GEOGRAPHIC AND TEMPORAL GRADIENTS OF CIRCUMALPINE OLIGO-MIOCENE CARBONATES BASED ON HIGH RESOLUTION QUANTIFICATION OF COMPONENT DIVERSITY

High resolution determination and quantification of biotic components in thin sections are used to determine component diversities, biotic relationships, taphonomic pathways (microtaphofacies) and facies patterns within Oligocene to Lower Miocene carbonates of the circumalpine region. The studied thin sections originate from detailed studies and facies reconstructions of localities both north and south of the Alps. Multivariate analysis (MDS, Cluster analysis) is used to analyze component distributions within and between facies as well as localities. Bivariate analysis is used to explore component relationships. The results of detailed facies analysis and statistical analysis of components show high variations of component dominance and determining environmental factors at different scales. The studied localities differ in the diversity and abundance of coralline algae, larger and smaller benthic foraminifera, corals and bryozoans which represent the dominant components. Taxonomic gradients can be established for coralline algae and larger foraminiferal taxa which can, in part, be determined at high resolutions in thin section. Major environmental factors influencing component presence, carbonate fabrics and facies architectures include global climatic change during the Oligocene and crossing into the Miocene, regional paleogeographic developments within the Mediterranean Tethys and Paratethys as well as variations in local shelf gradients and terrigenous influx.