The Carboniferous chronostratigraphic scale: history, status and prospectus

The Carboniferous chronostratigraphic scale is a hierarchy of two subsystems, six series and seven stages developed during nearly two centuries of research. Carboniferous stage nomenclature developed with the proposal of numerous regional stages/substages based primarily on palaeobotanical, foraminiferal and ammonoid biostratigraphy, especially in Western Europe, the former Soviet Union, China and the USA. From the regional stages, seven ‘global stages’ have been identified (in ascending order): Tournaisian, Visean, Serpukhovian, Bashkirian, Moscovian, Kasimovian and Gzhelian. Three of the four ratified Carboniferous GSSPs use conodont evolutionary events as the primary signal for correlation – bases of Tournaisian, Bashkirian and base of Asselian. The GSSP of the Visean base has a foraminiferal event as its primary signal. Issues in the development of a Carboniferous chronostratigraphic scale include the rank of chronostratigraphic units, provinciality, conodont biostratigraphy, palaeobotanical biostratigraphy and the development of astrochronology and other methods of chronology and correlation.