The Devonian of Czechoslovakia and its Stratigraphic Significance

Abstract Biostratigraphic studies in the classic Barrandian area of central Bohemia allow correlation of conodont, tentaculite, and in some parts also graptolite and goniatite zonations in the time-span Lochkovian to Eifelian. These studies supplement knowledge of the Bohemian Lower Devonian stages Lochkovian, Pragian, Zlichovian and Dalejan and contribute to detailed characteristics of the Silurian/Devonian boundary (the international stratotype was accepted for the Barrandian in 1972), the Lower/Middle Devonian boundary (auxiliary stratotype accepted in 1981) and other chronostratigraphic limits. Some limits and intervals reflect in the lithology and fossil content possible global events, especially the Lochkovian/Pragian Boundary Event (shallowing and recirculation), the Basal Zlichovian Event (recirculation), the Daleje Event (transgressive), the Basal Chotec Event (anoxic) and the most evident Kacak Event (anoxic), all explainable by eustatic sea level fluctuations. The Barrandian sections allow study of small size cyclicity expressed in micro-rhythms which suggest differences in duration of individual biostratigraphic zones and stages. The Devonian of Moravia offers in its basinal facies faunas of Rhenish type preserved in metaquartzite of rather high grade metamorphism (up to the staurolite metamorphic zone). Within the shallow water carbonates study of stromatoporoids, corals, conodonts, etc. enable new biostratigraphic zonal subdivision and recognition of large scale cyclicity and possible global events within the Middle (the Kacak Event) and Upper Devonian (the suite of Frasnian-Famennian events, the Hangenberg Event etc.). New finds point to a greater extent of Devonian rocks even within metamorphic units of the Bohemian Massif and West Carpathian Mountains.