What doesn’t meet the eye: molecular insights into adhesive technologies of Neolithic harvesting tools from Central-North Italy

This study explores the geographical distribution and molecular composition of adhesive substances employed by Neolithic communities in north-central Italy. By applying advanced mass spectrometric techniques—specifically Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) and Gas Chromatography/Mass Spectrometry (GC/MS)—we chemically characterized organic residues recovered from flint blades and complete and fragmentary wooden sickles, across multiple archaeological sites. The dual analytical approach proved especially effective in detecting and identifying molecular markers in samples where the preserved adhesive was present only in trace amounts, thus overcoming limitations imposed by minimal sample volumes and potential contamination. Our comprehensive analysis revealed a diverse portfolio of adhesive materials, notably birch bark tar, Pinaceae resin, and bitumen. The coexistence of these substances within the same chronological framework suggests a complex technological and procurement strategy among Neolithic groups. Local resources, such as pine resins, were likely exploited alongside non-local materials, implying the existence of well-established exchange networks and adaptive responses to regional environmental conditions. By coupling archaeological investigation with molecular characterization, this research demonstrates that even minimally preserved organic residues can yield significant compositional data, thereby contributing to a more nuanced reconstruction of prehistoric technological networks and socio-economic interactions.