Record details

    Steps toward a global standard for Ordovician stratigraphy
Statement of responsibility
    Barry D. Webby
    Webby, Barry D.
Source title - serial
    Newsletter on stratigraphy
    Vol. 36, no. 1
    p. 1-33
    4 obr., 8 s.bibl.
    Francouzské, ruské resumé
    Zkr. název ser.: Newslett. Stratigr.
Subject group
    historie geologie
    korelace stratigrafická
    mezinárodní spolupráce
    stratigrafická hranice
    zóny biostratigrafické
Geographical name
    Velká Británie
Abstract (in english)
   This paper traces the development of the Ordovician concept from Charles Lapworth's original proposal in 1879 to recent decisions of the International Subcommission on Ordovicin Stratigraphy aimed at establishing a unified global nomenclature of Series and Stage divisions using key markers (graptolites and/or conodonts) with high global correlatin potential. Lapworth incorporated the rocks with overlap relationships and common faunas of Sedgwick's Cambrian and Murchison's Silurian classifications into his new system, so also providing a simple solution to the Sedwick-Murchison dispute. But adoption of Lapworth's Ordovician System was resisted by British workers until the end of the 1890s, and then the international community took until 1960 to officially ratify the name.
   Greater interest for adopting standardized stratigraphic procedures and classification followed the establishment in 1974 of the IUGS/ICS-supported International Subcommission on Ordovician Stratigraphy, and relevant inter-system boundary wotking groups. The Cambrian-Ordovician Boundary Working Group agreed in 1982 to the base of the ordovician System at or near the traditional British (and Scandinavian) base of the Tremadoc, but this remains to be ratified officially as it requires an accompanying boundary stratotype definition, a task for the newly reconstituted Subcommission Cambrian-Ordovician Boundary Working Group. The Ordovician-Silurian Boundary Working Group chose a boundary at the base of the graptolite Akidograptus acuminatus Zone at Dob's Linn, Scotland, i.e. at level above the widespread and distinctive cool-water Hirnantia Fauna regarded as latest Ordovician. This was retified officially by ICS and IUGS in 1985.
   In global terms, only minority support exists for a major bipartite subdivision of the Ordovician system. The majority prefer a division into three Series, and since 1995 there has been Subcommission agreement, a 90per Ordovician Series. Further, it has been agreed by an 82
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    25. 6. 2008
Import date
    8. 8. 2012