The study of the destructive roles of the endolithic lichen Verrucaria buschirensis , family Verrucariaceae on the world heritage site Persepolis

Esmaeillou M., Sohrabi M. & Ofoghi H.
Journal of Research on Archaeometry
8(1): 171–183
DOI: 10.52547/jra.8.1.171
The establishment of lichens on stone surfaces can cause serious damages to the surface. While the harms by the epilithic settlement is restricted to visual damages, the endolithic settlement will also bring about serious damage to the depths of the rock and will form small holes and fractures within the rock, which in turn will allow other organisms to penetrate and prompt further impairments. Considering the historical importance of the surfaces of carved stones at the world heritage site of Persepolis and the damages induced by lichens in these valuable works, the purpose of this study was to investigate the destructive role of lichens of the Verrucariaceae family at this legendary site. In this study, thin sections were prepared to identify the type and texture of the rock in terms of petrography. In order to detect organic substances on the rock surface as well as their color difference, pyrographic and FTIR studies were conducted. Additionally, using an electron microscope and an optical stereomicroscope, the damages caused by biopits resulting from lichen thallus in the stone were examined. In conjunction with petrographic studies, the type and origin of the stones as well as their vulnerability were identified. Based on the FTIR analysis, it was determined that the stone’s color changed from gray to white due to calcium oxalate precipitation. The results of electron microscope imaging showed that the establishment of lichen (Verrucaria buschirensis of the Verrucariaceae family and the penetration of hyphae into the stone severely damaged the surface of the stones at Persepolis, and any neglect will result in further irreparable damages. Keywords: Biodeterioration, FTIR, Petrography, biopit, Stone Damages.
Wednesday, 08 March 2023 13:40