Untersuchungen an periglazialen Deckschichten im Nationalpark Berchtesgaden, Nordliche Kalkalpen

Studies at the western margin of the Hagengebirge in the Northern Limestone Alps indicate that periglacial processes led to the formation of slope deposits also in those parts of the Alps that were ice-free during the glacials or that had become ice-free during the Late Glacial. In these places Quaternary slope deposits widely occur on the cherty to marly Jurassic rocks of the subalpine slopes. Similar to the Mittelgebirge, three Pleistocene slope deposits created by periglacial processes (basal, middle, upper layer) and a Holocene top layer can be distinguished. There are, however, considerable short-distance variations in the vertical structure and the sedimentological aspects of the slope deposits. Their probable causes are discussed. In contrast to the highly loess-influenced middle and main layers of the Mittelgebirge, in the Alpine study area granulometric and clay-mineralogical analysis do not reveal any aeolian sediment components. Due to the absence of means of absolute dating the age of the slope sediments can as yet only be inferred from field observations and in comparison to palaeoclimate reconstructions from adjacent Alpine areas. In this way the formation of basal, middle and upper layer are to be attributed to a Wuermian depression of the periglacial zone and may be placed in the younger Late Glacial. For the debris-rich top layer, because of its stratigraphic poosition, overlying fossil Holocene soils, and because of the poor development of the surface soils, an Upper Holocene age is assumed. Among other things because of their uncertain age, the value of the slope sediments as palaeoclimate indicators is as yet very limited. However, the Quaternary slope deposits, serving as the substrates of present soil formation, are of great importance for understanding pedogenesis and for assessing ecological site properties.