The Mary Rose

Preserving a 460 year old wreck

An international team of researchers has analysed the sulphur and iron composition in the wooden timbers of the Mary Rose, an English warship wrecked in 1545, which was salvaged two decades ago.

The team used synchrotron X-rays from the Stanford Synchrotron Radiation Laboratory (USA) and the European Synchrotron Radiation Facility (France) in order to determine the chemical state of the surprisingly large quantities of sulphur and iron found in the ship. These new results provide insight to the state of this historic vessel and should aid preservation efforts. They are published this week in the Proceedings of the National Academy of Sciences Early Edition.

The Mary Rose served as English King Henry VIII's principal warship for 35 years until she went down outside of Portsmouth in 1545. In 1982 the hull was recovered from the sea and is currently undergoing a conservation process. The first author of the publication, Magnus Sandström, and his colleagues showed recently that the accumulation of sulphur within shipwrecks preserved in seawater is common by studying the Swedish warship Vasa, which remained on the seabed for 333 years. Their research concluded that sulphur in contact with oxygen could pose conservation problems. Over time, sulphur can convert to sulphuric acid, which slowly degrades the wood until the hull's stability is lost.

The authors examined the Mary Rose to determine the potential threat and found about 2 tons of sulphur in different compounds rather uniformly distributed within the 280-ton hull. To determine the sulphur species present in the wood, researchers first carried out experiments at SSRL. The team needed to obtain complimentary information in order to know the precise location of sulphur species at the micron scale and they then came to the ESRF. By studying thin wood slices perpendicularly cut to the cell walls at X-ray microscopy beamline ID21, they found high concentrations of organo-sulphur compounds in the lignin-rich areas between the cells, which may have helped preserve the ship while it was submerged in the seawater. This helped to understand how accessible and reactive the different sulphur compounds found are to acid-producing oxidation.

Plenty of iron and pyrite is also present in the Mary Rose, which is a concern, since in the moist wood iron ions can catalyse the conversion of sulphur to sulphuric acid in the presence of oxygen. The authors suggest that chemical treatments to remove or stabilize the remaining iron and sulphur compounds, and reducing humidity and oxygen access, are requirements for long-term preservation.

At the Mary Rose Trust they are already investigating new treatments to prevent new acid formation. For slowing down the organo-sulphur oxidation reaction and prevent new acid formation, wood samples from the Mary Rose are being treated with antioxidants in combination with low and high grade polyethylene glycol (PEG). Another approach to slow down acid formation in PEG treated conserved archaeological wood is to maintain it in a stable climate. It is hoped that keeping a constant low humidity of 50-55% without variations of temperature will stop changes in sulphur speciation. To maintain a stable microclimate within the wood structure a surface coating offers a possible solution, although the effectiveness of this approach has yet to be tested. “This ongoing research is considered to be an important step forward in devising improvements to the current Mary Rose hull treatment programme”, explains Mark Jones, curator of the Mary Rose. ###

Reference: Magnus Sandström, Farideh Jalilehvand, Emiliana Damian, Yvonne Fors, Ulrik Gelius, Mark Jones and Murielle Salomé. Sulphur accumulation in the timbers of King Henry VIII's warship Mary Rose: a pathway in the sulphur cycle of conservation concern, PNAS, Proc. Natl. Acad. Sci. USA published 26 September 2005, 10.1073/pnas.0504490102.

This press release is also available in Spanish and French.
Contact: Montserrat Capellas press@esrf.fr +33-476-88-26-63 European Synchrotron Radiation Facility

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Site Q — found in Guatemala

Long-sought Maya City — Site Q — found in Guatemala

New Haven, Conn. -- A team of scientists including Marcello Canuto, professor of anthropology at Yale, has found incontrovertible proof of Site Q, a long-speculated Maya city, during a mission to the northwest Peten region of Guatemala

In 1997, an earlier expedition headed by Ian Graham of Harvard's Peabody Museum and David Stuart, now at the University of Texas at Austin, found evidence at La Corona that led them to suggest first that La Corona was Site Q. Research since then has helped confirm their initial ideas and this finding provides the incontrovertible evidence.

The proof—an in-situ panel carved with over 140 hieroglyphs that fill in a key 30 year chapter in classic Maya history—was found in a little known ancient royal center called La Corona.

Roughly 40 years ago, the antiquities market was flooded with many exquisitely carved monuments of apparent Mayan origin. Many were purchased for private and museum collections despite a lack of provenance. Because of their similar style and shared subject matter, it was suggested that they came from some still unknown site located somewhere in the Peten lowlands. This site called Site Q — an abbreviation of the Spanish “ ¿que? ” or “ which? ” —has been the target of many expeditions.

The expedition to Guatemala this past April was to set up camp for an in-depth study later this year. On their last day in camp, Canuto and his team happened upon what they believe to be one of the monuments of Site Q.

“This panel exactly mirrors the style, size, subject matter, and historical chronology of the Site Q texts,” said Canuto. “This discovery, therefore, concludes one of the longest and widest hunts for a Maya city in the history of the discipline.”

In addition to confirming the existence and location of Site Q, the find is one of the longest hieroglyphic texts discovered in Guatemala in the last several decades. Canuto also noted that the two blocks making up the panel appeared to be in their original location in a temple platform and were in no way damaged or looted.

“The discovery reinforces the existence of a ‘royal road,’ a strategic overland route that links the Maya capital to its vassal kingdoms in the southern lowlands,” said team member David Freidel, professor of anthropology at Southern Methodist University. “For this reason, the forested enclave of Laguna del Tigre should receive serious consideration as a World Heritage Region.”

The group will be returning to Guatemala to continue the study, which was supported in part by the National Geographic Society, the El Perú-Waka’ Archaeological Project directed by David Freidel and Héctor Escobedo, and the Wildlife Conservation Society.

Other researchers included a mapping team of Damien Marken and Lia Tsesmeli, and an epigrapher Stanley Guenter, all of Southern Methodist University. Logistics for the expedition were carried out by Roan McNabb of the Wildlife Conservation Society, and Salvador Lopez, head of the department of Monumentos Prehispánicos of the Guatemalan Instituto de Antropologia e Historia (IDAEH). ###

Contact: Janet Rettig Emanuel janet.emanuel@yale.edu 203-432-2157 Yale University

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