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Holocene and Lale Yislulian Paleogeography and Paleohydrology Prace Geograficzne nr 189 (2003)

Józef Edward Mojski

SELECTED PROBLEMS OF THE INTERGLACIAL R1VER YALLEYS INVESTIGATION IN THE POLISH PLAIN

The following introductory remarks are of principle significance for the study of the origin and evolution of the Pleistocene river valleys in the terri-tory of Poland:

—    the study of the greatest interglacial valley is of primary importance;

-    it is elear, that we must know the location of the finał erosion base i.e. marinę sea level;

-    in some places the syn- and postsedimentary neotectonic movements are of high importance for the present-day hipsometric State of the interglacial river valleys;

—    the average thickness of the Quatemary cover in Poland is mainly from 50 to 200 m. Therefore for the all paleogeomorfic reconstructions a consid-erable density of boring profiles is necessary.

1. During the each Pleistocene interglacial the erosional base had existed mainly outside of Poland's territory. Such a base had been the North Sea Basin in the west, the Black Sea Basin in the south-east and sometimes the Baltic Sea Basin (Fig. I). As yet we have rather little data available conceming Mazowian (Holsteinian) and Eemian Interglacial Seas, but for older intergla-cials there is a complete lack of data (Fig. 2, Tab. I). Only the knowledge of the Holocene sea is sufficient (a.o. Mojski, Ed. 1995). The erosional bases of all others (up to 5, Lindner et al. 2002) are as yet completely unknown.

The extent of the Holsteinian Sea in the northem Europę is very well known. During the maximum expansion the sea covered a significant part of German Lowland, from NW up to Berlin. Further to east there existed a widespread limnic basin now called the “Paludina Bank” lakę. The eastern boundary of that basin was recently studied in the western part of Polish Plain (Skompski 1994). The top of limnic deposits in this part of Poland lies now at 20 m a.s.l. (Fig. 1). The traces of the Holstein Sea have been found lately in the most NE part of Germany (von Bulów 2002) with the top of adequate deposits at 0 m. A similar hights (-20 m b.s.l.) concem the Holsteinian (Mojski 2002 = Sztum Sea, Makowska 1982) marinę deposits at the lower Yistula River