The new chronostratigraphic classification of the Ordovician System and its relations to major regional series and stages and to δ ¹³ C chemostratigraphy

TLDR

The extensive work of the International Subcommission on Ordovician Stratigraphy has produced a new global classification of the Ordovician System into three series and seven stages. The new units are correlated with regional chronostratigraphic series using biostratigraphic data, subdivided into 20 stage slices based on graptolite and conodont zones for precise correlations, and linked to a composite δ13C curve spanning the Ordovician. All stages now have formal GSSPs and the new stage names have been ratified by the International Commission on Stratigraphy.

Abstract

The extensive work carried out during more than a decade by the International Subcommission on Ordovician Stratigraphy has resulted in a new global classification of the Ordovician System into three series and seven stages. Formal Global Boundary Stratotype Section and Points (GSSPs) for all stages have been selected and these and the new stage names have been ratified by the International Commission on Stratigraphy. Based on a variety of biostratigraphic data, these new units are correlated with chronostratigraphic series and stages in the standard regional classifications used in the UK, North America, Baltoscandia, Australia, China, Siberia and the Mediterranean-North Gondwana region. Furthermore, based mainly on graptolite and conodont zones, the Ordovician is subdivided into 20 stage slices (SS) that have potential for precise correlations in both carbonate and shale facies. The new chronostratigraphic scheme is also tied to a new composite δ13C curve through the entire Ordovician.