Taxonomic problems of some zonal species of the genus Palmatolepis and the correlation of the Frasnian of the East European Platform with conodont zonations

Abstract

Most of the Frasnian regional stages of the Ukhta region, South Timan, Russia, are composed of basinal deposits, however, the hassi and jamieae zones of the Standard Conodont Zonation cannot be easily recognised in this region. A revision of the previously elaborated succession of the Timan-Pechora associations revealed that the correlation problems are connected with the taxonomic interpretation of the zonal species Palmatolepis hassi and Palmatolepis jamieae. Analysis of the conodont collection of Professor W. Ziegler from the Rhenish Slate Mountains, Germany, especially from the interval encompassing the Lower hassi to Upper rhenana zones, has provided evidence of the lack of validity of the jamieae Zone as a separate stratigraphic unit. This statement is based on the composition of the jamieae and Lower rhenana conodont associations and the absence of P. jamieae near the lower boundary of the zone in the stratotype and other sections of the Rhenish Slate Mountains, becoming more common upsection. The correlation between the Timan-Pechora conodont associations III–XI, the Standard Conodont Zonation (Ziegler and Sandberg 1990) and the Frasnian Zonation (Klapper 1989; Klapper and Kirchgasser 2016) is suggested herein. The Domanikian Regional Stage corresponds to the punctata–Late hassi zones of the Standard Conodont Zonation and to Frasnian Zones 5–10. The boundaries of Frasnian Zones 8–9 need to be further specified in South Timan. The correlation between the Standard Conodont Zonation and the Frasnian Zonation of Klapper is elaborated.