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Michael Wagreich, University of Vienna, Center for Earth Sciences (Austria)
Herbert Summesberger, Natural History Museum Vienna (Austria)
Andreas Kroh, Natural History Museum Vienna (Austria)
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Several Santonian-Campanian boundary sections within the Gosau Group of the Northern Calcareous Alps of Austria and Germany have been investigated. The Schattau section in the Gosau Group records a nearly complete fossiliferous section across the boundary. The crinoid Marsupites testudinarius laevigatus, which is characteristic for the lower part of the latest Santonian Marsupites zone, has been found within a Micraster bed of the marly Bibereck Formation. Co-occurring ammonites, such as Boehmoceras arculus and Placenticeras maherndli, indicate also a Late Santonian age together with the zonal markers Placenticeras paraplanum and Cordiceramus muelleri muelleri, which occur below the Micraster bed, in the sandy Sandkalkbank Member (Hochmoos Formation). This indicates the Late Santonian Paraplanum ammonite Zone. Within the Micraster bed, both planktonic foraminifera Globotruncanita cf. elevata and Globotruncanita stuartiformis have their first (local) appearance. Dicarinella asymetrica is still present up to the top of the section, indicating the asymetrica-elevata concurrent range zone. Nannofossils give evidence for standard zone CC17 and UC12-13. Strontium and carbon isotope data, although interpreted with caution, allow some further correlations of the section to sections in the Lattengebirge (Germany). This indicates that Globotruncanita elevata and Globotruncanita stuartiformis have their first occurrences in the late Santonian, whereas the first occurrence of the nannofossil Broinsonia parca parca is an early Campanian event.
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