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Although the Pleistocene deposits exposed in the steep coastal cliffs of Mecklenburg-Vorpommern have been studied for more than a century, the depositional conditions of many lithostratigraphic units remain unclear. There is, in particular, a question whether the individual tills (locally more than 9 successive till units) are mainly subglacial deposits or resedimented (mass flows) in origin (at least in part). The Pleistocene deposits preserve information concerning the former glacial depositional processes. Detailed micromorphological analysis of these deposits can provide key information regarding these processes and thereby aid in the reconstruction of former glacial environments. The island of Rügen is located on the southwestern Baltic Sea coast and was situated in the marginal zone of the Scandinavian Ice Sheet during the last glacial period (Weichselian). Therefore, the region is considered as an ideal area for reconstructing the complex fluctuations in the position of the margin of this ice sheet as it expanded across the Baltic Sea and into northern Germany. Successive glacial advances and retreats of the ice sheet can be reconstructed by specific glacial sedimentation processes and flow-direction criteria derived from a variety of glacial deposits. The investigation area is located near Sassnitz on Rügen, where an imbricated and folded Weichselian succession disconformably overlies Maastrichtian chalk bedrock. The individual till units were sampled for micromorphological analyses to identify the former depositional conditions. Detailed description of the sedimentology and variation in facies, the description of macroscale deformation structures provides the context for the detailed micromorphology study. The three dimensional analysis of the microfabrics is based on the microstructural mapping methodology which enables the identification and interpretation of polyphase deformation within subglacial sediments.
This thesis aims to develop a palaeogeographic and chronostratigraphic model of the southwestern Baltic Sea area, to improve our understanding of the depositional history of the Late Pleistocene on both a local and a transregional scale. New sedimentological, palaeontological and numerical age data will be presented from three reference sites located at the coast of NE Germany. So far, the chronostratigraphic assignment of Saalian and Weichselian sediments of NE Germany has been based mainly on lithostratigraphic methods and on sparse numerical age data, resulting in a fragmentary age database. Modern sedimentological approaches, such as facies analyses, have been applied only at a few isolated profiles. Thus, a reliable reconstruction of the depositional environments and their stratigraphic positions is still missing for the study area, which makes the correlation between Pleistocene successions from NE Germany and other circum-Baltic regions problematic. To address these lithostratigraphic and geochronologic issues, three crucial profiles were re-investigated using a multiproxy approach, including sedimentological, geochronological, and palaeontological techniques. The Glowe and Kluckow sites are located on the peninsula of Jasmund (Rügen Island), whereas the Klein Klütz Höved (KKH) section is situated between Wismar and Travemünde at the coast of the Mecklenburg Bay. The age-constraining of critical horizons was conducted by luminescence dating of feldspar and quartz grain minerals. Together, these successions represent the Late Saalian to Late Weichselian period and give rise to the following picture. The Glowe and Kluckow sections reveal that ice-free conditions dominated the study site between 47 and 42 ka. Deposition occurred in a steppe-like environment with moderate summers and cool winters. Meandering and braided river systems inhabited by various freshwater species, such as Anodonta cygnea, Pisidium amnicum and Perca fluviatilis, shaped the landscape. A subsequent cooling phase resulted in the establishment of a periglacial landscape and the formation of ice-wedges. This phase is shown in this thesis to be connected to the Klintholm advance documented at 34±4 ka in Denmark. Furthermore, the data indicate the formation of a lacustrine basin during the transition of MIS 3 to MIS 2 under sub-arctic climate conditions. A potential link to the Kattegat ice advance (29 – 26 ka) will be proposed. At 23±2 ka, the study area was characterised by proglacial and ice-contact lakes related to the Last Glacial Maximum ice advance of the Scandinavian Ice Sheet (SIS). This is the first documented SIS advance of Weichselian age, which reached Jasmund at 22±2 ka. The KKH sedimentary succession comprises deposits of Late Saalian to Late Weichselian age: after a period of deglaciation between ~139-134 ka (Termination II; MIS 6), which is preserved in a glaciofluvial sequence deposited in a braided river system, a lacustrine environment was established in an arctic to subarctic climate. During this time, the landscape was vegetated by typical Late Saalian flora communities. The Eemian interglacial is represented by lacustrine to brackish deposits covering the reference pollen zones 1 to 3. During this initial part of the Eemian, thermophile forest elements spread (Quercus, Ulmus), indicating a deciduous forest. The presence of brackish ostracods represents the influence of a marine transgression between 300 and 750 years after the beginning of the Eemian period. A hiatus of more than 90,000 years separates the Eemian from the overlying Late Weichselian sediments. During the Late Weichselian period, the deposition at KKH was dominated by glaciolacustrine and subglacial facies, where the first Weichselian ice advance occurred at 20±2 ka. The sedimentological and geochronological findings in this thesis provide valuable information for the reconstruction of the palaeoenvironmental history from the Late Saalian to Late Weichselian period. The Late Saalian palaeoenvironmental setting is reconstructed, including Termination II and the initial phase of the Eemian interglacial. Furthermore, the Eemian marine transgression is shown to have occurred 300 to 750 years after the beginning of this interglacial. The first proven Weichselian advance of the SIS approached NE Germany between ~23 and ~20 ka. In contrast, there is no evidence to support a pre-LGM advance of Weichselian age to the study area, as proposed by several authors, neither at Glowe and Kluckow, nor at the KKH site. Based on the presented results, and contra what was previously assumed, the MIS 3 Ristinge and Klintholm advance of the SIS, documented in Denmark, did not reach NE Germany.