Carboniferous ammonoid genozones

Abstract

Considerable progress has been made by international teams in refining the traditional ammonoid zonation that remains the backbone of Carboniferous stratigraphy. The Carboniferous ammonoid genozones, with a few gaps, are now recognized throughout the entire system in most successions worldwide. Refined collecting and documentation of occurrences in Western Europe, North Africa, the Urals, China, and North America, aimed to establish the first evolutionary occurrences, and facilitated correlation with foraminiferal and conodont scales for most of the Carboniferous. From ten to eleven ammonoid genozones are now recognized in the Mississippian, and eight to nine genozones in the Pennsylvanian. Of these, the established lower boundaries of the subsystems are reasonably well correlated with the ammonoid zonation, whereas correlations with the ratified foraminiferal-based lower boundary of the Viséan and other stage boundaries, currently under discussion, need further research. Future success in the ammonoid geochronology will also depend on accurate identification and re-illustration of the type material, including material described by pioneers of ammonoid biostratigraphy.

Acta Geologica Polonica

“…1). However, the boundaries of the Viséan and Serpukhovian substages, including the Viséan/Serpukhovian boundary, remain disputed, depending to some extent on the index fossils used (see e.g., Poletaev et al 1990;Sanz-Lopez et al 2006;Kulagina et al 2013;Cózar et al 2015Cózar et al , 2019Aretz et al 2020;Nikolaeva 2020). Thus, both the Donetzian and the Mezhivian are treated here as corresponding to the upper Viséan.…”