by Kostova, B., Mihaylova, K., Dumanov, B. and Berberova, R.
ABSTRACT
An archaeometric study of pithoi from Bulgarian archaeological sites was carried out using analytical tech-niques such as powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, and thermal and X-ray fluorescence (XRF) analysis. New data was obtained – the composition of raw clay (montmorillo-nite-illite clay with different clay/non-clay minerals ratios) and the firing temperature of the ceramic were determined (three firing temperature ranges: up to 500℃, between 500 and 700℃ and between 700℃, and the thermal decomposition temperature of calcite). The advantages of thermal analysis were used to calculate the loss on ignition (LOI) for the correction of the XRF results. The porosity of the ceramic was determined by thermal analysis and FTIR, and a linear functional relationship was established: an increasing density of the structure with an increasing firing temperature. The experimental results show continuity in the raw materials and technologies used to produce ceramic from the Roman Age to Late Antiquity. This supports the archaeo-logical interpretation of a transformation of economic settlement models with a preservation of demographic composition in the region of the Sarnena Sredna Gora and the southern foothills (Bulgaria).
