New age constraints from the SW Baltic Sea area – implications for Scandinavian Ice Sheet dynamics and palaeo‐environmental conditions during MIS 3 and early MIS 2

Abstract

The study of two cliff outcrops from the Jasmund Peninsula provides new information on the ice-sheet dynamics and palaeo-environmental conditions during MIS 3 and the ensuing transition to MIS 2 in the southwestern Baltic Sea region. We identified interstadial fluvial sediments, with mollusc and vertebrate fauna, which were deposited between 47 and 42 ka in a steppe-like landscape. A subsequent cooling phase led to the formation of a proglacial lake, between 30 and 22 ka, indicated by varve-like, rhythmically bedded silty clay. This proglacial lake formation can be correlated to the blocking of the Baltic Basin by the Kattegat ice advance, previously dated to c. 29-26 ka. The transition from proglacial to terminoglacial lacustrine deposits reflects the immediate advance of the Scandinavian Ice Sheet (SIS) into the study area after the transition from MIS 3 to early MIS 2. The SIS finally reached the area at 23AE2 ka (Brandenburgian phase; advance from the northeast). A subsequent ice retreat accompanied by the deposition of meltwater sediments was followed by a re-advance of the SIS, resulting in a glaciotectonic deformation event across the study area. The age control for our study is based on optically stimulated luminescence (OSL). The investigated Pleistocene sediments show ice-free conditions during MIS 3 and early MIS 2, indicating that neither the Ristinge nor the Klintholm advance reached the SW Baltic Sea coast of Jasmund. area and its implications for the dynamics of the SIS at local and regional scales during MIS 3 and early MIS 2. This is the first reconstruction of the depositional environment and the timing of the SIS entering the study area during MIS 2.

A multi‐proxy palaeoenvironmental and geochronological reconstruction of the Saalian‐Eemian‐Weichselian succession at Klein Klütz Höved, NE Germany

“…Kenzler et al . , ). We would also like to point out that the complete removal of potential early‐ to mid‐Weichselian till deposits at KKH would require an erosional force that is typically associated with an ice advance or exceptionally high‐energy fluvial/littoral processes, capable of transporting away glacial debris including metre‐sized boulders.…”

“…; Kenzler et al . ). Most luminescence dating studies use quartz or K‐rich feldspar grains; however, both minerals have distinct advantages and disadvantages (Murray et al .…”

“…An accurate estimation of the water content of the sampled units over the entire time of their burial is an important but challenging task (Kenzler et al . ). This is especially the case for settings such as at KKH, where the investigated units were glaciotectonically dislocated and uplifted, which is likely to have altered their position relative to the groundwater table (Kenzler et al .…”

“…This is especially the case for settings such as at KKH, where the investigated units were glaciotectonically dislocated and uplifted, which is likely to have altered their position relative to the groundwater table (Kenzler et al . , ).…”

The Baltic Sea: geology and palaeoenvironmental evolution – introduction

“…The Late Pleistocene glaciation history in the SW Baltic Sea is discussed in two contributions: (i) Obst et al (2017) use seismic profiles and numerous sediment cores recovered during the exploration of planned offshore wind farms at the SE margin of the Arkona Basin to unravel the complex succession of till deposits since the Late Saalian in this region, and (ii) Kenzler et al (2017) studied cliff outcrops from the Jasmund peninsula documenting the Scandinavian Ice Sheet advance at the transition from Marine Isotope Stage 3 into the Last Glacial Maximum. The significance of neotectonic processes is highlighted.…”