Stratigraphic constraints for the upper Oligocene to lower Miocene Puchkirchen Group (North Alpine Foreland Basin, Central Paratethys)

Herein, we present a new stratigraphic model for the upper Oligocene to lower Miocene Puchkirchen Group which comprises deep-marine deposits in the central North Alpine Foreland Basin. Stratigraphic constraints are inferred from the integration of new bio- (calcareous nannoplankton) and chemostratigraphic (delta C-13(bulk)) data from the drill-site Hochburg 1. The first occurrences of Helicosphaera carteri and H. ampliaperta are recorded in the section and indicate a stratigraphic range from nannoplankton zones NP25 to upper NN2/CNO6 to CNM4. The correlation with the upper Chattian to lower Burdigalian is strongly supported by the delta C-13(bull), record that mirrors major trends in global reference records between similar to 24.2 Ma and similar to 20.2-19.8 Ma. Seismic surveys suggest that at least 100 m of sediment have been eroded from the top of the Puchkirchen Group at Hochburg 1, and deposition extended even further into the Burdigalian. Within the Puchkirchen Group, the boundary between the Lower and Upper Puchkirchen formations occurs at similar to 22.2-22 Ma. The new age model for Hochburg 1 significantly improves previous stratigraphic concepts of the Puchkirchen Group and resolves some long-lasting stratigraphic issues in the study area. The implications of the new correlation for analyses of sedimentary budget, subsidence rates, sequence stratigraphy and the regional stage concept challenge our understanding of the development of the North Alpine Foreland Basin as well as the Central Paratethys.