Cretaceous-paleogene (K/PG) biostratigraphy, sedimentology and tectono-stratigraphic position of Ziyarettepe formation: Eastern Sakarya zone (Ardanuç/Artvin), NE Turkey

The Eastern Sakarya Zone (Eastern Pontides ) NE in Turkey, extending parallel to the Black Sea coast, was represented by pelagic, hemipelagic, and neritic sedimentary sequences during the Late Cretaceous and Paleogene. These sediments in the Eastern Black Sea Section have been studied over time under different names. The Ziyarettepe Formation, which is the subject of this study, is characterized by its neritic and hemipelagic sedimentary features. Ziyarettepe Formation; sedimentological, biostratigraphic, chemostratigraphic and tectono-stratigraphic aspects. This research was carried out under the hypothesis that the data obtained in previous studies should be evaluated in a different stratigraphic position according to the expanding literature. During the study, neritic and hemi-pelagic carbonates were mapped in terms of distribution, thickness, and rock types, and interactions with other units were determined. Five measured stratigraphic sections were collected from the Ziyarettepe Formation characterizing the base-surface relationship to determine sedimentary structure-fabric relations, biostratigraphic and chemostratigraphic data. Sedimentological (macro-microfacies analysis), micropaleontological-biostratigraphical (study of fosil by thin section and wash samples) and chemostratigraphical (geochemical analysis) investigation methods were applied to the samples obtained. As a result of paleontological studies in the Ziyarettepe Formation, 16 species and 14 genus of planktonic foraminifera, 9 species and 13 genus of benthic foraminifer, and 1 species of green algae were identified. It was interpreted that the clastic and irregular distribution of macro- and microfossils in the Ziyarettepe Formation is due to the effects of sea level changes, regional tectonism and global events.The shell structure of the fossil reveals the processes of transport from shallow habitats, transport to the platform-platform edge-slope edge and deposit under these conditions. The stratigraphic age of the Ziyarettepe Formation is given both chemostratigraphically and biostratigraphically (mainly foraminifera) in the range of late Campanian to Thanetian. Together with chemostratigraphic analyzes (whole rock elements, stable O-C isotopes, Sr isotopes and REE) it could be shown for the first time that the K/Pg transition was also recorded in this basin.