Tectonic and environmental controls on Upper Triassic–Jurassic carbonate successions of the eastern Northern Calcareous Alps (Stumpfmauer, Austria)
Year: 2026
Type: article
Abstract: The western Neo-Tethys Austroalpine and Southern Alps sedimentary successions are proven archives of environmental and climatic changes and tectonic activity across the Triassic to Jurassic times. These Upper Triassic–Jurassic, dominantly carbonate, shelf deposits witnessed the extensional tectonics related to the opening of the Penninic Ocean to the north-west and the partial closure of the Neo-Tethys Ocean to the south-east and contribute to the reconstruction of the evolution of a rifted passive margin. Lower Jurassic shallow subtidal to peritidal facies are recorded on structural highs in the Southern Alps, whereas Northern Calcareous Alps successions are reported to lack Jurassic shallow-water platform carbonates, which did not resume after the End Triassic Extinction. This study focusses on the facies characterization of upper Norian–Jurassic successions in the eastern Northern Calcareous Alps distinguishing nine superimposed sedimentary units (Unit A-I) overlying the Hauptdolomit and Plattenkalk peritidal facies. Detailed microfacies analysis reports, previously unrecognized, lowermost Jurassic ooidal and peritidal carbonates, documenting a stratigraphic evolution comparable with the Lombardy Basin in the Southern Alps. Upper Triassic–Lower Jurassic stratigraphic successions, fairly continuous except a latest Triassic subaerial exposure, are adjacent to sectors with stratigraphic gaps and angular unconformities between eroded upper Norian or Rhaetian shallow-marine carbonates overlain by Lower or Middle Jurassic condensed pelagic facies due to platform drowning. On the Stumpfmauer, outcrops with breccias reworking Upper Jurassic platform lithoclasts embedded in basinal radiolaria wackestone were mapped for the first time, unconformably covering Lower Jurassic shallow-marine carbonates. These differences in stratigraphic architecture point to syn-sedimentary tectonics with fault-controlled structural highs and lows. This novel proposed reconstruction with revision of the regional stratigraphy provides fundamental constrains for the interpretation of the tectono-sedimentary architecture of a sector of the Bajuvaric units in the eastern Northern Calcareous Alps and demonstrates the importance of thorough carbonate facies characterization for geological reconstructions of pre-orogenic scenarios.
Institutions: University of Milan, University of Cagliari
Language: English
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,890
OpenAlex ID: W7214523894