead to the formation of harmful acids.

This project, which brings together researchers from Sheffield University, the University of Copenhagen, Columbia University, New York, the ESRF and the Mary Rose Trust, has applied a new x-ray computed tomography method to unlock detailed information about these deposits.

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According to Sheffield University, applying this method also overcomes an added challenge of studying artefacts where care must be taken to avoid damaging the fragile remains as these experiments can be performed without destroying the sample.

In a statement, Professor Cussen said: “It is remarkable that this technique, available at the ESRF, allows us not only to image and locate these nanoparticles in Mary Rose wood, but also to evaluate their structure. This is the first time zinc sulphide nanostructures have been observed in Mary Rose wood. This is because it is really challenging to assess the range of material present within archaeological samples.”

The new technique is said to combine x-ray computed tomography with pair distribution function analysis (ctPDF). The team has used it to map out the location and structure of nanostructured compounds lodged within the ship’s wooden hull. The team also uncovered the location of organic polymer deposits within the wood, a result of polymer treatments applied to compensate for degradation of the wood. If the polymer starts to break down, it would produce degrading acids that could damage the Mary Rose.

“These developments mean that potential threats to the wood can be tracked - a vital step in developing conservation strategies for the future of the Mary Rose,” said Prof Cussen. “With the insights we have gathered from this experiment we’ve been developing new magnetic nanoparticle-based treatments to target and remove these harmful species from the Mary Rose. This will help us preserve this priceless artefact for years to come. This x-ray method could also be used to inform strategies to preserve other important archaeological discoveries.

The team’s findings are detailed in Matter in a paper titled ‘Location and characterization of heterogeneous phases within Mary Rose wood.’