Coniacian Through Santonian Foraminiferal Biostratigraphy and Cooling Signals Along the Northwestern Tethyan Margin - New Results from the Upper Gosau Subgroup, Austria

We revisit a Coniacian through Santonian succession of the Upper Gosau Subgroup (Austrian Northern Calcareous Alps) on the northwestern Tethyan margin to investigate biostratigraphy, palaeoecology, and possible cooling signals across shallow- to deeper-water settings. The stratigraphic framework is constructed using calcareous nannofossil and planktonic foraminiferal biostratigraphy, while benthic foraminiferal assemblages and stable isotope data are used to reconstruct ecological and palaeoceanographic change. Stable isotope records further suggest the presence of cooling trends across the studied palaeoenvironments, indicating that such signals are expressed in both shallow and deeper settings. The offset in isotopic values between benthic and planktonic foraminifera illustrate distinct trends in bottom and surface waters, facilitating the assessment of temperature gradients independent of depositional environments. Emphasis is placed on benthic foraminiferal assemblages, which display distinctly different communities reflecting palaeoecological patterns. In addition to other shallow-water indicators, benthic foraminifera reveal a clear bathymetric gradient, documenting a progressive deepening from neritic settings to upper- and mid-slope environments. Among forms indicative of shallower environments, we document miliolid taxa such as Quinqueloculina sp. and large agglutinated forms (e.g., Haplophragmium sp.). A second assemblage, including taxa such as Gavelinella spp. and Reussella sp., occurs alongside these but is more abundant in more distal, neritic to upper bathyal and slope settings. Together, these assemblage patterns provide insights into the organization of benthic ecosystems along the northwestern Tethyan margin. By integrating biostratigraphic, palaeoecological, and geochemical proxies, the study refines regional integration and facilitates robust correlations across the basin's full depth range. assesses how northwestern Tethyan palaeocommunities responded to environmental and climatic change during the Late Cretaceous.