VÝZKUM HRANICE KŘÍDA/TERCIÉR V MAGURSKÉM FLYŠI V ROCE 2000

Cretaceous/Tertiary boundary in the sub-CCD flysch facies of the Magura Flysch of West Carpathians at the Uzgruň-section was studied by methods of biostratigraphy (Foraminifera, Radiolaria, Dinoflagellata, calcareous nanofossils) and organic+inorganic geochemistry. The section consists of 9,1 m thick rhythmic alternation of claystones, marlstones, siltstones and sandstones. Autochthonous agglutinated fauna from hemipelagites allowed to determine the base of Rzehakina fissistomata Zone. Stratigraphically leading dinocysts were identified in the turbidite claystones (neritic elements redeposited downslope). The first occurrence of Carpate lla cornuta evidence the basal Paleocene 77 cm above the first occurrence of R. fissistomata. Calcareous nannofossils and planktonic foraminifera occur in turbidite marlstones only in the Maastrichtian part of section. Also well-preserved radiolarian assemblage was found just in the Maastrichtian. Organic and inorganic analytic methods did not show differences between turbidite and hemipelagite claystones. Organic matter consist of inertinite kerogen with low hydrogen index - probably partly oxidized terrestric phytodetrit. Sulphur and iron contents indicate the oxidized to fairly reduced environment.