Archaeometric study of waterlogged wood from the Roman cryptoporticus of Lisbon

Abstract

The Roman cryptoporticus of Lisbon, discovered in 1773, is located in the heart of the historical centre of Lisbon. The monument was constructed in the middle of the 1st century AD and was probably used as an artificial platform or foundation for other constructions, in the old port front of the Roman city of Felicitas Iulia Olisipo. The wood materials, subject of this study, were recovered during the archaeological excavations and include structural elements (i.e., parts of window frames), utilitarian items (i.e., spoon) and several unidentified fragments. The identification of archaeological woods was done, along with pyrolysis-gas chromatography/mass spectrometry analysis. Preliminary results stress the use of pine wood and underline how the degradation of the samples is evident, by the detection of a large amount of oxidized lignin compounds, and by the lower amounts of cellulose and hemicellulose compounds.