Facies character and evolution of a mixed carbonate–siliciclastic shelf: Upper Triassic–Lower Jurassic succession in the eastern Northern Calcareous Alps (Stumpfmauer, Austria)

Abstract Western Tethys sedimentary successions constitute fundamental archives of Late Triassic–Early Jurassic environmental, carbonate production and tectonic changes. During the Triassic, Northern Calcareous Alps (Austria) belonged to passive margin, characterised by deposition early-dolomitized peritidal Hauptdolomit (Norian) adjacent basinward Dachstein shelf passing upward mixed carbonate–siliciclastic Kössen Formation (Upper Norian–Rhaetian). The Fm. was subdivided into lower shallow-water Hochalm Member upper Eiberg Member, accumulated in an intraplatform basin coeval carbonates Rhaetian Limestone). Mb. overlying strata were extensively studied as a continuous marine record across Triassic/Jurassic boundary. In contrast, successions, time-equivalent Upper Limestone, located North Basin, are poorly investigated. This study focusses on approximately 350 m thick Norian Lower succession cropping out eastern (Stumpfmauer). 32 distinguished lithofacies compose seven, vertically superimposed, units (A–G), belonging (Unit A cyclothems, Unit B claystone/marlstone with fossiliferous beds, C coral boundstone floatstone), Limestone D subtidal cyclothems claystone), transitional E ooidal coated grain peloidal grainstone basal transgressive lag, F bivalve-rich, microbialite oncoidal lithofacies, previously attributed Limestone) Hettangian–Sinemurian Kalksburg G cross-laminated quartz chert). detailed characterisation presented this contributes knowledge stratigraphy depositional environments identified can be framed evolution share similarities systems from Carpathians, Transdanubian Range, Southern Dinarides suggesting coherent response climate controls different palaeogeographic domains.