Palaeoenvironmental and climatic changes during the early pleistocene recorded in the lacustrine-boggy-fluvial sediments at Komorniki, NE Poland

The lacustrine-boggy-fluvial sequence at Komorniki, NE Poland was subject to complex (geological, palynological, diatomological and malacological) investigations. These sediments occur between the Narevian and Nidanian glaciations tills and belong to the Augustovian Interglacial of Poland correlated with the Cromerian 1 Interglacial of the Netherlands. Two cold stages of a glacial rank and one warm stage of interglacial rank (with dominant pollen of Quercus, Ulmus, Carpinus, Alnus, Tilia and Corylus in sediments corresponding to the climatic optimum) have been distinguished in the pollen succession. The latter is similar to that known from the Augustovian Interglacial profiles at Szczebra, Kalejty and Czarnucha. Diatom succession from the Komorniki section includes certain unidentified, apparently new small species of Stephanodiscus, Staurosirella and Pseudostaurosira side be side with the Pleistocene extinct taxon of Stephanodiscus niagarae var. insuetus and a relatively widespread species of S. rotula characterizing by some morphological peculiarities. In the composition of the malacofauna the fluvial extinct species of Fagotia wuesti and Sphaerium cf. rivicola are the most important molluscs for the biostratigraphy. Among them, Sphaerium cf. rivicola is known from the late Tiglian in the Netherlands. Fagotia wuesti is characteristic of the Bavel Interglacial in the Netherlands, as well as of the Borntal and Artern interglacials in Germany.