Extending the inter-Adriatic trade of bitumen beyond the fifth millennium BCE

Grotta dei Cervi (Apulia, Southern Italy) is the most important European figurative art site for its Neolithic red and brown paintings found in the various galleries of the cave. It was frequented with particular intensity between an advanced phase of the Early Neolithic (first half of the sixth millennium BCE) and continued up to the end of the Bronze Age (last centuries of the second millennium BCE). Among the more than thirty thousand finds, some ceramic shards had black residues on them. These residues were sampled so that molecular and isotopic investigations could be carried out. GC–MS-MS and EA–IRMS after fractionation of the samples allowed us to identify bitumen on some archaeological potsherd remains and to identify its geographic source by comparison with geological samples from Majella and Selenicë, two deposits located respectively in Italy and Albania and known to have been exploited since Neolithic times. All the bitumens from Porto Badisco correlate with each other and with the Selenicë geological samples. Isotopic fingerprints strongly support the biomolecular evidence and confirm the Albanian origin of the archaeological bitumen. The data presented herein provide the first evidence of export and trade of raw bitumen across the Adriatic Sea from Selenicë to Apulia during the Neolithic age thus bringing back to the fifth millennium BCE the transport of bitumen across the Adriatic Sea in the central Mediterranean area