Lower-Middle Devonian (upper Emsian-Eifelian, serotinus-kockelianus zones) conodont faunas from the Prague Basin, the Czech Republic

Abstract

Lower-Middle Devonian conodonts (serotinus-kockelianus zones) from the Třebotov Limestone (Daleje-Třebotov Formation) and Choteč Limestone (Choteč Formation) were studied. The following sections in the Prague Basin were sampled in an attempt to refine the conodont biostratigraphy of this sequence: Barrandov road cut, Prastav quarry at Holyně, Jelínek mill quarry at Chýnice and Červený quarry near Suchomasty. Another aim was to collect new data from sections which have not been sampled before: Na Škrábku quarry at Choteč, U Němců section at Karlštejn and Na vyhlídce section at Hostím. The main focus was on clarifying ranges of individual conodont taxa and thus enabling more precise correlations to be made. Among the most important findings is the lower occurrence of Polygnathus costatus partitus Klapper, Ziegler & Mashkova (the defining species for the Lower-Middle Devonian boundary), recorded in its regional reference section (Prastav quarry) but 2.2 m below the previous boundary. The correlation between the onset of the Basal Choteč event, as well as the occurrence of Polygnathus sp. aff. Polygnathus trigonicus, with the base of the costatus Zone is supported by the results of this study.