THE NEW "VOKA" KEY SECTION OF LATE PLEISTOCENE DEPOSITS ON THE SOUTHERN COAST OF THE GULF OF FINLAND

Abstract

Glacial deposits are widespread throughout the southern coast of the Gulf of Finland, but the thickness of the Quaternary cover there usually does not exceed 5 m and increases only within older buried valleys. Glaciolacustrine deposits, especially late Valdai supramorainic varved clays, are widespread in the preglint lowland along the shore. Their thickness is up to 3–4 m and as much as 25–27 m in some places, for instance, in Yuminda, Loksa, and Kyasmu (Estonia). Older deposits of middle Pleistocene age and Mga Interglacial transgression are known only in the eastern part of the southern coast of the Gulf of Finland in the Neva River valley mainly based on drilling data. Boreholes penetrated deposits of the Mga (Eemian) transgression and, probably, a part of the middle Pleistocene Interstadial along the southern coast of the gulf only in one region, namely Prangli Island and the adjacent region of the Estonian coast [1, 2]. Exposures of such sediments in the pre-glint lowland have not yet been discovered.