Chemical characterization of organic residues on Late Roman amphorae from shipwrecks off the coast of Marsala (Trapani, Italy)

[Display omitted] •Residue analysis conducted on Roman and Late Roman amphorae from western Sicily.•Gas Chromatography and Mass Spectrometry detect olive oil and resin in amphorae.•Nuclear Magnetic Resonance validated data obtained by GC-MS.•Africana IIA and Keay 8A linked with the transport of olive oil.•Residue analysis deepens understanding of amphora use-life and recycling. Organic residues were extracted from thirty-three different types of Roman and Late Antique amphorae retrieved from underwater contexts in the custody of the Archaeological Museum “Baglio Anselmi” of Marsala in Sicily. The samples were analysed using GC-MS and 1H NMR, finding biomarkers of plant oils (including saturated and unsaturated fatty acids, alcohols and alkanes present in plant waxes) were identified in seven samples. The biomarkers for Pinaceae spp., used for making pitch, were identified in one sample. The results obtained shed light on the function of different types of North African amphorae, traditionally interpreted as containers for olive oil, wine and fish sauce, presenting new evidence to reassess the system of trade between Sicily and North Africa in Late Antiquity.