Foraminifera – based estimation of water depth in epicontinental seas: Badenian deposits from Glavnica Gornja (Medvednica Mt., Croatia), Central Paratethys

Abstract

This study presents the first attempt to estimate the palaeo-depth, and to assess the environmental conditions at the sea bottom, by means of foraminifers during the deposition of earlier Badenian deposits in the North Croatian Basin. The studied stratigraphic record, the Glavnica Gornja section is located in Mt. Medvednica, in the southwestern part of the Pannonian Basin System, and it belongs to the Upper Lagenidae Zone (Moravian substage of the Badenian). Three methods were tested to estimate the palaeo-depth; the plankton/benthos (P/B) ratio indicated the lower to upper bathyal zone, the modified P/B ratio indicated 886-987 m depth for the bathyal zone, whereas the Hohenegger method indicated 142-204 m depth for the outer shelf. Of the three estimates, the last is considered as best fitting the general environmental demands of the dominant and common small benthic forams. The well oxygenated sea bottom was temporarily replaced by more stressful conditions in the middle part of the studied interval, pointing to occasional variations in the organic flux.