Characterization of archaeological ceramics from eastern Siberia by total-reflection X-ray fluorescence spectrometry and principal component analysis

Abstract

The study of the composition of archaeological ceramics provides information used to assess possible transportation routes and cultural connections between ancient people living in different regions. Total-reflection X-ray fluorescence (TXRF) was applied for the analysis of ceramics as a promising method due to the rapidity, cost-efficiency, and capability to analyze a very small amount of a sample (<20 mg), which is important for the preservation of archaeological material. Two techniques of sample preparation for the TXRF analysis of ceramics have been considered. The analysis of suspensions was applied to obtain information on the bulk composition of ceramics. Acid leaching was used for the elemental analysis of the clay component of the ceramics, with the separation of non-soluble mineral phase. The proposed TXRF techniques have been successfully validated by the analysis of reference material and comparison with independent analytical methods. Reproducibility (interlaboratory precision) was evaluated for the proposed TXRF leaching method involving two different laboratories. The application of grazing incidence X-ray fluorescence (GI-XRF) showed homogeneous distribution of elements in the specimen and correspondence of the measurements to the conditions of total external reflection. TXRF method was applied to collect the first data on the composition of archaeological samples of ceramics from Popovsky Lug, eastern Siberia (Russia). The obtained data on the elemental composition were used to classify the samples by statistical methods of analysis, including the method of principal components and factor analysis. Three different compositional groups of ceramic have been separated and accepted as corresponding to archaeological interpretation.