Foraminiferal biochronology, microfacies analysis and environmental interpretation of Bashkirian-Moscovian (lower and middle Pennsylvanian) successions in the Hadim Nappe (Central Taurides)

This study aims to investigate fusulinid fauna, biostratigraphy, microfacies properties and data related to the late Paleozoic Gondwanan glaciation in Hadim Nappe Bashkirian and Moscovian successions along three measured sections (Yassıpınar, Bademli and Gölbelen) in central Taurides. In this study, one hundred forty six fusulinid species belonging to twenty five genus were determined. One genus and twelve species were described for the first time (Depratina turani n. sp., Aljutovella typica n. sp., Tikhonovichiella praetikhonovichi n. sp., Beedeina minuta n. sp., Beedeina tauridiana n. sp., Praefusulinella guvenci n. gen. n. sp., Praefusulinella okuyucui n. gen. n. sp., Praefusulinella rhombiforma n. gen. n. sp., Praefusulinella tekini n. gen. n. sp., Fusulinella obtusa minuta n. sub. sp., Fusulinella absoluta n. sp. and Fusulinella propriaforma n. sp.). Nine fusulinid zones were determined for Bashkirian and Moscovian successions of the Hadim Nappes. These are, Plectostaffella jakhensis-Eostaffella postmosquensis-Eostaffella pseudostruvei angusta Assemblage Zone, Plectostaffella bogdanovkensis-Plectostaffella varvariensis Lowest Occurrence Zone, Pseudostaffella antiqua-Pseudostaffella sofronizkyi Lowest Occurrence Zone, Staffellaeformes staffellaeformis-Staffellaeformes parva parva Lowest Occurrence Zone, Tikhonovichiella tikhonovichi-Verella spicata Lowest Occurrence Zone, Aljutovella aljutovica-Solovievaia ovata ovata Lowest Occurrence Zone, Priscoidella priscoidea-Eofusulina triangula Lowest Occurrence Zone, Fusulinella vozhgalensis devexa-Beedeina schellwieni Lowest Occurrence Zone and Fusulinella bocki bocki Lowest Occurrence Zone in ascending. Most of the described fusulinid zones and their fusulinid assemblages in studied Hadim Nappe sections are quite similar with the regions including Mississippian and Pennsylvanian successions such as Moscow Basin, the Southern Urals, Elburz, Donbass and Donets Basin. The Hadim Nappe Serpukhovian-Bashkirian stage boundary was observed only in the Yassıpınar measured section and the base of the Bashkirian stage determined by the first appearance datum (FAD) of the Plectostaffella bogdanovkensis Reitlinger and Plectostaffella varvariensis (Brazhnikova and Potievskaya) fusulinid species. The Bashkirian-Moscovian stage boundary is rich in fusulinid assemblages and observed only in the Yassıpınar and the Gölbelen measured sections. This stage boundary was determined by the first appearance datum (FAD) of the Aljutovella aljutovica (Rauzer-Chernousova) which is one of the index specimens of the Aljutovella aljutovica-Solovievaia ovata ovata zone. Detailed microfacies studies were carried out to construct the depositional environment. It can be concluded that the sea level change is directly related to the type of microfacies and its effects on lithology and the biodiversity as positively or negatively. The upper Serpukhovian-lower Bashkirian successions are represented by shallow marine environments deposits including sandstone and oolitic grainstone microfacies types with low biodiversity. Additionally, the depositional environment of the interval between upper Bashkirian to Moscovian indicates a relative sea level rise with some local sea level falls corresponding to bioclastic grainstone microfacies types and the increasing of the abundance and diversity of fusulinid assemblages. The sandstone microfacies at the base of Kasimovian stage indicate a considerable sea level fall. The isotope studies (mainly δ13C) which were carried out in Yassıpınar, Gölbelen and Bademli measured sections pointed out that the Hadim Nappe Mississippian and Pennsylvanian successions effected by the Late Paleozoic Gondwanan glaciation (Glacial Period II-III) and the eastern Australian Glacial Periods (C3 and C4). The sea level fall and its effects related with the Late Paleozoic Gondwanan Glacial Period II (Serpukhovain-Bashkirian boundary) were described by δ13C values and microfacies types with low faunal composition from the Yassıpınar measured section in Hadim Nappe. The positive orientation of the δ13C isotope values, carbonate rich deposits and related microfacies types beginning from middle part of the Bashkirian up to the Moscovian (Kashirian substage) refer to relatively deeper depositional environment and warmer climate conditions comparing to the chronostratigraphically lower parts. The negative δ13C isotope values recovered from the Yassıpınar and Gölbelen measured sections indicates a stability on sea level with some local falls from Kashirian to the end of Myachkovian substages of the Moscovian stage. The major sea level fall in Yassıpınar and Gölbelen measured sections corresponds to the base of Kasimovian stage supported by the increasing of the sandstone microfacies types and negative orientation of δ13C isotope values. It is argued that the sea level fall at the base of Kasimovian stage related with the beginning of the Late Paleozoic Gondwanan Glacial Period III and a new cooler climate conditions.