Deterioration of ancient ceramic vessels fragments by cyanolichens

PASSO, ALFREDO Y SOTO DAIANA

Teheran

Congreso; First International Conference on Biodeterioration of Historical and Cultural Heritage; 2013

Research Center for Iraniean Cultural Heritage, University of Alzahra

Lichens have the ability to colonize a wide range of substrates, both natural and artificial, and causing significant weathering and deterioration. There is a vast literature about how lichens affect historical and archeological substrates, such as monuments, frescoes, ruins, rock art, etc,. However, few records can be found of lichens growing over pottery or ceramic vessels. In northeastern Argentina there are numerous archeological sites of prehispanic cultures. In the province of La Rioja, in the town of Famatina (Antinaco Valley), the archeological site known as La Cuestecilla is located, wich belongs to the Aguada culture, ca. 600-1200 AC. It comprises residential, public, ceremonial and productive places. It is surrounded by small villages with fields, yards and geoglyphs. All settlements have abundant archeological material, on surface and stratigraphy. However, the presence of fragments of ceramic vessels is noteworthy, many remarkably decorated, scattered all over the place. Recently, the presence of three cyanolichens species growing on the fragments was detected. This are Peltula obscurans, Lichinellasp. and a third unidentified species belonging to Lichinaceae. These species are mostly found on the fragments margins, but also often overgrowing the outer surface, where the decorations are. These species are causing a considerable deterioration, as hyphae penetrate in the substrate producing a desintegration of the ceramic material. We present the preliminary results of the deterioration of ceramic fragments of archeological interest, caused by cyanolichens. Special emphasis will put on the possibility of estimating the growth rate of these species and the deterioration mechanism, in order to establish the amount of damage caused and possible conservation strategies.