Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 90. (Budapest 1998)

Bajzáth, J.: Plant macrofossils from the Hungarian Pleistocene III. Palaeobotanical study of Győrújfalu, Western Hungary

ations found at 25 m depth, where the dominant fossils were mainly trees. It is not surprising because the sediment at 25 m was different from the other samples. There were transported lumps of round shape and light-blue colour. The plant assemblage of them may have been allochthonous with a chance of long-distance transport. The plants may have come from the marginal vegetation of the river. The plant associations were very similar at each depth, however, the percentage of each association is different. The diversity of wet habitats and vegetation patterns at each depth, from the open water to the fen carr, indicates a meandering river system with abandoned channels, oxbow lakes and swamps. The open muddy habitats with ruderal, pioneer vegetation and driftwoods show the past moving and floods of the mainstream in that region. Based on both macrofossil and pollen analysis it seems that there is no complete record of the whole interglacial vegetational cycle at Győrújfalu. A mixture of borealtype woodland and termophylous plants points out the position of the assemblage in the vegetational cycle. The flora of lower depths (30, 33 m) belongs to the end of the first and the beginning of the second part of the vegetational cycle (protocratic-mesocratic phase), when coniferous forests still existed but a mixed deciduous forest replaced it gradually. The vegational succession in the water was always more rapid than the vegetational succesion of dry habitats, i.e. reforestration (I

VERSEN 1964). The flora of the upper part (20, 25?, 28 m) belongs to the later transitional phase of the vegetational cycle characterised by the expansion of the coniferous forest due to the climatic deterioration (ANDERSEN 1964). It is supported by the presence of typical oligocratic elements such as Tsuga, Abies and Carpinus pollen grains. The question is whether these two parts of the vegetational cycle belong to one forest succession or not. It is possible that partial records of two diffrent interglacials (20-28 m and 30—33 m) of the Cromer interglacial complex are superimposed. This assumption is confirmed by the vertebrate remains (JÁNOSSY & KROLOPP 1994). The mollusc and vertebrate record of Hungary shows significant climatic changes within the Cromer interglacial complex. Palaeontologists therefore divide the main biozone into at least three subzone (warm, cool and warm phases, Betfian, Nagyharsányhegyian, Templomhegyian, respectively) based on the different fossil assemblages. Summing up both the palaeontological and palaeobotanical results it seems that the flora in Győrújfalu belongs to two different interglacials within the Cromer interglacial complex. The flora of the lower deposit (30-33 m) is significantly older than the upper part of the locality. Acknowledgements - This study was supported by the Hungarian Scientific Research Found (OTKA F 14893). REFERENCES ANDERSEN, S. TH. (1964): Interglacial plant succession in the light of environmental changes. - Vidi Im. Congr. IN QU A Warsaw. 1961, Rep. II: 359-368. BAJZÁTH. J. (1995): Plant macrofossils from Hungarian Pleistocene I. Gymnospermatophyta in Győrújfalu. Annls hist.-nat. Mas. nam. hung. 87: 9-11.