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.
In the present study, we performed gastropod analyses on loess–palaeosol sequences from northeast Armenia (Southern Caucasia) covering at least three glacial–interglacial cycles. The elaborated ecostratigraphy shows significant patterns of species composition related to the succession of pedocomplexes and loess, respectively. Pedocomplexes included species that can be associated with high‐grass to forest‐steppe biomes, indicating increased humidity for these sections compared to the loess layers. In contrast, loess layers that relate to glacial periods are associated with gastropod species of semidesert environments with shrub‐ and shortgrass‐steppes, indicating semiarid to arid conditions. Furthermore, the loess deposits do not show any evidence for cold‐adapted gastropod species. Therefore, we suggest that average July temperatures in the study area were above 10 °C, even during periods of loess deposition. Consequently, we propose that the limiting factor for tree growth during glacial periods was aridity, rather than temperature. In addition, we observe environmental differences between the various glacial times, with our results indicating a trend towards steadily increasing aridity in Southern Caucasia across the Middle to Late Pleistocene.
Here, we provide a detailed taxonomic reassessment of a historically collected chondrichthyan dental assemblage from the lower Kimmeridgian of Czarnogłowy in north-western Poland and discuss its significance for better understanding hybodontiform diversity patterns prior to their post-Jurassic decline in fully marine environments. In spite of its low taxonomic diversity, consisting of four large-toothed taxa (viz., Strophodus udulfensis, Asteracanthus ornatissimus, Planohybodus sp. and cf. Meristodonoides sp.), this assemblage is remarkable in that there are only very few Mesozoic hybodontiform assemblages with more large-toothed genera or even species. Comparisons with other European Late Jurassic hybodontiform-bearing localities demonstrate fairly homogenous distribution patterns characterized by large-bodied epipelagic forms of high dispersal ability. This is in stark contrast to post-Jurassic hybodontiform associations, which are dominated by smaller species that were predominantly bound to marginal marine and continental waters, suggesting a major reorganization of chondrichthyan communities during the Early Cretaceous.
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