Series (geology)

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Corresponding units
in chronostratigraphy and
Chronostratigraphy geochronology
Aeonothem aeon
Arathem era
system period
series epoch
step Age

A series ( Engl . Series ) is in the Earth's history , a time unit of Chronostratigraphy . In the geochronological division of the earth's history, it corresponds to the unit epoch . The terms are often not used correctly as synonyms , as they are defined slightly differently. The time unit “series” or “epoch” usually covers periods of several million to several tens of millions of years.


The series is the next higher chronostratigraphic unit above the level that represents the basic unit in chronostratigraphy. The imaginary isochronous boundaries of the chronostratigraphic unit “series” are, like the other units of chronostratigraphy, relatively dated , ie in the context of the other chronostratigraphic series and systems , and are specifically tied to rock. For this purpose, a GSSP must be defined for all chronostratigraphic boundaries . The absolute age and length of time of a chronostratigraphic series is not included in this definition. The period of time that corresponds to a series in geochronology is called an epoch. The absolute ages of the boundaries set in the terrain can still change due to the methodological inaccuracies of the age determination methods. The chronostratigraphic series used internationally are defined and ratified by the ICS (International Commission on Stratigraphy) (see geological time scale ).


In exceptional cases, a series can only represent a single level (e.g. the Pridolium is level and series), but it usually comprises several levels . In chronostratigraphy, the hierarchical unit above the series is the system . In geochronology, the epoch is a sub-unit of the period and is itself divided into several ages.


The names of the series are designated either by adding the attributes "lower", "middle" or "upper" to the system names or by adding the prefixes "lower", "middle" and "upper" to the system names. There are z. In some cases, however, their own names are also used (e.g. Llandovery , Wenlock and Lodlow in the Silurian ). The latter were originally defined as levels and only later raised to the hierarchical rank of a series. In geochronology, the epoch names are usually combined by the period name with the addition of the adjectives "early" and "late" (e.g. early chalk etc.). The term “series” in geology is problematic, because in older linguistic usage the term “series” also refers to lithostratigraphic units or units in the hierarchical rank of a level (e.g. in the work by Chicha et al. , 1967). The term is sometimes mistakenly combined with the names of systems (e.g. “chalk series”). Such terms and combinations should be avoided in the future. In the older literature there is also the term department to designate a series. This term should no longer be used today either.


  • A. Salvador: International Stratigraphic Guide (A Guide to Stratigraphic Classification, Terminology and Procedures). 2nd ed., XIX + 214 pp., International Union of Geological Sciences, Geological Society of America, Washington / DC 1994, ISBN 0-8137-7401-2 .
  • Fritz F. Steininger & Werner E. Piller: Recommendations (guidelines) for handling the stratigraphic nomenclature. Courier Forschungsinstitut Senckenberg, 209: 1-19, Frankfurt am Main 1999, ZDB -ID 530500-7 .
  • North American Commission on Stratigraphic Nomenclature (NACSN): North American stratigraphic code. American Association of Petroleum Geologists Bulletin, 89: 1547-1591, Tulsa, Oklahoma 1983, ISSN  0149-1423 PDF
  • Ivan Cicha, Ján Seneš and Jiří Tejkal: Chronostratigraphy and Neostratotypes Miocene of the central Paratethys. Volume IM 3 (Carpathian) The Carpathian series and its stratotype. 312 pp., Bratislava 1967