Zur Struktur und Entstehung von Eiskeil–Grossformen in Lieth/Elmshorn (Schleswig-Holstein)

Abstract. The deposits near the surface of the Permian and Quarternary in the western part of the “Lieth lime quarry” have been intensively periglacially modified. Three ice-wedge pseudomorphs, which run approximately parallel, are 0.5 m wide and reach a depth of more than 3 meters. These features are of particular importance to periglacial science due to their setting in Zechstein-ashes and -limestones, their unusual size and their spatial relationship to several similarly large structures. Their development can be explained by geological factors. The fine-grained calcarious rocks, within which the wedges are developed, offer good conditions for intensive frost action, in a similar fashion to the exposed Zechstein rocks with their shallow overburden of quaternary material. An unusually large mechanical strength of the surrounding ashes compared with sedimentary rocks elsewhere in northern Germany favoured the emergence of larger structures. Spatial relationships, similar dimensions and orientation of the three large ice wedge pseudomorphs point to a connection with salt-tectonic structures. The structure of the latter had a considerable impact on the overall geometry of the ice wedges. Field relationships between structure, thickness, soil type and colour of individual fill units suggests two different phases of formation: A one-sided opening and backfilling appears to have taken place within two structures. The likely age of the reported structures possibly pre-dates the Weichselian glaciation.