LATEGLACIAL OF LAKE ONEGA - CONTRIBUTION TO THE HISTORY OF THE EASTERN BALTIC BASIN

New stratigraphy data especially diatom analyses are presented from th e area north of Lake Onega relevant to the discussion on possible Late glacial connection between the Baltic Sea and White Sea. Following the deglaciation 12,000-11,000 years ago Lake Onega basin was occupied by a system of ice dammed lakes which drained to the Lake Ladoga basin. When the ice retreated from the threshold leading to the White Sea 11, 000 years ago the water level dropped and since that the lake was cont rolled by its thresholds to the White Sea and the Baltic basin. Lake O nega has remained distinctly above the spa level and no Late Weichseli an sea connection existed between the White Sea and Baltic basins. The marine diatoms frequently found in sediments are reworked older fossi ls as also suggested by some earlier workers. Lake Onega drained to th e White Sea basin over the Maselga threshold and also to Lake Ladoga b etween 11,000 and 10,000 radiocarbon years ago, and to the White Sea a lone between 10,000 and 9500 years ago, and the present outlet of Lake Onega, River Svir, originated 9500 years ago.