A NEW INTERGLACIAL STAGE IN POLAND (AUGUSTOVIAN) AND THE PROBLEM OF THE AGE OF THE OLDEST PLEISTOCENE TILL

Several new boreholes have been investigated in northeastern Poland. T hey proved up to ten undisturbed till beds in superposition. Two inter glacial lacustrine sequences have also been found. The lower interglac ial sequence rests on the oldest till in the region and is probably ov erlain by two Elsterian tills. The upper interglacial sequence rests d irectly upon the latter two tills and has yielded a pollen succession typical of the Mazovian (Holsteinian) stage. The lower interglacial se quence shows a different pollen succession, unlike any other known in Poland. It has been therefore defined as a new, Augustovian interglaci al stage, containing two warm events (optimum phases) separated by a c old period with only boreal flora. The lithostratigraphical position o f the new interglacial suggests a classical Cromerian age. However, al though the pollen succession of the upper optimum stage of the Augusto vian is superficially very similar to the British Pastonian, correlati on with the Leerdam Interglacial is possible, but it may also represen t a completely new warm episode of the Cromerian. The paper presents d iscussion on possible different age interpretations of this warm stage and the underlying till. (C) 1998 Elsevier Science Ltd. All rights re served.