Glacial deposits and Late Weichselian ice-sheet dynamics in the northeastern Baltic Sea

Glacial deposits and landforms, interpreted from the continuous seismic re ection data, have been used to reconstruct the Late Weichselian ice-sheet dynamics and the sedimentary environments in the northeastern Baltic Sea. The bedrock geology and topography played an important role in the glacial dynamics and subglacia l meltwater drainage in the area. Drumlins suggest a south–southeasterl y  ow direction of the last ice sheet on the Ordovician Plateau. Eskers demonstrate that subglacia l meltwater  ow was focused mostly within bedrock valleys. The eskers have locally been overlain by a thin layer of till. Thick proximal outwash deposits occupy elongated depression s in the substratum, which often occur along the sides of esker ridges. Ice-margina l grounding-lin e deposit in the southern part of the area has a continuation on the adjacent Island of Saaremaa. Therefore, we assume that its formation took place during Palivere Stadial of the last deglaciation , whereas the moraine bank extending southwestward from the So˜rve Peninsula is tentatively correlated with the Pandi- vere Stadial. The wedge-shape d ice-margina l grounding-lin e deposit was locally fed by subglacia l meltwater streams during a standstill or slight readvance of the ice margin. The thickness of the glacier at the groundingline was estimated to reach approximatel y 180 m. In the western part of the area, terrace-like morphology of the ice-margina l deposit and series of small retreat moraines 10–20 km north of it suggest stepwise retreat of the ice margin. Therefore, a rather thin and mobile ice stream was probably covering the northeaster n Baltic Sea during the last deglaciation