Palaeontological, diagenetic and facies characteristics of Cretaceous/Paleogene boundary sediments in the Ordu, Yavuzlu and Uzunisa areas, Eastern Pontides, NE Turkey

Abstract

The region discussed in this paper is located in the eastern part of the Pontide tectonic unit in north-east Turkey. From north to south it comprises the Ordu, Yavuzlu and Uzunisa areas, which form part of the Pontide fore-arc basin. The region shows different facies developments through the Upper Cretaceous to the Eocene, and the K/Pg boundary section is represented by limestones, sandstones, and glauconitic sandstones. While investigating the palaeontological, diagenetic and facies characteristics of the boundary sediments, it was observed that the Maastrichtian age is represented by thicker successions than the Paleocene in the northern and southern parts of the study area. By contrast, in the centre, the Paleocene epoch is represented by a thicker sequence. It was also determined that the area has become deeper from north to south, owing to rifting during the Maastrichtian–Paleocene and uplift to the north.