Givetian/Frasnian (Middle/Upper Devonian) transition in the eastern Taurides, Turkey

Authors: RECEP ÖZKAN, ATİKE NAZİK, AXEL MUNNECKE, DİLEK GÜLNUR DEMİRAY, EBERHARD SCHINDLER, TUBA AYDIN ÖZBEK, EMİNE ŞEKER ZOR, İSAK YILMAZ, RAINER BROCKE, RECEP HAYRETTİN SANCAY, VOLKER WILDE, MEHMET NAMIK YALÇIN

Abstract: Devonian strata, including siliciclastic and carbonate rocks that were deposited in shallow marine to coastal environments, are widely distributed in the eastern Taurides of southern Turkey. To document the regional formation of the Givetian (Middle Devonian)/ Frasnian (Upper Devonian) boundary, a section in the eastern Taurides was studied in high resolution with regard to biostratigraphy, microfacies, sequence stratigraphy, and the global Frasne Event. The integrated biostratigraphic investigation was based on calcareous benthic foraminifers, ostracods, conodonts, and palynomorphs, which provide a biostratigraphic frame that allows to recognize the Givetian/Frasnian boundary. On the basis of the lithological variation in the outcrop as well as on depositional textures and biotic components as observed in thin sections, fourteen microfacies types of both siliciclastic and carbonate rocks can be distinguished. These microfacies are interpreted to have been deposited in settings that range from distal shelf to lagoonal depositional environments. The sequence stratigraphic interpretation allows to recognize two successive depositional sequences. The first one is a complete sequence including lowstand systems tract deposits, overlain by transgressive systems tract and highstand systems tract deposits. The second sequence is only represented by transgressive systems tract sediments. The Givetian/Frasnian boundary corresponds to the highstand systems tract of Sequence 1. The late Givetian Frasne Event can be detected lithologically and can be compared with other areas. Its position is confirmed biostratigraphically.

Keywords: Foraminifers, ostracods, conodonts, palynomorphs, microfacies analysis, sequence stratigraphy, Frasne Event, North Gondwanan margin

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