Abstract
In this study, the author set out to determine the chemical composition and possible use of a substance, which remnants were found on a tile fragment made of soft brown shist. This item was discovered in the occupa-tion layer of a Neolithic settlement belonging to the Boborykino culture (Mergen 3), located on the terrace of Lake Mergen in the forest-steppe of the Ishim area (south of Western Siberia). By analogy with the complexes of the Boborykino culture in the Tobol area — Yurtobor 3 (7701 ± 120 BP (UPI 559)) and Tashkovo 1 (7440 ± 60 BP (LE 1534)) — which age was determined using carbon-14 dating, the Mergen 3 settlement can be attributed to the second half of the 7th millennium Cal. BC. The fragment measuring 3.0 × 2.1 × 0.55 cm has a spherical indenta-tion in the centre measuring 2.0×2.0×0.2 cm with a volume of 0.118 cm3 (0.118 ml). The whole item probably had a square shape with rounded and slightly raised edges. A visual analysis of the spot was carried out using an MBS-10 binocular microscope at a magnification of 16×. The analysis revealed a brown substance on the edges of the indentation, which looked like a dark porous carbon-like spot in the centre. These remnants were studied using a Bruker ALPHA FT-IR spectrometer with an Eco-ATR module — a single reflection ATR sampling module equipped with a zinc selenide crystal (ZnSe) that allows you to analyse liquid, solid and powder samples without preliminary sample preparation. The measurements were performed in the wavenumber range of 300–4000 cm-1 at a resolution of 4 cm-1. Some of the most significant absorption bands (709; 975; 1,024; 1,027 cm-1) were ob-served, which characterise vibrations bending and stretching the bonds in the skeleton of an organic molecule containing single С–С and С–О bonds. The obtained spectra are most consistent with the IR absorption spectra of resin acids, in particular, dehydroabietic acid that is present in resin obtained from coniferous trees. Consider-ing the small volume of the above-mentioned substance and the limited of its burning, the author excludes the use of this tile as a lamp, the use of the substance for the preparation of glue that held together the parts of complex tools, as well as the use of the substance for healing wounds and for cosmetic purposes, which involved addi-tional ingredients. Signs of burning indicate the use of the artefact for rituals, in particular for obtaining finely dis-persed soot employed when applying tattoos. The conducted experiment showed that the soot from a burnt drop of fresh resin covered 4 cm2 of the wrist area. Soot formed at the very beginning of the combustion process (probably combustion of volatile components), then the substance was oxidised without noticeable emissions. The remnants of the porous substance on the tile confirm the importance of the moment of resin burning with the abundant production of soot. However, the possibility that there were other unknown areas of...