Stone Age Weapon Pulled From Lithuanian River Reveals 10,000-Year-Old Birch Tar Glue

Archaeologists working in the cold waters of the Žeimena River in eastern Lithuania have recovered one of the most revealing Stone Age weapons ever found on the East Baltic Plain: a 17.8-centimetre bone projectile point still bearing the black, tar-like adhesive that once glued it into its wooden shaft. The artefact, dredged up during an underwater visual survey of the Garnys 1 site in 2022 at a depth of roughly 2.5 metres, has now been subjected to a battery of modern laboratory techniques, and the results, published in Archaeological and Anthropological Sciences, push back the dated record of adhesive technology in the region to the early Boreal period, around 10,000 years ago.

The point itself is a classic example of what archaeologists call a plain point, a barbless projectile head belonging to the broad Type 1 category first defined by J. G. D. Clark in his 1936 study of Mesolithic settlement in northern Europe. Straight in profile, oval to subcircular in cross-section, and tapering to a conical tip and a long, pointed conical base, the artefact was carved from the metapodial bone of a large ruminant. What makes it extraordinary is not its shape, which has parallels across the European Plain, but the survival of a circumferential band of dark residue about 8 millimetres wide and up to a millimetre thick, preserved roughly 6.5 centimetres from the base, exactly where a hunter would have seated the point into its haft.

Because plain points are notoriously difficult to date on morphology alone, the research team, led by Justyna Orłowska and Grzegorz Osipowicz of Nicolaus Copernicus University in Toruń together with colleagues from the Lithuanian Institute of History and Vilnius University, took the unusual step of radiocarbon dating the adhesive itself. A 7.1-milligram sample of the residue, removed with an ethanol-cleaned scalpel, was analysed by accelerator mass spectrometry at the Poznań Radiocarbon Laboratory. The uncalibrated result of 8840 plus or minus 40 years before present calibrates, using the IntCal20 curve, to between 10,154 and 9,711 calibrated years before present, or roughly 8205 to 7762 cal BC. That makes the Garnys point the oldest directly radiocarbon-dated plain bone point of this morphological type from Lithuania, and one of the oldest osseous projectile points yet dated in the country.

Identifying the animal that supplied the raw material required a different toolkit. Macroscopic examination suggested a large cervid metapodial, but poor collagen preservation limited the ZooMS analysis, a technique that fingerprints collagen peptides by MALDI-ToF mass spectrometry, to just five diagnostic markers. Even so, the preserved marker set was sufficient to assign the bone to the deer family, and when combined with the artefact’s dimensions and cortical thickness, the evidence points most plausibly to an elk, Alces alces, metatarsal. Red deer and roe deer cannot be entirely excluded, but fallow deer can be ruled out outright, since the species never occurred naturally in prehistoric Lithuania.

Under the microscope, the point tells the story of its own manufacture. High- and low-magnification wear analysis at the Traceology Laboratory in Toruń revealed that the lateral edges, tip and base were shaped by flat scraping, leaving characteristic multi-planar surface bands that survive best near the base, where they were shielded by the haft. The tip also shows probable remnants of rough scraping with a denticulated tool, and linear, unidirectional sheen across the surface indicates that the finished point was deliberately burnished. The tip is broken, but the fracture is non-diagnostic, and the researchers note that post-depositional damage in the riverbed appears the more likely cause than an impact in flight.

The chemical identity of the black residue was resolved through two complementary techniques. Attenuated total reflectance Fourier-transform infrared spectroscopy, applied first as a rapid, minimally destructive screen, produced a spectrum closely comparable to experimentally produced birch bark tar, showing aliphatic carbon-hydrogen stretching bands, carbonyl absorptions and carbon-oxygen bands typical of an oxygenated, triterpenoid-rich organic material. Because such functional groups are not individually diagnostic, the team turned to gas chromatography-mass spectrometry. The chromatographic profile of the underivatised solvent extract matched the experimental birch tar reference closely, particularly in the retention-time region of lupane-type triterpenoids, and two principal peaks corresponded in both retention time and mass spectra to analytical standards of lupeol and betulin, the signature compounds of birch bark transformed by heating under oxygen-limited conditions.

