image: Mineralized textile fragment on the surface of a thin copper-based plate from the Nausharo site (Kachi-Bolan region, Balochistan, Pakistan), dating from the first half of the 3rd millennium BC. The weaving technique, a balanced plain weave, is directly identifiable. The textile fibers show simultaneously a mineral character with various dense copper compounds and an organic signature derived from the original cellulose. view more
Credit: Image credit: Christophe Moulhérat
A study explores how textiles undergo fossilization by mineralization. How textiles fossilize in archeological settings remains poorly understood. Cellulose textiles found buried next to metallic objects can undergo a mineralization process that facilitates preservation, but the underlying mechanisms remain unclear. Loïc Bertrand and colleagues used a combination of analytical techniques to examine the preservation of ancient textiles dating from the 3rd-2nd millennium BCE that were found buried near copper artifacts and sourced from excavations in the Near East and archaeological collections of the Louvre Museum. The techniques include second harmonic generation microscopy, semiquantitative synchrotron X-ray microtomography, and nanoscale infrared imaging. The analysis uncovered three main stages of preservation through mineralization: water transports antimicrobial metal cations released by the corrosion of the nearby metal and soil solutes to the textile fibers; the cations and solutes are absorbed, causing the fibers to swell and form an inorganic crust and resulting in cellulose degradation; and the fibers undergo gradual silicification, which involves the condensation of siliceous compounds. The findings provide insight into the process of mineralization at the nanoscale and how it aids the preservation of textiles that are several millennia old. Additionally, the study demonstrates how imaging techniques, including second harmonic generation microscopy, can help investigate preservation of materials, according to the authors.
Article #20-04139: "In-place molecular preservation of cellulose in 5,000-year-old archaeological textiles," by Corentin Reynaud et al.
MEDIA CONTACT: Loïc Bertrand, Université Paris-Saclay, Saint-Aubin, FRANCE; tel: +33681332823; e-mail: loic.bertrand@universite-paris-saclay.fr
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Journal
Proceedings of the National Academy of Sciences