Trace fossil and fades changes in the Upper Cretaceous-Middle Eocene flysch deposits of the Julian Prealps (Italy and Slovenia): consequences of regional and world-wide changes

The abundance and diversity of flysch trace fossil assemblages, including graphoglyptids and forms produced by echinoids, as well as the ratio of pre‐depositional to post‐depositional forms, show distinct large‐scale changes through the Maastrichtian to Eocene in the Julian Prealps. The changes were related to general facies changes and controlled by sedimentation rate, degree of erosion of the deep‐sea floor, substrate properties, oxygenation of the sediment, and food supply. The most significant changes occurred around the late Paleocene‐early Eocene to early‐middle Eocene boundaries and may be related to regional paleogeography and, tentatively, worldwide climate, especially to changes of temperature, fertility, and oxygenation of deep‐sea waters.