Resolving the age of deformed Ordovician carbonates in the central Okcheon Belt, Korea: Conodont and brachiopod constraints and palaeogeographic implications

초록

A deformed carbonate succession traditionally designated the "Great Limestone Series" at Cheongpung (Jecheon, central Okcheon Belt, Korea) lies along the western margin of the Taebaeksan Complex, where intense deformation and limited fossils have long hindered reliable stratigraphic correlation and age determination. Here we present integrated conodont and brachiopod evidence from thin micritic limestone beds of the Danri Limestone interval (the Gomyeongri Formation in previous stratigraphic usage). Conodonts include Rossodus tenuis (Miller, 1980) and Teridontus sp., indicating a Tremadocian (Early Ordovician) age for the fossil-bearing horizon. The same beds yield abundant silicified billingsellide brachiopods assigned to Tritoechia cheongpungensis n. sp., which is closely comparable to the Early Ordovician Tritoechia faunas reported from North and South China. This study provides the first reliable age data for the Danri Limestone, enabling improved correlation of the western-margin Joseon Supergroup with well-studied Lower Ordovician successions in Korea and adjacent regions. It further establishes a temporal framework for evaluating Early Palaeozoic carbonate-platform develop (c) 2026 Nanjing Institute of Geology and Palaeontology. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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