tailieunhanh - Late Campanian larger benthic foraminifera from the Zekeriyaköy Formation (İstanbul, NW Turkey): taxonomy, stratigraphy, and paleogeography

North of İstanbul, the thick Upper Cretaceous volcanic and volcanoclastic sequence of the Yemişliçay Group is nonconformably overlain by the neritic clastic and carbonate sequence of the Zekeriyaköy Formation. This unit, either placed within the volcanic sequence or interpreted to overlie it, was studied near Zekeriyaköy for its larger foraminifera, previously recurrently referred to as the Maastrichtian. The basal epiclastic sandstone beds of the Zekeriyaköy Formation immediately above the volcanic sequence contain Praesiderolites dordoniensis and rare rudist shells. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 1-21 http earth TÜBİTAK Research Article doi yer-2007-9 Late Campanian larger benthic foraminifera from the Zekeriyaköy Formation İstanbul NW Turkey taxonomy stratigraphy and paleogeography 1 2 2 2 3 2 4 Mert Eren ERDEM Ercan ÖZCAN Ali Osman YÜCEL Aral I. OKAY Sadıkcan ERBAY Sibel KAYĞILI 1 İsak YILMAZ 1 Department of Geological Engineering Faculty of Engineering İstanbul University-Cerrahpaşa İstanbul Turkey 2 Department of Geological Engineering Faculty of Mines İstanbul Technical University İstanbul Turkey 3 Eurasia Institute of Earth Sciences İstanbul Technical University İstanbul Turkey 4 Department of Geological Engineering Fırat University Elazığ Turkey Received Accepted Published Online Final Version Abstract North of İstanbul the thick Upper Cretaceous volcanic and volcanoclastic sequence of the Yemişliçay Group is nonconformably overlain by the neritic clastic and carbonate sequence of the Zekeriyaköy Formation. This unit either placed within the volcanic sequence or interpreted to overlie it was studied near Zekeriyaköy for its larger foraminifera previously recurrently referred to as the Maastrichtian. The basal epiclastic sandstone beds of the Zekeriyaköy Formation immediately above the volcanic sequence contain Praesiderolites dordoniensis and rare rudist shells. The higher sandstone and limestone beds comprise assemblages of Lepidorbitoides campaniensis Orbitoides megaloformis Vanderbeekia catalana Siderolites gr. calcitrapoides Sirtina orbitoidiformis Praestorrsella roestae Lenticulina rotulata Planorbulina sp. agglutinated and rotaliid foraminifera rudist fragments bryozoans and red algae. Lepidorbitoides the most abundant foraminifera in the studied material has predominantly L. campaniensis-type embryons with a single auxiliary chamberlet and rarely L. bisambergensis-type embryons characterized by having 2 such .