Causes of the freshwater reservoir effect and determination of ceramic components as a result of the study of vessels from a Bronze Age hearth complex in central Russia

Two Bronze Age vessels from the prehistoric lakeside settlement along with the sample of modern day sapropel from the same lake were subsequently studied using 14C, XRD, SEM/EDS analyses. Anomalously ancient radiocarbon dates were obtained for all types of dated materials. The ceramic pastes of the vessels and the sapropel showed their same phase composition and similar elemental composition. The cause of anomalously ancient radiocarbon dates in the samples of ceramic pastes and sapropel was calcite, the mineral phase of which was fixed. The fact that lacustrine-derived calcite is a component in the ceramic pastes of the studied vessels among other things, indicates the use of sapropel from this lake as one of the components in their manufacture. The presence of the α-quartz mineral phase indicates that the firing of the vessels under study was carried out at temperatures with the upper level of values not exceeding ~573 °C.