Upper Devonian conodonts from the Timan-Pechora region, Russia, and correlation with a Frasnian composite standard

A Frasnian composite standard provides a refined scaling for the thirteen-fold conodont zonation first developed in the Montagne Noire, France, but since replicated in North America, Australia, and now the Timan-Pechora region of Russia. Zones 4–13 are identifiable in seven cores from the Ukhta area of southern Timan and a core from the Bagan Field of the Khoreyver Basin. Scaling of the zones through graphic correlation demonstrates the diachronism in different sections of the bases of many conodont species, including those of zonally defining Palmatolepis. This can be effectively shown in a correlation diagram scaled to a composite standard based on graphic correlation, whereas it is obscured by the assumption of synchronism inherent in conventional zonal correlation charts. Newly described species occurring in the Timan-Pechora region and elsewhere are Ozarkodina nonaginta, Ancyrognathus amplicavus, Mesotaxis johnsoni, Palmatolepis amplificata, P. mucronata, P. ormistoni , and P. timanensis. A number of other species described earlier from the region also occur outside Russia, mainly in Canada and Australia. Distribution patterns in the composite standard indicate close faunal connections between the Timan-Pechora, western Canada, and Western Australia.