Glacitectonic deformation in the Upper Weichselian led to the tectonic framework of large-scale folds and displaced thrust sheets of Maastrichtian (Upper Cretaceous) chalk and Pleistocene glacial deposits in the southwestern Baltic Sea region. They form surface expressions of sub-parallel ridges and elongated valleys in between and on the Jasmund Peninsula. Geomorphological mapping and detailed landform analyses give another insight into the arrangement and the formation history of these proglacial surface structures. Light detection and ranging (LiDAR) digital elevation models (DEM) analysis techniques were applied to a proglacial rather than a subglacial environment. Results suggest a division into a northern part with morphological ridges striking NW-SE and a southern part with SW-NE trending ridges. The observation of partly truncated northerly ridges and their superimposition by the southern sub-complex suggest that the northern part was generated earlier than the southern part. The applied spatial analyses tools were used to develop a new, self-consistent genetic model integrating all parts of the 100 km 2 large Jasmund Glacitectonic Complex. Results suggest a more consistent terminology for the tectonic setting and a revised genetic model for Jasmund, including three evolutional stages that are characterized by different ice flow patterns.

The Wissower Bach Syncline on the Jasmund Peninsula (NE Germany) has been examined to understand the complicated glacitectonic environment in the southern Baltic Sea region, comprising folds and thrust faults from the Weichselian Pleniglacial. Soft-sediment thin sections from a SW-dipping thrust fault at the southwestern limb of the syncline between Cretaceous chalk (hangingwall) and Pleistocene deposits (footwall) were analysed using micromorphology and microstructural mapping. Within the diamicton bounding the fault, three different clast microfabrics were distinguished: an older, but dominant S1 fabric; a second S2 foliation orientated perpendicular to S1; and a younger subvertical S3 fabric. These fabrics developed during large-scale folding and thrusting, subsequent fabric rotation adjacent to the thrust fault accompanied by dewatering of the diamicton and extension; the latter implying late-stage reactivation and gravitational relaxation at the southwestern limb of the syncline as the ice retreated. The combination of a 3D microstructural model and the macroscale information has led to the development of a detailed model for the evolution of the Wissower Bach Syncline during glacitectonism and the localised reactivation of the associated thrusts in response to ice retreat. Moreover, this methodology provides a robust dataset on which to interpret the structural evolution of glacitectonic complexes.

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Abstract. The Kieler Ufer cliff section is a structural key location in the late Weichselian thrust-dominated-to-fold–thrust-dominated glacitectonic complex of Jasmund. Restoration and balancing of geological cross sections from the eastern coast (southern sub-complex) enabled strain quantification and the illustration of stress orientation. The entire horizontal shortening of the Kieler Ufer section is 1280 m (51.6 %) at its minimum. The thrust faults generally inclined towards south indicate a local glacier push from the S/SSW, which fits well into the glacio-dynamic model suggested by Gehrmann and Harding (2018).

Abstract. Soft-sediment thin sections from a SW-dipping thrust fault at the south-western limb of the Wissower Bach syncline (NE Rügen) give rise to the complicated glacitectonic environment in the south-western Baltic Sea region. Micromorphology, microstructural mapping, and macroscale information have led to the development of a detailed model for the evolution of the syncline during late Weichselian glacitectonism.

Abstract. A thrust-bound footwall syncline located within the proximal part of the southern Jasmund Glacitectonic Complex is investigated, exploring the spatio-temporal relationship between glacitectonic macro- and microstructures. Orientation and geometry of macroscale folds and thrust faults reveal a two-phased deformation history recorded by the sedimentary sequence. The deformation is a result of glacitectonic imbrication and subsequent ice flow across Jasmund Peninsula during the late Weichselian. Clast microfabrics preserved within the folded glacial diamicts reveal that till-internal deformation is mainly related to subglacial shearing within the glacier bed, which predates large-scale imbrication and folding.

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Late Pleistocene glacitectonism at the southern Scandinavian Ice Sheet margin caused folding and thrusting of Upper Cretaceous chalk layers and Pleistocene glacial deposits in parts of the southwestern Baltic Sea area in Europe. Beside Møns Klint (SE Denmark), the Jasmund Glacitectonic Complex (JGC) on Rügen Island (NE Germany) is a similar striking example of glacitectonic deformation creating large composite ridges. In spite of a long research history and new results from modern datasets, the structural development of the JGC is still poorly understood, especially the detailed evolution of the southern JGC and its relationship to the northern JGC remain enigmatic. In this contribution, we demonstrate how the understanding of the JGC benefits from the application of established structural geological methods comprehending the formation of fold-and-thrust belts. The methods include cross-section balancing of the eastern coast (southern JGC) and quantification of the amount of folding and faulting. The proposed geometric model shows the current fold-and-thrust stack of glacially deformed sedimentary strata ca. 5720 m in length evolved by shortening from the original length (11,230 m) by 5510 m (49.1%). We present a spatial and temporal development of fault-related folding with a transition from detachment folds through fault-propagation folds to fault-bend folds. Together with morphological information from a digital elevation model, the thrust faults mapped in the cliff section are mainly inclined towards the S to SW and imply that a local glacier push occurred from the south. These results highlight the complexity and individual architecture of the JGC when compared to other Pleistocene and modern glacitectonic complexes. Resolving its structural development provides new insight into the deformation history and shortening of this spectacular glacitectonic complex lying in the southwestern Baltic Sea region.