Discovery of the Late Triassic (Middle Carnian–Rhaetian) radiolarians in the volcano-sedimentary sequences of the Kocali Complex, SE Turkey: Correlation with the other Tauride units

Abstract

The Kocali Complex in SE Turkey includes pelagic sediments (pelagic limestones, cherts, etc.), basic volcanic rocks of oceanic crust origin together with platform-derived sediments. Its depositional age was previously assigned as Late Jurassic–Early Cretaceous. In order to study the radiolarian contents of volcano-sedimentary sequences in this complex, six stratigraphic sections have been measured mainly at the NE and NW Adiyaman city. Radiolarian faunas from these stratigraphic sections reveal that the age of these sequences ranges from middle Carnian to Rhaetian. Based on these data, the depositional age of the complex is older than the previously assigned. Lithological characteristics (widespread Triassic basic volcanic rocks associated with pelagic sediments) and radiolarian contents of these sequences have close similarities with the sequences of the Alakircay Nappe of the Antalya Nappes in western and central Taurides. Based on taxonomic studies, 99 taxa have been determined of which one genus ( Adiyamanium) and four species ( Monocapnuchosphaera kocaliensis, Paronaella speciosa, Ferresium okuyucui and Adiyamanium crassum) are described as new.