Geoarchaeological features of the early Holocene complexes in the Southern Angara region

About 30 Early Holocene sites are known in the Southern Angara region. The age of 20 of them has been established beyond doubts. The radiocarbon dates obtained for the earliest cultural horizons demonstrate that the age of these complexes corresponds to the period of Younger Dryas (~12,900-11,700 cal BP). However, our analysis revealed the incorrectness of most chronological definitions: some data have a large error (σ ± 300-500 years); other dates have high index of δ15N and the overrated ratio of carbon and nitrogen isotopes (C/N). Only one date which has been obtained for the lower horizon of Kholmushino 3 site (12,569-12,150 cal BP) can be currently considered as valid. Based on the latest data for the Kholmushino 3 and Ust-Khaita sites, the Early-Middle Holocene boundary in the Southern Angara region can be preliminarily determined as ~8600-8500 cal BP.