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International Commission on Stratigraphy (ICS)

The International Commission on Stratigraphy is the largest and oldest constituent scientific body in the International Union of Geological Sciences (IUGS). Its primary objective is to precisely define global units (systems, series, and stages) of the International Chronostratigraphic Chart that, in turn, are the basis for the units (periods, epochs, and age) of the International Geologic Time Scale; thus setting global standards for the fundamental scale for expressing the history of the Earth.​

ICS website:

ICS logo

International Chronostratigraphic Chart


Permissions and Copyright Agreement

  • version 2022/10: pdf


David A. T. Harper

Earth Sciences and Principal

Van Mildert College, Durham University

Durham DH1 3LE, United Kingdom

Tel.: +44-1913347143



Shuzhong Shen
Professor and Academician, School of Earth Sciences and Engineering, Nanjing University

163 Xianlin Avenue, Nanjing 210023, China

Secretary General
Philip Gibbard 

Scott Polar Research Institute

University of Cambridge

Lensfield Road, Cambridge CB2 1ER, United Kingdom

Tel: +44 (0)1223 336540



Translations of the International Chronostratigraphic Chart

Old versions of the International Chronostratigraphic Chart

Change Log file: txt

2019/5: pdf2018/8: pdf2018/7: pdf2017/2: pdf2016/10: pdf2016/4: pdf;

2015/1: pdf2014/10: pdf2014/2: pdf2013/1: pdf2012: pdf2010: pdf2009: pdf;

2008: pdf

Global chronostratigraphical correlation table for the last 2.7 million years

ICS Quaternary Chart1

Ordovician Chronostratigraphic Chart


Correlation of regional chronostratigraphic schemes with the new global stages and series for the Ordovician System by Bergstrom et al. (2008)

  • version 2008: jpg

ICS OrdChartHigh

Ordovician Carbon Isotope Curve


by Bergstrom et al. (2008)

  • version 2008: jpg


Permian Time Scale

  • version 2012: jpg

ICS Permian Time Scale
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