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- Englisch (3)
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- Archaeometry (1)
- Biodeterioration (1)
- Dead Sea Scrolls (1)
- Fungi (1)
- Manuscript studies (1)
- Non-destructive testing (1)
- Oxalates (1)
- Parchment (1)
- Raman (1)
- SEM-EDS (1)
Organisationseinheit der BAM
In this work, we applied scanning electron
microscopy (SEM), microanalysis and Raman spectroscopy
to study the fungi inhabiting a richly illuminated parchment
document and the damage induced by their activity. To that
aim, we collected samples of fungal mycelium from the
deteriorated areas on a removable adhesive tape specifically
intended for lifting fungi without damaging the support.
SEM analysis of the adhesive tape samples showed the cooccurrence
of several species of fungi. One strain closely
resembling Acremonium species was observed only in the
tape micrographs but no agar cultures were obtained. Its
fungal structures showed the production of abundant
oxalates with an outstanding leaching of the calciumbased
materials of parchment (typically manufactured with
gypsum and lime). Needle-like crystals of calcium oxalate
produced by the fungus forming a uniform and quite
regular grid around conidial slimy heads were documented.
As a result, the areas affected by moulds were weakened,
stained and characterised by a powdery patina rich in
calcium. Confocal µ-Raman confirmed the presence of
oxalates while EDS showed the presence of calcium in
crystals. We conclude that the defacement of the parchment
was due to both collagenolytic activity, and to the
biotransformation of calcium-based minerals by fungi.
The miraculously preserved 2000-year-old Dead Sea Scrolls, ancient texts of invaluable historical significance, were discovered in the mid-20th century in the caves of the Judean desert. The texts were mainly written on parchment and exhibit vast diversity in their states of preservation. One particular scroll, the 8-m-long Temple Scroll is especially notable because of its exceptional thinness and bright ivory color. The parchment has a layered structure, consisting of a collagenous base material and an atypical inorganic overlayer. We analyzed the chemistry of the inorganic layer using x-ray and Raman spectroscopies and discovered a variety of evaporitic sulfate salts. This points toward a unique ancient production technology in which the parchment was modified through the addition of the inorganic layer as a writing surface. Furthermore, understanding the properties of these minerals is particularly critical for the development of suitable conservation methods for the preservation of these invaluable historical documents.