New evidence of adhesive as hafting material on Middle and Upper Palaeolithic artefacts from Gura Cheii-Rasnov Cave (Romania)

摘要

Making use of analytical, chemical and mineralogical methods, this paper focuses on the analysis of inclusions in order to address the question of the provenance of prehistoric artefacts excavated in Gura Cheii-Rasnov Cave (Romania). The study represents the first discovery of bitumen on lithic tools belonging to the Upper and Middle Palaeolithic in Europe. The material was identified through several analytical procedures, such as Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray fluorescence (EDXRF), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD).Gas chromatography-mass spectrometry (GC-MS) allows the analysis of bitumen and related compounds: resins and oils, tar and pitch, and waxes. Lipids extracted from the lithic artefacts showed that the main organic constituents were palmitic (C_(16:0)) and stearic (C_(18:0)) acids, together with minor saturated (myristic C_(14:0), pentadecanoic C_(15:0), palmitic C_(16:0), iso-C_(16:0) C17:0) and unsaturated (palmitoleic C_(16:1) and oleic C_(18:1)) fatty acids. The use of GC-MS also allows identifying C_(15+) alkanes (such as C_(23)H_(48) - tricosane, C_(24)H_(50) - tetracosane, C_(25)H_(52) - pentacosane). All these hydrocarbons confirm that the black substance is highly weathered bitumen, the source of which remains unknown. The composition of this black substance suggests that the organic traces are remnants of a hafting material used by Palaeolithic people to glue handles onto their tools.