Cenomanian–Turonian oceanic anoxic event (OAE2) imprint on the northwestern part of the Adriatic Carbonate Platform and a coeval intra-platform basin (Istria and Premuda Island, Croatia)

The Cenomanian–Turonian boundary (CTB) on the intra-Tethyan Adriatic Carbonate Platform (AdCP) is generally characterised by a transition between microbially laminated and/or bioclastic limestones to calcisphere-rich massive limestone with bioturbated intervals, organic-rich interbeds, firmgrounds, as well neptunian dikes, carbonate turbidites, tempestites and slumped structures. Compilation of results from two study sites in northwestern part AdCP previous research (on Istria Peninsula islands Sea Croatia) provides more complete overview geological events paleoenvironmental conditions that transformed formerly contiguous shallow-marine environments during this time period. For first time, comparison protected inner-platform area (Barban section) coeval intra-platform basin (Premuda Island CTB was made. This utilized combination litho-, bio-, microfacies studies SEM, EDS, TOC, ?13C ?18O stable isotope analyses. stratigraphic successions start deposits Milna Formation conformably overlain drowned-platform Sveti Duh platform Veli Rat contemporaneously developed intraplatform basin. These are turn Gornji Humac Formation, which represents re-establishment depositional systems AdCP, whereas deeper water environment persisted until Santonian. Despite diagenetic modifications deposits, TOC analyses indicate influence global Oceanic Anoxic Event 2 (OAE2). Combination local regional synsedimentary tectonics Late Cretaceous sea-level changes accompanied anoxic hypoxic conditions, extinction numerous benthic foraminifera, diversification expansion planktonic foraminifera calcareous dinoflagellates, provide new insights into character interval Tethyan realm.