The new chronostratigraphic classification of the Ordovician System and its relations to major regional series and stages and to δ13C chemostratigraphy



  • XU CHEN,



Stig M. Bergström [], School of Earth Sciences, Division of Geological Sciences, The Ohio State University, 155 Oval Mall, Columbus, Ohio 43210, USA; Chen Xu [], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China; Juan Carlos Gutiérrez-Marco [], Instituto de Geológia Económica, CSIC-UCM, Facultad de Ciencias Geológicas, 28040 Madrid, Spain; Andrei Dronov [], Geological Institute of the Russian Academy of Sciences, Pyzhevsky per. 7, Moscow 119017, Russia; manuscript received on 1/11/2007; manuscript accepted on 20/2/2008.


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.