Subdued mountains of Central Europe

Slope deposits, which veil entire slopes or large parts of them in a rather uniform manner (cover beds), are ubiquitous in the subdued mountains of Central Europe. Here we provide an overview of the current state of knowledge about these deposits. The Central European cover beds are divided into (1) the upper layer, which is ubiquitous and has a relatively constant thickness; (2) the intermediate layer, whose distribution is mainly restricted to flat relief, slope depressions, and leeward slopes; and (3) the basal layer, which is again quite widespread. Both the upper and intermediate layers contain intermixed loess, whereas the basal layer is loess free and typically has a high bulk density. Apart from the loess content, the composition of the layers differs, reflecting the different proportions of fractured and chemically weathered rock that have been added from upslope. This results in a remarkable diversity depending on the bedrock and thus causes remarkable regional differences. Cover beds were mainly formed by periglacial gelifluction. The upper layer may have formed during several short episodes of Late Glacial activity. In contrast, the underlying strata may be diachronous but show recurrent vertical sequences. This is probably due to the fact that loess-free layers usually could not be deposited as long as there was loess in the environment, which may have been inherited from older deposits. Thus, the last phase of surface washing, during which older loess was removed, determines the age of the lower layers. OSL dating of intermediate layers encounters methodological problems due to the heterogeneity of the material, but most dates fall within the upper Pleniglacial, with outliers up to 50kyr old. Loess-like deposits, especially in the foot zones of the mountains, allow luminescence dating, which constrains the time of formation of interbedded intermediate layers. Indications of the age of basal layers are rare and suggest that they may have formed during different glacials.