The Baltic Ice Lake in south Finland and its outlets

Abstract

Abstract In Finland the earliest stages of the ancient Baltic have traditionally been divided into the Pre-Baltic ice lake(s), the Baltic Ice Lake and the Yoldia phase. The Pre-Baltic ice lake stage has also been called the ‘Late Glacial Yoldia Sea’ and ‘Karelian Ice Lake’. There are certain indications of a low water level during the Allerod in southern Finland before the earlier phase of the Baltic Ice Lake. Two drainages of the Baltic into the Atlantic Ocean seem to have occurred, the first through the Oresund Strait in Denmark from about 12.7 to 10.2 ka BP (Bolling-Allerod-Younger Dryas), and the second/last one at the end of the Baltic Ice Lake period through the area of Billingen, central Sweden, at about 10.2 ka BP (Younger Dryas). The possible connection of the Baltic with the White Sea (Arctic Ocean) has also been under discussion for a long time. Recently Finnish geologists have been studying this problem in north and south Russian Karelia, but no evidence of a connection between the White Sea and the Baltic has been found. The last drainage of the Baltic Ice Lake is not clearly proved by the Finnish varve chronology. Morphologically the drainage can be seen as a lowering by about 25–26 m of the highest Baltic coast line in the zone between the 2nd and 3rd Salpausselka in western Finland. The subsequent rapid Yoldia regression took place before the beginning of the Ancylus transgression. Some sediment series demonstrate a brief marine influence from the ocean along the Finnish coast during the Yoldia phase.