Proglacial lake shorelines of Estonia and adjoining areas

A uniform database of the proglacial lake coastal landforms of Estonia, Latvia and NW Russia was created and used to reconstruct the spatial distribution of proglacial lakes using the kriging point interpolation and GIS approaches. Correlation of the Late Glacial coastal landforms confirms that the proglacial lake stage A1 in Estonia is synchronous with the BglI level in Latvia and with one level in NW Russia of undefined index. Proglacial lake A1 was formed concurrently with the Pandivere-Neva ice-margin about 13,300 cal. yrs BP. Proglacial lake A2 level formed probably about 12,800 cal. yrs BP and correlates with the level of BglII in Latvia and GIII in NW Russia. Simulated isobases of proglacial lake water-levels show a relatively regular pattern of the land uplift along the eastern coast of the Baltic and in the northern part of the Lake Peipsi basin, with a steeper tilt towards the northwest. Isobases in the southern part of the Lake Peipsi basin are curving towards SE and are up to 14 m higher than expected from the regional trend. This phenomenon can reflect the forebulge effect during the deglaciation and its later collapse. Shoreline reconstruction suggests that proglacial lakes in the Peipsi and Baltic basins were connected via strait-like systems and had identical water levels. Our reconstructions also show that after the glacier halted at the Pandivere-Neva ice margin about 13,300 cal. yrs BP, there was a connection with the initial Baltic Ice Lake in the west of the Gulf of Riga.