Sulfur accumulation in the timbers of King Henry VIII's warship Mary Rose: A pathway in the sulfur cycle of conservation concern

doi:10.1073/pnas.0504490102

Sulfur accumulation in the timbers of King Henry VIII's warship Mary Rose: A pathway in the sulfur cycle of conservation concern

^*Department of Structural Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden; ^‡Department of Chemistry, University of Calgary, Calgary, AB, Canada T2N 1N4; ^§Department of Physics, Ångström Laboratory, Uppsala University, P.O. Box 530, SE-751 21 Uppsala, Sweden; ^¶The Mary Rose Trust, College Road, HM Naval Base, Portsmouth, PO1 3LX, United Kingdom; and ^∥European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex, France

Edited by Harry B. Gray, California Institute of Technology, Pasadena, CA (received for review May 31, 2005)

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Fig. 1.
Isometric of the Mary Rose hull showing the main constructional features, excluding decks, internal structures, and fittings. Dimensions: stem to bow, 40.9 m; breadth, 11.7 m. Sample positions are indicated for oak cores 2-4 (cores 1a, 1b, and 5 are from magazine-stored timbers).
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Fig. 2.
Total sulfur and iron in mass % from x-ray fluorescence line scan (9) along oak core 2 from a hull rider (cf. Fig. 1).
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Fig. 3.
Normalized sulfur K-edge XANES spectra (SSRL) from sections of oak cores from surface (0 mm) and inwards. (a) Core 1a: oak beam, magazine stored in airtight wrap. (b) Core 2: hull rider under PEG treatment. The major peak at 2,473 eV originates from reduced sulfur species (thiols R-SH, disulfides R-SS-R′, elemental sulfur S₈, and pyrite FeS₂). The minor peak at 2,482.4 eV (core 1a) corresponds to oxidized sulfur in sulfate.
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Fig. 4.
XANES evaluation of sulfur species by fitting linear combinations of standard spectra. (a) Core 1a (0-5 mm): 1, disulfides R-SS-R′ 31 atom % S; 2, thiols R-SH 23%; 3, elemental sulfur S₈ 36%; 4, sulfoxide R₂SO [or R(SO)R′] 4%; 5, sulfate $\text{[math]}$ 6%. (b) Core 2 (15-17 mm): 1, R-SS-R′ 29%; 2, R-SH 18%; 3, S₈ 35%; 4, R₂SO 5%; 6, pyrite FeS₂ 13%. (c and d) Wooden remains of a gun shield from the Mary Rose with salt formation on the surface (see photo, d): 3, S₈ 6%; 5, sulfate 63% (standard: melanterite FeSO₄·7H₂O); 6, FeS₂ 26%; 7, sulfonate $\text{[math]}$ 5%.
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Fig. 5.
X-ray photoelectron spectra of oak core 1b (cf. Table 2). The vertical lines mark binding energies in the energy range 150-210 eV of the element-specific photoelectrons Cl_2p, B_1s, S_2p, and Si_2s. The mean S 2p_3/2 binding energies were 163.7 and 168.8 eV for the reduced (S_red) and oxidized (S_ox) sulfur species, respectively. Cracks in the core correspond to increased intensities of the chloride and sulfate peaks.
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Fig. 6.
SXM images at 2,473 eV (higher reduced sulfur concentration → brighter color) and micro-XANES of oak wood from the Mary Rose.(a Upper) Hull timber under spray treatment shows reduced sulfur accumulated in middle lamella. (Lower) The micro-XANES curves correspond to 1, bright particle; 2, middle lamella; 3, pyrrhotite 4C (Fe_1-xS) as standard; and 4, pyrite FeS₂ as standard. (b) Freshly salvaged (in 2004) oak wood from the Mary Rose after 459 years on the seafloor. (Left) The SXM image at 2,473 eV displays two layers of thiols in high concentration in the lignin-rich cell wall of a vessel (top right), which is a channel for water flow in oak wood (cf. Fig. 8); the dark patches surrounded by cell walls are the lumina. (Right) The 2,483 eV image shows a few bright sulfate particles.