The Tournaisian is in the
ICS geologic timescale
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochr ...
the lowest
stage
Stage or stages may refer to:
Acting
* Stage (theatre), a space for the performance of theatrical productions
* Theatre, a branch of the performing arts, often referred to as "the stage"
* ''The Stage'', a weekly British theatre newspaper
* Sta ...
or oldest
age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone or something has been alive or has existed
** East Asian age reckoning, an Asian system of marking age starting at 1
* Ageing or aging, the process of becoming older ...
of the
Mississippian, the oldest
subsystem
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed ...
of the
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
. The Tournaisian age lasted from Ma to
Ma. It is preceded by the
Famennian
The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used b ...
(the uppermost stage of the
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
) and is followed by the
Viséan
The Visean, Viséan or Visian is an age in the ICS geologic timescale or a stage in the stratigraphic column. It is the second stage of the Mississippian, the lower subsystem of the Carboniferous. The Visean lasted from to Ma. It follow ...
.
Name and regional alternatives
The Tournaisian was named after the
Belgian
Belgian may refer to:
* Something of, or related to, Belgium
* Belgians, people from Belgium or of Belgian descent
* Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German
*Ancient Belgian language, an extinct languag ...
city of
Tournai
Tournai or Tournay ( ; ; nl, Doornik ; pcd, Tornai; wa, Tornè ; la, Tornacum) is a city and municipality of Wallonia located in the province of Hainaut, Belgium. It lies southwest of Brussels on the river Scheldt. Tournai is part of Euromet ...
. It was introduced in scientific literature by Belgian geologist
André Hubert Dumont
André — sometimes transliterated as Andre — is the French and Portuguese form of the name Andrew, and is now also used in the English-speaking world. It used in France, Quebec, Canada and other French-speaking countries. It is a variation ...
in 1832. Like many Devonian and lower Carboniferous stages, the Tournaisian is a unit from West European regional stratigraphy that is now used in the official international time scale.
The Tournaisian correlates with the regional North American
Kinderhookian
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly ...
and lower
Osagean stages and the Chinese Tangbagouan regional stage. In British stratigraphy, the Tournaisian contains three substages: the Hastarian, Ivorian and lower part of the Chadian (the upper part falls in the Viséan).
Stratigraphy
The base of the Tournaisian (which is also the base of the Carboniferous
system
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...
) is at the first appearance of the
conodont
Conodonts (Greek ''kōnos'', "cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which ...
''
Siphonodella
''Siphonodella'' is an extinct genus of conodonts.
''Siphonodella banraiensis'' is from the Late Devonian of Thailand. ''Siphonodella nandongensis'' is from the Early Carboniferous of the Baping Formation in China.New material of the Early Car ...
sulcata'' within the
evolutionary lineage from ''Siphonodella praesulcata'' to ''Siphonodella sulcata''. The first appearance of
ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...
species ''
Gattendorfia subinvoluta'' is just above this and was used as a base for the Carboniferous in the past. The
GSSP
A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted b ...
for the Tournaisian is near the summit of La Serre hill, in the
Lydiennes Formation of the
commune
A commune is an alternative term for an intentional community. Commune or comună or comune or other derivations may also refer to:
Administrative-territorial entities
* Commune (administrative division), a municipality or township
** Communes of ...
of
Cabrières, in the
Montagne Noire
The Montagne Noire ( oc, Montanha Negra, known as the 'Black Mountain' in English) is a mountain range in central southern France. It is located at the southwestern end of the Massif Central at the juncture of the Tarn, Hérault and Aude departm ...
(southern
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
).
[The GSSP was published by Paproth ''et al.'' (1991)] The GSSP is in a section on the southern side of the hill, in an 80 cm deep trench, about 125 m south of the summit, 2.5 km southwest of the village of Cabrières and 2.5 km north of the hamlet of
Fontès
Fontès (; Languedocien: ''Fontés'') is a commune in the Hérault department in southern France.
Population
See also
*Communes of the Hérault department
The following is a list of the 342 Communes of France, communes of the Hérault Depa ...
.
The top of the Tournaisian (the base of the Viséan) is at the first appearance of the
fusulinid
The Fusulinida is an extinct order within the Foraminifera in which the tests are traditionally considered to have been composed of microgranular calcite. Like all forams, they were single-celled organisms. In advanced forms the test wall was di ...
species ''
Eoparastaffella simplex'' (
morphotype
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...
1/morphotype 2).
The Tournaisian contains eight conodont
biozone
In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties of ...
s:
*the zone of ''
Gnathodus
''Gnathodus'' is an extinct conodont genus in the family Idiognathodontidae.
Use in stratigraphy
The Tournaisian, the oldest age of the Mississippian (also known as Lower Carboniferous), contains eight conodont biozones, 3 of which are defi ...
pseudosemiglaber'' and ''
Scaliognathus anchoralis''
*the zone of ''Gnathodus semiglaber'' and ''
Polygnathus communis''
*the zone of ''
Dollymae bouckaerti''
*the zone of ''Gnathodus typicus'' and ''
Siphonodella
''Siphonodella'' is an extinct genus of conodonts.
''Siphonodella banraiensis'' is from the Late Devonian of Thailand. ''Siphonodella nandongensis'' is from the Early Carboniferous of the Baping Formation in China.New material of the Early Car ...
isosticha''
*the zone of ''Siphonodella quadruplicata'' and ''
Patrognathus andersoni'' (upper zone of ''Patrognathus andersoni'')
*the lower zone of ''Patrognathus andersoni''
*the zone of ''Patrognathus variabilis''
*the zone of ''Patrognathus crassus''
The Tournaisian coincides with
Romer's gap
Romer's gap is an example of an apparent gap in the tetrapod fossil record used in the study of evolutionary biology. Such gaps represent periods from which excavators have not yet found relevant fossils. Romer's gap is named after paleontologist ...
, a period of remarkable little terrestrial fossils, thus constituting a discontinuity between the
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
and the more modern terrestrial
ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
s of the Carboniferous.
References
Bibliography
* ; 1832: ''Mémoire sur la constitution géologique de la province de Liège'', Mémoires couronnés par l'Académie Royale des Sciences et Belles-Lettres de Bruxelles 8 (3), VII.
* ; 2004: ''A Geologic Time Scale 2004'',
Cambridge University
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
Press
* ; 2006: ''The Carboniferous system, use of the new official names for the subsystems, series and stages'', Geologica Acta 4(3), pp 403–407
* ; 2006: ''Global time scale and regional stratigraphic reference scales of Central and West Europe, East Europe, Tethys, South China, and North America as used in the Devonian–Carboniferous–Permian Correlation Chart 2003 (DCP 2003)'', Palaeogeography, Palaeoclimatology, Palaeoecology 240 (1-2): pp 318–372
* ; 1937: ''Die Devon-Karbon-Grenze'', Comptes Rendus (2) du Cinquième Congrès International de Stratigraphie et Géologie du Carbonifère, Heerlen 1935 (2), pp 703–714
* ; 1991: ''Decision on the Devonian–Carboniferous Boundary Stratotype'', Episodes 14 (4), pp 331–336
External links
Early Carboniferous timescaleat the website of the Norwegian network of offshore records of geology and stratigraphy
www.palaeos.com
{{DEFAULTSORT:Tournaisian
Mississippian geochronology
Geological ages
.
Stratigraphy of Europe
Tournai