Seismic correlation of Palaeozoic rocks across the northern Baltic Proper - Swedish-Estonian project since 1990, a review

After a short historical review of the correlation of Palaeozoic rocks between Estonia and Sweden, this paper focuses on the results of marine seismic studies, achieved during the cooperative Swedish–Estonian project since 1990. The most recent seismic correlation scheme of the Cambrian, Ordovician, and Silurian strata and their distribution at the seafloor across the northern Baltic Proper are presented. Thickness changes and trends, as well as the sedimentary structures, reef bodies, and erosional features of different seismic units, are treated in connection with structural and facies changes in the Palaeobaltic Basin. The immediate background of this project is outlined and the locations of the seismic lines shot during the joint expeditions to the Baltic Sea are shown.