Geomorphological Mapping and Spatial Analyses of an Upper Weichselian Glacitectonic Complex Based on LiDAR Data, Jasmund Peninsula (NE Rügen), Germany

Abstract

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.

Blieschow on Jasmund – geomorphology and glacigenic landforms: keys to understanding the deformation chronology of Jasmund

“…3, help to reveal the evolution of Jasmund's deformation stages. The dominant wavelength of the composite ridges in the northern sub-complex is about 260 m. The dominant wavelengths in the southern sub-complex are generally smaller, with 135 to 195 m. This could point to slight differences in formation time and mechanisms between the northern and southern ridge domain, with regard to exerted stresses and glacier velocities (Gehrmann and Harding, 2018). The ridges are periodically spaced, which is characteristic of even small fold-and-thrust belts like the Jasmund Glacitectonic Complex (see Benediktsson et al, 2010;Noble and Dixon, 2011) (Fig.…”

“…It is a major example of large-scale glacitectonic folding and thrusting (Groth, 2003;Müller and Obst, 2006;Ludwig, 2011;Gehrmann et al, 2017). The structural framework shows a glacitectonic complex, which was probably formed after the Last Glacial Maximum (MIS 2) in response to a readvance of the Scandinavian Ice Sheet (SIS) during the Pomeranian phase (W2, 17.6 ka BP) (Müller and Obst, 2006;Litt et al, 2007;Gehrmann and Harding, 2018). It has a surface expression in the form of two major sets of subparallel composite ridges (Fig.…”

“…Areas forming morphological highs SE and SW of the southern ridge set (undifferentiated landforms) differ from the composite ridges by their chaotic ridge pattern. Although there is not yet a lot of evidence, these landforms might be interpreted as hummocky moraines (Gehrmann and Harding, 2018).…”

“…The analysis of high-resolution digital elevation models (DEMs) derived from lidar data (provided by the LAiV M-V, Landesamt für innere Verwaltung Mecklenburg- Vorpommern) provides a novel research tool for sedimentological and tectonic studies at the Jasmund Glacitectonic Complex (Gehrmann and Harding, 2018). This analysis provides the basis for a re-examination of Jasmund's evolution and the development of a new structural model.…”

“…Why the Pomeranian W2 ice stream moved from the SE to NW is still under debate (e.g. Ludwig, 2011;Gehrmann and Harding, 2018). Characteristic cross profiles of composite ridges with steep distal and flat proximal slopes can be observed in the northern sub-complex and in the southwestern district of the southern ridge domain.…”