Evolution of the Yoldia Sea in the eastern Baltic

The Yoldia stage in the Baltic Sea has never been properly defined stratigraphically and the correlation of its shorelines is confused. Subdivision of bottom sediments from the Yoldia Sea on the basis of faunal evidence and diatom flora is difficult due to very poor or mixed faunal and floral assemblages. According to recent studies in Sweden, there was only a short (100–150 years) influx of salt water during the middle part of the Yoldia stage. Other investigations suggest that the saline water did not reach the eastern part of the Baltic Sea and the Gulf of Finland. There are ‘brackish-water’ diatoms in Yoldian sediments of the Baltic States and St. Petersburg area, probably due to redeposition processes