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Conodont platform elements from selected sections of Devonian and their application in biostratigraphic correlation
Formáčková, Aneta ; Slavík, Ladislav (advisor) ; Kumpan, Tomáš (referee) ; Spalletta, Claudia (referee) ; Dojen, Claudia (referee)
The presented work consists of three separate papers that have been published in peer- reviewed journals. The published studies summarize and refine the existing knowledge about some conodont faunas of the Devonian with a primary focus on P1 elements and their potential in biostratigraphy. The dissertation thesis consists of three main parts. The first part is designed as an introduction, a summary of the objectives of the presented work, and methodologies used during the conodont sampling and sample processing and samples for thin sections. The second part of the work presents a general overview of the problems of conodont elements in biostratigraphy of the Devonian, characterizes the geological conditions and paleogeographic development of the areas from which the studied elements come from. The third part summarizes the results, brings a discussion on the herein presented data published in articles and contains the final word on the researched issues. The published studies on which this work is based are focused on platform elements of ozarkodinids and icriodontids, whose global distribution in time and space enables their study in different environments and stratigraphic levels. The microfacial characteristics of the studied sections and the issue of conodont biostratigraphy in the Devonian are...
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Silurian Scolekodonts of the Barrandian area
Tonarová, Petra ; Fatka, Oldřich (advisor) ; Slavík, Ladislav (referee) ; Michalík, Jozef (referee)
Scolecodonts (= jaws of the polychaete worms) have always been a relatively neglected group of microfossils. In the Prague Basin (Czech Republic), only two major studies exclusively focused on scolecodonts have been published. The aim of the present research was to fill in this gap - by a restudy of the historical collections of Žebera and Šnajdr, and its comparison with results gained from newly collected late Silurian samples and scolecodont faunas from other areas. It has turned out that the jawed polychaete fauna in the Prague Basin was much more diversified than previously reported. The last report on late Silurian scolecodonts by Šnajdr (1951) concluded that there are four determined and two species left in open nomenclature present. Restudy of the original collection has shown that there are at least 11 different species from families Mochtyellidae, Polychaetaspidae, Ramphoprionidae, Paulinitidae, Atraktoprionidae, Skalenoprionidae and Hadoprionidae. The new collection from similar stratigraphical level gained at least 25 species, including one newly described ("Mochtyella" pragensis). The taxonomic re-study also focused on the species Kettnerites kosoviensis that is a type species of the genus and was described in the Prague Basin. The new samples come from the limestone which is in contrast to...
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Family Spathognathodontidae (Conodonta) from the Silurian/Devonian boundary (sections Na Požárech and Praha-Radotín; Prague Synform) and its biostratigraphical correlation
Hušková, Aneta ; Slavík, Ladislav (advisor) ; Kumpan, Tomáš (referee)
This work is focused on conodont biostratigraphy of the Silurian/Devonian boundary interval in the Prague Synform. The Na Požárech and Praha-Radotín sections were selected in order to study conodont diversity and changes in conodont faunas in different carbonate facies - shallower and deeper-water limestones around the Silurian/Devonian boundary and also to test the assumption, whether differences in bathymetry affect the diversity of taxa of the family Spathognathodontidae. In total 22 samples were analysed, particularly 13 samples from the section Praha-Radotín and 9 samples from the section Na Požárech. All samples were processed in laboratory and the obtained conodont material was studied in detail. The conodont material is abundant in both sections (more than thousand elements) and shows a high diversity and disparity in the family Spathognathodontidae. In total 17 taxa were identified and a new species Zieglerodina petrea is described. This new taxon is easily recognizable because of a distinct morphology and could be usefull for the identification of the base of Devonian in the Prague Synform. Its potential use in global correlation will, however, need further and thorough studies. Also conodonts of the family Icriodontidae are surprisingly abundant in both sections. Thin sections (13 from...
