Račiněves - a new Middle Pleistocene interglacial in the Czech Republic
Bulletin of Geosciences, volume 76, issue 2;
pages: 127 - 139;
Micromorphology of Palaeosols,
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The staircase-like aggradation river terraces which contain, together with the overlying loess blankets and intervening palaeeosol complexes, a practically complete record of the entire Quaternary, are typical of the inner uplands of the Bohemian Massif. Despite of doubtless relative stratigraphy of well-defined local Quaternary sequences, the calibration of dates and interregional correlations are still open to debate. Each fossiliferous occurrence and particularly that with achaeological context is, therefore, extremely valuable. It was just like that in the gravel pit at Račiněves open in the gravels of the Straäkov Terrace with the surface at 224.5 m a. s. l. (70 m above the river) and the base at about 210 m a. s. l. (55 m relative height). The gravel body is built of two separate units. The lower one, 12-14 m thick, was deposited by the Vltava River in braided stream mode during the glacial. The upper unit, max. 2 m thick, represents fossiliferous deposits of an interglacial meandering river of the same first-order climatic cycle. The contact between units is sharp, erosional. The third unit which overlies the Straškov terrace is represented by loess and slope sediments with two intervening palaeosols. In addition to mollusc shells and mammalian fauna the upper fluvial unit contains stone artefacts. These stone implements together with intentionally split macromammalian bones and missing parts of large animals evidence a repeated temporary Palaeolithic hunting camp and butchering place. Both the molluscan assemblage and the mammalian fauna evidence an interglacial woodland with local open to steppe habitats in the wider surroundings broken by a wide Vltava River flood plain with riverine forests and small oxbow lakes, ponds and swamps respectively. The terrace has been morphostratigraphically classified as older Mindelian. One of the two analysed palaeeosols identified within the overlying unit is correlated with PK VI (Holsteinian) which also implies the same age of the underlying terrace. Contrary to that, the biostratographical analysis of genus Arvicola dates the upper unit into 'a wider sector of the Holsteinian interglacial'. Due to these inconsistences any effort made for more accurate dating is premature. Therefore, it can be now stated that the fossiliferous unit, which is an integral part of the Straškov Terrace, corresponds probably to the time span between the Cromerian (G/M) interglacial and the onset of the Elsterian glacial s. s. Račiněves represents a remarkable locality for central Bohemia. It yielded extraordinary biostratigraphical, morphostratigraphical and palaeopedological data in combination with archaeological finds. Because of the uncertain dating the locality is denominated the Račiněves interglacial of early Middle Pleistocene age.