Devonian carbonates of the Moravian Karst area, Bohemian Massif, are preserved in two principal lithostratigraphic units, Macocha Formation (MF) and Líšeň Formation (LF), which are separated by abrupt facies boundaries. Outcrop-scale facies analysis and quantitative microfacies analysis of selected boundary sections between the MF and LF reveals the former to be represented by shallow-water carbonate platform facies (loferites and peri-reefal deposits), whereas the latter to consists of hemipelagic, upper-slope to base-of-slope facies (periplatform ooze, carbonate debris flows deposits and calciturbidites). The boundary between the two formations is believed by us to represent a carbonate platform-drowning surface. There are significant time-shifts in the platform drowning surfaces (onset of the LF sedimentation) within the interval from the Upper Frasnian (Pa. rhenana Zone) to lowermost Famennian (Pa. crepida Zone). Diachronous nature of the boundary points to alternative (most probably tectonic) controls on the drowning of the carbonate platform than to a simple ecological-stress induced drowning associated with the Frasnian/Famennian boundary.

Klíčová slova:
Devonian, Moravia, carbonates, standard microfacies, carbonate platform drowning

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