Ostracod biostratigraphy and Strontium isotope stratigraphy of the Miocene sequences of the AyrancĎ Basin (Karaman/Turkey)

We investigate the stratigraphy of the Miocene fossil ostracod fauna from the Ayrancı Basin in southern Turkey, based on five key stratigraphic sections. Abundant ostracods belonging to the Neomonoceratina helvetica-Aurila soummamensis Biozone were found within the limestones of the Mazı Formation. This formation also records the initial appearance of Carinocythereis and Praeorbulina glomerosa curva-Orbulina suturalis, which are indicative of the Orbulina universa planktonic foraminiferal Biozone. The Divlek Formation, characterized by fossiliferous argillaceous limestones and marls, contains a diverse and well-preserved ostracod assemblage, allowing correlation of this lithological unit with the late appearance of Cyprideis during the Miocene. The formation age has been determined to span from the Tortonian, with an age range of 7.1–8.4 Ma based on 87Sr/86Sr ratios of two samples.