Thirty years of the first international stratotype: The Silurian-Devonian boundary at Klonk and its present status

Chlupáč, Ivo; Vacek, František

doi:10.18814/epiiugs/2003/v26i1/002

Cited by 14 publications

(6 citation statements)

References 7 publications

(9 reference statements)

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“…In recent years, the Phanerozoic time scale has been reformulated in terms of Global Standard Stratotypesections and Points that precisely define the beginnings of periods or other time intervals (e.g. Chlupác & Vacek 2003). Accepted convention for boundary definition stresses the first appearances of animal fossils and frowns on GSSP placement at unconformities, where biostratigraphic ranges may be truncated.…”

Section: Issues and Opportunitiesmentioning

confidence: 99%

The Ediacaran Period: a new addition to the geologic time scale

Knoll

Walter

Narbonne

et al. 2006

LET

318

152

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The International Union of Geological Sciences has approved a new addition to the geologic time scale: the Ediacaran Period. The Ediacaran is the first Proterozoic period to be recognized on the basis of chronostratigraphic criteria and the first internationally ratified, chronostratigraphically defined period of any age to be introduced in more than a century. In accordance with procedures established by the International Commission on Stratigraphy, the base of the Ediacaran Period is defined by a Global Stratotype Section and Point (GSSP) placed at the base of the Nuccaleena Formation cap carbonate directly above glacial diamictites and associated facies at Enorama Creek in the Flinders Ranges of South Australia. Its top is defined by the initial GSSP of the Cambrian Period. The new Ediacaran Period encompasses a distinctive interval of Earth history that is bounded both above and below by equally distinctive intervals. Both chemostratigraphic and biostratigraphic data indicate that the subdivision of the period into two or more series is feasible, and this should be a primary objective of continuing work by the Ediacaran Subcommission of the ICS.

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Section: Issues and Opportunitiesmentioning

confidence: 99%

The Ediacaran Period: a new addition to the geologic time scale

Knoll

Walter

Narbonne

et al. 2006

LET

318

152

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“…3) (Kříž et al 1986, Kříž 1998a. Two international GSSP stratotypes have been established in the late Silurian strata of the Prague Basin, that define the boundary between the Ludlow and Přídolí series and the Přídolí Series and the Lower Devonian Series (see Chlupáč et al 1972, Chlupáč and Vacek 2003, Fatka et al 2003, Manda and Frýda 2010 for discussion and references). The Požáry Formation is facially less varied than the Kopanina Formation due to a significant transgression that took place around the Ludlow/Přídolí boundary interval (Kříž et al 1986, Kříž 1998a, Vacek et al 2018.…”

Section: Geological Settingsmentioning

confidence: 99%

Review of ascocerid cephalopods from the upper Silurian of the Prague Basin (Central Bohemia) – history of research and palaeobiogeographic relationships

Aubrechtová

2019

Fossil Imprint

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Abstract The order Ascocerida Kuhn, 1949 includes rare and morphologically unique early Palaeozoic cephalopods, in which periodic shell truncation occurred during ontogeny; mature shells subsequently became inflated, with thin sigmoidal septa and phragmocone chambers situated above the living chamber. The ascocerids are at present known mainly from North America and Baltoscandic Europe. The group was first described by J. Barrande in the mid 1800’s from the upper Silurian of Bohemia. Finds of ascocerid fossils in Bohemia are generally scarce but Barrande’s collection includes tens of well-preserved specimens. These are briefly reviewed in the present paper and additional, more recently collected material is also discussed. In Bohemia (Prague Basin), ascocerids occur in limestones of Ludlow to late Přídolí age. Their maximum diversity and abundance was reached close to the Ludlow/Přídolí boundary interval. Five out of the fourteen currently recognized Bohemian species are also known from late Silurian strata in Sweden (the island of Gotland). The ascocerids thus illustrate palaeobiogeographic relationships between the Prague Basin and Baltica during the late Silurian.

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“…In 1960, the IUGS created a committee to study the Silurian-Devonian boundary, and a GSSP was designated in 1972 at Klonk in the Czech Republic, with its primary signal the LO of the graptolite Monograptus uniformis. This was the first ratified GSSP and has long been held up as a model of how well the GSSP method works (e.g., Chulpáč and Vacek, 2003). Indeed, Cowie et al (1986) stated that "much inspiration and guidance has been derived.…”

Section: Devonianmentioning

confidence: 99%

The GSSP Method of Chronostratigraphy: A Critical Review

Lucas

2018

Front. Earth Sci.

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The use of boundary stratotypes to define chronostratigraphic units began in the 1960s, and, in the 1980s, these were called Global Stratotype Sections and Points (GSSPs). Approximately two-thirds of the GSSPs of the bases of the Phanerozoic stage (71 of 102 in September 2018) have been ratified by the International Commission on Stratigraphy. However, this apparent progress toward precise definition of a Phanerozoic chronostratigraphic timescale is underlain by multiple problems of philosophy and methodology that include: (1) inconsistency in how chronostratigraphic units are being named and defined; (2) arbitrary decisions as to GSSP level, many based on arbitrarily chosen points in hypothetical chronomorphoclines of microfossils; (3) hierarchical reductionism, which makes the stage base the same as the base of the series, system, erathem and eonothem, thereby trivializing the significance of the boundaries of these larger chronostratigraphic units; (4) stability achieved by the non-scientific process of designating a GSSP once ratified as immutable; (5) the unworkable concept of a standard set of global stages; (6) the fallacy that a GSSP location can somehow define a recognizable (correlateable) global time line; (7) imprecision in GSSP correlation because the primary signals are largely single taxon biotic events that are inherently diachronous due to the limitations of fossil distributions by sampling, facies and provincialism; and (8) the politics of the International Commission on Stratigraphy and the small groups of specialists who select and vote on GSSPs. Chronostratigraphy needs to return to the concepts of natural chronostratigraphy, with improvements based on modern techniques like quantitative biostratigraphy. We need to standardize the chronostratigraphic scale, and the International Commission on Stratigraphy needs to rethink the philosophy and practices by which this is being done, so that we can move forward to produce the most informative chronostratigraphy possible based on a consistent methodology that allows the updating and obtaining of high accuracy and precision as new data become available.

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Thirty years of the first international stratotype: The Silurian-Devonian boundary at Klonk and its present status

Cited by 14 publications

References 7 publications

The Ediacaran Period: a new addition to the geologic time scale

The Ediacaran Period: a new addition to the geologic time scale

Review of ascocerid cephalopods from the upper Silurian of the Prague Basin (Central Bohemia) – history of research and palaeobiogeographic relationships

The GSSP Method of Chronostratigraphy: A Critical Review

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