Biostratigraphic and sedimentary record of the Annulata Events in the Moravian Karst (Famennian, Czech Republic)

Abstract

The biostratigraphy and facies of halfgraben limestones in the southern part of the Moravian Karst (Czech Republic) have been studied from Uppermost Palmatolepis crepida to Upper Palmatolepis gracilis expansa conodont Zones. Only one Annulata Event horizon was detected, reflecting condensed sedimentation with the possible influence of erosion on the bypass slope. The “Wagnerbank” equivalent above the Annulata Events in the uppermost part of the Upper Palmatolepis rugosa trachytera Zone was not clearly recognized. The conodont data suggest the event beds in the Ochoz, Hosteˇnice 2, and Mokra sections represent the Lower Annulata Event. Correlation of the Annulata Event bed in the Hosteˇnice 1 section with the Upper Event remains tentative. Recorded microfacies were deposited slightly below or above the storm wave base. The Annulata Event beds correspond to mudstones/ wackestones to floatstones/rudstones with cephalopods and other fauna. Other microfacies include mostly various wackestones to packstones up to floatstones/rudstones. Conodont biofacies show the increase in both epipelagic taxa in the Annulata Event beds and “granulated” polygnathids above the Annulata Event beds. The cause of the increase in alternognathids in the Annulata Event beds remains questionable. Both the microfacies and conodont biofacies are generally similar to those seen widely distributed in other European and Moroccan sections, thus documenting the global nature of the Events.