Choice of conodont Idiognathodus simulator (sensu stricto) as the event marker for the base of the global Gzhelian Stage (Upper Pennsylvanian Series, Carboniferous System)

Abstract

We propose that the level at which the conodont species Idiognathodus simulator (Ellison 1941) (sensu stricto) first appears be selected to mark the base of the Gzhelian Stage, because we believe that this is the optimal level by which this boundary can be correlated. This taxon has a short range and a wide distribution, as shown by correlation of glacial-eustatic cyclothems across the Kasimovian-Gzhelian boundary interval among Midcontinent North America and the Moscow and Donets basins of eastern Europe, based on scale of the cyclothems along with several aspects of biostratigraphy. Outside of these areas, I. simulator (sensu stricto) is known also from other parts of the U.S., and is reported from the southern Urals and south-central China in its expected position between other widespread taxa. Its first appearance is consistent with the current ammonoid placement of the boundary (first appearance of Shumardites cuyleri), and it is also compatible with certain aspects of the distribution of Eurasian fusulinid faunas (e.g., lectotype of Rauserites rossicus).

High‐precision U‐Pb zircon age calibration of the global Carboniferous time scale and Milankovitch band cyclicity in the Donets Basin, eastern Ukraine

“…The conodont species Streptognathodus simulator [ Ellison , 1941] has been proposed as the index to define the base of the global Gzhelian Stage [ Chernykh et al , 2006; Heckel et al , 2008]. This species was originally described from the Heebner Shale Member of the Oread limestone [ Ellison , 1941] in the midcontinent of North America, and has been widely used as a marker for the boundary in the Moscow Basin [ Barskov and Alekseyev , 1975] and in the Urals [ Chernykh and Reshetkova , 1987; Chernykh , 2002; Davydov and Popov , 1991].…”

Tooth whorl structure, growth and function in a helicoprionid chondrichthyan Karpinskiprion (nom. nov.) (Eugeneodontiformes) with a revision of the family composition

“…This conodont assemblage is typical of the base of the I. simulator Zone. The first appearance of its index species is recommended to be regarded as the base of the global Gzhelian Stage of the Upper Pennsylvanian (Heckel et al 2008;Villa et al 2009). Thus, the deposition of this layer was coeval with the Kosherovo Formation of the Rusavkino and Gzhel sections in central Russia (Alekseev et al 2009), which also yielded Campyloprion specimens described by earlier authors (Karpinsky 1924a;Obruchev 1964;Itano & Lucas 2018).…”

Conodont faunas across the Kasimovian–Gzhelian boundary (Late Pennsylvanian) in South China and implications for the selection of the stratotype for the base of the global Gzhelian Stage

“…It is important to note that taxa such as Idioprioniodus and Gondolella (Heckel et al ., ), considered to have been offshore or deeper water species in the North American Midcontinent region and elsewhere, are uncommon in the Naqing and Narao sections. The reason for this is not apparent, but it raises the possibly that the abundance of these forms in the North America Midcontinent area may be related to the unique environmental conditions developed in the Midcontinent seaway (Algeo & Heckel ; Herrmann et al .…”

“…In 2007, I. simulator was chosen to be the marker species for the base of the global Gzhelian Stage by the Task Group and the Subcommission on Carboniferous Stratigraphy (SCCS) (Heckel et al . ; Villa et al . ).…”