Title

A.V. AMANTOV, M.G. AMANTOVA (VSEGEI)

Modeling of postglacial development of Lake Ladoga and eastern part of the Gulf of Finland

On the basis of a combination of physical models of the isostatic relaxation after deglaciation with geological­geomorphological verification the attempted reconstruction of the late-­glacial development of Lake Ladoga and the eastern part of the Gulf of Finland was carried out, with evaluation of the dynamics of changes of coastal lines and the estimation of amplitude of possible deep regressions in the south­western sector. The theoretical version of the pattern of glacioisostatic motion suggests turn of isobases from the northeastern to approximately northern direction, in relation to the axis of the Ladoga-­Ilmen ice stream. Quantitative assessment of differentiation of hydro­-isostatic movements emphasizes the different behavior of the southeastern part of lake Ladoga, most pronounced around the culmination of the Ladoga transgression ~3200 cal. B.P., when the transition from short­term in geological scale bifurcation to River Neva drainage took place.
Keywords: Lake Ladoga, Gulf of Finland, isostasy, hydro­isostasy, Holocene, geology, glaciation.