Tertiary relief development of the central Harz Mountains and the information given by the analyses of karst sediments

摘要

The formation and age of high level planation surfaces is discussed in the context of relief development in the Harz Mountains in Cenozoic times. The plateau of Elbingerode shows special geological and geomorphological conditions, because Devonian limestone crops out and a karst relief has developed preserving Cenozoic sediment residuals. Two sedimentary deposits near Hartenberg (510 in a.s.l.) and north of Huttenrode (475 in a.s.l.) were investigated in greater detail. They are located near the divide between the catchments directly draining the northern margin of the Harz Mountains and the tributaries to the Bode River. Lignite from the Hartenberg profile was dated as Oligocene by palynological analysis. At both sites muscovite-bearing fine sands have very good to good sortings that give evidence of a sedimentation in littoral, lagoonal, estuarine or lacustrine shallow water environments. It is assumed, that the fine sands were deposited, when a planation surface close to base level was in existence in the central Harz Mountains. A comparison with the Oligocene to Miocene marine fine sands rich in mica in the foreland of the Harz Mountains (190-260 m a.s.l.) supports this assumption. There is no ultimate evidence of a marine influence on the fine sand deposits in the central Harz Mountains, but many arguments support the conclusion, that they were deposited in a sedimentation area close to a coast line within the Oligocene to Miocene time periods just as the fine sands in other uplands of Western and Central Germany.