Multi-instrumental analysis of asphalts of archaeological interest

Use was made of thermal and other techniques to characterise three native asphalt samples. The purpose was to support archaeological investigations reconstructing their thermal history and composition. The first sample (from a Roman quarry in central Italy) proved to have 37% impurities, no sign of oxidation or degradation and to have never been heated to above 100°C. The second sample (from a Roman ship sunk south of France) was pure, but partially oxidised, with a saturated fraction in its structure. Analyses of the latter sample, obtained from the eye of a Thracian bronze head, revealed that the asphalt had been heated to over 100°C and then mixed with natural wax.