ReviewAre sackungen diagnostic features of (de)glaciated mountains?

- Global review of sackung-type DSGSDs
- First 10Be exposure dating of sackung in the Carpathians
- Comparison of sackungen originated in paraglacial and non-glaciated landscapes
- Critical reassessment of the relevancy of sackungen in the paraglacial geomorphology

Deep-seated gravitational slope deformations (DSGSDs) with characteristic sackung landforms (e.g., double crests, trenches, uphill-facing scarps, and toe bulging) are considered by some researchers to be diagnostic features indicating past mountain glaciations. However, an extensive literature review on sackung features throughout the world reveals that in some regions, paraglacial processes are not the causes of such phenomena. Sackungen occur across a diverse spectrum of mountain types, with different morphoclimatic histories, including regions that have never experienced glaciation. To reinforce that sackungen may originate independently of glaciation, we also include two case studies from the Western Carpathians (Czech Republic and Slovakia) which are supported by detailed geomorphic mapping, trenching and absolute dating (10Be, 14C and OSL). On the Ondřejník ridge (Outer Western Carpathians, Czech Republic), sackungen occur in the mid-Holocene in the medium-high mountains which are beyond the Pleistocene glacial limits. On the Salatín Mt. (Tatra Mts., Slovakia), the sackungen, which occur in formerly glaciated terrain, date between ~ 7.5 and 4.2 ka BP, representing a > 4 ka time lag after the disappearance of glaciers. This suggests that the direct link between the ice retreat and the onset of sackung formation is not obvious, even in the case of the once glaciated mountain range. Although paraglacial stress release is undoubtedly one of the crucial causes of sackung genesis, in many mountain regions, it is not the only important mechanism. Therefore, despite occurring in numerous (de)glaciated mountains, sackung features cannot be considered as proof of past mountain glaciations, e.g., during analysis of extra-terrestrial settings.