Upper Devonian (Upper Frasnian-Lower Famennian) conodont biostratigraphy of the Ayineburnu Formation (Istanbul Zone, NW Turkey)

Conodont faunas, which generally represent the pelagic palmatolepid-polygnathid or palmatolepid biofacies and correlate well with the standard Upper Devonian conodont zonation, were obtained from an incomplete stratigraphic section of the Ayineburnu Formation, Istanbul Zone, Turkey. Three of the upper Frasnian standard conodont zones extending from the Lower rhenana Zone into the linguiformis Zone, and six of the lower Famennian standard conodont zones extending from the Middle triangularis Zone into the Uppermost crepida Zone have been recognized with these conodont faunas. Zonal indices for the Lower triangularis Zone and the Frasnian/Famennian (F/F) boundary are not present. Strata assigned to the linguiformis Zone are overlain by a one meter unsampled interval. The next sample represents the Middle triangularis Zone, the conodont faunas of which are densely covered by matrix, suggesting a reworking. Also, the presence of the Lower and Middle crepida Zones is based on the recognition of only the lower and upper limits, respectively. The boundary between these zones could not be determined due to the absence of the zonally diagnostic taxa.