VÝSLEDKY VÝZKUMU HRANICE KŘÍDA/TERCIÉR V MAGURSKÉM FLYŠI U UZGRUNĚ

Vol.9,(2002)

Miroslav Bubík Marie Adamová Marta Bąk Juraj Franců Przemyslaw Gedl Radek Mikuláš Lilian Švábenická Alfred Uchman

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Abstract
The Cretaceous/Cenozoic transition was studied in the deep-sea/sub-CCD flysch sediments of the Carpathian Flysch using micropaleontology, sedimentology and geochemistry. The position of the boundary was estimated in the section based on integrated stratigraphy (chemostratigraphy and biostratigraphy: calcareous nannofossils, dinocysts, foraminifers, and radiolarians). The boundary layer itself was not found, but a weak Ir enrichment in three muddy turbidites is interpreted as reworking of it. The base of the benthic foraminifer Rzehakina fissistomata zone was recorded 2.5 m below the boundary. The last occurrence of the nannofossil Micula prinsii and planktonic foraminifer Abathomphalus mayaroensis was recorded in the highest calcareous turbidite mudstone 0.65 m below the boundary, and Maastrichtian radiolarian assemblage of the Amphipyndax tylotus Zone 1.45 m below the boundary. The dinocyst index species Carpatella cornuta was found just 35 cm above the base of the Ir bearing turbidite layer. No extinctions among benthic foraminifers were observed at the boundary. The dinocyst record shows prolonged stepwise return across the whole studied section (uppermost Maastrichtian - basal Danian). This multidisciplinary study has allowed the modelling of paleoenvironmental changes across the Cretaceous/Tertiary transition. The changes in the deep sea Magura Flysch Basin result from the interplay between a trend of increasing bottom-water oxygenation with two low-oxygen episodes in the uppermost Maastrichtian, the formation of an oxygen minimum zone in the water column above, increasing plankton productivity, possible upwelling, and shifts in the level of the CCD. At the boundary itself there was no sudden change, but rather a prolonged trend of increasing primary as well as benthic

Keywords:
KT boundary; stratigraphy; Ir anomaly; extinction; palaeoenvironmental analysis; Outer Carpathian Flysch; Rača Unit
References

Bąk, M. (1999): Uppermost Maastrichtian radiolaria from the Magura Nappe deposits, Czech Outer Carpathians. - Ann. Soc. Geol. Polon., 69, 3-4, 137 - 159. Krakow.

Bąk, M. - Sawłowicz, Z. (2000): Pyritized radiolarians from the Mid-Cretaceous deposits of the Pieniny Klippen Belt – a model of pyritization in an anoxic environment. Geologica Carpathica, 51 (2): 91-99.

Brinkhuis, H. - Bujak, J.P. - Smit, J. - Versteegh, G.J.M. - Visscher, H. (1998): Dinoflagellate-based sea surface temperature reconstructions across the Cretaceous-Tertiary boundary. Palaeogeography, Palaeoclimatology, Palaeoecology, 141: 67-84.

Bubik, M. (1995): Cretaceous to Paleogene agglutinated foraminifera of the Bílé Karpaty unit (West Carpathians, Czech Republic). - In: Kaminski, M. A. - Geroch, S. - Gasinski, M. A. (eds.): Proceedings of the Fourth International Workshop on Agglutinated Foraminifera, Krakow, Poland, September 12 - 19, 1993. Grzybowski Foundation Special Publication no. 3, 71 - 116.

Bubik, M. - Bąk, M. - Švábenická, L. (1999): Biostratigraphy of the Maastrichtian to Paleocene distal flysch sediments of the Rača Unit in the Uzgruň section (Magura group of nappes, Czech Republic). - Geologica Carpathica, 50, 1, 33 - 48. Bratislava.

Bubik, M. - Adamová, M. - Franců, E. - Franců, J. - Gedl, P. - Švábenická, L. (2001): Výzkum hranice křída/terciér v magurském flyši v roce 2000. - Geol. výzk. Mor. Slez. v roce 2000, 22 - 26.

Foreman, H.P. (1977): Mesozoic Radiolaria from the Atlantic basin and its borderlands. In: Swain, F.M. (Ed.): Stratigraphic Micropaleontology of Atlantic Basin and Borderlands, 305-320pp.

Geroch, S. - Nowak, W. (1984): Proposal of zonation for the Late Tithonian - Eocene, based upon the arenaceous foraminifera from the outer Carpathians, Poland. - In: Oertli, H. (Ed.): Benthos ´83; 2nd International Symposium on Benthic Foraminifera, Pau (France), April 11 - 15, 1983. Elf Aquitaine, ESSO REP and TOTAL CFP, pp. 225-239.

Kuhnt, W. - Moullade, M. - Kaminski, M. A. (1996): Cretaceous palaeoceanographic events and abyssal agglutinated foraminifera. - In: Moguilevsky, A. - Whatley, R. (eds): Microfossils and Oceanic Environments. - University of Wales, Aberystwyth Press, 63-77.

Švábenická, L. (2001): Late Campanian/Late Maastrichtian penetration of high-latitude calcareous nannoflora to the Outer Western Carpathian depositional area. – Geologica Carpathica, 52, 1, 23-40.

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