International Commission on Stratigraphy

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The International Commission on Stratigraphy (ICS) , sometimes unofficially referred to as the International Stratigraphic Commission , deals with stratigraphic and geochronological issues on a worldwide basis.

The ICS is the largest scientific sub-organization of the International Union of Geological Sciences (IUGS) and constitutes a permanent commission that meets far more often than the quarterly meetings that are set by the IUGS in the context of congresses or working groups.

The ICS currently has 15 sub-commissions that are responsible for the individual systems of the Phanerozoic , the Neoproterozoic , the Precambrian and stratigraphic classification in general .


One of the main goals of the ICS is the development of a multidisciplinary and globally valid geological time scale . This project was started in 1974 and aims to facilitate regional palaeontological and geobiological comparisons. For this purpose, a so-called GSSP ( Global Boundary Stratotype Section and Point ) is to be defined for each chronostratigraphic unit , which meets strict and uniform criteria.

In addition, the ICS defines the so-called GSSA ( Global Standard Stratigraphic Age ), which, based on globally verifiable tectonic cycles ( mountain formations ), is exclusively defined by an absolute age and is still relevant for almost all unit boundaries of the Precambrian . In addition, the ICS supports the open and international exchange between geoscientists in all fields of the geoscientific sub-areas.

The International Commission on Stratigraphy has created numerous subdivisions that work on a regional or national level and are responsible for field work, the classification of local results and the organization of scientific conferences on site.


The ICS published both different results and scientific papers as well as regularly updated guidelines, which in the International Stratigraphic Chart (International stratigraphic table ) are published. This table summarizes both the proposals currently being discussed and the currently valid guidelines which were issued after the last ICS meeting. The proposals of the ICS are formulated as recommendations and deal with the dating and selection of geological formations and other stratigraphic units as well as with questions of nomenclature . They are not official until they have been confirmed (ratified) or rejected by the IUGS umbrella organization. In fact , the results of the ICS meetings are almost always immediately accepted and applied in everyday geoscientific life. Exceptions are rare and concern cases in which there is a significant difference of opinion even after lengthy discussion at the meetings. Such issues are clarified before the IUGS general assembly.

Such a controversy arose when the traditionally established Quaternary was declared as an informal unit in an important stratigraphic standard work in 2004 and the Pleistocene and Holocene were assigned to the Neogene . The reasons for this were that the Tertiary had previously been formally replaced by the units Paleogene and Neogene, and the discussion that existed at that time about the Pliocene- Pleistocene boundary, in which the assignment of the Gelasium , a traditionally tertiary unit, to the Pleistocene, a traditionally Quaternary unit, was called for. Thus it seemed to a part of the geoscientific community as a logical consequence to abandon the Quaternary as a stratigraphic unit. However, this aroused violent opposition in the other part of this community, especially among numerous geologists concerned with the Quaternary. The dispute was finally ended with a clear majority decision, among 18 voting “officers” of the ICS, to define the Quaternary with the addition of the Gelasium to the Pleistocene as a formal unit of the international geological time scale in the rank of a system or a period , which was done in June 2009 has been confirmed by the IUGS.

Web links

Individual evidence

  1. Felix M. Gradstein, James G. Ogg, Alan G. Smith (Eds.): A Geologic Time Scale 2004. Cambridge University Press, Cambridge (UK) 2004, ISBN 0-521-78673-8
  2. Lucas Lourens, Frederik J. Hilgen, Nicholas J. Shackleton, Jacques Laskar, Doug Wilson: The Neogene Period. Pp. 409-439 in: Felix M. Gradstein, James G. Ogg, Alan G. Smith (Eds.): A Geologic Time Scale 2004. Cambridge University Press, Cambridge (UK) 2004, ISBN 0-521-78673-8 , P. 412
  3. Philip L. Gibbard, Martin J. Head, Michael JC Walker, Subcommission on Quaternary Stratigraphy: Formal ratification of the Quaternary System / Period and the Pleistocene Series / Epoch with a base at 2.58 Ma. Journal of Quaternary Science. Vol. 25, No. 2, 2010, pp. 96-102, doi: 10.1002 / jqs.1338