Calciturbidite composition related to exposure and flooding of a carbonate platform (Triassic, Eastern Alps)



The compositional variation of calciturbidites (Pedata/Pötschen Formation), deposited adjacent to the Dachstein Formation carbonate platform in the Triassic Hallstatt Basin, was analysed using detailed field measurements and point-counting of thin sections. The 35 m long section is located in the Northern Calcareous Alps of Austria. Six point-count groups were distinguished separating basinal from platform-derived input. Summary statistics, cluster and correspondence analysis of the point-count data reveals a close relationship between the biota present on the Dachstein carbonate platform and the calciturbidite composition. The variations in turbidite composition are attributed to fluctuations in sea level and resulting flooding and exposure of the platform, which alternately created and destroyed shallow-water habitats on the platform top.