International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

Ichnology of Upper Cretaceous deep-sea thick-bedded flysch sandstones: Lower Istebna Beds, Silesian Unit (Outer Carpathians, southern Poland)

Pages: 107 - 120

Authors: JACEK RAJCHEL, ALFRED UCHMAN

Abstract: The Ophiomorpha rudis ichnosubfacies of the Nereites ichnofacies was recognized in thick- and very thick-bedded sandstones of the Lower Istebna Beds (Campanian–Maastrichtian), which were deposited mainly in deep-sea clastic ramps and aprons. It contains mainly Ophiomorpha rudis (produced by deeply burrowing decapod crustaceans) and rarely Zoophycos isp. and Chondrites isp. The impoverished Paleodictyon ichnosubfacies of the Nereites ichnofacies is present in the medium- and thin-bedded packages of flysch sandwiched between the thick- and very thick-bedded sandstones. They contain Chondrites isp., Phycosiphon incertum, Planolites isp., Arthrophycus strictus, Thalassinoides isp., Ophiomorpha annulata, O. rudis, Scolicia strozzii and Helminthorhaphe flexuosa. The relatively low diversity of this assemblage is influenced by limited areas covered by muddy substrate, which favours deep-sea tracemakers, and partly by a lowered oxygenation in the sediment.

Keywords: Upper Cretaceous, Polish Carpathians, Silesian Nappe, flysch, trace fossils, Ophiomorpha rudis

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