Variability of the Chemical Composition of Early Neolithic Ceramic Vessels of the Tunka Valley According to Portable X-ray Fluorescence Analysis

This article presents the results of portable X-ray fluorescence analysis (pXRF) conducted on a collection of Early Neolithic ceramics (~8.5–7 ka cal BP) from the Tunka Valley (Southwestern Baikal region). The sample includes 20 vessel fragments from excavations at the Tuyana and Elovka-Nugan 1 sites, located on opposite banks of the Irkut River, 6 km apart. Measurements were carried out using an Olympus Vanta M portable analyzer on sections of the inner surface of vessel fragments with the upper layer removed. The pXRF data were analyzed and interpreted using multivariate statistics methods: principal components analysis (PCA), k-means and hierarchical clustering. Various combinations of elements such as Al, Si, K, Ca, Ti, Fe, Rb, Sr, Y, Zr were tested to differentiate the vessels. Ultimately, based on the analysis of fragments of a single vessel, it was determined that the most suitable combination is Fe, Rb, Sr, and Zr. Despite the small collection size, it proved to be quite representative for interpreting the results. Comparison of pXRF data with the morpho-typological features of the ceramic vessels, visual diagnostics of the moulding compounds, and geomorphological characteristics of the sites revealed differences in the chemical composition of the two types of ceramics: Netimpressed and Khaita. It was established that the hunter-gatherers of the Early Neolithic in Tunka Valley occupied different areas, and this is likely related to both the dynamic hydrological regime of the Irkut River and the seasonal selection of campsites, determined by subsistence strategies. At the Elovka-Nugan 1 site, the bearers of the Net-impressed pottery tradition exploited several raw material sources. In this case, a certain correlation can be observed between the geochemical characteristics of the pottery and the different areas of the site where archaeological assemblages were recorded (middle floodplain, high floodplain, high-altitude slope). One Net-impressed vessel from the Tuyana site shows close chemical similarity to vessels from the Elovka-Nugan 1 site. Two types of raw materials were used for Khaita ceramics, and one of them stands out from the crowd. It is concluded that at least 8 different groups of hunter-gatherers (apparently not contemporaneously) inhabited this area, each possessing the traditions of both Khaita and Net-impressed pottery and exploiting different raw material sources

Ceramic · Chemical composition · Compositional data · Excavation · Pottery · Principal component analysis · Cultural Heritage Materials Analysis · Soil and Environmental Studies · X-ray Spectroscopy and Fluorescence Analysis