Trace fossils of the Pagliaro Formation (Paleocene) in the North Apennines, Italy

Siliciclastic flysch deposits of the Pagliaro Formation contain the world’s most diverse Palaeocene ichnoassemblage (40 ichnogenera, 58 ichnospecies and 2 ichnotaxa left in the open nomenclature). In the underlying thick-bedded calcareous flysch of the Monte Antola Formation 21 ichnogenera and 30 ichnospecies are identified. It shows that the Cretaceous-Paleogene boundary event did not cause any significant influence on tracemakers in the deep-sea in scale of formations. A percentage of pre-depositional forms and graphoglyptids in the ichnoassociation of the Pagliaro Formation is much higher than in the Monte Antola Formation. These differences are probably caused by environmental differences (diverse siliciclastic, food-rich sea floor versus monotonous calcareous nutrient-poor sea floor), and preservational potential (delicate scouring and casting occurs more frequently in siliciclastic flysch than in calcareous ones). An influence of evolutionary changes, however, ie a general increase of ichnodiversity and percentage of graphoglyptids from the Late Cretaceous to Palaeocene, cannot be excluded