THE CROMERIAN INTERGLACIAL IN THE AREA OF THE MAXIMUM GLACIATION EXTENT IN SOUTHERN POLAND

In southern Poland, the profile in Konczyce, gives a new insight on the ice-sheet maximum extent. Until now, it has been called: the South Polish Glaciation, Cracovian or Sanian and has been correlated with Elsterian (Mindel).

The site in Konczyce, presents the profile of Quaternary deposits resting on the Miocene clays. The lower, 9 m thick, segment of the profile comprises river gravels and sands, locally topped with a preserved cover of sandy alluvial loams. Above the river deposits, erratic boulders, fluvioglacial sands and gravels, glacial till occurs. These glacial series are again covered with river deposits (mainly gravel-sized flysch sandstones originating from the Carpathians and singular rounded pieces of crystalline rocks originating from washing of glacial deposits). This tripartite lower segment of the profile is overlain by almost 10 m thick upper segment. The latter comprises the series of silts and silty loess-like loams with 3 layers of organic deposits (peat) at its lower part. The palynological examination of the lower, about 3.5 m thick fragment of these overlying silty series led to identification of pollen assemblages with Pinus silvestris, Alnus glutinosa, Betula alba, Corylus, Tilia cordata, Ulmus, and Fraxinus. This pollen succession was believed to be the closest to the younger optimum of the Ferdynandovian Interglacial, which used to be correlated with the Cromerian IV. However, the middle of the organic deposits can be assigned now to the Interglacial II of the Cromerian Complex, i.e. to the earlier stage than it has been accepted.

The paleomagnetic tests of the lowermost deposits, resting on the upper river series, show reversal magnetic polarity associated with Matuyama epoch. This outcome allows for a new interpretation of the glacial deposits. The river series underlying the upper segment of the profile can be related to the earliest Cromerian Complex. The glacial deposits occurring more below are older than the Cromerian and can be paralleled with the Günz or with the pre-Cromerian traces of the oldest glaciations found in England and Holland or with the Nebraskan glaciation in North America. Based on the paleomagnetic and palynological examinations the glacial deposits in Koñczyce profile are older than 750 ka BP and are likely to correspond to the Menapian.