Lateglacial and Holocene water-level variations along the NE German Baltic Sea coast: review and new results Reinhard Lampe

摘要

A comprehensive overview is given of the current knowledge regarding the Lateglacial and Holocene water-table evolution along the West Pomeranian coast, which is related to the four evolutionary stages of the Baltic Sea: the Baltic Ice Lake, the Yoldia Sea, the Ancylus Lake and the Littorina Sea. The first three stages were characterized by intensive water-table fluctuations in the Baltic basin. The balance between glacio-isostatic uplift and water-table rise due to meltwater and river discharge produced either a temporary connection with the ocean or isolation from it. New findings are presented on the water levels reached during the different stages. Only at about 8 ky BP did the Baltic obtain a permanent connection with the ocean. The first marine sediments in the recent coastal zone, ca. 7.8 ky old, are found at -15 m and are related to the initial Littorina Sea. The maximum of the main Littorina-transgression was reached at -1.5 m to -2.0 m ca. 5.8 ky BP. The course of the sea level reveals that later only some minor oscillations took place, correlated with climatic fluctuations. These indicate a control by regional changes in the North Atlantic circulation rather than by global sea-level alterations. Isostatic movements were determined by comparing the reconstructed relative sea-level curve with curves assumed as nearly eustatic. The resulting isostatic curve shows uplift at 11.5 ky BP of about 55 m, which decreased until 7.8 ky BP to 6m and ceased at ca. 3 ky BP. Currently, the coastal zone experiences a slight tilting with uplift in the northeastern part and inundation in the southwestern area.