engleski

The Eocene flysch deposits of the Istrian Peninsula in Croatia and Slovenia: regional, stratigraphic, sedimentological and ichnological analyses

The Istrian flysch deposits are connected with the Pyrenean tectonic phase. They accumulated in a narrow shortliving deep-sea trough from the Lutetian in the northwest and from the Late Eocene in the southeast. This polarity is connected with feeding of the trough from the north west. The flysch deposits pass into underlying hemipelagic marls, or gravity flow deposits, which overlay a carbonate platform. Locally, they overlay discordantly the carbonate platform. The flysch deposits are about 300-350m thick and dominated by thin- and medium-bedded turbidites in the lower and middle parts, and by medium- thick- bedded turbidites in the upper part. The thick-bedded turbidites are connected with a regressive phase. The underlying hemipelagic marls are totally bioturbated and comprise low diverse trace-fossil assemblage that resembles the Zoophycos-Cruziana transitional ichnofacies. The flysch deposits are only partially bioturbated and comprise very diverse trace-fossil assemblage with numerous K-selected predepositional forms, including diverse graphoglyptids. The assemblage is compared to the Nereites ichnofacies and indicates ecologically stable, well-oxygenated, moderately oligotrophic environment between turbidite deposition, typical of the Eocena flysch deposits in the Carpatians, Alps, and probably in the other areas.

Flysch; Eocene; Ichnology; Istria; Croatia; Slovenia

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