Planktonic foraminifera biostratigraphy of the atbaşi formation in the north of İzmit

In this study, the planktonic foraminiferal biostratigraphy of the Atbaşı Formation outcrops north of the Izmit province in the Kocaeli Peninsula were studied. The samples were collected from two measured stratigraphic sections in the Akveren Formation, Atbaşı Formation and Çaycuma Formation. Globotruncana aegyptiaca,Gansserina gansseri and Abathomphalus mayaroensis, Parvularugoglobigerina eugubina (P?), Parasubbotina pseudobulloides (P1a), Subbotina triloculinoides (P1b), Globanomalina compressa (P1c), Praemurica uncinata (P2) and Morozovella angulata (P3) planktonic foraminifera biozones were defined in the Akveren Formation, while Morozovella angulata (P3), Globanomalina pseudomenardii (P4), Morozovella velascoensis (P5), Pseudohastigerina wilcoxensis/Morozovella velascoensis (E2), Morozovella marginodentata (E3) planktonik foraminifera biozones were described in the AtbaşıFormation with the determined planktonic foraminifera genus and species in these samples. In addition, the base of Çaycuma Formation begins with the Morozovella marginodentata biozone.