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Global correlation of Permian conodont zonations

Due to distinct provincialism since Kungurian to the end of Permian, Middle and Upper Permian conodont zones established in the Equatorial Warm Water Province (EWWP) can not be correlated precisely with those recognized in the North Cool Water Province (NCWP) and the peri-Gondwana Cool Water Province(GCWP). However, four horizons, which define the boundaries of five conodont evolutionary stages during Permian have strong potential for inter-provincial correlation (Table 1). They are in ascending order: 1) the first appearance of Sweetognathus whitei, which is closely related to the last occurrence of Carboniferous-type conodonts such as Streptognathodus and Adetognathus; 2) the first appearance of Neostreptognathodus pequopensis; 3) the base of the Jinogondolella nankingensis Zone; and 4) the base of the Clarkina postbitteri – Iranognathus erwini Zone.

The Asselian, Sakmarian and Artinskian are to be established in the Urals, which is in the NCWP, and all other Permian stages are to be established in West Texas and South China, which are located in the EWWP. Permian Series and Stage boundaries should be defined at horizons close to the above-mentioned horizons so that they are as correlatable as possible outside the type area. A study on geographical clines in morphology for each index conodont is also necessary and will be the key to improve inter-province correlation (Henderson and Mei, in prep.).

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