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Present State of Biostratigraphy of the Silurian/Devonian boundary in the Prague Synform
Hušková, Aneta ; Slavík, Ladislav (advisor) ; Budil, Petr (referee)
This work summarizes current results in study of fossil faunas on the Silurian/Devonian boundary from stratigraphically important localities of the Prague Synform. The main aim of the present thesis is to discover new directions of prospective studies that would lead to an improved recognition of the Silurian-Devonians boundary in different facies. The work includes biostratigraphical summary of marine fossil organisms that could be used for a detailed correlation of this stratigrapic interval. The correlation of the Silurian-Devonian boundary is still an actual issue, therefore the present overview of the biostratigraphic data from the key (stratotype) area can be a useful contribution to the global research. Key words: Silurian/Devonian boundary, Barrandian, Prague Synform, biostratigraphy
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Silurian Scolekodonts of the Barrandian area
Tonarová, Petra ; Fatka, Oldřich (advisor) ; Slavík, Ladislav (referee) ; Michalík, Jozef (referee)
Scolecodonts (= jaws of the polychaete worms) have always been a relatively neglected group of microfossils. In the Prague Basin (Czech Republic), only two major studies exclusively focused on scolecodonts have been published. The aim of the present research was to fill in this gap - by a restudy of the historical collections of Žebera and Šnajdr, and its comparison with results gained from newly collected late Silurian samples and scolecodont faunas from other areas. It has turned out that the jawed polychaete fauna in the Prague Basin was much more diversified than previously reported. The last report on late Silurian scolecodonts by Šnajdr (1951) concluded that there are four determined and two species left in open nomenclature present. Restudy of the original collection has shown that there are at least 11 different species from families Mochtyellidae, Polychaetaspidae, Ramphoprionidae, Paulinitidae, Atraktoprionidae, Skalenoprionidae and Hadoprionidae. The new collection from similar stratigraphical level gained at least 25 species, including one newly described ("Mochtyella" pragensis). The taxonomic re-study also focused on the species Kettnerites kosoviensis that is a type species of the genus and was described in the Prague Basin. The new samples come from the limestone which is in contrast to...
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Environmental changes and biostratigraphy of the Emsian-Eifelian interval (Lower-Middle Devonian) in the Prague Basin, the Basal Choteč event
Berkyová, Stanislava ; Frýda, Jiří (advisor) ; Budil, Petr (referee) ; Slavík, Ladislav (referee)
The present study focuses on the Emsian-Eifelian (Lower-Middle Devonian) carbonate sequences of the Prague Basin. The Třebotov Limestone (Daleje-Třebotov Formation) and the Choteč Limestone (Choteč Formation) and their equivalents represent the stratigraphic units studied. The main goal of this study is to characterize environmental changes, known as Basal Choteč event, that were described from the boundary interval of the Třebotov and Choteč Limestone. In order to do so, sedimentological (microfacies analysis), geochemical (δ13 Ccarb, δ18 Oapatite) and paleontological (taxonomy of conodonts) studies were carried out. Eight microfacies types of carbonate rocks were described and interpreted in this study. Beside that, massive accumulations of calcispheres, peloids, prasinophytes and occurrences of blue-green algae (Girvanella) were recorded especially in the Choteč Limestone. The multidisciplinary approach mentioned resulted in characterization of the sedimentary environment of the studied units as well as their development in time. The main result of the present study is the model of the Basal Choteč event. A hypothesis of enhanced nutrient load is suggested here as a triggering mechanism for intense micritization and peloid formation and prasinophyte blooms, which were together with greater...
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Late Silurian Conodont Faunas from Barrandian - selected problems
Carls, P. ; Slavík, Ladislav ; Valenzuela-Ríos, J. I.
Working on biostratigraphy of the late Silurian and of the early Devonian by means of conodont successions from Bohemia and other regions, we realize that the relevant modern literature conveys several problematic opinions and practices of identification and zonation. Silurian/Devonian boundary and adjacent strata, conodonts have been and still are important biostratigraphic tools. However, the more intense the work with them was, the more frequently mischief with their application happened. Many important taxa have been lumped; it affected negatively the precision of stratigraphic correlation. The conodont stratigraphy of late Silurian-early Devonian urgently needs revision.
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