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EN
Petrographic studies covered 20-60 mm coarse gravel and 4-10 mm medium-grained fractions of two till horizons (units ŁS II and ŁS IV) and two beds of sand-gravelly-outwash deposits(units ŁS I and ŁS III) associated with the Odra Glaciation (MIS6) in Łubienica-Superunki on the North Mazovian Lowland. Regardless of the facies type and grain sise, crystalline rocks dominate over all other petrographic groups in all samples. The percentage of crystalline rocks is greater among coarse gravel (average 74.7%) than among medium-grain gravel (average 67.8%). The share of carbonate rocks is limited only to the both lower units ŁS I and ŁS II. The upper units (ŁS III and ŁS IV) are deprived of these rocks, both in the medium and coarse gravel fraction. Sandstones, presented in all samples, were in the range of 5-20%. From the other petrographic groups, individual chalk limestones clasts, dolomites, flints and quartz grains were identified in the material. The indicator erratics were identified in all four units. Their percentage content stands for 10-18% of the total sample of coarse-grained fraction. Among them, the most common were the erratics derived from the Åland Islands, and then from the area of south-eastern Sweden (Smaland) and from Dalarna in central Sweden. Amongst the erratics with limited indicator significance, Lower Paleozoic limestones and Jotnian sandstones were most frequent. Single fragments of Ordovician red and Paleoporella limestone were present. These rocks, including the Lower Paleozoic grey limestone, occurred only in thelowerunits(ŁS I and ŁS II). The results of the research suggest that the two lower sediment units should be correlated with a ice-sheet advance (Middle Polish Complex, Odranian Stadial?), and the two upper ones - with a separate, subsequent advancement (Wartanian?). The paper is another methodological contribution to the consideration of abandoning the tedious testing of glacial till and focusing on a much faster petrographic analysis of fluvioglacial sediments associated with the same ice sheet. This is demonstrated by the comparable results of the petrographic analysis of short transport outwash sediments and till from a single glacial period.
PL
Osady piaszczysto-żwirowe pochodzące z transgresji stadiału młodszego zlodowacenia warty w ŁubienicySuperunkach zostały zbadane pod kątem składu petrograficznego frakcji średniożwirowej i grubożwirowej. Stwierdzono wyraźną przewagę skał krystalicznych, brak skał węglanowych oraz dziesięcioprocentowy udział piaskowców. Kwarc zmniejsza swój udział z około 9% we frakcji średniożwirowej do 0,6% we frakcji grubożwirowej. We frakcji 20–60 mm zidentyfikowano narzutniaki fennoskandzkie. Wśród nich były narzutniaki przewodnie z Wysp Alandzkich i sąsiadujących regionów Uppland i dna północnego Bałtyku oraz z obszaru południowo-wschodniej Szwecji (Småland). Wśród narzutniaków wskaźnikowych nie znaleziono ani jednego egzemplarza skały węglanowej.
EN
Sandy and gravel deposits, originating from the ice sheet transgression during the younger stadial of the Warthanian glaciation in Łubienica-Superunki, have been examined in terms of petrographic composition of the middle-coarse gravel fraction and pebble fraction. The distinct predomination of crystalline rocks, no carbonate rocks and a 10% share of sandstones have been ascertained. Quartz has reduced its share from about 9% in the middle-coarse gravel fraction to 0.6% in pebble fraction. The Scandinavian erratics have been identified within the 20–60 mm fraction. Among them the indicator erratics from the Åland Islands, neighboring Uppland, North Baltic bottom and Småland have been found. There was no single carbonate rock found among the so called statistical erratics.
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