An example for black shale development on a carbonate platform (Late Triassic, Seefeld, Austria)

East of Seefeld/Tyrol the Hauptdolomit facies (Triassic, Norian) is accompa nied by an organic-rich intercalation, the Seefeld facies. Three facies wer e distinguished, which developed within a separate basin within the Hauptdo lomit carbonate platform. These facies have been investigated in an environ mental and palaeoecological context applying microfacies analysis, palynolo gy, organic petrology, organic geochemistry and stable isotope geochemistry . As the controlling factors of sedimentation, sea level changes are sugges ted for large scale fluctuations, and climatic changes for variations on a smaller scale. Within the basin facies a mum-scaled rhythm can be observed, which was obviously seasonally controlled. A major amount of organic mater ial of the deposit has been produced by microbial activity under anoxic con ditions. Causes for the absence of pollen and spores in many black shale de posits are discussed.