Investigating Greenhouse climate control on coal-bearing cycles in the Tethyan Upper Cretaceous Gosau Group (Northern Calcareous Alps, Austria）

Climate-controlled sea-level rise and fall have important effects on the depositional processes of strata. During periods of widespread glaciation, climate cycles influence sea-level rise and fall by controlling ice sheet growth and melting. The Late Cretaceous period was characterized by a typical greenhouse climate, and evidence for the presence of ice is strongly debated. However, the sedimentary record shows short-term larger sea-level fluctuations, and there is growing evidence for aquifer-eustasy (Sames et al. 2020) as an additional mechanism controlling sea-level rise and fall during this period. Field observations, microscopic observations, and analytical studies on upper Santonian to lower Campanian coal-bearing strata of the Gosau Group in the Northern Calcareous Alps (Hofer et al. 2011) have led to the identification of marginal marine mixed carbonate-siliciclastic cycles. Coal layers and lacustrine fine-grained sediments are present and attest to continental sedimentation with raised groundwater table, whereas intermittent marine strata with foraminifera and calcareous nannoplankton give evidence for marine incursions and high sea-level intervals. In a frame of a University of Vienna project, such Upper Cretaceous coal-bearing cycles in European basins will be investigated in detail to infer regional and Tethyan-wide controlling processes on sea-level and groundwater-table.