Holocene oscillations of the Baltic Sea and Lake Ladoga levels and early human movements

Multidisciplinary studies conducted in Russian Karelia substantiated the existence of a major Baltic-Ladoga waterway in the Karelian Isthmus that emerged ca. 9500 cal BCE, and remained in action for ca. 7000 years. The predominant location of prehistoric sites in the catchment area indicates that this waterway effectively controlled the movements of hunter-gatherer groups during the greater part of the Holocene. A general increase of population density and sedentary behaviour, signalled by the beginning of intensive pottery-making at ca. 5560–5250 cal BCE, occurred in an environment of increased biodiversity and the establishment of mixed boreal – broad-leaved forests observable in the pollen records. The transgression of Lake Ladoga reached its peak between 1500 and 1000 BCE, resulting in the breakthrough of the Neva River and a general fall in the water level of the Ladoga-Volkhov-Ilmen hydrological system. The availability of low-lying fertile soils stimulated the rapid expansion of agriculture, recognized by the occurrence farming-related pollen and changes in the sedimentation, resulting in the rapid spread of farming communities.