Original paper

Evaluating landscape development and karstification of the Central Schwabische Alb (Southwest Germany) by fossil record of karst fillings

Ufrecht, Wolfgang


In the central part of the Schwäbische Alb relics of the Bohnerz-Formation (claret to violet clay stirred with iron concretions) are widely spread in karst fissures and depressions. Considerable translocations into karst holes took place during land forming processes most likely caused by tectonics. Periods of translocation can be reconstructed through mammal fossils, that were admixed within the Bohnerz-sediments when they were flushed into karst fissures. For analyzing geomorphological processes and landform genesis such datable sediments provide time aspects that can be refered to distinct positions in relief and thus help to reconstruct landscape evolution through time. Focussing on that the distribution of fossiliferous sediments in the karst holes (mostly roofless caves) in the hilly Kuppenalb, around Salmendingen and in the Bärenhöhle (Bears Cave) nearby Erpfingen, are of outstanding importance. In both sites karst sediments are preserved today in exposed positions in isolated hills which tower above a lower and younger relief. Thus they provide a minimum altitude of the former land surface. Due to palaeontological data the Salmendingen karst holes are bound to the Upper Miocene land surface. Post Upper Miocene denudation by the river Danube caused the next deeper sedimentation relief-unit to which the Bärenhöhle belongs. Fossil molluscs and mammal bones and teeth confirm that this cave developed during the Upper Pliocene and the older Pleistocene over a period of more than 5 million years.As a result, it can be shown that in the northern Schwäbische Alb both the present-day relief and the deep karstification mirrored in a large number of caves, developed essentially in the late Tertiary and early Pleistocene. Denudation and endogene karst corrosive processes were initiated by incising of the river Danube and its tributaries into the bedrock, causing gradual the lowering of the karst water table.