Late Pleistocene and early Holocene paleogeography of the Darss Sill area, southwestern Baltic

Abstract

Abstract Today, about 73% of the water exchange between the Baltic and the North Sea takes place through the Darss Sill area. In hydrographic terms the Darss Sill is a major morphological unit separating the deeper areas of the Mecklenburg Bay and the Arkona Basin from each other. It is characterized by an average water depth of 16 m. The main bathymetric features are the Gedser Reef with a water depth of less than 10 m and the Kadet Channel which has a maximum water depth of 32 m. According to previous authors there are two different ice marginal lines between Falster (Denmark) and the Darss peninsula (Germany). The recent Kadet Channel is regarded as a large glacial valley cutting the ice marginal lines. Joint Danish and German investigations in the Darss Sill area (1989–1991) indicate the existence of only one marginal line in this region, which is represented by a till cropping out in the area between Falster and the German coast. The formation of the marginal line ca. 13,500 BP caused a damming of a pre-existing subglacial drainage system in the Gedser Reef area. Southeast of the recent Kadet Channel glaciofluvial drainage occurred towards the NE through a deep channel into the Baltic Ice Lake immediately after the retreat of the ice. During the Baltic Ice Lake transgression the channel was filled by sandy sediments from sources east of the investigated area. This accumulation process resulted in the blocking of the channel at the time of the Baltic Ice Lake highstand maximum. At this time occasional overflow in the Kadet Channel area must have started. The main erosion and deepening of the Kadet Channel must, however, be ascribed to the Ancylus Lake overflow.