The researchers are careful about what this identification does and does not prove. Lupeol and betulin also occur naturally in birch bark, so they are interpreted within the broader chromatographic pattern and archaeological context rather than as standalone markers, and the GC-MS data characterise only the solvent-soluble, gas-chromatography-amenable fraction of the residue. Even with those caveats, the finding is remarkable. Birch bark tar is a thermally transformed product, made by dry-distilling bark, and its presence on a weapon from the ninth millennium BC in the southeastern Baltic adds a crucial data point to a growing map of Mesolithic adhesive use that stretches from Star Carr in Britain to the Dutch North Sea seabed and the Early Mesolithic site of Krzyż Wielkopolski 7 in Poland.

Perhaps the most vivid insights come from the hafting traces themselves. Beyond the adhesive band, the point preserves distinct impressions of wrapping and compression marks near the base, and within the tar itself the researchers identified a clear imprint of a fibre strand, almost certainly from the binding material. Taken together with the adhesive’s distribution, the evidence points to a specific assembly sequence: the point was inserted into a socketed shaft, bound with fibrous ligatures, and then sealed with birch tar, which would have strengthened the joint and improved its water resistance. Unlike the side-mounted bone points known from sites such as Friesack IV, Ulkestrup Lyng and Krzyż Wielkopolski 7, the Garnys evidence more closely supports a non-detachable point mounted in a socketed shaft, a configuration the team has reconstructed in a step-by-step illustration.

What was the weapon for? Unbarbed points are generally interpreted as heads for lances or spears, and they may also have served as central prongs in multi-tined leisters used for fishing. The Garnys point’s broken tip prevents a definitive functional attribution, but its morphology and its riverine context are consistent with a lance or spearhead deployed in aquatic settings, perhaps for fishing or for hunting semi-aquatic mammals such as beaver and otter, both documented targets of bone-point weaponry in the ethnographic and archaeological record. Beaver remains make up roughly 7 to 10 percent of the faunal assemblage at Garnys 1, lending contextual weight to that interpretation.

The Garnys 1 site itself, discovered in 2017 and investigated since, has yielded hundreds of wooden, osseous, lithic and ceramic artefacts from a riverbed with exceptional organic preservation, and radiocarbon dates on other barbed bone points from the same stretch of river cluster in the Mesolithic, around 7700 to 7300 cal BC. Together with the new dating, the point confirms that the Žeimena River corridor was intensively used by hunter-gatherer-fishers across the Mesolithic, Subneolithic and Neolithic. More broadly, the study demonstrates how wear analysis, biomolecular fingerprinting and organic chemistry can be woven together to extract a full biography from a single artefact, especially in waterlogged contexts where even adhesives and surface deposits survive. For a region where most osseous points are contextless stray finds, the Garnys point offers a rare, precisely dated and technologically legible window into the craftsmanship of Europe’s early postglacial hunters.

Subject of Research: Interdisciplinary analysis of an early Mesolithic osseous projectile point with birch bark tar adhesive from the Garnys 1 site, Lithuania

Article Title: An early mesolithic osseous projectile point from the Garnys 1 site, Lithuania: interdisciplinary analysis of a rare find from the East Baltic Plain

Article References: Orłowska, J., Bosiak, M., Piličiauskas, G., Piličiauskienė, G., Matiukas, A., & Osipowicz, G. (2026). An early mesolithic osseous projectile point from the Garnys 1 site, Lithuania: interdisciplinary analysis of a rare find from the East Baltic Plain. Archaeological and Anthropological Sciences, 18(10), Article 211. https://doi.org/10.1007/s12520-026-02576-5

Image Credits: AI Generated

DOI: 10.1007/s12520-026-02576-5

Keywords: Mesolithic, bone projectile point, birch bark tar, Lithuania, Garnys 1, ZooMS, GC-MS, radiocarbon dating, hafting, hunter-gatherers, East Baltic, underwater archaeology