GSSP for Pragian Stage
Definition:The base of the Pragian Stage is defined at the base of Bed 12 in VelkÃ¡ Chuchle Quarry, in the southwest part of Prague, Czech Republic, where it coincides with the first occurrence of the conodont Eognathodus sulcatus sulcatus.
Sedimentology:The upper Lochkovian consists of gray, fine-grained, biodetrital, bituminous platy limestones with uncommon cherts and subordinate very thin intercalations of calcareous mudstone beds that are millimeters to a few centimeters thick. The Lochkovian - Pragian boundary, based on the first occurrence of conodont Eognathodus sulcatus, lies within this sequence, which shows no marked lithological change. Except for its lower part, the Pragian is represented by the Dvorce-Prokop Limestone. This is light gray, biomicritic to finely biodetrital in the lowest part and passes upward into darker gray micritic limestones.
Primary Markers:First occurrence of conodont Eognathodus sulcatus sulcatus at the base of bed 12.
The boundary is above the Paranowakia intermedia Zone. The base of the subsequent Zone with Nowakia sororcula (possibly = Nowakia kabylica) lies just below the boundary, while the lowest occurrence of typical specimens of the worldwide Pragian index Nowakia acuaria s.s. is above the boundary.
The boundary falls just below the lowest occurrence of the Pragian index Angochitina comosa, close to the first occurrence of Gotlandochitina philippoti, and close to the last occurrence of Eisenackia bohemica.
Correlation Events:Conodont FAD Eognathodus sulcatus sulcatus and Latericriodus steinachensis> Morph beta
Other Locations around the World:Eognathodus sulcatus sulcatus has been accepted as part of the standard conodont zonal sequence. The name taxon and zone are now recognized in the Czech Republic, Germany, Austria, China, Australia, Nevada, Alaska and Canada.
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