The Characterization of Paints and Waterproofing Materials From the Shipwrecks Found at the Archaeological Site of the Etruscan and Roman Harbour of Pisa (Italy)*

Abstract

This work presents the results of a diagnostic survey on the shipwrecks from the archaeological site of the ancient harbour of San Rossore (Pisa, Italy). The original waterproofing, caulking and painting materials were characterized by Fourier transform infrared spectroscopy (FTIR), gas chromatography -mass spectrometry (GC-MS), energy-dispersive X-ray microanalysis (EDX) and X-ray diffraction (XRD). The major constituents of the waterproofing and caulking materials detected on the planks were tricyclic abietanes showing a high degree of aromatization. These compounds are indicative of a pitch obtained from the wood of trees of the Pinaceae family.The analysis of the organic components of the paint samples revealed diterpenoid acids characteristic of Pinaceae resins together with linear long-chain alcohols and fatty acids, highlighting the presence of beeswax. Noticeably, the characteristic odd carbon number alkanes that are normally present in beeswax were not detected. The EDX and XRD analyses showed that hematite, calcite, cerussite and kaolinite were employed as pigments to paint the ships' hulls.

Application of Gas Chromatography coupled with Mass Spectroscopy (GC/MS) to the analysis of archeological ceramic amphorae belonging to the Carthaginian fleet that was defeated in the Egadi battle (241 B.C.)

“…Further confirmation derived from the identification of heating markers such as retene and 8-isopropyl-1,3-dimethyl phenantrene [7], [8].…”

“…This compound is indicative of the pitch production method: it is formed by heating resin-bearing wood, where the wood is burned to simultaneously extract resin from the source wood and convert it to pitch [7], [8].…”

“…The chromatograms show several diterpenoid acids such as dehydroabietic acid and 7-oxodehydroabietic acid, together with polycyclic aromatic hydrocarbons, such as retene and dehydrogenated derivatives, that are markers for pine resin in aged materials [7], [10].…”

Organic Residues in Archaeology: The Highs and Lows of Recent Research

“…The effects of degradation on the chemical composition of organic materials during their use and subsequent burial is reasonably well understood (3,4,6,8,(26)(27)(28)(29)(30). However, the increasing importance of isotopic analysis of various types of materials raises the question of whether isotopic values are stable under burial conditions.…”

“…The use of different chromatographic methods to analyse the same material is also becoming more routine, particularly in the area of dyes and paints where organic colourants may be mixed with different binding materials (165,166). Where inorganic colourants are also present, a combination of chromatographic and other techniques such as XRF, XRD, SEM, SEM-EDX, Raman and FT-IR can provide a complete characterization of the paints, dyes or other materials being analysed (28,122,(167)(168)(169). This approach has also proved successful in the analysis of vessel contents suspected of being paints, inks, medicines or cosmetics (168,170,171).…”