Evidence from the Neva River Valley, Russia, of the Holocene history of Lake Ladoga

Abstract

Two new sections have been discovered in the River Neva Valley, which connects Lake Ladoga - the largest lake in Europe - with the Gulf of Finland of the Baltic Sea. The Nevskij Lesopark (Parkland) section is in the lower part of the River Neva, and the Nevskij Pjatachok section at the river head. Both sections represent peat sediments covered by sands of the Lake Ladoga transgression. On the basis of the radiocarbon dates, as well as pollen and diatom analyses of the new sections, the River Neva was formed at c. 2800-3000 yr. BP., and the level of Lake Ladoga was eroded down to its present level at 2400 yr. B.P. These results support previous ideas that the connection between Lake Ladoga and the Gulf of Finland opened as a result of the last great rise of the lake level, which was named the 'Ladoga transgression'. The evidence from the River Neva also confirms that there was no connection in this area between the Baltic Sea and Lake Ladoga at the time of the Ancylus Lake, because of the existence of uninterrupted peat deposition from Preboreal time.