Colour of the past. First Archaeometric investigations of Caucasian rock art paintings in Georgia

Abstract

Abstract: This research presents the first archaeometric investigation on Damirgaya and Trialeti Rock art sites and the Neolithic settlement Khramis Didi Gora, South Caucasus, Georgia. The aim is to characterize rocks and pigments, to assess painting technology, including the possible identification of organic binders and the compatibility of inorganic pigments with those locally available. In order to build up our awareness and solve scientific curiosity, the research questions are cleared up through the comparison with adjacent archaeological sites, from Armenia, Azerbaijan and Anatolia, where traces of monochromatic red pigment were recovered in settlements, barrows, on artifacts, such as grinding tools and mainly on rock art. Several analytical techniques, specifically Optical Microscopy (OM) on samples as such and thin sections, X-ray Powder Diffraction (XRPD), and Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX) were used to obtain mineralogical and chemical composition of the samples. Moreover, with the contribution of Fourier-Transform Infrared (FTIR) and Raman Spectroscopy, inorganic compounds were better characterized in both rock paintings and grinding tools. On the contrary, it was not possible to define organic compounds such as binders, possibly due to their low amount or absence. In terms of compatibility with local supplies, with the help of thin section and cross section analysis, it was possible to deduce that the mineralogical composition of the rocks is relatively similar to pigment samples. In terms of pigments, hematite was the major pigment used for rock art and grinding tools, while in terms of rock samples, that of Trialeti is an igneous basaltic dacite, whereas that of Damirgaya is a rock mainly composed of quartz, but it is also characterized by other minerals, such as iron oxides are likely present, as well as phyllosilicates.