Bitumen in potsherds from two Apulian Bronze Age settlements, Monopoli and Torre Santa Sabina: Composition and origin

Bitumen was found to occur on archaeological potsherds collected from two Apulia Middle Bronze Age sites, Monopoli and Torre Santa Sabina (Italy). Bitumen from two different areas, Majella (Italy) and Selenicë (Albania), were analyzed as potential reference samples to assess the geographic origin of the archaeological bitumen using geochemical analytical techniques. Analysis of the archaeological samples from different layers at both sites showed that the bitumen possesses the same gross composition and biomarker distribution patterns. Sterane and terpane profiles from the archaeological samples were very similar to some of the geological samples collected from Selenicë. In both archeological and selected Selenicë samples, sterane distributions were dominated by the C29 homologues (46-54%), followed by the C27 (26-33%) and C28 homologues (ca. 21%). Other biomarkers, such as gammacerane and oleanane, as well as the stable carbon isotopic composition of the asphaltene fraction, also suggest that the bitumen from the two archaeological sites was imported from Albania during Middle Bronze Age.