Specifics of the Holocene sedimentation in small lakes of the southern Lake Ladoga region

Abstract

The sedimentation in small lakes of the Lake Ladoga region is closely related to the late and post-glacial evolution of Lake Ladoga that has experienced significant fluctuations in water level throughout its history. The results of studying sediments in small lakes in the Ladoga region made it possible to identify the following specifics of Holocene sedimentation. The accumulation of predominantly minerogenic sediments in the lakes of the Ladoga region has been occurring since the last deglaciation of the study area. The structure of lake sediment sections depends on the elevation of the reservoir. In sediments of lakes located at high absolute levels, minerogenic sediments are replaced by organogenic sediments ~ 11,000 cal BP. In the structure of sediments of lakes located below 15-20 m above sea level a transitional layered horizon is often observed between minerogenic and organogenic deposits, and the age at which gyttja began to form in these lakes depends on the time of isolation of their basins from Lake Ladoga. However, this scheme is not entirely applicable to the southern part of the Ladoga region, where a different structure of bottom sediments of small lakes is noted.

Keywords:

Lake Ladoga, the Holocene, Ladoga transgression, bottom sediments, dynamics of organic matter, diatom analysis, small lakes, southern Ladoga region, Lake Voloyarvi, Lake Nikolskoye, Lake Rybezhskoye