The Flandrian history of Lake Höytiäinen, eastern Finland

The present paper on the Flandrian history of Lake Höytiäinen, eastern Finland, is based on stratigraphical and shore morphological investigations. Lake Höytiäinen is situated on the proximal side of a great end moraine, Jaamankangas. The final retreat of the ice during the Weichselian glaciation started from Jaamankangas about 10 000 years B.P. Lake Höytiäinen was isolated from the final stage of the Yoldia Sea 8 500—8 900 years B.P. This age is compatible with the result of Sauramo and Auer (1928). The diatom analysis does not show any influence of salt water before the isolation. After the isolation a transgression started on the SE-side of the isolation threshold and a regression on the NWside of it. The shore-line displacement of the lake is studied only stratigraphically because no raised beach before the clear shore of 1859 has been found. In 1859 the water of Lake Höytiäinen forced a dam of the canal being built in Jaamankangas and eroded a new outlet through it to Lake Pyhäselkä. The water level fell in a month about 9.5 metres.