Upper Campanian bentonite layers in the Scaglia-type limestone of the northern Dinarides (SE Slovenia)

The research area is located in south-eastern Slovenia and belongs to the eastern extensions of Slovenian Basin adjacent Adriatic Carbonate Platform. studied section 25 m thick consists grey, brownish reddish pelagic limestones calciturbidites, two bentonite layers 110 10 cm thick. Both volcanoclastic horizons consist greenish, fine-grained muddy material. To date, no other bentonites similar age are known wider Southern Alpine Dinaridic region. late Campanian Campanian/Maastrichtian succession was determined from planktonic foraminifera calcareous nanoplankton assemblages. XRD analysis revealed presence calcite, quartz, muscovite/illite smectite, which prevails clay fraction indicative clays. We interpret these as resulting direct deposition volcanic ash a marine environment with concomitant admixture detrital material (quartz, muscovite) later diagenetic carbonatization. geochemical composition suggests felsic origin. most likely source Late Cretaceous–Paleogene bimodal rhyolitic/basaltic volcanism documented along Sava Suture Zone present-day Croatia, Bosnia Herzegovina, Serbia, North Macedonia. In Central Apennines three locations have been documented. Further spatial temporal volcanogenic could yield important data on paleogeographic tectonic evolution Adria/Apulia continental margin.