Mastogloia Sea

The Mastogloia Sea (also Early Littorina Sea, Initial Littorina Sea) is one of the prehistoric stages of the Baltic Sea in its development after the last ice age. It is characterised by distinctive deposits of the calciferous shell of species of the diatom Mastogloia that were used for paleoenvironmental reconstructions. This transition took place at different times in different parts of the Baltic basin c. 9000 years ago following the Ancylus Lake stage and preceding the full Littorina Sea stage.