Insights into the Cretaceous-Paleogene boundary in Central Anatolia, Turkey: A comprehensive multi-proxy study

The Mudurnu-Göynük Basin, Central Anatolia, Turkey, hosts a complete record of the Cretaceous-Paleogene transition. Two stratigraphic sections, Göynükw and Okçular, were logged at high resolution and analyzed using micropaleontological, mineralogical, and geochemical methods. The micropaleontological analysis allowed the identification of the uppermost Maastrichtian planktonic foraminiferal biozone CF1 (Plummerita hantkeninoides) and the lowermost Danian biozones P0, Pα, P1a, P1b, and P1c. The Cretaceous-Paleogene boundary (KPB) at both sites corresponds to a sharp extinction of the large, ornate planktonic foraminifera (e.g., Globotruncana, Racemiguembelina, Planoglobulina), negative shifts in carbon and oxygen isotope ratios (δ¹³C_carb and δ¹⁸O_carb), decreases in calcite and smectite contents, increases in quartz, phyllosilicates, kaolinite and illite contents, peaks in mercury (Hg), tellurium (Te) and trace element contents. Furthermore, magnetic susceptibility values decrease continuously throughout the Maastrichtian CF1 Zone, and this decrease even accelerates before the KPB, coinciding with an increase in Hg and Te contents. This accelerated decline in magnetic susceptibility values may correspond to one of the major Deccan eruptions that formed the Poladpur Formation. The new dataset suggests that environmental change began in the uppermost Maastrichtian and culminated in the KPB. The total ecosystem recovery may have occurred a few hundred thousand years after the KPB, as supported by the reappearance of the larger planktonic foraminifera and δ¹³C_carb values similar to those before the KPB.