Comment on “Uppermost Permian to Lower Triassic conodont biostratigraphy and carbon isotope records from Southern Armenia” by Chen Han et al. [Palaeogeography, Palaeoclimatology, Palaeoecology, 667 (2025), 112,870]

Abstract

Han et al. (2025) claim to provide an improved conodont biostratigraphy and carbon isotope records for the uppermost Permian and Lower Triassic succession in Southern Armenia. Specifically, they present results from the Permian-Triassic boundary (PTB) at the Chanakhchi and Vedi II sections and from the Induan-Olenekian boundary (IOB) at the Ogbin II section. However, the conodont and isotope stratigraphy for the PTB does not show any substantial improvement, and discrepancies with earlier works are not discussed. Furthermore, no serious attempt to solve these discrepancies through larger-scale sampling is made. Consequently, this led Han et al. (2025) to detect the PTB only above the first microbialite layers following the Boundary Clay at Chanakhchi section and the indication of the PTB at the Vedi II section with the FAD of I. isarcicella. For the identification of the IOB no unequivocal proxies were used such that the placement of the boundary remains uncertain and ambiguous. Thus, the claim to improve and refine the stratigraphy in the uppermost Permian and Lower Triassic from Armenia is not achieved.